E. Pretsch, P. Buhlmann, C. Affolter
Structure Determination of Organic Compounds Tables of Spectral Data Third Completely Revised and Enlarged English Edition Corrected first Printing
Springer
Professor Emoe Pretsch ETH Zurich Laboratory of Organic Chemistry CH-8092Zurich Switzerland Dr. Philippe Biihlmann Department of Chemistry School of Science The University of Tokyo Hongo 7-3-1, Bunkyo-Ku Tokyo 113-0033 Japan Dr. Christian Affolter Aengerich 8 CH-3303 Muenchringen Switzerland
ISBN 3-540-678 15-8 Springer-Verlag Berlin Heidelberg New York CIP-Data applied for Pretsch, Ernoe: Structure determination of organic compounds : tables of spectral data / E. Pretsch ; P. Biihlmann ; C. Affolter. - 3., completely rev. and enl. engl. ed.. Berlin ; Heidelberg ; New York ; Barcelona ; Hong Kong ; London ; Milan ; Paris ; Singapore ; Tokyo : Springer, 2000 ISBN 3-540-67815-8 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in other ways, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer-Verlag. Violations are liable for prosecution act under German Copyright Law. Springer-Verlag Berlin Heidelberg New York a member of BertelsmannSpringer Science+Business Media GmbH 0 Springer-Verlag Berlin Heidelberg 2000
Printed in Germany Copyright for the CD-ROM: Upstream Solutions GmbH, CH-6052 Hergiswil, Switzerland The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Typesetting: Camera-ready by editors Cover layout: design & production GmbH, Heidelberg Printed on acid-free paper SPIN: 10896235 52/3020 - 5 4 3 2 1 0 .
Preface
While modern techniques of nuclear magnetic resonance and mass spectrometry changed the ways of data acquisition and greatly extended the capabilities of these methods, the basic parameters, such as chemical shifts, coupling constants, and fragmentation pathways remain the same. This explains the ongoing success of the earlier editions of this book. However, since the amount of available data has considerably increased over the years, we decided to prepare an entirely new manuscript. It follows the same basic concepts, i.e., it provides a representative, albeit limited set of reference data for the interpretation of 13C NMR, 'H NMR, IR, mass, and UV/Vis spectra. On the other hand, the book has undergone a number of changes. The amount of reference data has been doubled at least (especially for MS and IR) and the order and selection of data for the various spectroscopic methods is now arranged strictly in the same way. In addition, the the enclosed compact disc contains programs for estimating NMR chemical shifts and generating isomers based on structural information. Unfortunately, our teachers and colleagues, Prof. Wilhelm Simon and Prof. Thomas Clerc are no longer among us, and Prof. Joseph Seibl has retired years ago. Their contributions to developing the concept and the earlier editions of this work cannot be overemphasized. We also thank numerous colleagues who helped us in many different ways to complete the manuscript. We are particularly indebted to Dr. Dorothee Wegmann for her expertise with which she eliminated many errors and inconsistencies of the first versions. Special thanks are due to Dr. Rich Knochenmuss (ETH Zurich) for the MALDI mass spectra of matrix materials, Dr. Kikuko Hayamizu for her help with the Spectral Database System of the National Institute of Materials and Chemical Research, Tsukuba, Ibaraki (Japan), Prof. Bernhard Jaun and Dr. Martin Badertscher (ETH Zurich) for critically reading parts of the manuscript. Dr. Martin Badertscher is also thanked for the tutorial of the structure generator, Assemble 2.0, and Upstream Solutions (Hergiswil, Switzerland) for providing free versions of the computer programs on the enclosed compact disk. In spite of great efforts and many checks to eliminate errors, it is likely that some errors or inconsistencies remain. We would like to encourage our readers to contact us with comments and suggestions or any kind of problems when using the book or the enclosed programs under one of the following addresses: Prof. Ern0 Pretsch, Laboratory of Organic Chemistry, CH-8092 Zurich, Switzerland, e-mail:
[email protected], or Prof. Philippe Buhlmann, Department of Chemistry, University of Minnesota, 207 Pleasant St., SE, Minneapolis, MN 55455, USA, e-mail:
[email protected]. Zurich and Tokyo, August 2000
Table of Contents
VII
Table of Contents
1 Introduction .........................................................................
1
Scope and Organization ........................................................ Abbreviations and Symbols ..................................................
1 3
2 Summary Tables ..................................................................
5
1.1 1.2
2.1
2.2 2.3 2.4 2.5
2.6
General Tables .................................................................... 2.1.1 Calculation of the Number of Double Bond Equivalents from the Molecular Formula ..................................... 2.1.2 Properties of Selected Nuclei ..................................... 13c NMR Spectroscopy ...................................................... lH NMR Spectroscopy ........................................................ IR Spectroscopy ................................................................. Mass Spectrometry .............................................................. 2.5.1 Average Masses of Naturally Occurring Elements with Exact Masses and Representative Relative Abundances of Isotopes ................................................................ Ranges of Natural Isotope Abundances of Selected 2.5.2 Elements ............................................................... Isotope Patterns of Naturally Occurring Elements ......... 2.5.3 Calculation of Isotope Distributions........................... 2.5.4 Isotopic Abundances of Various Combinations of 2.5.5 Chlorine. Bromine. Sulfur. and Silicon ....................... Isotope Patterns of Combinations of C1 and Br ............. 2.5.6 Indicators of the Presence of Heteratoms ...................... 2.5.7 Rules for Determining the Relative Molecular Weight 2.5.8 (Mr) ..................................................................... Homologous Mass Series as Indications of Structural 2.5.9 Type .................................................................... 2.5.10 Mass Correlation Table ............................................ 2.5.11 References ............................................................. UVNis Spectroscopy ..........................................................
5 5 6 7 10 13 18 18 24 25 26 28 30 31 33 34 36 46 47
3 Combination Tables ............................................................
49
Alkanes. Cycloalkanes ......................................................... Alkenes. Cycloalkenes ......................................................... Alkynes ............................................................................ Aromatic Hydrocarbons ........................................................ Heteroaromatic Compounds ..................................................
49 50 51 52 53
3.1 3.2 3.3 3.4 3.5
Vlll
Table of Contents
Halogen Compounds ........................................................... Oxygen Compounds ............................................................ 3.7.1 Alcohols and Phenols .............................................. 3.7.2 Ethers ................................................................... 3.8 Nitrogen Compounds....................... ................................ 3.8.1 Amines ................................................................. 3.8.2 Nitro Compounds ................................................... 3.9 Thiols and Sulfides .............................................................. 3.10 Carbonyl Compounds.......................................................... 3.10.1 Aldehydes .............................................................. 3.10.2 Ketones ................................................................ 3.10.3 Carboxylic Acids .................................................... 3.10.4 Carboxylic Esters and Lactones ................................. 3.10.5 Carboxylic Amides and Lactams ................................ 3.6 3.7
4 13C NMR Spectroscopy ..................................................... 4.1
4.2
4.3
4.4
4.5
4.6 4.7
4.8
Alkanes ............................................................................. 4.1.1 Chemical Shifts ..................................................... 4.1.2 Coupling Constants ................................................ 4.1.3 References ............................................................. Alkenes ............................................................................. 4.2.1 Chemical Shifts ..................................................... 4.2.2 Coupling Constants ................................................ 4.2.3 References ............................................................. Alkynes ............................................................................ 4.3.1 Chemical Shifts ..................................................... 4.3.2 Coupling Constants ................................................ 4.3.3 References ............................................................. Alicyclics .......................................................................... 4.4.1 Chemical Shifts ..................................................... 4.4.2 Coupling Constants ................................................ 4.4.3 References ............................................................. Aromatic Hydrocarbons ........................................................ 4.5.1 Chemical Shifts ..................................................... 4.5.2 Coupling Constants ................................................ 4.5.3 References ............................................................. Heteroaromatic Compounds .................................................. 4.6.1 Chemical Shifts ..................................................... 4.6.2 Coupling Constants ................................................ Halogen Compounds ........................................................... 4.7.1 Fluoro Compounds. ................................................ 4.7.2 Chloro Compounds ................................................. 4.7.3 Bromo Compounds ................................................. 4.7.4 Iodo Compounds .................................................... 4.7.5 References ............................................................. Alcohols. Ethers. and Related Compounds ............................... 4.8.1 Alcohols ............................................................... 4.8.2 Ethers ...................................................................
54 56 56 57 59 59 60 62 63 63 64 65 66 68 71 71 71 80 81 82 82 86 87 88 88 89 89 90 90 95 95 96 96 102 103 104 104 111 112 112 114 115 116 116 117 117 119
Table of Contents
4.9
4.10
4.1 1
4.12
4.13
4.14
5
Nitrogen Compounds ........................................................... 4.9.1 Amines ................................................................. 4.9.2 Nitro and Nitroso Compounds ................................... 4.9.3 Nitrosamines ......................................................... 4.9.4 Imines and Oximes ................................................. 4.9.5 Hydrazones and Carbodiimides ................................... 4.9.6 Nitriles and Isonitriles ............................................. 4.9.7 Isocyanates. Thiocyanates and Isothiocyanates .............. 4.9.8 References............................................................. Sulfur-Containing Functional Groups ..................................... 4.10.1 Thiols .................................................................. 4.10.2 Sulfides ................................................................ 4.10.3 Disulfides and Sulfonium Salts ................................. 4.10.4 Sulfoxides and Sulfones ........................................... 4.10.5 Sulfonic and Sulfinic Acids and Derivatives ................. 4.10.6 Sulfurous and Sulfuric Acid Derivatives...................... 4.10.7 Sulfur-Containing Carbonyl Derivatives ..................... Carbonyl Compounds .......................................................... 4.11.1 Aldehydes .............................................................. 4.11.2 Ketones ................................................................ 4.1 1.3 Carboxylic Acids and Carboxylates ............................ 4.1 1.4 Esters and Lactones ................................................. 4.1 1.5 Amides and Lactams ................................................ 4.11.6 Miscellaneous Carbonyl Derivatives ........................... Miscellaneous Compounds ................................................... 4.12.1 Derivatives of Group IV Elements ............................. 4.12.2 Phosphorus Compounds .......................................... 4.12.3 Miscellaneous Organometallic Compounds .................. Natural Products ................................................................. 4.13.1 Amino Acids ......................................................... 4.13.2 Carbohydrates ........................................................ 4.13.3 Nucleotides and Nucleosides ...................................... 4.13.4 Steroids ................................................................ Spectra of Solvents and Reference Compounds ......................... 4.14.1 3C NMR Spectra of Common Deuterated Solvents ..... 4.14.2 I3C NMR Spectra of Secondary Reference Compounds . 4.14.3 13C NMR Spectrum of a Mixture of Common Nondeuterated Solvents ............................................
H NMR Spectroscopy ....................................................... 5.1
5.2 5.3
Alkanes ............................................................................. 5.1.1 Chemical Shifts ..................................................... 5.1.2 Coupling Constants ................................................ 5.1.3 References............................................................. Alkenes ............................................................................. 5.2.1 Substituted Ethylenes .............................................. 5.2.2 Dienes .................................................................. Alkynes ............................................................................
IX
121 121 123 124 124 125 126 127 127 128 128 128 130 130 131 131 132 133 133 134 136 138 140 142 144 144 145 147 148 148 152 154 156 157 157 159 160 161 161 161 166 167 168 168 174 175
Table of Contents
X
5.4 5.5 5.6 5.7
5.8 5.9
5.10
5.1 1
5.12
5.13
5.14
Chemical Shifts and Coupling Constants .................... 5.3.1 Alicyclics .......................................................................... Aromatic Hydrocarbons ........................................................ Heteroaromatic Compounds .................................................. 5.6.1 Non-Condensed Heteroaromatic Rings ........................ 5.6.2 Condensed Heteroaromatic Rings ............................... Halogen Compounds ........................................................... 5.7.1 Fluoro Compounds ................................................. 5.7.2 Chloro Compounds ................................................. 5.7.3 Bromo Compounds ................................................. 5.7.4 Iodo Compounds .................................................... Alcohols, Ethers, and Related Compounds ............................... 5.8.1 Alcohols ............................................................... 5.8.2 Ethers ................................................................... Nitrogen Compounds ........................................................... 5.9.1 Amines ................................................................. 5.9.2 Nitro and Nitroso Compounds .................................. 5.9.3 Nitrosamines, Azo, and Azoxy Compounds ................. 5.9.4 Imines, Oximes, Hydrazones, and Azines .................... 5.9.5 Nitriles and Isonitriles ............................................. 5.9.6 Cyanates, Isocyanates, Thiocyanates, and Isothiocyanates Sulfur-Containing Functional Groups ..................................... 5.10.1 Thiols .................................................................. 5.10.2 Sulfides ................................................................ 5.10.3 Disulfides and Sulfonium Salts ................................. 5.10.4 Sulfoxides and Sulfones ........................................... 5.10.5 Sulfonic, Sulfinic, Sulfurous, and Sulfuric Acids and Derivatives ............................................................ 5.10.6 Thiocarboxylate Derivatives ...................................... Carbonyl Compounds .......................................................... 5.1 1.1 Aldehydes .............................................................. 5.1 1.2 Ketones ................................................................ 5.1 1.3 Carboxylic Acids and Carboxylates ............................ 5.1 1.4 Esters and Lactones ................................................. 5.1 1.5 Amides and Lactams ................................................ 5.1 1.6 Miscellaneous Carbonyl Derivatives ........................... Miscellaneous Compounds ................................................... 5.12.1 Silicon Compounds ................................................ 5.12.2 Phosphorus Compounds .......................................... 5.12.3 Miscellaneous Compounds ....................................... Natural Products ................................................................. 5.13.1 Amino Acids ......................................................... 5.13.2 Carbohydrates ........................................................ 5.13.3 Nucleotides and Nucleosides ...................................... 5.13.4 References ............................................................. Spectra of Solvents and Reference Compounds ......................... 5.14.1 H NMR Spectra of Common Deuterated Solvents ....... 5.14.2 1H NMR Spectra of Secondary Reference Compounds ...
*
175 176 180 186 186 193 198 198 199 200 201 202 202 204 207 207 210 210 211 212 213 214 214 215 216 216 217 217 218 218 219 220 221 223 226 228 228 229 232 233 233 236 237 239 240 240 242
Table of Contents
5.14.3
XI .
1H NMR Spectrum of a Mixture of Common Nondeuterated Solvents ............................................
243
6 IR Spectroscopy..................................................................
245
Alkanes ............................................................................. Alkenes ............................................................................. 6.2.1 Monoenes ............................................................. 6.2.2 Allenes ................................................................. 6.3 Alkynes ............................................................................ 6.4 Alicyclics .......................................................................... 6.5 Aromatic Hydrocarbons ........................................................ 6.6 Heteroaromatic Compounds .................................................. 6.7 Halogen Compounds ........................................................... 6.7.1 Fluoro Compounds ................................................. 6.7.2 Chloro Compounds ................................................. 6.7.3 Bromo Compounds ................................................. 6.7.4 Iodo Compounds .................................................... 6.8 Alcohols, Ethers, and Related Compounds ............................... 6.8.1 Alcohols and Phenols., ............................................ 6.8.2 Ethers, Acetals, Ketals ............................................. 6.8.3 Epoxides ............................................................... 6.8.4 Peroxides and Hydroperoxides .................................... 6.9 Nitrogen Compounds ........................................................... 6.9.1 Amines and Related Compounds ................................ 6.9.2 Nitro and Nitroso Compounds ................................... 6.9.3 Imines and Oximes ................................................. 6.9.4 Azo Compounds ..................................................... 6.9.5 Nitriles and Isonitriles ............................................. 6.9.6 Diazo Compounds .................................................. 6.9.7 Cyanates and Isocyanates .......................................... 6.9.8 Thiocyanates and Isothiocyanates ............................... 6.10 Sulfur-Containing Functional Groups ..................................... 6.10.1 Thiols and Sulfides ................................................. 6.10.2 Sulfoxides and Sulfones ........................................... 6.10.3 Thiocarbonyl Derivatives ......................................... 6.10.4 Thiocarbonic Acid Derivatives ................................... 6.1 1 Carbonyl Compounds .......................................................... 6.1 1.1 Aldehydes .............................................................. 6.1 1.2 Ketones ................................................................ 6.1 1.3 Carboxylic Acids .................................................... 6.1 1.4 Esters and Lactones ................................................. 6.1 1.5 Armdes and Lactames .............................................. 6.1 1.6 Acid Anhydrides ..................................................... 6.1 1.7 Acid Halides .......................................................... 6.1 1.8 Carbonic Acid Derivatives ........................................ 6.12 Miscellaneous Compounds ................................................... 6.12.1 Silicon Compounds ................................................ 6.12.2 Phosphorus Compounds ..........................................
245 248 248 251 252 253 255 258 260 260 261 262 262 263 263 264 266 267 268 268 270 272 274 275 276 277 278 280 280 281 283 283 286 286 287 290 292 295 298 300 301 304 304 305
6.1 6.2
Table of Contents
XI1
6.12.3 Boron Compounds .................................................. 6.13 Amino Acids ...................................................................... 6.14 Solvents. Suspension Media. and Interferences .......................... 6.14.1 Infrared Spectra of Common Solvents ......................... 6.14.2 Infrared Spectra of Suspension Media .......................... 6.14.3 Interferences in Infrared Spectra ..................................
308 309 310 310 311 312
7 Mass Spectrometry .............................................................
313
7.1
7.2
7.3 7.4
7.5
7.6
7.7
Alkanes ............. ............................................................ 7.1.1 Unbranched Alkanes ................................................ 7.1.2 Branched Alkanes .................................................... 7.1.3 References ............................................................. Alkenes ............................................................................. 7.2.1 Unbranched Alkenes ................................................ 7.2.2 Branched Alkenes .................................................... 7.2.3 Polyenes and Polyynes ............................................ 7.2.4 References ............................................................. Alkynes ....................................................................... 7.3.1 Aliphatic Alkynes ................................................... 7.3.2 References ............................................................. Alicyclic Hydrocarbons ............ ..................................... 7.4.1 Cyclopropanes ....................................................... 7.4.2 Saturated Monocyclic Alicyclics ................................ 7.4.3 Polycyclic Alicyclics ............ ............................... 7.4.4 Cyclohexenes ......................................................... 7.4.5 References ............................................................. Aromatic Hydrocarbones ....................................................... 7.5.1 Aromatic Hydrocarbons ............................................ 7.5.2 Alkylsubstituted Aromatic Hydrocarbons ..................... 7.5.3 References ...................... .................................. Heteroaromatic Compounds .................................................. 7.6.1 General Characteristics ............................................. 7.6.2 Furans .................................................................. 7.6.3 Thiophenes ............................................................ 7.6.4 Pyrroles ................................................................ 7.6.5 Pyridines ............................................................... 7.6.6 N-Oxides of Pyridines and Quinolines......................... 7.6.7 Pyridazines and Pyrimidines ............................... 7.6.8 Pyrazines ...... ....................................... 7.6.9 Indoles .................................................................. 7.6.10 Quinolines ............................................................ 7.6.1 1 Cinnoline .............................................................. 7.6.12 References ........... ............................................. Halogen ............................................................................ 7.7.1 Saturated Aliphatic Halides ....................................... 7.7.2 Polyhaloalkanes ..................................................... 7.7.3 Aromatic Halides .................................................... 7.7.4 References .............................................................
313 313 313 314 315 15 315 316 316 317 317 317 318 318 319 319 319 320 321 321 321 322 323 323 323 323 324 324 325 325 326 326 326 327 327 328 328 329 329 329
Table of Contents
Alcohols ........................................................................... 7.8.1 Aliphatic Alcohols .................................................. 7.8.2 Alicyclic Alcohols .................................................. 7.8.3 Unsaturated Aliphatic Alcohols ................................. 7.8.4 Vicinal Glycols., .................................................... 7.8.5 Aliphatic Hydroperoxides ......................................... Phenols ................................................................ 7.8.6 7.8.7 Benzyl .................................................................. 7.8.8 Aliphatic Ethers ..................................................... Unsaturated Ethers .................................................. 7.8.9 7.8.10 Alkyl Cycloalkyl Ethers .......................................... 7.8.11 Cyclic Ethers ......................................................... 7.8.12 Aliphatic Epoxides .................................................. 7.8.13 Methox ybenzenes ................................................... 7.8.14 Alkyl Aryl Ethers ................................................... 7.8.15 Aromatic Ethers ..................................................... 7.8.16 Aliphatic Peroxides ................................................. 7.8.17 References ............................................................. 7.9 Nitrogen Compounds........................................................... 7.9.1 Saturated Aliphatic Amines ...................................... 7.9.2 Cycloalkylamines ................................................... 7.9.3 Cyclic Amines ....................................................... 7.9.4 Piperazines ............................................................ 7.9.5 Aromatic Amines ................................................... 7.9.6 Aliphatic Nitro Compounds ...................................... 7.9.7 Aromatic Nitro Compounds ...................................... 7.9.8 Diazo ................................................................... 7.9.9 Azobenzenes .......................................................... 7.9.10 Aliphatic Azides ..................................................... 7.9.1 1 Aromatic Azides ..................................................... 7.9.12 Aliphatic Nitriles .................................................... 7.9.13 Aromatic Nitriles .................................................... 7.9.14 Aliphatic Isonitriles (R-NC) ..................................... 7.9.15 Aromatic Isonitriles (R-NC) ..................................... 7.9.16 Aliphatic Cyanates (R-OCN) .................................... 7.9.17 Aromatic Cyanates (R-OCN) .................................... 7.9.18 Aliphatic Isocyanates (R-NCO) ................................. 7.9.19 Aromatic Isocyanates (R-NCO) ................................. 7.9.20 Aliphatic Thiocyanates (R-SCN) ............................... 7.9.21 Aromatic Thiocyanates (R-SCN) ............................... 7.9.22 Aliphatic Isothiocyanates (R-NCS) ............................ 7.9.23 Aromatic Isothiocyanates (R-NCS) ............................ 7.9.24 References ............................................................. 7.10 Sulfur-Containing Functional Groups ..................................... 7.10.1 Aliphatic Thiols ..................................................... 7.10.2 Aromatic Thiols ..................................................... 7.10.3 Aliphatic Sulfides ................................................... 7.10.4 Alkyl Vinyl Sulfides ............................................... 7.10.5 Cyclic Sulfides .......................................................
7.8
Xlll
330 330 331 331 331 332 332 332 333 334 335 335 336 337 337 337 337 338 339 339 339 340 341 341 341 342 342 342 342 343 343 344 344 344 345 345 345 346 346 347 347 347 348 349 349 349 350 350 351
XIV
Table of Contents
7.10.6 Aromatic Sulfides ................................................... 7.10.7 Disulfides .............................................................. 7.10.8 Aliphatic Sulfoxides ................................................ 7.10.9 Alkyl Aryl and Diaryl Sulfoxides ............................... 7.10.10 Aliphatic Sulfones .......................................... 7.10.1 1 Cyclic Sulfones...................................................... 7.10.12 Alkyl Aryl Sulfones ................................................ 7.10.13 Diaryl Sulfones ...................................................... 7.10.14 Aromatic Sulfonic Acids .......................................... 7.10.15 Alkylsulfonic Acid Esters ......................................... 7.10.16 Arylsulfonic Acid Esters .......................................... 7.10.17 Aromatic Sulfonamides ............................................ 7.10.18 Thiocarboxylic Acid S-Esters .................................... 7.10.19 References ............................................................. 7.11 Carbonyl Compounds .......................................................... 7.1 1.1 Aliphatic Aldehydes ................................................ 7.1 1.2 Unsaturated Aliphatic Aldehydes ................................ 7.1 1.3 Aromatic Aldehydes ................................................ 7.1 1.4 Aliphatic Ketones ................................................... 7.1 1.5 Unsaturated Ketones ................................................ 7.1 1.6 Alicyclic Ketones ................................................... 7.1 1.7 Aromatic Ketones ................................................... 7.11.8 Aliphatic Carboxylic Acids .................... ........ 7.1 1.9 Aromatic Carboxylic Acids ....... ........................ 7.1 1.10 Carboxylic Acid Anhydrides ...................................... 7.11.11 Saturated Aliphatic Esters ......................................... 7.11.12 Unsaturated Esters ................................................... 7.1 1.13 Esters of Aromatic Acids ........... ........................... 7.1 1.14 Lactones ................................... ........................ 7.1 1.15 Aliphatic Amides .................................................... 7.1 1.16 Amides of Aromatic Carboxylic Acids ........................ 7.1 1 . 17 Anilides ................................................................ 7.1 1.18 Lactams ................................................................ 7.1 1.19 Imides .................................................. 7.1 1.20 References ............................................................. 7.12 Miscellaneous Compounds ................................................... 7.12.1 Trialkylsilyl Ethers .............. ............................... 7.12.2 Alkyl Phosphates ................................................... 7.12.3 Aliphatic Phosphines .............................................. 7.12.4 Aromatic Phosphines and Phosphine Oxides .... 7.12.5 References ............................................................. 7.13 Mass Spectra of Common Solvents and Matrix Compounds ....... 7.13.1 Electron Impact Ionization Mass Spectra of Common Solvents ............................................................... 7.13.2 Spectra of Common FAB MS Matrix and Calibration Compounds ........................................................... 7.13.3 Spectra of Common MALDI MS Matrix Compounds ... 7.1 3.4 References .............................................................
351 351 352 352 353 354 354 355 355 355 356 356 357 357 358 358 358 358 359 359 359 360 360 361 361 361 362 363 364 364 365 365 365 367 368 369 369 369 369 370 370 371 371 374 380 383
Table of Contents
8 UV/Vis Spectroscopy .............................................. 8.1 8.2 8.3 8.4
8.5
8.6
Correlation Between Wavelength of Absorbed Radiation and Observed Color ..... ............................. UV/Vis Absorption o mophores .......................... UV/Vis Absorption of Conjugated Alkenes ................ 8.3.1 UV Absorption of Dienes and Polyenes ...................... 8.3.2 UV Absorption of a$-Unsaturated Carbonyl Compounds UVNis Absorption of Aromatic Compounds ........................... 8.4.1 UV Absorption of Monosubstituted Benzenes .............. 8.4.2 UV Absorption of Substituted Benzenes 8.4.3 UV Absorption of Aromatic Carbonyl Compounds ....... UV/Vis Reference Spectra ..................................................... 8.5.1 UVNis Spectra of Alkenes and Alkynes ..................... 8.5.2 UVNis Spectra of Aromatic Compounds .................... 8.5.3 UVNis Spectra of Heteroaromatic Compounds ............ 8.5.4 UVNis Spectra of Miscellaneous Compounds ............. 8.5.5 UVNis Spectra of Nucleotides .................................. UVNis Absorption of Common Solvents ...............................
Subject index ...........................................................................
xv 385
385 385 387 387 388 390 390 39 1 392 393 393 394 399 401 403 404 406
SUBJECT INDEX
Index Terms
Links
A Acenaphthene
C96
H181
Acenaphthylene
C96
H181
Acetaldehyde
C133
H218
Acetaldoxime
H211
I274
I287
N/N-Acetals
11
O/O-Acetals
4
9
C120
H206
I245
I246
I264
I265
– methyl
41
O/S-Acetals
8
9
Acetamides
37
C140
H224
Acetanilides
M365
Acetate ion
C137 37
39
I291
I293
C137
H220
I291
M371
H226
I299
C81
C134
C160
H243
M371
U405
Acetates Acetic acid
U403 – esters
C138
– anhydride
C142
Acetoisonitrile
C126
Acetone – dimethylhydrazone
C125
Acetone-d6
C157
H240
Acetonitrile
C126
C160
M371
U405
C157
H240
Acetonitrile-d3
H212
H219
H243
This page has been reformatted by Knovel to provide easier navigation.
Index Terms Acetophenone
Links C135
H219
M390
M397
Acetyl bromide
C142
H226
N-Acetyl-γ-butyrolactam
H227
Acetyl chloride
C142
– iodide
C142
N-Acetyl pyrrolidine
H225
N-Acetyl-γ-valerolactam
H227
Acetylacetone
C118
Acetylene Acetylenes
I289
M360
C135
H220
I289
C88
C89
H175
3
10
32
33
35
45
51
C88
H175
I246
I252
M317
32
40
H226
M385 – aliphatic
M317
Acetylenic ethers
M334
Acid – bromides
I300
– chlorides
4
6
46
I300
– fluorides
I300
– halides
C142
– iodides
I300
Acids
H226
I300
3
4
6
7
9
10
11
12
14
15
32
33
34
38
40
45
65
C136
C137
H220
I290
U386
– aliphatic
M360
– aromatic
M361
This page has been reformatted by Knovel to provide easier navigation.
Index Terms
Links
Acids (Cont.) – α-methyl
41
– α,β-unsaturated
U388
Acridine
C110
H197
Acrylaldehyde
C133
H218
Acrylate ion
C137
Acrylic acid
C137
Acryloisonitrile
C126
Acrylonitrile
U401
H221
I251
C126
H212
I251
– chloride
C142
H226
– fluoride
H226
N-Acyl-piperidine
H225
Acryloyl
Adamantane
C94
H177
Adenine
C154
H238
Adenosine
C155
H238
Alanine
C148
H233
I292
β-Alanine
C148 4
7
10
32
33
34
40
42
45
56
C117
H202
I263
M330
U386
– alicyclic
32
37
M331
– aliphatic
C117
H202
M330
– primary
36
38
M330
– tertiary
34 4
6
9
12
14
32
34
35
40
42
45
63
C133
H218
I245
I286
Alcohols
– unsaturated Aldehydes
U404
M331
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Index Terms Aldehydes (Cont.)
Links M358
– aliphatic
37
– allyl
35
– aromatic
M358
– α-methyl
39
– α,β-unsaturated
U388
Aldimines
C124
H211
I273
Aldoximes
4
C125
H211
Alicyclic – alcohols
M331
– ketones
32
35
C135
H219
H220
M359
32
37
40
42
C90
H176
I247
I253
37
41
Alicyclics
C136
M318 – condensed
C94
– polycyclic
32
33
C94
M319
C117
H202
C85
H174
C145
H229
3
7
10
32
39
40
42
43
49
C71
H161
I245
M313
U385
Aliphatic – alcohols – dienes – phosphorus compounds Alkanes
– aromatically substituted
H165
– branched
M313
– cyclic
M330
32
37
40
42
50
C90
H176
I247
I253
M318
This page has been reformatted by Knovel to provide easier navigation.
Index Terms – halogen-substituted – monosubstituted – polycyclic
Links M328 C74
H162
H163
32
33
37
41
4
7
8
10
32
37
40
41
42
45
50
C82
H168
I246
I248
M315
33
I253
3
10
32
33
35
45
51
C88
H175
I246
I252
M317
C86
H174
I251
M319 – unbranched Alkenes
M313
U385 – branched
M315
– conjugated
U387
– cyclic
32
– unbranched Alkynes
M315
U385 – aliphatic Allenes
M317 C85 U385
Allophanates
M303
Allyl – alcohols – aldehydes
C118
M331
35
– cyanide
M318
– ethers
M334
– methyl ether
C119
Allylamine
C122
Allylic couplings
H169
Amide protons
H223
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Index Terms Amides
Links 3
4
7
8
9
14
15
32
39
45
68
C140
H223
I295
– aliphatic
M364
– of aromatic carboxylic acids
M365
– primary
I295
– secondary
I295
– tertiary
I295
Amine protons Amines
– aliphatic – alkenylsubstituted
H207 3
7
8
9
10
32
34
37
38
39
45
59
C121
H207
I245
I268
I312
M386
40
42
I269
M339
H209
M340
I251
– aromatic
M341
– benzylic
M341
– cyclic
C123
– cycloalkyl
M339
– methyl – primary – protonation induced shifts
36 I268
I269
C121
– secondary
I268
Amino acids
15
C148
M380
M382
10
C121
3-Aminoquinoline
H233
I309
H208
I268
Ammonium – compounds – ion
H208
– protons
H207
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Index Terms
Links
5α-Androstane
C156
5β-Androstane
C156
Anhydrides
6
11
14
C142
H226
I298
M361
– cyclic
11
12
Anilides
M365
Anilines
8
33
37
42
43
C122
H209
U390
H180
H206
I266
H180
U398
U395 – alkylsubstituted Anisole
43 C119 U395
Anthracene
C96
Anthraquinone
I290
Antimony compounds
C99
C147
4
7
8
9
33
35
37
41
42
43
46
52
C96
H180
I255
M321
46
52
M321
C151
H234
C119
H206
M337
4
7
8
9
33
35
37
41
42
43
46
52
C96
H180
I255
M321
46
52
M321
Arenes
– condensed Arginine Aromatic – ethers – hydrocarbons
– – condensed – phosphorus compounds Arsenic compounds Aspartic acid
C146 C99
C147
C150
H234
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Index Terms
Links
7-Azaindole
C109
Azepane
C123
Azetidine
C123
H209
Azides – aliphatic
M342
– aromatic
M343
Azines
H211
Aziridines
7
C123
Azo compounds
H210
I274
Azobenzenes
H211
M342
Azomethane
H211
Azoxy compounds
H210
Azulene
H209 U396
I274
C96
B Benzaldehydes Benzanthracene Benzene
C133
H218
U392
U397
I287
U390
U398 C96
C102
C160
H180
H243
I257
M372
U390
U394
U405
Benzene-1,3-diol
C118
Benzene-d6
C157
H240
M372
4
7
8
9
33
37
42
43
H182
U390
H217
M356
Benzenes
46 – halogen-substituted
I261
– monosubstituted
C97
– mulitiply substituted – perhalogenated Benzenesulfonamide
U391 40 C131
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Index Terms
Links
Benzenesulfonic acid
C131
H217
– methyl ester
H217
Benzenesulfonyl chloride
C131
H217
Benzenethiol
C128
H214
Benzimidazole
C109
H193
Benzoate – ion
C137
– methyl
I294
Benzoates
I291
1,3-Benzodioxolane
C120
H206
Benzoic acid
C137
H221
I292
U390
H212
I275
U390
H219
I289
U397
U397 – esters
U392
– substituted
U392
Benzoic anhydride
C142
Benzoisonitrile
C126
Benzonitrile
C126
I299
U396 Benzophenone γ-Benzopyrones
C135 43
1,2-Benzoquinone
C136
I290
U397
1,4-Benzoquinone
C136
H220
I290
U397
14
35
C136
I288
Benzoquinones
I289 2,1,3-Benzothiadiazole
C109
H194
Benzothiazole
C109
H194
Benzotriazole
H194
2,1,3-Benzoxadiazole
C109
H194
Benzoxazole
C109
H193
Benzoxazoles
C109
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Index Terms
Links
Benzoyl – chloride – derivatives
C142
H226
43
Benzo[l,4]dioxin
H195
Benzo[l,4]dithiin
H195
Benzo[b]furan
C109
H193
Benzo[b]thiophene
C109
H193
– alcohols
C118
H203
– bromide
C115
– chloride
C114
– fluoride
C113
Benzyl
– groups
9
– iodide
C116
– mercaptan
I264
M332
I280
– vinyl sulfide
C129
Benzylamine
C123
Benzylic amines
M341
N-Benzylideneaniline
C124
H211
N-Benzylidenemethylamine
C124
H211
Benzylthiol
C128
Bicyclo[2,2,2]octane
C94
Bicyclo[3,l,0]hexane
C94
Bicyclo[3,3,0]octane
C94
Bicyclo[4,l,0]heptane
C94
Bicyclo[4,2,0]octane
C94
Bicyclo[4,3,0]nonane
C94
Biphenyls
M321
2,2-Bis(ethylthio)propane
C129
Bis(isopropyloxy)methylphosphine
H230
Bis(tert-butylthio)methane
C129
U394
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Index Terms
Links
Boranes
10
I308
Borates
10
I308
Boric acid esters Boron compounds
I308 10
C147
H178
H232
26
28
30
41
42
45
54
C115
H200
I262
U385
– aliphatic
44
M328
– aromatic
I262
M329
26
28
30
41
42
45
54
C115
H200
I262
U385
– aliphatic
44
M328
– aromatic
I262
M329
I308 Bromides
Bromo compounds
Bromoacetic acid
C115
Bromoacetone
C135
Bromoacetylene
H200
Bromoalkanes
M328
Bromobenzenes
C115
H200
Bromocyclohexane
C115
H200
Bromocyclopropane
C90
H200
Bromoethane
C115
H200
Bromoethylene
C115
H200
Bromoform
C115
H200
Bromoform-d
C157
H240
Bromomethane
C115
H200
Bromopropanes
C115
H200
Bromopyridines
C115
N-Bromosuccinimide
H227
I298
C85
C87
1,3-Butadiene
I261
U401
H174
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Index Terms
Links
Butadiyne
C89
Butane
C71
H161
2,3-Butanedione
C135
1-Butanethiol
C128
H214
tert-Butanol
C117
H203
C81
C117
1-Butanol 2-Butanone
C134
Butenes
H168
N-Butylacetamide
H225
N-tert-Butylacetamide
C141
H225
– acetate
H221
I294
– group
H163
– isocyanate
C127
– isothiocyanate
C127
– methyl ethers
C119
– methyl ketones
C134
– methyl sulfides
C129
H215
– acetate
C138
H221
– cyanide
C126
H212
– dimethylamine
C122
– disulfides
H216
– fluoride
H198
I264
Butyl
I279
tert-Butyl
– group
C75
– methyl sulfone
C130
S-Butyl thioacetate
C132
Butylamine
H208
Butyldichlorophosphine
C145
Butyldimethylphosphine
C145
Butyldimethylphosphine sulfide
C146
H163
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Index Terms
Links
tert-Butylamine
C121
tert-Butylbenzene
H181
tert-Butylbromide
C115
H200
tert-Butylchloride
C114
H199
tert-Butylfluoride
C112
tert-Butyliodide
C116
H201
C89
H175
Butyraldehydes
C133
H218
Butyric acid
C137
H221
– anhydride
C142
I299
γ-Butyrolactam
C141
H225
γ-Butyrolactone
C139
H223
I293
Butyronitrile
C126
Butynes
C 12
C NMR Spectroscopy
C71
Calibration compounds for MS
M374
ε-Caprolactone
C139
Carbaldehydes
4
6
12
14
32
34
35
40
42
45
63
C133
H218
I245
I286
M358
12
14
C143
H227
I301
I302
Carbamates – phenyl Carbazole
43 C110
H197
Carbodiimides
C92
C125
Carbohydrates
C152
H236
C143
I312
U386
Carbon – dioxide
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Index Terms
Links
Carbon (Cont.) – disulfide
C143
C160
I311
M372
I310
I312
U405 – monoxide
C143
– tetrabromide
C115
– tetrachloride
C114
C160
M373
U405
– tetrafluoride
C112
– tetraiodide
C116
Carbonate ion
C143
Carbonic acid derivatives
11
12
14
15
C143
H227
I285
I301
63
C133
H218
I286
M358
M386
I302 Carbonyl compounds – α,β-unsaturated
U388
Carbonyl groups
6
10
11
Carboxamides
3
4
6
7
8
9
14
15
32
39
45
68
C140
H223
I295
15
C136
C137
H220
I290
U386
6
11
14
C142
H226
I298
M361
– aliphatic
M364
– of aromatic carboxylic acids
M365
– primary
I295
– secondary
I295
– tertiary
I295
Carboxyl protons Carboxylate anions Carboxylic acid anhydrides
H220
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Index Terms
Links
Carboxylic acid anhydrides (Cont.) – cyclic
11
12
3
4
6
7
8
9
12
14
15
32
33
40
42
43
66
C138
H221
I292
U386
– of aromatic acids
65
M363
– ethyl
35
38
42
– methyl
36
39
41
C138
Carboxylic acid esters
I293 – phenyl
42
I293
– propyl
37
39
– saturated
M361
– unsaturated
M362
– α,β-unsaturated – vinyl
65
U388
I293
Carboxylic acids
3
4
6
7
9
10
11
12
14
15
32
33
34
38
40
45
65
C136
C137
H220
I290
U386
– aliphatic
M360
– aromatic
M361
– α-methyl
41
– α,β-unsaturated Catechol Chlorides
U388 I257
I264
3
4
8
9
26
28
29
33
36
38
40
41
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Index Terms
Links
Chlorides (Cont.)
– aliphatic – aromatic Chloro compounds
– aliphatic – aromatic
45
54
C114
I261
M373
U385
3
4
8
9
32
42
54
M328
I261
M329
3
4
8
9
26
28
29
33
36
38
40
41
45
54
C114
H199
I261
M373
U385
3
4
8
9
32
42
54
M328
I261
M329
9
Chloroacetate ion
C137
Chloroacetic acid
C114
Chloroacetone
C135
Chloroacetylene
H199
Chloroalkanes Chlorobenzenes
H199
C137
3
4
8
32
42
M328
C114
H199
I257
I261
U390
U395
1-Chlorobutane
H199
Chlorocyclohexane
C114
Chlorocyclopropane
C90
H199
Chloroethane
C114
H199
Chloroethylene
C114
H199
Chloroform
C114
C160
H199
H243
I310
I312
M373
U401
H240
M373
U405 Chloroform-d
C157
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Index Terms
Links
Chloromethane
C114
H199
Chloropropanes
C114
H199
Chloropyridines
C114
Chlorotrimethylsilane
H228
Chlorotriphenylsilane
H228
Cholesterol
C156
Chromone
H195
Chrysene
U398
Cinnoline
C110
Citric acid
U403
H196
M327
M321
Condensed – alicyclics
C94
– aromatics
46
52
– heteroaromatic rings
C109
H193
Conjugated alkenes
U387
– dienes
C85
H174
– common
C160
H243
Coronene
U399
Coumarin
H195
Contaminants
Coupling – H–C–N–H
H223
– with hydroxy protons
H202
– with SH protons
H214
Crotonaldehyde
I287
U393
Crotonic acid
I292
U394
– esters
I294
18-Crown-6 Cubane
M376
M379
C94
Cyanates
H213
– aliphatic
M345
I277
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Index Terms
Links
Cyanates (Cont.) – aromatic Cyanides
M345 4
35
37
39
C126
H212
I246
I275
I276
M318
U386
– aliphatic
M343
– aromatic
M344
α-Cyano-4-hydroxycinnamic acid
M381
M382
32
37
40
42
49
C90
H176
I247
I253
M318
– alkenes
32
33
50
I253
– amines
C123
H209
M340
34
36
C119
H204
32
35
C135
C136
H219
H220
M359
C129
H215
M351
32
37
40
42
49
C90
H176
I247
I253
M318
Cycloalkanols
32
37
M331
Cycloalkanones
32
35
41
42
C135
C136
H219
H220
Cyclic – alkanes
– ethers
M335 – ketones – sulfides Cycloalkanes
M359 Cycloalkenes
32
33
50
I253
Cyclobutanes
C90
C95
H176
I254
H219
I288
1,2-Cyclobutanedione
H220
Cyclobutanol
H203
Cyclobutanone
C136
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Index Terms
Links
Cyclobutenes
C93
Cycloheptane
C90
H176
I248
I254
Cycloheptanone
C136
I288
Cycloheptatriene
C93
H177
Cycloheptene
C93
H177
Cyclohexadienes
C93
H177
M319
Cyclohexane
C95
C160
H176
H243
M372
U405
H179
I245
Cyclohexanecarboxaldehyde
C133
Cyclohexane-d12
C158
Cyclohexanecarbonyl chloride
C142
Cyclohexanecarboxylate ion
C137
Cyclohexanecarboxylic acid
C137
1,3-Cyclohexanedione
H220
Cyclohexanes
41
H241
C92
I254 Cyclohexanethiol
C128
H214
Cyclohexanol
C118
H203
I264
Cyclohexanone
C136
H219
I288
Cyclohexanones
M360
Cyclohexanonitrile
C126
Cyclohexene 2-Cyclohexene-l-one Cyclohexenes N-Cyclohexyl acetamide
C93
H176
C136
I289
35
39
40
I248
I254
M319
50
C141
Cyclohexyl – acetate
C138
– methyl ether
C119
– methyl ketone
C135
Cyclohexylamine
C122
H208
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Index Terms
Links
Cyclohexyldimethylamine
C122
Cyclohexyldimethylphosphine
C145
Cyclohexylmethylamine
H209
1,3-Cyclooctadiene
C177
1,5-Cyclooctadiene
C93
Cyclooctatetraene
C93
Cyclooctene
C93
H177
Cyclopentadiene
C93
H176
Cyclopentane
C95
H176
Cyclopentanes
C91
I254
C136
H219
I288
40
C93
H176
7
49
C90
C95
H176
H178
I245
I250
I251
I254
M318
C90
H203
Cyclopentanone Cyclopentenes 2-Cyclopenten-l-one Cyclopropanes
Cyclopropanol Cyclopropanone Cyclopropenes Cyclopropenone
C136
H219 C93
H176
I248
I254
C136
Cyclopropyl methyl ketone
C90
C135
Cyclopropylamine
C90
H208
Cylohexylmethylamine
C122
Cysteine
C149
Cystine
C149
Cytidine
C154
H238
Cytosine
C154
H237
H234
U404
D Decalins 2'-Deoxyadenosine
C94 C155
H239
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Index Terms
Links
2'-Deoxyguanosine
C155
Diacetamide
C143
Diacetyl
C135
N,N-Diacetylmethylamine
C143
Diazen-N-oxides
H210
Diazen-N-sulfides
I274
Diazo compounds
35
Diazophenyl derivatives
43
Dibenz[a,h]anthracene
U399
Dibenzo-l,4-dioxin
C110
Dibenzofuran
C110
Dibenzothiophene
C110
Dibenzoylamine
M367
Dibromoacetic acid
C115
1,1-Dibromoacetone
C135
Dibromoethanes
C115
1,1-Dibromoethylene
C115
cis-1,2-Dibromoethylene
C115
trans-l,2-Dibromoethylene
C115
H239 H220 I274 I276
M342
U386
H197
H200
Dibutyl – carbonate
C143
– phthalate
M373
– sulfide
C128
– sulfone
M354
H227
Di-tert-butyl – ketone
C134
– hydrazone
C125
– sulfide
C128
– sulfone
H216
– thioketone
C132
Di-tert-butyldiazene-1 -oxide
H211
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Index Terms
Links
Dichloroacetate ion
C137
Dichloroacetic acid
C114
1,1-Dichloroacetone
C135
Dichlorodimethylsilane
H228
Dichloroethanes
C114
1,1 -Dichloroethylene
C114
cis-1,2-Dichloroethylene
C114
Dichloromethane
C114
α,α-Dichlorotoluene
C114
Dicyclohexyl carbodiimide
C125
C137
H199
H199
U405
32
33
41
H174
U387
U393
– aliphatic
C85
H174
– conjugated
C85
H174
Dienes
Diesters
43
– unsaturated
43
Diethanolamine
45
C122
Diethyl – disulfide
C130
– ether
C160
H204
M372
U405
– ethylphosphonate
C145
– ketone
C134
– sulfate
C131
– sulfide
C128
– sulfite
C131
H243
I266
H217
N,N-Diethyl – acetamide
C141
– butyramide
C141
– formamide
C140
Diethylamine
C121
H208
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Index Terms
Links
1,3-Diethylurea
H227
Diethylnitrosamine
C124
Difluoroacetic acid
C112
1,1-Difluoroethane
H198
Difluoromethane
C112
Diglyme
C160
H243
Dihydrazides
I296
9,10-Dihydroanthracene
C96
H181
C119
H205
C96
H181
Dihydrofurans 9,10-Dihydrophenanthrene 3,4-Dihydro-2H-pyran
C119
2,3-Dihydrothiophene
H215
2,5-Dihydrothiophene
C129
H215
2,6-Dihydroxyacetophenone
M381
M382
2,5-Dihydroxybenzoic acid
M381
M382
1,1-Diiodoethane
H201
1,2-Diiodoethane
C116
cis-l,2-Diiodoethylene
C116
trans-1,2-Diiodoethylene
C116
Diiodomethane
C116
H201
H201
Diisopropyl – carbodiimide
C125
– ketone
C134
– sulfide
C128
Diisopropylamine
H208
Diisopropylnitrosamine
C124
H210
12
14
Diketones
I287
15
C135
I288 Dimedone
C118
Dimethoxymethane
C120
2,2-Dimethoxypropane
C120
H206
This page has been reformatted by Knovel to provide easier navigation.
Index Terms N,N-Dimethyl acetamide
Links C141
H225
Dimethyl – acetylenedicarboxylate
C139
– butylphosphonite
C145
– carbonate
C143
H227
C81
C119
– ether – ethylphosphonate
H231
– fumarate
C139
– glycol
M372
– maleate
C139
– malonate
C139
– methylphosphonate
H231
– oxalate
C139
– phenylphosphonate
H231
– succinate
C139
– sulfate
C131
H217
– sulfide
C128
H215
– sulfite
H217
– sulfone
C130
H216
– sulfoxide
C130
C160
– sulfoxide-d6
C158
H241
– trithiocarbonate
C143
H204
H216
H243
C160
H224
N,N-Dimethyl – formamide
C81
C140
H243 – sulfinamide
H217
– thioacetamide
C132
Dimethylamine
C121
N,N-Dimethylaniline
C122
Dimethylazine
H212
3,3-Dimethyl-2-butanone
C134
H208
This page has been reformatted by Knovel to provide easier navigation.
Index Terms
Links
4,4-Dimethyl-2,5-cyclohexadien-1-one
C136
5,5-Dimethyl-1,3-cyclohexanedione
C118
N,N’-Dimethylethylenediamine
C122
NN-Dimethylformamide
I297
1,3-Dimethyl-2-imidazolidinone
C143
Dimethylnitrosamine
C124
2,4-Dimethyl-3-pentanone
C134
Dimethylphosphine
H229
Dimethylphosphine sulfide
H230
2,2-Dimethyl-l-propanethiol
C128
2,2-Dimethyl-1 -propanol
C117
Dimethylsilane
H228
Dimethylsilanol
H229
1,3-Dimethylurea
H227
Dimethylvinylphosphine sulfide
H230
Dineopentyl sulfide
C128
N,N-Dinitromethylamine
C124
Dioctyl phthalate
M373
Diols
M371 H210
42
1,3-Dioxane
H206
I265
1,4-Dioxane
C119
C160
H205
I265
M372
U405
1,3,2-Dioxathiane oxide
C131
1,3,2-Dioxathiolane dioxide
H217
1,3-Dioxolane
C120
H206
– disulfide
C130
H216
– ether
C119
H206
– methylphosphonate
C146
– sulfide
C129
– sulfone
COO
H243
Diphenyl U395
H215
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Index Terms
Links
Diphenyl (Cont.) – sulfoxide
M353
Diphenylamine
C123
Diphenylsilanol
H229
Diphenylvinylphosphine oxide
H229
Diphenylvinylphosphine sulfide
H230
N,N-Dipropyl acetamide
C141
Dipropyl sulfide
C128
Dipropylamine
C121
Dipropylnitrosamine
C124
U396
H208
Disulfide – dimethyl
U403
Disulfides
40
45
C74
C75
C98
C130
H161
H162
H183
H216
I280
M351
U386 1,2-Dithiane
H216
1,3-Dithiane
C129
1,4-Dithiane
C129
1,3-Dithietane
C129
Dithioacids
I283
Dithiocarbonates
I285
M302
Dithiocarboxylic acid esters
C132
M357
Dithioerythritol
M376
1,3-Dithiolane
C129
Dithiophosphate – trimethyl
C146
Dithiothreitol
M376
Dithranol
M381
M383
Divinyl – ether
I266
This page has been reformatted by Knovel to provide easier navigation.
Index Terms
Links
Divinyl (Cont.) – ketone
H219
DMSO
C130
DSS
C159
I289 H216 H242
E Elements – isotope patterns Enamines
23 I251
End absorption
U405
Enol esters
M363
Enols
C118
H204
I263
7
34
45
C119
H204
I245
I250
I254
I265
I266
Epoxides
– aliphatic Esters
M336 3
4
6
7
8
9
12
14
15
32
33
40
42
43
66
C138
H221
I292
U386
– of aromatic acids
65
M363
– ethyl
35
38
42
– methyl
36
41
C138
– phenol
42
I293
– propyl
37
39
– saturated
M361
– unsaturated
M362
– α,β-unsaturated
65
– vinyl
I293
Ethane
C71
I293
U388 C81
H161
This page has been reformatted by Knovel to provide easier navigation.
Index Terms
Links
1,2-Ethanedithiol
C128
Ethanesulfonyl chloride
C131
Ethanethiol
C128
H214
U402
Ethanol
C117
C160
H202
H243
M371
U405
Ethanolamine Ethers
C122 3
4
8
9
32
33
40
41
42
45
57
C119
H204
I245
I263
I264
U386 – acetylene – aliphatic – alkenylsubstituted
M334 32
M333
I251
– alkyl aryl
M337
– alkyl cycloalkyl
M335
– allyl
M334
– aromatic
C119
H206
M337
34
36
C119
H204
H221
H243
– cyclic
M335 – ethyl
38
– methyl
36
– phenol
42
– propyl
39
I245
– unsaturated
M334
– vinyl
M334
N-Ethyl acetamide
C140
H224
C138
C160
M372
U405
Ethyl – acetate – acrylate
H222
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Index Terms
Links
Ethyl (Cont.) – benzoate
H222
– cyanate
H213
– disulfides
H216
– group
C74
H162
– isocyanate
H213
I278
– isocyanide
C126
H213
– isothiocyanate
H213
– methyl ether
C119
– methyl ketone
C134
– methyl sulfide
H215
– methyl sulfone
C130
H216
– N-methylcarbamate
C143
H227
– nitrite
H232
– phenyl ketone
H219
– thiocyanate
C127
– trifluoroacetate
H222
– vinyl ether
H204
– vinyl sulfide
C129
N-Ethyl formamide
C140
Ethylamine
C121
Ethylbenzene
H181
Ethylene
H219
H213
H208
C86
C87
– carbonate
C143
H227
– glycol
C117
M371
– – dimethyl ether
C119
– oxide
I266
– sulfide
C129
– trithiocarbonate
H227
Ethylenes, monosubstituted
H170
N-Ethylidene-tert-butylamine
C124
H168
H215
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Index Terms
Links
Ethylidene triphenyl phosphorane
C147
Ethylmethylamine
C122
Ethylthioethyne
C129
Ethyltriacetylsilane
C144
Ethylurea
H227
Ethynyl methyl ketone
C135
F Fast atom bombardment (FAB) mass spectra Fatty acid derivatives Fermi resonance
M374 42 I245
I252
M381
M383
Fluorene
C96
H181
M321
Fluorides
10
29
35
36
38
43
54
C112
H198
I260
M373
10
29
35
36
38
43
54
C112
H198
I260
M373
Ferulic acid
– aliphatic
M328
– aromatic
M329
Fluoro compounds
– aliphatic
M328
– aromatic
M329
Fluoroacetic acid
C112
Fluoroacetone
C134
Fluoroacetylene
H198
Fluoroalkanes
M328
Fluorobenzene
C113
Fluorocyclohexane
C113
Fluorocyclopropane
H198
I279
I286
H198
This page has been reformatted by Knovel to provide easier navigation.
Index Terms
Links
Fluoroethane
C112
H198
Fluoroethylene
C112
H198
Fluoromethane
C112
H198
1-Fluorooctane
C112
Fluoropropanes
C112
Fluoropyridines
C113
Formaldehyde
C133
H218
Formamides
C140
H224
I297
Formanilides
M365
Formate ion
C137 I291
I293
M362
C137
H220
I291
Formates Formic acid – esters
9
Formic anhydride
C142
Fructose
C153
Fullerene
C96
Fulvene
C93
H176
I254
C104
C111
H186
M371
35
41
H188
I258
I259
M323
C107
C144
Furan
H237
U400 5H-Furan-2-one Furans Furazan
H223
H186
Furyl ketones
40
42
H166
H168
C99
C106
G Geminal Coupling Germanium compounds
H232 Glucose
C152
H236
Glutamic acid
C150
H234
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Index Terms
Links
Glycerol
C117
M379
Glycine
C148
H233
Glycol ethers
32
33
42
Glycols
32
33
39
41
C117 – ethylene
39
– vicinal
M331
Group IV elements
C144
Guanidines
M303
Guanidinium ion
U386
Guanine
C154
U404
Guanosine
C155
H238
H 1
H NMR Spectroscopy
Halides
H161 3
4
8
9
26
54
C112
H198
I260
M328
– aliphatic
M328
– aromatic
M329
Haloboroxines Halogen compounds
I308 3
4
8
9
26
54
C112
H198
I260
M328
– aliphatic
M328
– aromatic
M329
Halogenides
3
4
8
9
26
54
C112
H198
I260
M328
– aliphatic
M328
– aromatic
M329
This page has been reformatted by Knovel to provide easier navigation.
Index Terms Heptane Heteroaromatic compounds Heteroatom indicators
Links C71
U405
9
53
I258
M323
H186
H243
M372
29
Hexabromoethane
C115
Hexachloroacetone
C135
Hexachloroethane
C114
Hexadecylpyridinium bromide
M377
Hexafluoroethane
C112
Hexane
C104
C71
I289 M380 C160
U405 1-Hexanethiol
C128
2,5-Hexanedione
C135
Hexanols
C117
2-Hexanone
C134
Histidine
C151
Homoallylic couplings
H169
Homologous mass series
32
Hydrazides
36
Hydrazines
H182
Hydrazones
C125
Hydrochlorides
I309
Hydrogen bonds
H202
Hydroperoxides
I267
– aliphatic Hydroxylamines
I296 H211
M332 34
4-Hydroxyproline
C151
N-Hydroxypyridinium chloride
C104
Hyrdrogen bonds
H235
H235
9
This page has been reformatted by Knovel to provide easier navigation.
Index Terms
Links
I Imidazole
41
C104
C111
H186
H227
Imidazolium – anion
C104
– cation
C104
Imidazolo[l,2-a]pyridine
H195
Imides
H186
11
12
C143
I296
M367
U386
– cyclic
12
M367
Imines
4
C124
H211
Indane
C94
C96
H181
I272
1-Indanone
H220
Indazole
C109
H194
C94
C96
H181
C109
H193
M326
Indene Indium, trimethyl Indoles
C146 43 U401
Indolizine Iodides
C109
H194
30
43
46
54
C116
H201
I262
U385
30
43
46
54
C116
H201
I262
U385
H201
U395
– aliphatic
M328
– aromatic
M329
lodo compounds – aliphatic
M328
– aromatic
M329
Iodoacetylene
H201
Iodoalkanes
M328
Iodobenzene
C116
Iodobenzenes
I261
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Index Terms
Links
1-Iodobutane
H201
Iodocyclohexane
C116
H201
Iodocyclopropane
C90
H201
Iodoethane
C116
H201
Iodoethylene
C116
H201
Iodomethane
C116
H201
Iodopropanes
C116
H201
Iodopyridines
C116
IR Spectroscopy
I245
Isobutane
H161
Isobutenes
H173
Isobutyraldehyde
C133
Isobutyric acid
C137
Isobutyronitrile
H218
I287
C126
H212
I276
Isocyanates
C127
H213
I277
– aliphatic
M345
– aromatic
M346
Isocyanides
C126
H212
I275
– aliphatic
M344
– aromatic
M344
Isocyanurates
I296
Isoleucine
C149
H233
Isonitriles
C126
H212
– aliphatic
M344
– aromatic
M344
Isopropanol
C117
H203
– acetate
C138
H221
– benzoate
H222
I275
Isopropyl
– group
C75
– isocyanate
H163
H213
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Index Terms
Links
Isopropyl (Cont.) – methyl ketone
C134
– methyl sulfone
C130
– phenyl ketone
H219
H219
N-Isopropyl – acetamide
C141
H225
– formamide
H224
Isopropylamine
C121
Isopropylbenzene
H181
Isopropyldimethylamine
C122
Isoquinoline
C110
Isoquinoline N-oxide
H196
Isoquinolines
M326
Isothiazole
C104
H186
Isothiocyanates
C127
H213
H208
H196
U401
I278
M347
C120
H206
U386 Isotope patterns – for combinations of C1, Br, S, and Si
26
– calculation of
24
28
Isotopes – abundance of
16
– patterns for elements
23
Isoxazole
C104
22 H186
K Karplus equation Ketals
H167 4
37
I264
I265
– ethylene
39
43
– thioethylene
44
Ketenes
I289
U386
This page has been reformatted by Knovel to provide easier navigation.
Index Terms
Links
Ketimines
C124
Ketoesters
I293
Keto-enol tautomerism Ketones
I273
I274
3
4
7
8
12
14
15
32
33
34
35
37
40
42
43
45
64
C134
H219
I287
M359
– α,(β-unsaturated
U388
– aliphatic
H220
– alkyl phenyl
U392
– aromatic
M360
– cyclic
M359
32
35
41
42
C135
C136
H219
H220
9
C125
H211
12
14
35
68
C140
C141
H223
H225
I295
I296
M365
11
12
32
33
34
35
36
38
40
66
C139
H223
M359 – ethyl
39
– halogeneted
C134
– long-range couplings
H220
– methyl – unsaturated Ketoximes
I246 M359 4 I274
L Lactams
Lactic acid Lactones
I292
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Index Terms
Links
Lactones (Cont.)
I292
M364
Lead compounds
C99
C105
C106
C107
C144
H171
H183
H232
Leucine
C148
H233
Lithium tetramethylborate
C147
Long-range couplings
H167
H178
H180
H169
H220 Lysine
C150
H234
M Magic bullet
M376
Maleic anhydride
C142
Maleinimide
C143
Malonic acid
C137
Malonitrile
C126
Mass spectrometry
M313
H226
I299
H221
I292
Matrix-assisted laser desorption ionization (MALDI) mass spectra
M380
McLafferty rearrangement
M315
M317
M323
M325
M331
M332
M338
M339
M343
M344
M353
M355
M358
M359
M360
M361
M362
M364
3
7
8
10
32
33
41
45
62
C128
H214
I280
Mercaptans
U386 – aliphatic
M349
– aromatic
M349
2-Mercaptoethanol
C128
This page has been reformatted by Knovel to provide easier navigation.
Index Terms Mercury compounds Methacrylonitrile Methane
Links C99
C146
H183
M323
H171
H178
H202
H243
M318 C71
H161
Methanesulfonic acid
C131
– ester
H217
Methanesulfonyl chloride
C131
H217
Methanethiol
C128
H214
Methanol
C117
C160
M371
U405
Methanol-d1
C158
H241
Methanol-d4 C158
H241
Methionine
C149
N-Methyl acetamide
C140
H224
– acetate
C138
H221
– acrylate
C139
H222
– benzenesulfonate
C131
– benzoate
C139
H222
– butyrate
C138
H222
– chloroacetate
C139
– cyclohexanecarboxylate
C138
– dichloroacetate
C139
– disulfides
H216
– dithioacetate
C132
– esters
C138
– formate
C138
H221
C72
C74
– isobutyrate
C138
H222
– isocyanate
C127
H213
– isocyanide
H213
Methyl
– group
H162 I278
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Index Terms
Links
Methyl (Cont.) – isopropyl ether
C119
– isothiocyanate
C127
– methanethiolsulfinate
C131
– methanethiolsulfonate
C131
– nitrate
H232
– perchlorate
H232
– phenyl sulfone
H216
– phenyl sulfoxide
H213
I279
C130
H216
M352
– pivalate
C138
H222
– propiolate
C139
– propionate
C138
– propyl ether
C119
– propyl ketone
C134
– dimethylhydrazone
C125
– propyl sulfone
COO
– thiocyanate
H213
– trichloroacetate
C139
– valerate
C138
H222
– vinyl ether
C119
H204
– vinyl ketone
C135
H219
– vinyl sulfide
H215
– vinyl sulfone
H216
– vinyl sulfoxide
H216
H222 H219
N-Methyl – γ-butyrolactam
H225
– formamide
C140
– phthalimide
C143
– β-propiolactam
H225
– succinimide
C143
– δ-valerolactam
H225
H224
I297
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Index Terms
Links
S-Methyl thioacetate
C132
Methyl-tert-butylamine
C122
Methylamine
C121
H208
N-Methylaniline
C122
H209
N-Methylazetidine
C123
Methylazine
H212
N-Methylaziridine
C123
1-Methylbenzotriazole
C109
2-Methylbutane
C71
3-Methyl-2-butanone
C134
3-Methyl-l-butyne
H175
Methylcyclopropane
I270
C95
Methylene – chloride
M372
– fluoride
H198
Methylenecyclopentadiene
C93
Methylenedioxy group
I245
Methylisopropylamine
C122
Methyllithium
C147
4-Methylmorpholine
H209
2-Methyl-2-nitropropane
C123
Methyloxirane
H204
Methylphenyldiazene
H211
Methylphosphine
H229
1-Methylpiperazine
H209
1-Methylpiperidine
C123
2-Methylpropane
H232 H210
H209
C71
2-Methyl-2-propanesulfonic acid
C131
– chloride
C131
2-Methyl-2-propanethiol
C128
2-Methyl-2-propyl isocyanide
H213
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Index Terms
Links
Methylpropylamine
C122
N-Methylpyridinium iodide
C104
N-Methylpyrrolidine
C123
Methylsilane
H228
N-Methyl-N-silylaminosilane
H228
Mineral oil Molecular weight, determination of
I311 31
Monosaccharides
C152
H236
Monosubstituted naphthalenes
H184
H185
Morpholine
C119
C123
H205
H209
44
C96
H180
N Naphthacene
U398
Naphthalenes
43 U398
– monosubstituted
C100
C101
1,4-Naphthoquinone
C136
I290
Naphthoquinones Neopentane 14
1
N- H coupling
43 C71 H212
H223
C124
I271
Nitrates
C78
I271
U386
Nitric acid esters
C78
I271
U386
4
35
37
39
C126
H212
I246
I275
M318
U386
Nitramines
Nitriles
– aliphatic
M343
– aromatic
M344
Nitro compounds
3
4
8
10
34
36
38
60
C123
H210
I270
U386
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Index Terms
Links
Nitro compounds (Cont.) – aliphatic
M341
– aromatic
M342
Nitrobenzene
C124
H210
3-Nitrobenzyl alcohol
M375
M379
1-Nitrobutane
C123
H210
2-Nitrobutane
C123
Nitrocyclohexane
C124
Nitrocyclopentane
H210
N-Nitrodimethylamine
C124
Nitroethane
C123
Nitroethylene
H210
Nitrogen compounds Nitromethane
C121
H207
H210
U402
46
C123
I272
U396
H210
29
59
I268
M339
3
C123
C124
1-Nitrooctane
C123
2-Nitrophenol
H203
2-Nitrophenyl octyl ether
M376
M380
Nitropropanes
C123
H210
Nitrosamines
C124
H210
10
36
H210
U386
Nitrosobenzene
C124
H210
Norbornadiene
C94
Norbornane
C94
Norbornene
C94
Norcamphor
H177
Nucleotides
U403
– and nucleosides
C154
Nujol
U390
H210
N-Nitromethylamine
Nitroso compounds
I272
H237
I311
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Index Terms
Links
O Octane
C71
n-Octanes
C76
Olefins
4
7
8
10
32
37
40
41
42
45
50
C82
H168
I246
I248
M315
33
50
I253
U385 – branched – cyclic
M315 32
– unbranched
M315
Organometallics
C147
Ornithine
C150
Ortho esters
9
H232 C120
Ovalene
U399
Oxalic acid
C137
1,3-Oxathiane
C129
1,4-Oxathiane
C129
H215
Oxazole
C104
H186
Oxetane
C119
H205
N-Oxides Oximes
4
9
I272
U386
I273
– aromatic
I273
Ozonides
I292
34
– aliphatic Oxiranes
H206
C125
H211
7
34
45
C119
H204
I245
I250
I254
I265
I266
I267
This page has been reformatted by Knovel to provide easier navigation.
Index Terms
Links
P 1,3-Pentadiene
H174
Penta(isopropyloxy) phosphorane
C147
Pentaerythritol
C117
Pentane
C71
M371
U405
2,4-Pentanedione
C118
C135
H220
1-Pentanethiol
C128
1-Pentanol
C117
Pentanones
C134
3-Penten-l-yne
H175
2-Pentyne
H175
H180
U398
H203
I264
U390
42
56
Peracids
I267
Perchlorate – methyl
H232
Perfluoralkanes
C113
Perfluoroalkyl derivatives
44
Peroxides
I267
– aliphatic
M337
– cyclic
36
Perylene Phenanthrene
U399 C96
Phenazine
C110
Phenol
C118 U395
– derivatives
42
– esters
42
– ethers
42
Phenolate Phenols
U390
U395
9
33
I263
M332
This page has been reformatted by Knovel to provide easier navigation.
Index Terms
Links
Phenothiazine
C110
Phenoxathiin
C110
Phenoxazine
C110
H197
– acetate
C138
H222
– isothiocyanate
H213
I279
– propyl ketone
H219
Phenyl I294
N-Phenyl – acetamide
C141
– formamides
H224
– methanesulfonamide
H217
Phenylacetylene
H175
Phenylalanine
C150
Phenylphosphonic acid
C146
Phosphanes
10
Phosphates
10
– alkyl
43
– alkyl esters – ethyl
H225
I297
H234
I306
M369 35
Phosphine
H229
Phosphine oxides
H229
Phosphine sulfides
H229
Phosphines
C145
M369 H229
I305
H231
I306
M369
Phosphinic acid – anhydrides
I307
– esters
I306
Phosphonic acid – derivatives – esters
C145 I306
Phosphonium compounds
C145
Phosphonous acid derivatives
H230
H229
This page has been reformatted by Knovel to provide easier navigation.
Index Terms Phosphoranes
Links C147
Phosphoric acid – anhydrides
I307
– derivatives
C145
– esters
H231
I306
Phosphorus compounds
10
30
H229
I246
I283
I305
– aliphatic
C145
H229
– aromatic
C146
Phosphorus ylids
H231
43 C145
35
38
M369
M370
I312
M363
M373
H197
M327
H226
I299
Phthalate – esters
44
– diethyl
I294
Phthalazine
C110
Phthalic acid
I292
– anhydride
C142
Phthalimide
I298
Piperazines
C123
M341
Piperidines
41
C123
– N-alkylsubstituted
42
H209
2-Piperidone
M365
M366
Pivalaldehyde
C133
H218
Pivalate ion
C137
Pivalic acid
C137
H221
I291
32
33
37
C94
M319
45
M316
U387
M374
M375
M377
Polycyclic alkanes Polyenes Polyethylene glycol Polyethers Polyhaloalkanes
M361
41
58 M329
This page has been reformatted by Knovel to provide easier navigation.
Index Terms Polyols
Links C117
Polypeptides Polyynes Potassium bromide
I291
I296
M316 I311
Progesterone
C156
Proline
C151
H235
Propane
C71
C81
1,3-Propane sultone
H217
Propanediols
C117
1,3-Propanedithiol
H214
Propanesulfonic acids
C131
Propanesulfonyl chlorides
C131
Propanethiols
C128
H214
1-Propanol
C117
H202
2-Propanol
C117
U405
Propargyl alcohol
C118
Propioisonitrile
C126
H213
β-Propiolactone
C139
H223
Propiolaldehyde
C133
Propiolic acid
C137
Propionaldehyde
C133
Propionate ion
C137
Propionates
H161
I293
H218
I293
Propionic acid
C137
– anhydride
C142
Propionitrile
C126
Propionyl chloride
C142
H220 H212
Propyl – acetate
H221
– group
C74
– isocyanate
H162
H213
This page has been reformatted by Knovel to provide easier navigation.
Index Terms N-Propyl acetamide
Links C141
H224
2-Propyl – isocyanide
H213
– isothiocyanate
H213
– thiocyanate
H213
Propylamine
C121
H208
C87
H168
Propylene Propylene carbonate
C143
N-Propylidene isopropylamine
C124
Propyne
C89
H175
Protonation of amines
C121
Purine
C109
H194
4H-Pyran
C119
H205
2H-Pyran-2-one
C139
H223
Pyrans
41
2H-Pyran-2-thione
H217
Pyrazine
C104
– N-oxide
H187
Pyrazoles
41
H187
M323
M326
C104
C111
H186
Pyrazolium – anion
C104
– cation
C104
Pyrazolo[l,5-a]pyridine
H194
Pyrene
C96
U399
Pyridazine
C104
H187
– N-oxides
H187
M325
Pyridazines
M325
Pyridine
C104
C111
C160
H187
H243
M372
U400
U405
– N-oxide
C104
H187
M325
Pyridine-d5
C158
H241
U400
This page has been reformatted by Knovel to provide easier navigation.
Index Terms Pyridines – alkylsubstituted
Links 4
41
43
C108
H191
M324
42
Pyridinium ion
C104
2-Pyridone
M365
Pyridone derivatives
C105
H187
42
Pyrimidine
C104
Pyrones
H205
Pyrrole
C104
H187
M325
U400
C111
H186
M318
H189
I258
I259
U400 Pyrroles
41 M324
Pyrrolidine Pyrrolidines
C123 40
2-Pyrrolidone
M366
Pyrryl ketones
42
Pyruvic acid
H209
I292
Q Quadrupole relaxation
H207
Quinazoline
C110
H196
M327
Quinoline
C110
H195
U401
– N-oxide
H196
M325
Quinolines
43
44
M326
Quinones
14
35
C136
I289
I290
U397
C110
H196
M327
Retro-Diels–Alder reaction
M319
M360
Ribose
C152
Quinone oximes Quinoxaline
I288
I273
R
This page has been reformatted by Knovel to provide easier navigation.
Index Terms
Links
S Salicylaldehyde
I287
Salicylic acid
I292
– derivatives
43
Selenium compounds
C99
Selenacyclopentadiene
C104
H186
Serine
C149
H233
SH chemical shifts
H214
Silane
H228
Silanes
10
40
H228
I246
10
26
37
40
41
C73
C83
C99
C100
C101
C105
C106
C107
H171
H183
H228
I304
M369
H243
I310
I304 Silanols
H228
Silicon compounds
Siloxanes
I304
Silyl ethers
M369
Sinapinic acid
M382
M383
Sodium – propionate
H220
– tetraphenylborate
H232
Solvents
C157
H240
M371
U405
D-Sorbitol Spin quantum number
C117 2
Spiro[4,5]decane
C94
Spiro[5,5]undecane
C94
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Index Terms
Links
Steroids
C156
trans-Stilbene
U394
Styrene
I251
I257
U390
Succinic acid
C137
H221
I292
– anhydride
C142
H226
I299
Succinimide
C143
H227
I297
U403
Succinonitrile
C126
Sulfates
C131
Sulfides
3
7
8
9
32
33
36
41
45
62
C128
H215
I280
U386
– aliphatic
M350
– aromatic
M351
– cyclic
C129
– ethyl
39
– methyl
38
– vinyl
H215
U394
M351
I246
M350
Sulfinates
I281
Sulfinic acid esters
I281
Sulfinic acids
C131
H217
Sulfolane
C130
M377
3-Sulfolene
H216
Sulfonamides
I281
I282
– aromatic
M356
Sulfonates
38
– ethyl
38
Sulfones
40
I282
34
38
40
H216
I281
I282
– aliphatic
M353
– aryl
M354
C130
M355
This page has been reformatted by Knovel to provide easier navigation.
Index Terms
Links
Sulfones (Cont.) – cyclic
M354
– ethyl
38
Sulfonic acid esters
I282
M355
M356
Sulfonic acids
C131
H217
M355
Sulfonium salts
C130
H216
34
38
C130
H216
26
29
36
38
39
41
I273
I274
I278
I302
M323
M346
M347
U386
Sulfuric acid derivatives
C131
H217
Sulfurous acid derivatives
C131
H217
Sulfoxides
I281 – aliphatic
M352
– aryl
M352
Sulfur compounds
Suspension media IR
I311
T Telluracyclopentadiene Terephthalic acid
C104 I292
Tertiary alkylamides
H224
Testosterone
C156
Tetrabromoethylene
C115
Tetrabutylammonium ion
H208
Tetrabutylphosphonium iodide
C145
Tetrachloroethylene
C114
Tetraethylammonium ion
C121
H208
Tetraethylphosphonium iodide
C145
H229
Tetrahydrofuran-d8
C158
H241
This page has been reformatted by Knovel to provide easier navigation.
Index Terms Tetrahydrofurans 1,2,3,4-Tetrahydronaphthalene Tetrahydropyran
Links 40
C119
C160
H205
H243
I265
M371
U405
C94
C96
H181
42
C119
H205
43
44
Tetrahydrothiapyrane
M351
Tetrahydrothiophene
M351
1,1,2,3-Tetrahydroxypropane
C117
Tetralins
40
α-Tetralone
H220
Tetramethyl orthocarbonate
C120
H206
Tetramethylammonium ion
C121
H208
N,N,N',N′-Tetramethylethylenediamine
C122
Tetramethylgermane
C144
Tetramethyllead
C144
2,2,4,4-Tetramethyl-3-pentanone
C134
Tetramethylphosphonium iodide
C145
Tetramethylsilane
C144
N,N,N',N′-Tetramethylthiourea
C143
Tetramethyltin
C144
N,N,N',N'-Tetramethylurea
C143
Tetraphenylarsonium chloride
C147
Tetraphenylgermane
C144
Tetraphenyllead
C144
Tetraphenylsilane
C144
Tetraphenyltin
C144
Tetrapropylammonium ion
C121
Tetravinylsilane
C144
1,2,4,5-Tetrazine
C104
Tetrazole
C104
1,2,3-Thiadiazole
C104
1,2,5-Thiadiazole
H186
H232
H228
M372
This page has been reformatted by Knovel to provide easier navigation.
Index Terms
Links
Thiairane
C129
H215
Thiane
C129
H215
Thiazole
C104
H186
Thiethane
C129
H215
Thioacetals
8
Thioacetamide
C132
U403
Thioacetic acid
C132
H217
Thioacid – chlorides
I283
– fluorides
I283
Thioamides
4
C78
C132
Thioanisole
C129
H215
Thiobenzamide
C132
Thiocarbamides
4
C132
I283
Thiocarbonates
I284
I285
I302
Thiocarbonic acid derivatives
I283
I283
Thiocarbonyl – compounds
U386
– derivatives
I283
– groups
C132
Thiocarboxylate derivatives
H217
Thiocarboxylic acid O-esters
4
Thiocarboxylic acid S-esters
C132
H217
M357
4
C132
H217
H213
I278
Thiocarboxylic acids Thiocyanate
I279
Thiocyanate – anion
C127
– inorganic
U402
Thiocyanates
C127
– aliphatic
M346
– aromatic
M347
This page has been reformatted by Knovel to provide easier navigation.
Index Terms
Links
Thioesters
C132
H217
I283
M357
Thioethers
3
7
8
9
32
33
36
41
45
62
C128
H215
I280
U386
– aliphatic
M350
– aromatic
M351
– cyclic
C129
– ethyl
39
– methyl
38
– vinyl
H215
M351
I246
M350
Thioethylene ketals
44
Thioglycerol
M376
M379
Thioketones
4
C132
Thiolactams
I283
I283
Thiolane
C129
H215
– oxide
C130
H216
3
7
8
10
32
33
41
45
62
C128
H214
I280
H190
Thiols
U386 – aliphatic
M349
– aromatic
M349
Thiophenes
C104
C111
H186
I259
M323
U400
– alkylsubstituted
42
Thiophenol
U396
5H-Thiophen-2-one
H217
Thiophenoyl derivatives
43
2H-Thiopyran
H215
4H-Thiopyran
H215
This page has been reformatted by Knovel to provide easier navigation.
Index Terms Thiosulfonic acid ester
Links I282
Thioureas
C142
I284
1,4-Thioxane
C119
H205
Threonine
C149
H233
Thymidine
C154
H238
Thymine
C154
H237
C78
Tin compounds Toluene
I285
I303
C99
C105
C106
C107
C144
H171
C103
C160
H180
H243
I257
M372
U390
U394
U400
U405 p-Toluenesulfonates
M356
1,2,4-Triazine
H187
1,3,5-Triazine
C104
H187
1,2,3-Triazole
C104
C111
1,2,4-Triazole
C104
C111
1,2,5-Triazole
H186
1,3,4-Triazole
C104
1,1,1-Tribromoacetone
C135
1,1,1-Tribromoethane
C115
Tribromoethylene
C115
H186
Tributyl – phosphate
C145
– phosphite
C145
Tributylphosphine
C145
– oxide
C145
– sulfide
C146
Trichloroacetaldehyde
C133
Trichloroacetate ion
C137
Trichloroacetic acid
C114
1,1,1-Trichloroacetone
C135
I287 C137
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Index Terms
Links
1,1,1-Trichloroethane
C114
2,2,2-Trichloroethanol
C118
Trichloroethylene
C114
Trichloromethylsilane
H228
Trichloropropylsilane
C144
α,α,α-Trichlorotoluene
C114
H199
Triethanolamine
C122
M377
Triethoxyphosphine sulfide
H231
H203
Triethyl – orthoformate
C120
– phosphate
C145
– phosphite
H230
Triethylamine
C121
Triethylphosphine
H229
– oxide
H229
– sulfide
H230
Trifluoroacetates
H206
H208
U402
I296
Trifluoroacetic acid
C112
C137
1,1,1-Trifluoroacetone
C134
Trifluoromethane
C112
2,2,2-Trifluoroethanol
C118
Trifluoromethyl group
38
40
α,α,α-Trifluorotoluene
C113
H198
Trihydroxymethane
C117
Triiodomethane
C116
H198 M329
H201
Trimethyl – borate
H232
– orthoformate
C120
– phosphate
H231
– phosphite
C145
H230
Trimethylacetonitrile
C126
H212
H206
This page has been reformatted by Knovel to provide easier navigation.
Index Terms
Links
Trimethylamine
C121
Trimethylborane
C147
2,2,4-Trimethylpentane
U405
Trimethylphenylammonium ion
H209
Trimethylphosphine
H229
– sulfide
H230
Trimethylsilane
H228
Trimethylsilyl compounds
40
Trimethylsilyloxyl compounds
41
H208
3-(Trimethylsilyl)-1-propanesulfonate
C159
H242
2,2,3,3-D4-3-(Trimethylsilyl)–propionate
C159
H242
Trimethylsulfonium iodide
C130
H216
Trimethylvinylsilane
C144
H228
1,3,5-Trioxane
C120
Triphenybismuth
C147
Triphenyl – phosphate
C146
– phosphite
C146
Triphenylamine
C123
Triphenylantimony
C147
Triphenylarsane
C147
Triphenylmethanol
H203
Triphenylphosphine
C146
– oxide
C146
Tripropylamine
C121
Tris(dimethylamino) phosphite
H230
Tris(dimethylamino) phosphine
C145
1,3,5-Trithiane
H215
Trithiocarbonates
C142
H227
I285
I302
M322
M332
Tropylium ion
I283
I284
This page has been reformatted by Knovel to provide easier navigation.
Index Terms Tryptophan
Links C151
H235
Twistane
C94
Tyrosine
C150
H234
Ultramark
M374
M378
Unsaturated ketones
C135
Uracil
C154
H237
U404
Ureas
15
C143
H227
I301
12
14
C143
H227
I301
I302
U
I302 Urethanes – phenyl
43
Uridine
C154
UV/Vis spectroscopy
U385
V Valeraldehyde
C133
Valeric acid
C137
H221
δ-Valerolactam
C141
H225
δ-Valerolactone
C139
H223
Valeronitrile
C126
H212
Valine
C148
H233
– coupling
H166
H168
– glycols
M331
I276
Vicinal
Vinyl – acetate
H222
– alcohol
C118
– bromide
H200
– chloride
H199
– compounds
35
C83
This page has been reformatted by Knovel to provide easier navigation.
Index Terms
Links
Vinyl (Cont.) – ethers
I249
I250
– fluoride
C112
H198
– formate
H221
– iodide
H201
– isocyanate
C127
– isocyanide
H213
Vinylphosphine
C145
H213
M334
I278
W Water
I312
Water-d2
M371
H242
X Xanthates
I284
Xanthone
H197
Xylene
U405
Xylose
H236
I285
Z Zwitterions Zinc compounds
I309 H183
This page has been reformatted by Knovel to provide easier navigation.
1.1
Scope and Organization
1
1 Introduction
1.1 Scope and Organization The present data collection is intended to serve as an aid in the interpretation of molecular spectra for the elucidation and confirmation of the structure of organic compounds. It consists of reference data, spectra, and empirical correlations from 13C and l H nuclear magnetic resonance (NMR), infrared (IR), mass, and ultraviolet-visible (UV/vis) spectroscopy. It is to be viewed as a supplement to textbooks and specific reference works dealing with these spectroscopic techniques. The use of this book to interpret spectra only requires the knowledge of basic principles of the techniques, but its content is structured in a way that it will serve as a reference book also to specialists. Chapters 2 and 3 contain Summary Tables and Combined Tables of the most relevant spectral characteristics of structural elements. While Chapter 2 is organized according to the different spectroscopic techniques, Chapter 3 provides for each class of structural elements spectroscopic information obtained with various techniques. These two chapters should assist users that are less familiar with spectra interpretation to identify the classes of structural elements present in samples of their interest. The following four chapters cover data from 13C NMR, 'H NMR, IR, and mass spectroscopy, and are ordered exactly in the same manner by compound types. These cover the various skeletons (alkyl, alkenyl, alkynyl, alicyclic, aromatic, and heteroaromatic), the most important substituents (halogen, single-bonded oxygen, nitrogen, sulfur, and carbonyl), and some specific compound classes (miscellaneous compounds and natural products). Finally, a spectra collection of common solvents, auxiliary compounds (such as matrix materials and references) and commonly found impurities is provided for each method. Not only the strictly analogous order of the data but also the optical marks on the edge of the pages help fast cross-referencing between the various spectroscopic techniques. Although currently, UV/vis spectroscopy is only marginally relevant to structure elucidation, its importance might increase by the advent of high throughput analyses. Also, the reference data presented in Chapter 8 are useful in connection with optical sensors and the widely applied UV/vis detectors in chromatography and electrophoresis. Since a large part of the tabulated data either comes from our own measurements or is based on a large body of literature data, comprehensive references to published sources are generally not included. Whenever possible, the
2
1
Introduction
data refers to conventional modes and conditions of measurement. For example, unless the solvent is indicated, the NMR chemical shifts were determined usually with deuterochloroform or carbon tetrachloride as solvent. Likewise, the IR spectra were measured using solvents of low polarity, such as chloroform or carbon disulfide. Mass spectral data were recorded with electron impact ionization at 70 eV. While retaining the basic structure of the previous editions, numerous new entries have been added. Altogether, the amount of data has been more than doubled. The section on mass spectrometry (MS) is entirely new and contains a unique collection of fragmentation rules for the various compound classes. As a new feature, prototype IR spectra for each class of compounds schematically show the analytically relevant absorption bands. The Combination Tables of the earlier editions have been extended and arranged in two chapters, the first organized according to band positions and the second according to compound classes. The enclosed compact disc contains programs for estimating 13C and lH chemical shifts of organic compounds containing up to 15 non-hydrogen atoms. Both programs are available for Windows and Macintosh systems and require a Java environment for the graphical structure input. Technical details about the requirements and installation procedures are given in the corresponding ReadMe files. Extensive help files are available as part of the programs. In addition, the structure generator Assemble 2.0 (also limited to 15 non-hydrogen atoms) is available for Windows systems. Based on the molecular formula and available structural information, it is capable of generating all possible structural isomers. An extensive hypertext based tutorial describes its main features. It is especially recommended as a quality control tool to check if alternative solutions that also agree with the experimental data have gone unnoticed.
1.2
Abbreviations and Symbols
1.2 Abbreviations and Symbols al alk alken ar as ax comb d
aliphatic alkyl alkenyl aromatic asymmetric axial combination frequency doublet 6 IR: deformation vibration NMR: chemical shift DMSO dimethyl sulfoxide equatorial eq molar absorptivity E fragment Frag skeletal vibration Y geminal gem halogen hal in plane vibration iP coupling constant J molecular radical ion M+' mass to charge ratio m/Z fkquency V out of plane vibration OOP shoulder sh stretching vibration st symmetric SY TMS tetramethylsilane vicinal vic
3
2.1 General Tables
5
2 Summary Tables
2.1 General Tables 2.1. I
Calculation of the Number of Double Bond Equivalents from the Molecular Formula
General Equation:
2 + Z n i( v i - 2) double bond equivalents =
i
2
ni: number of atoms of element i in molecular formula vi: formal valence of element i
Short Cut:
For compounds containing only C, H, 0, N, S , and halogens, the following steps permit a quick and simple calculation of the number of double bond equivalents: 1. 0 and divalent S are deleted from the molecular formula 2 . Halogens are replaced by hydrogen 3. Trivalent N is replaced by CH 4. The resulting hydrocarbon, C,H,, is compared with the saturated hydrocarbon, CnHzn+2. Each double bond equivalent reduces the number of hydrogen atoms by 2: double bond equivalents =
2n+2-x 2
6
2 Summary Tables
2.1.2 Properties of Selected Nuclei
Isotope
1H 2H 3H 1OB 1lB
13c
I4N I5N 170
I9F 31P 33s 1 17sn
119sn 195Pt 199Hg 207Pb
Frequency Relative Relative Natural Spin abundane quantum [MHZ] at sensitivity sensitivity number, I 2.35 Tesla of nucleus at natural [%I abundance
99.985 0.015 0.000 19.58 80.42 1.108 99.635 0.365 0.037 100.000 100.000 0.76 7.61 8.58 33.8 16.84 22.6
112 1 112 3 312 112 1 112 512 112 112 312 112 112 112 112 112
100.0 15.4 106.7 10.7 32.1 25.1 7.3 10.1 13.6 94.1 40.5 7.6 35.6 37.3 21.5 17.8 20.9
Electric quadrupole moment [e x 10-24 cm21
1 1 9 . 6 ~ 1 0 - ~ 1 . 5 ~ 1 0 - ~2 . 8 ~ 1 0 - ~ 0 1.2 2 . 0 ~ 1 0 - ~3 . 9 ~ 1 0 - ~7 . 4 ~ 1 0 ' ~ 1 . 6 ~ 1 0 ' ~ 1.3~10-1 3 . 6 ~ 1 0 - ~ 1 . 6 ~ 1 0 - ~1 . 8 ~ 1 0 - ~ 1.0~10-3 1.0~10-3 1.9~10-2 1.0~10-3 3.8~10-6 2 . 9 ~ 1 0 - ~l . l ~ l O - -~2 . 6 ~ 1 0 ' ~ 8.3~10-1 8.3~10-1 6 . 6 ~ 1 0 - ~6 . 6 ~ 1 0 - ~ 2 . 3 ~ 1 0 - ~1 . 7 ~ 1 0 - -~6 . 4 ~ 1 0 - ~ 4 . 5 ~ 1 0 - ~3 . 4 ~ 1 0 - ~ 5.2x10-* 4 . 4 ~ 1 0 - ~ 9 . 9 ~ 1 0 - ~3 . 4 ~ 1 0 - ~ 5 . 7 ~ 1 0 - ~9 . 5 ~ 1 0 - ~ 9 . 2 ~ 1 0 - ~2 . l ~ l O - ~
2.2 13C NMR Spectroscopy
7
2.2 13C
NMR Spectroscopy
Summary of the Regions of Chemical Shifts, 6, for Carbon Atoms in Various Chemical Environments (6 in ppm relative to TMS. Carbon atoms are specified as follows: Q for CH3, T for CH2, D for CH, and S for C).
8
2 Summary Tables
2.2 13C NMR Spectroscopy
9
I3C Chemical Shifts for Carbonyl Groups ( 6 i n ppm relative to TMS) R -H -CH3 -CH2CH3 -CH(CH3)2 -C(CH3)3 -n-CgH17 -CH2Cl -CHC12 -CCl3 -cyclohexyl -CH=CH2 -CSH -phenyl
R -H -CH3 -CH2CH3 -CH(CH3 )2 -C(CH3)3 -n-CgH17 -CH2C1 -CHC12 -CCl3 -cyclohexyl -CH=CH2 -C
R-CHO 197.0 200.5 202.7 204.6 205.6 202.6 193.3 176.9 204.7 194.4 176.8 192.0
R-COOCH3 161.6 171.3 173.3 177.4 178.8 174.4 167.8 165.1 162.5 175.3 166.5 153.4 166.8
R-COCH3 200.5 206.7 207.6 21 1.8 213.5 207.9 200.1 193.6 186.3 209.4 197.5 196.9
R-CONH, 167.6 173.4 177.2 180.9 176.3 168.3
R-COOH 166.3 176.9 180.4 184.1 185.9 180.7 173.7 170.4 167.1 182.1 171.7 156.5 172.6
R-COO171.3 182.6 185.1
R-COOCO-R 158.5 167.4 170.3 172.8 173.9 169.4 162.1 157.6 154.1
R-COCl
177.3 168.3 169.7
188.6 183.1 175.9 171.8 167.6 185.4 174.5 177.6
170.4 174.7 178.0 180.3 173.8 167.7 165.5 176.3 165.6
162.8
168.O
10
2 Summary Tables
2.3 1H NMR Spectroscopy Summary of the Regions of Chemical Shifts f o r Hydrogen Atoms in Various Chemical Environments ( S i n ppm relative to TMS)
2.3 'H NMR Spectroscopy
11
12
2 Summary Tables
2.4 IR Spectroscopy
2.4 IR Spectroscopy Summary of the Most Important IR Absorption Bands
13
14
2 Summary Tables
Summary of IR Absorption Bands of Carbonyl Groups (in cm-1)
2.4 IR Spectroscopy
15
16
2 Summary Tables
2.4 IR Spectroscopy
17
2 Summary Tables
18
2. 5 Mass Spectrometry 2.5.1 Average Masses of Naturally Occurring Elements with Exact Masses and Representative Relative Abundances of Isotopes [ 1-31
Element Isotope
Mass
Abundance
Element Isotope
Mass
Abundance
1.00795a 1.007825 100b 2.014101 0.01 15 (in water)
Ne 20Ne 21Ne 22Ne
20.179ga 19.992402 loob 20.993847 0.30 21.991386 10.22 (in air)
He 3He 4He
4.002602a 3.016029 0.000137 4.002603 100 (in air)
Na 23Na
22.989769 22.989769
100
Li 6Li 7 ~ i
6.941a 6.015122 7.016004
8.2lC 100
M 2fMg 25Mg 26Mg
24.3051 23.985042 24.985837 25.982593
100 12.66 13.94
9Be
9.012182 9.012182
100
AI 27~1
26.981538 26.981538
100
1OB 1lB
10.812a 10.012937 11.009306
Si 28Si 3Osi
28.08W 27.976927 28.976495 29.973770
100 5.0778 3.3473
31P
30.973762 30.973762
100
32.067a 31.972071 32.971459 33.967867 35.967081
100 0.80 4.52 0.02
35.4528 34.968853 36.965903
100b 3 1.96
H
1H 2H
Be B
24.gb 100
13c
12.0108a 12.000000 13.003355
100 1.08
4N 15N
14.0067Y 14.003070 15.000109
100 0.369
C 12C
N
29si
P
S 32s 33s 34s
36s
180
15.9994a 15.994915 16.999132 17.999116
100 0.038 0.205
9F
18.998403 18.998403
100
0
160 170
F
c1 35~1 37~1
2.5 Mass Spectrometry
Element Isotope
Mass
Abundance
Ar 36Ar 38Ar 40Ar
39.948a 0.3379 35.967546 0.0635 37.962776 39.962383 100 (in air)
K
39.0983 38.963706 39.963999 40.961826
100 0.0125 7.2167
40.078 39.962591 41.958618 42.958769 43.955481 45.953693 47.952534
100 0.667 0.139 2.152 0.004 0.193
39K 40K 41K
Ca 4 0a ~
4% a 43~a 44~a 4 6a ~ 48~a
sc
Element Isotope 57Fe 58Fe
Mass
19
Abundance
56.935399 57.933280
2.309 0.307
c o 59c
58.93320Oa 58.933200 100
Ni 58Ni 6oNi 61Ni 62Ni 64Ni
58.6934 57.935348 59.930791 60.931060 61.928349 63.927970
100 38.5198 1.6744 5.3388 1.3596
cu 63cu 65cu
63.546 62.929601 64.927794
100 44.57
Zn 64~n 66Zn 67~n 68Zn 70~n
65.39 63.929147 65.926037 66.927131 67.924848 69.925325
100 57.37 8.43 38.56 1.27
45sc
44.9559 10 44.955910
100
Ti 46Ti 47Ti 48Ti 49Ti 50Ti
47.867 45.952629 46.95 1764 47.947947 48.947871 49.944792
11.19 10.09 100 7.34 7.03
Ga 69Ga 71Ga
69.723 68.925581 70.924705
100b 66.367
V 51v
50.9415 49.947 163 50.943964
0.250 100
Cr 50cr 52cr 53cr 54~r
5 1.9962 49.946050 5 1.940512 52.940654 53.938885
Ge 70Ge 72Ge 73Ge 74Ge 76Ge
72.61 69.924250 71.922076 72.923459 73.921178 75.921403
56.44 75.91 21.31 100 20.98
5.187 100 11.339 2.823
AS
75As
74.921596 74.921596
100
Mn 55Mn
54.938050 54.938050
100
Fe 54Fe 56Fe
55.845 53.939615 55.934942
6.370 100
Se 74se 76s e 77se 78se 80s e 82Se
78.96 73.922477 75.919214 76.919915 77.917310 79.916522 81.916700
1.79 18.89 15.38 47.91 100 17.60
5%
2 Summary Tables
20
Element Isotope
Br 79Br 81Br
Kr 78Kr 8oKr 82Kr 83Kr 84Kr 86Kr
Rb
Mass
Abundance
79.904 78.918338 80.916291
100 97.28
83.80 77.920387 0.61b 79.916378 4.00 81.913485 20.32 82.914136 20.16 83.911507 100 85.910610 30.35 (in air)
85Rb 87Rb
85.4678 84.911789 86.909183
100 38.56
Sr 84sr 8% r 87~r 88Sr
87.62a 83.913425 85.909262 86.908879 87.905614
0.68 11.94 8.48 100
Y 89Y
88.905848 88.905848
Zr 90~r 91~r 92~r 94~r 96~r
91.224 89.904704 90.905645 91.905040 93.906316 95.908276
100 21.81 33.33 33.78 5.44
Nb
92.906378 92.906378
100
93Nb
Mo 9 2 ~ 0 94Mo
95.94 91.906810 93.905088 9 5 ~ 94.905841 ~ 9 6 ~ 0 95.904679 9 7 ~96.906021 ~ 9 8 ~ 0 97.905408 99.907478 O0M o
100
61.50 38.33 65.98 69.13 39.58 100 39.91
Element Isotope
Ru 96Ru
Mass
Abundance
101.07 95.907599 97.905288 98.905939 99.904229 100.905582 101.904350 103.905430
17.56 5.93 40.44 39.94 54.07 100 59.02
lo3Rh
102.905504 102.905504
100
Pd lo2Pd 04Pd 05Pd 06Pd 08Pd l0Pd
106.42 101.905608 103.904036 104.905084 105.903484 107.903894 109.905151
3.73 40.76 81.71 100 96.82 42.88
AS lo Ag lo9Ag
107.8682 106.905094 108.904756
100 92.90
Cd lo6Cd lo8Cd l0Cd ll1Cd 12Cd 13Cd 14Cd 16Cd
112.412 105.906459 107.904184 109.903006 110.904182 111.902757 112.904401 113.903358 115.904755
4.35 3.10 43.47 44.55 83.99 42.53 100 26.07
114.818 11 3 1 ~ 112.904061 114.903879 11%
4.48 100
98Ru 99Ru lo0Ru lolRu lo2Ru lo4Ru
Rh
*
In
Sn 1123, 114~5, 115~11 116sn 117sn 11*Sn
118.711 111.904822 113.902782 114.903346 115.901744 116.902954 117.901606
2.98 2.03 1.04 44.63 23.57 74.34 (contd.)
2.5 Mass Spectrometry
Element Isotope
Mass
Abundance
119sn 12OSn 1218, 1248,
118.903309 26.37 119.902197 100 121.903440 14.21 123.905275 17.77
Sb 121Sb 123Sb
121.760 120.903818 100 122.904216 74.79
Te 20Te 22Te 23Te 24Te 25Te 26Te 128Te 30Te
127.60 0.26 119.904021 7.48 121.903047 2.61 122.904273 123.902819 13.91 124.904425 20.75 125.903306 55.28 93.13 127.904461 129.906223 100
I
126.904468 126.904468 100
1271
Xe 124xe 126Xe 128Xe 129xe 130x2, 131xe 132xe 134xe 136xe
cs
131.29 0.33b 123.905896 0.33 125.904270 7.14 127.903530 128.904779 98.33 129.903508 15.17 130.905082 78.77 13 1.904154 100 133.905395 38.82 135.907221 32.99
133cs
132.905447 132.905447 100
Ba 130Ba 132Ba 134Ba 135Ba 136Ba 137Ba 138Ba
137.328 0.148 129.906311 0.141 131.905056 3.371 133.904503 9.194 134.905683 135.904570 10.954 136.905821 15.666 137.905241 100
Element Isotope
Mass
Abundance
La
138.9055 1 3 8 ~ a 137.907107 0.090 1 3 9 ~ a 138.906348 100
Ce 136ce 138ce 140ce 142ce
140.116 0.209 135.907145 0.284 137.905991 139.905434 100 141.909240 12.565
Pr 141Pr
140.907648 140.907648 100
Nd
144.24 141.907719 100 142.909810 44.9 143.910083 87.5 144.912569 30.5 145.913112 63.2 147.916889 21.0 149.920887 20.6
142Nd 143Nd 44Nd 145Nd 146Nd 148Nd 150Nd
Sm 144srn 147srn 1488, 149srn
150.36 11.48 143.911995 146.914893 56.04 147.914818 42.02 148.917180 5 1.66 149.917271 27.59 150sm 151.919728 100 152srn 1 5 4 ~ m 153.922205 85.05
Eu 151Eu 153Eu
151.964 150.919846 91.61 152.921226 100
Gd 152Gd 154Gd 155Gd 156Gd 157Gd ls8Gd 60Gd
157.25 151.919788 0.81 153.920862 8.78 154.922619 59.58 155.922120 82.41 156.923957 63.00 157.924101 100 159.927051 88.00
Tb 159Tb
158.925343 158.925343 100
21
22
2 Summary Tables
Element
Element Isotope
D? 6Dy 158Dy 160Dy 161Dy
162Dy 163Dy 164Dy
Ho 165130
Er 162Er 164Er 166Er
167Er 168Er 70Er
Tm l69Trn
Mass
Abundance
162.50 155.924279 0.21 157.924405 0.35 159.925194 8.30 160.926930 67.10 161.926795 90.53 162.928728 88.36 163.929171 100 164.930319 164.930319
100
167.26 161.928775 0.42 163.929197 4.79 165.930290 100 166.932045 68.22 167.932368 79.69 169.935460 44.42 168.934211 168.934211 100
Isotope 181Ta
168Yb 7oY b 171Yb 72Yb 173Yb 174Yb 176Yb
Lu 175Lu 176Lu
173.04 167.933894 0.41 169.934759 9.55 170.936322 44.86 171.936378 68.58 172.938207 50.68 173.938858 100 175.942568 40.09 174.967 174.940768 175.942682
100 2.66
177Hf 17*Hf
79Hf l8OHf
Ta 80Ta
178.49 173.940040 0.46 175.94 1402 14.99 176.943220 53.02 177.943698 77.77 178.944815 38.83 179.946549 100 180.9479 179.947466
0.40 86.49 46.70 100 93.79
Re 185Re 187Re
186.207 184.952956 186.955751
os
190.23 183.952491 0.05 185.953838 3.90 186.955748 4.81 187.955836 32.47 188.958145 39.60 189.958445 64.39 191.961479 100
1840, 1860, 1870, 1880s 1890, 1900, 1920,
1911, 1931,
Pt 190Pt 192Pt 194Pt 195Pt 196Pt 198Pt
Au
H% l9 Hg 198Hg 199Hg 2ooHg 201Hg
202Hg 204Hg 0.012
180.947996 100
183.84 180w 179.946707 182w 181.948206 1 8 3 ~ 182.950224 184w 183.950933 186w 185.954362
197Au
Hf 174Hf 176Hf
Abundance
W
Ir Yb
Mass
59.74 100
192.217 190.960591 59.49 192.962924 100 195.078 189.959931 0.041 191.961035 2.311 193.962664 97.443 194.964774 100 195.964935 74.6 10 197.967876 21.172 196.966552 196.966552 100 200.59 195.965815 197.966752 198.968262 199.968309 200.970285 201.970626 203.973476
0.50 33.39 56.50 77.36 44.14 100 23.00
2.5 Mass Spectrometry
Element Isotope
Mass
Abundance
T1 203Tl 205Tl
204.3833 202.972329 204.974412
Pb 204Pb 206Pb 207Pb 208Pb
207.2a 203.973029 205.974449 206.975881 207.976636
Element Isotope Bi
41.892 100 2.7 46.0 42.2 100
Mass
23
Abundance
209Bi
208.980383 208.980383
100
Th 232Th
232.038050 232.038050
100
U
238.0289 234.040946 235.043923 238.050783
0.0055d 0.73 100
234U 235U 238U
a Natural variations in the isotopic composition of terrestrial material does not allow to give a more precise value. Commercially available materials may have substantially different isotopic compositions if they were subjected to undisclosed or inadvertent isotopic fractionation. Materials depleted in 6Li are commercial sources of laboratory shelf reagents and are known to have 6Li abundances in the range of 2.0007-7.672 atom percent, with natural materials at the higher end of this range. Average atomic masses vary between 6.939 and 6.996; if a more accurate value is required, it must be determined for the specific material. Materials depleted in 235U are commercial sources of laboratory shelf reagents.
2 Summary Tables
24
2.5.2 Ranges of Natural Isotope Abundances of Selected Elements
El em ent Isotope
Range (atom %)
H 1H 2H
99.9816-99.9975 0.0184-0.0025
E 1em en t Isotope Si 28Si 29s i 3Osi
He ~ 1 3He 4 . 6 10-8-0.004 100-99.9959 4He
S 32s
Li
33s 34s
6Li 7 ~ i
7.21-7.71 92.79-92.29
B 1OB 1lB
C 12C 13c
18.927-20.337 8 1.073- 79.663 98.85-99.02 1.15-0.98
N 4N 15N
99.890-99.652 0.41 1-0.348
0 160 99.7384-99.7756 0.0399-0.0367 170 0.2217-0.1877 '80
Ne 2oNe 21Ne 22Ne
90.514-88.47 1.71-0.266 9.96-9.20
36s
Range (atom %) 92.21-92.25 4.694.67 3.10-3.08
94.537-95.261 0.787-0.73 1 4.655-3.993 0.02 1-0.015
c1 35c 1 37c 1
75.64-75.86 24.36-24.14
Element Isotope
Ce 13ke 0.186-0.185 138Ce 0.254-0.251 40Ce 88.449-88.446 142Ce 11.114-1 1.114
Nd 42Nd 143Nd 144Nd 145Nd 46Nd 148Nd 150Nd
Ca 4 0a ~ 96.982-96.880 4 2a ~ 0.656-0.640 0.146-0.13 1 43ca 4 4 ~ a 2.130-2.057 4 6 a ~ 0.0046-0.003 1 4 8a ~ 0.200-0.179
Hf
V
Pb
5ov
204Pb 206Pb 207Pb 208Pb
0.2502-0.2487 lV 99.75 13-99.7498
cu 63Cu 65Cu
69.24-68.98 3 1.02-30.76
Sr 84~r
8% r 87sr
88Sr
0.58-0.55 9.99-9.75 7.14-6.94 82.75-82.29
Range (atom %)
174Hf 176Hf 177Hf 78Hf 179Hf 80Hf
27.30-26.80 12.32-12.12 23.97-23.795 8.35-8.23 17.3 5- 17.06 5.78-5.66 5.69-5.53 0.1621-0.1619 5.271-5.206 18.606-18.593 27.297-27.278 13.630-1 3.619 35.100-35.076 1.65-1.04 27.48-20.84 23.65- 17.62 56.21-51.28
U 234U 0.0059-0.0050 235U 0.7202-0.7198 238U 99.2752-99.2739
Next Page 2.5 Mass Spectrometry
25
2.5.3 Isotope Patterns of Naturally Occurring Elements
The mass of the most abundant isotope is given under the symbol of the element. The lightest isotope is shown at the left end of the x axis.
Previous Page 26
2 Summary Tables
2.5.4 Calculation of Isotope Distributions The characteristic abundance patterns resulting from the combination of more than one polyisotopic element can be calculated from the relative abundances of the different isotopes. The following polynomial expression gives the isotope distribution of a polyisotopic molecule:
where pix is the relative abundance of the xth isotope of element i, the mass of the xth isotope of the element i is given by mix, and the exponent ni stands for the number of atoms of the element i in the molecule. The expansion of this polynomial expression after inserting the pix and mix values for all the isotopes 1, 2, 3, ... of the elements i, j, ... of a given molecule yields an expression that represents the isotope distribution:
wo Ao
+ w rA' + w s AS + w tA t + ...
where the values of W O , w r ,w s ,wt,... are the relative abundances of M+', [M+rl+', [M+sl+', [M+t]+', ..., respectively. The use of A(mix mil) allows to determine the values of r, s, t,. .. simply by expanding the general polynomial. A numerical value for A, which has no intristic meaning, is never needed. For example, for CBr2C12, the above equation gives rise to the following expression:
For sufficient resolution, (mix - mil) and (mjx - mjl) differ from one another. This results in very complex isotope patterns even for very small molecules. Thus, owing to the occurrence of 12C, 13C, 79Br, 81Br, 35Cl, and 37Cl, there are 18 signals for CBr2Clz. However, the limited resolution of most real life experiments makes many pairs of (mix - mil) and (mj, - m j l ) indistinguishable within experimental error, significantly reducing the number of separate peaks. For example, at unit resolution, one obtains ( " 8 1 ~-~m79Br) = (~7237~1 - m35~1)= 2. Consequently, the expression for BrCl becomes:
2.5 Mass Spectrometry 0
(P79Br A +P81Br A P79BrP35C1 A
2
1
b35C1
+p37C1 A 2 ) 2
0 +
27
=
b79Br P37C1 +P81Br P35C1) A +P37C1 P81Br A
4
This shows that at unit resolution, BrCl gives rise to only 3 peaks (M+', [M+2]+', [M+4]+') rather than to 4 peaks, as they are expected for very high resolution. Often, the contribution of isotopes of low abundance can be neglected without sacrificing much precision. For example, the effect of 2H on isotope patterns is usually insignificant. Also, 13C is often negligible when focussing on peaks of the series [M+2n]+', which then results in patterns that are characteristic for halogens, sulfur, and silicon. In large molecules, however, isotopes of low abundance cannot be neglected. For example, in the case of buckminster fullerene ( C ~ O )not , only M+' (relative intensity, 100%) and [M+l]+' (66.72%) but also [M+2]+' (21.89%), [M+3]+' (4.71%), and even [M+4]+' (0.75%) are quite significant ions. As shown above, typical isotope patterns can be readily calculated manually by applying the general equation and neglecting isotopes of low abundance. The outlined procedure can also be easily implemented and evaluated with generic computer software that allows simple calculations. Dedicated and user-friendly programs that already contain the necessary isotope abundances and masses are available. Incidentally, because the use of the above equation for systems with 1000 or more polyisotopic atoms results in excessive calculation times, more efficient but somewhat more complicated algorithms have been developed for implementation in dedicated programs [4]. Typical isotope patterns are given on the following pages.
28
2 Summary Tables
2.5.5 Isotopic Abundances of Various Combinations of Chlorine, Bromine, Sulfur, and Silicon
Elements
Mass Relative Eleabunments dance
Mass Relative Eleabunments dance
35 37
100 3 1.98
79 81
100 S1 97.88
70 72 74
100 63.96 10.23
158 160 162
5 1.09 s2 100 48.93
105 107 109 111
100 95.93 30.67 3.27
237 239 24 1 243
140 142 144 146 148 175 177 179 181 183 185 210 212 214 216 218 220 222 28 29 30
77.96 100 47.82 10.19 0.82 62.53 100 63.94 20.45 3.28 0.21 52.12 100 79.95 34.08 8.21 1.05 0.06
316 318 320 322 324 395 397 399 40 1 403 405 474 476 478 480 482 484 486 56 57 58 59 60
100
5.06 3.36
34.05 s3
100
97.89 3 1.94 17.40 s4 68.09 100 65.26 15.96 10.43 s5 5 1.09 100 97.94 47.89 9.38 5.32 s6 3 1.26 76.62 100 73.38 28.73 4.68 100 Si3 10.13 6.98 0.34 0.11
Mass Relative abundance 32 33 34 64 65 66 68 96 97 98 99 100 128 129 130 131 132 160 161 162 163 164 166 192 193 194 195 196 198
100 0.79 4.43 100 1.58 8.87 0.24 100 2.37 13.31 0.21 0.66 100 3.16 17.76 0.42 1.27 100 3-94 22.22 0.70 2.08 0.1 1 100 4.73 26.68 1.05 3.09 0.20
84 85 86 87 88
100 15.19 10.85 1.03 0.36
2.5 Mass Spectrometry
Elements CllBrl
Mass Relative Elements abundance 114 76.70 CllBr2 100 116 24.46 118 351 353 355 357 359 36 1 184 186 188 190 192
14.26 C12Brl 60.41 100 79.93 30.39 4.25 51.12 C13Br2 100 65.22 17.73 1.74
C14Br2
298 300 302 304 306 308 310
24.14 C14Br3 78.63 100 63.54 21.54 3.73 0.26
Cl l S l
67 68 69 70 71
100 CllS2 0.79 36.41 0.25 1.44
C12S2
134 135 136 137 138 139 140
100 c13s 1 1.58 72.82 1.08 16.14 0.21 1.06
CllBr4
C13Brl
29
Mass Relative Eleabunments dance 193 43.83 C11Br3 195 100 197 69.83 199 13.66 149 151 153 155
263 265 267 269 27 1 273 377 379 381 383 385 387 389 391 99 100 101 102 103 137 138 139 140 141 142 143 145
Mass Relative abundance 272 26.15 274 85.22 276 100 278 48.90 280 7.86 38.35 61.35 C12Br2 228 230 100 100 232 89.63 45.67 234 31.89 6.38 236 3.90 3 1.35 C14Brl 219 22 1 92.01 223 100 225 50.01 227 11.70 229 1.03 13.63 C14Br4 456 458 57.78 460 100 462 91.19 464 47.13 466 14.03 468 2.22 470 0.13 c12s1 102 100 103 1.58 104 40.85 105 0.57 106 3.08 108 99.64 Cl3S2 169 170 0.79 171 100 172 0.75 173 34.82 174 0.24 175 4.63 177 0.15
43.79 100 83.86 33.42 6.93 0.48 7.43 38.40 83.70 100 7 1.37 31.11 8.10 1.16 100 0.79 68.39 0.50 13.08 0.47 95.42 1.51 100 1.51 37.62 0.53 5.94 0.35
2 Summary Tables
30
Elements CllSil
Mass Relative Elements abundance 63 64 65 66 67
C12Sil 100 5.06 35.34 1.62 1.07
Mass Relative Elements abundance 98 99 100 101 102 103 104
C13Sil 100 5.06 67.32 3.24 12.38 0.52 0.34
Mass Relative abundance 133 134 135 136 137 138 139
100 5.06 99.30 4.86 33.90 1.55 4.30
2.5.6 Isotope Patterns of Combinations of CI and Br Signals separated by 2 units
-
160
239
320
399
The signals are separated by 2 mass units, and the combination of the lightest isotopes is given on the left side of the x axis. The mass for the most abundant signal is shown under the symbol of the element. See Chapter 2.5.5 for exact abundances of many of these combinations.
2.5 Mass Spectrometry
31
2.5.7 Indicators of the Presence of Heteroatoms
In low-resolution mass spectra, one often observes characteristic isotope patterns, specific masses of fragment ions, and characteristic mass differences (Am) between the molecular ion (M+') and fragment ions (Frag+), or between fragment ions. High resolution mass spectra can be used to confirm the elemental composition provided that the resolution is sufficient to discriminate alternative compositions. Moreover, tandem mass spectrometry (also called MS/MS) may be used to identify heteroatom-characteristiclosses from parent or fragment ions. Indication of 0: Am 17 from M+', in N-free compounds Am 18 from M+' Am 18 from Frag+, particularly in aliphatic compounds Am 28, 29 from M+' for aromatic compounds Am 28 from Frag+ for aromatic compounds mtz 15, relatively abundant mtz 19 mtz 31, 45, 59, 73 ,... + (14), mtz 32, 46, 60, 74 ,... + (14), mtz 33, 47, 61, 75 ,... + (14), for 2 x 0, in absence of S mtz 69 for aromatic compounds meta-disubstituted by oxygen Indication of N: M+' odd-numbered (indicates odd number of N in M+') Large number of even-numbered fragment ions Am 17 from M+' or Frag+, in O-free compounds Am 27 from M+' or Frag+, for aromatic compounds or nitriles Am 30,46 for nitro compounds mtz 30, 44, 58, 72,. , . + (14), for aliphatic compounds
Indication of S : Isotope peak [M+2]+' 2 5% M+' Am 33, 34, 47, 48, 64, 65 from M+' Am 34, 48, 64 from Frag+ mtz 33,34,35 mtz 45 in O-free compounds m/z 47, 61, 75, 89,... + (14), unless compound with 2 x 0 mtz 48, 64 for S-oxides
Indication of F: Am 19, 20, 50 from M+' Am 20 from Frag+ mtz 20 mtz 57 without mtz 55 in aromatics
Indication of C1: Isotope peak [M+2]+' 2 33% M+' Am 35, 36 from M+' Am 36 from Frag+ d z 35/37, 36/38, 49/51
32
2 Summary Tables
Indication of Br: Isotope peak [M+2]+' 2 98% M+' Am 79, 80 from M+' Am 80 from Frag+ m/z 79/81, 80182
Indication of I:
Isotope peak [M+l]+ of very low abundance at relatively high mass Am 127 from M+' Am 127, 128 from Frag+ mlz 127, 128, 254
Indication of P: m/z 47 in compounds free of S or 2 x 0 m/z 99 without isotope peak at m/z 1 0 0 in alkyl phosphates
2.5 Mass Spectrometry
33
2.5.8 Rules for Determining the Relative Molecular Weight (Mr)
The molecular ion (M+') is defined as the ion that comprises the most abundant isotopes of the elements in the molecule. Interestingly, the lightest isotopes of most elements that frequently occur in organic compounds and their common salts (H, C, N, 0, F, Si, P, S, C1, As, Br, I, Na, Mg, Al, K, Ca, Rb, Cs) are also the most abundant ones. Notable exceptions are B, Li, Se, Sr, and Ba. M+' is always accompanied by isotope peaks. Their relative abundance depends on the number and kind of the elements present and their natural isotopic distribution. The abundance of [M+'+l] indicates the maximum number of carbon atoms (C), according to the following relationship: Cmax = 100 [M+'+l] / (1.1 [M"]) [Mf'+2] and higher masses indicate the number and kind of elements that have a relatively abundant isotope two mass units heavier (such as S, Si, C1, Br). M+' is always an even number if the molecule contains only elements for which the atomic mass and valence are both even-numbered or both odd-numbered (such as H, C, 0, S, Si, P, F, Cl, Br, I). In the presence of other elements, M+' becomes an odd number unless the elements are present in an even number (this holds for N, 13C, 2H). M+' can only form fragment ions of masses that differ from that of the molecular ion by chemically logical values (Am). In this context, chemically illogical differences are Am = 3 (in the absence of Am = 1) to Am = 14, Am = 21 (in the absence of Am = 1) to Am = 24, Am = 37, 38 and all Am less than the mass of an element of characteristic isotope pattern in cases where the same isotope pattern is not retained in the fragment ion. M+' of a compound must contain all elements (and the maximum number of each) that are shown to be present in the fragment ions. If ionization is performed by electron impact, M+' is the ion with the lowest appearance potential. If a pure sample flows into the ion source through a molecular leak, M+' exhibits the same effusion rate as can be determined from the fragment ions. The abundance of M+' is proportional to the sample pressure in the ion source. For polar compounds, [M+H]+ is often observed in mass spectra obtained not only with fast atom bombardment and atmospheric pressure chemical ionizaton but also with electron impact ionization. In this latter case, the abundance of [M+H]+ changes in proportion to the square of the sample pressure in the ion source. In the absence of a signal for M+', the molecular weight must have a value that shows a logical and reasonable mass difference, Am, to all the observed fragment ions.
34
2 Summary Tables
2.5.9 Homologous Mass Series as Indications of Structural Type
Certain sequences of intensity maxima in the lower mass range and the masses of unique signals are often characteristic of a particular compound type. The intensity distribution of such ion series is in general smooth. Therefore, abrupt changes (maxima and minima) are of structural significance. The ion or ion series that is most indicative of a particular compound type is set in italics. Mass Elemental values m/z composition
Compound types
12 + 14m CnH2n-2
alkenes, monocycloalkanes,alkynes, dienes, cycloalkenes, polycyclic alicyclks, cyclic alcohols
13 + 14m CnH2n-1
alkanes, alkenes, monocycloalkanes, alkynes, dienes, cycloalkenes, polycyclic alicyclics, alcohols, alkyl ethers, cyclic alcohols, cycloalkanones, aliphatic acids, esters, lactones, thiols, sulfides, glycols, glycol ethers, alkyl chlorides
CnH2n-30 1 4 + 14m CnH2,
cycloalkanones
CnH2n-20 14m CnH2n+l
cycloalkanones
15 +
alkanes, alkenes, monocycloalkanes,polycyclic alicyclics, alcohols, alkyl ethers, thiols, sulfides, alkyl chlorides
alkanes, alkenes, monocycloalkanes, alkynes, dienes, cycloalkenes, polycyclic alicyclics, alkanones, alkanals, glycols, glycol ethers, alkyl chlorides, acid chlorides
alkanones, alkanals, cyclic alcohols, acid chlorides alkanones, alkanuls alkyl amines, aliphatic amides
aliphatic amides alcohols, alkyl ethers, aliphatic acids, esters, lactones, glycols, glycol ethers
aliphatic acids, esters, lactones aliphatic acids, esters, lactones
2.5 Mass Spectrometry
Mass Elemental values d z composition
Compound types
19 + 14m
alcohols, alkyl ethers aliphatic acids, esters, lactones glycols, glycol ethers thiols, sulfides
20 + 14m
alkylbenzenes glycols, glycol ethers thiols, sulfides
21 + 14m
alkylbenzenes aryl ketones alkyl chlorides acid chlorides
22 + 14m
alkylanilines polycyclic alicyclics
23 + 14m
polycyclic alicyclics
24
+ 14m
polycyclic alicyclics
25
+ 14m
alkynes, dienes, cycloalkenes, polycyclic alicyclics
39, 52+1, 64+ 1, 76+2, 91+1
alkylbenzenes,aromatic hydrocarbons, phenols, aryl ethers, aryl ketones
35
2 Summary Tables
36
2.5.10 Mass Correlation Table
Note: As long as it makes sense chemically, CH2, CH4, CH30, and 0 2 in the formulae of the second column may be replaced by N, 0, P, and S , respectively (M: molecular mass). Mass Ion
1
7
Li+'
Product ion and composition of the neutral particle lost
Substructure or compound type
[M+l]+, [M-11-
particularly in FAB spectra, in which M-cl occurs even for moderately basic and acidic compounds, but intensive M+' without M-cl is unusual
[M+7]+
in FAB spectra in the presence of Li+ in FAB spectra of organic Li+ salts
134-71-
12 13
14 15 16
O",
NH2+,
[M-
nonspecific; abundant: methyl, N-ethylamines
[M-
methyl (rare) nitro compounds, sulfones, epoxides, N-oxides primary amines
02++
17
OH', "3'
("3)
18
[M-181''
(H2O)
acids (especially aromatic acids), hydroxylamines,Noxides, nitro compounds, sulfoxides, tertiary alcohols primary amines nonspecific; abundant: alcohols, some acids, aldehydes, ketones, lactones, cyclic ethers 0 indicator
2.5 Mass Spectrometry
37
Mass Ion
Product ion and composition of the neutral particle lost
19
H3O+,F+
[M-19]+'
(F)
fluorides
F indicator
20
HF+', Ar++, CH2CN"
[M-20]+ '
(HF)
fluorides
F indicator
22
c02++
23
Na+'
[M+23]+
[M-23]-
Substructure or compound type
in FAB spectra in the presence of Na'; sometimes strong even if Na' is only an impurity in FAB spectra of organic Na' salts
terminal acetylenyl aromatics nitriles terminal vinyl, some ethyl esters and N-ethylamides, ethyl phosphates aromatic N, nitriles nonspecific; abundant: cyclohexenes, ethyl esters, propyl ketones, propyl-substituted aromatics aromatic 0, quinones, lactones, lactams, unsaturated cyclic ketones, allyl aldehydes diazo compounds; air (intensity 3.7 times larger than for 02+', m/z 32) nonspecific; abundant: ethyl phenols, furans, aldehydes
2 Summary Tables
38
Mass Ion
Product ion and composition of the neutral particle lost
Substructure or compound type
30
ethylalkanes, polymethyl compounds cyclic ethers, lactones, primary alcohols nitro and nitroso compounds
31
methyl esters, methyl ethers, primary alcohols N-methylamines hydrazides
32
cyclic peroxides; air (intensity 3.7 times smaller than for N2+', m/z 28) methyl esters, methyl ethers sulfides (together with isotope signal for 34s)
33
CH30H2+, SH', CH2F'
34
SH2"
[M-33]+'
(SH)
(OH + OH)
35
SH3+, C1+
36
HCl",
37
C3H' 37c1+
C3'
nonspecific (together with isotope signal for 34s) S indicator nonspecific; 0 indicator fluoromethyl nonspecific (together with isotope signal for 348) S indicator nitro compounds
(Cl)
chloro compounds (together with isotope signal for 37C1)
(OH + H20)
nitro compounds 2 x 0 indicator
[M-35]+'
[M-361''
(HC1) (H20 + H20)
chloro compounds 2 x 0 indicator chloro compounds (together with isotope signal for 3%1)
2.5 Mass Spectrometry
Mass Ion
38
C3H2+'
39
C3H3+ K+
39
Product ion and composition of the neutral particle lost
Substructure or compound type
[M-39]+' (C3H3) [M+39]+
aromatics in FAB spectra in the presence of K+; sometimes strong even if K+ is only an impurity in FAB spectra of organic Kf salts
[M-39]40
cyanomethyl 41
alicyclics (especially polyalicyclics), alkenes 2-methyl-N-aromatics, N-methylanilines
42
nonspecific; abundant: propyl esters, butyl ketones, butylaromatics, methylcyclohexenes acetates (especially enol acetates), acetamides, cyclohexenones, a$-unsaturated ketones
43
[M-43]+' (C3H7)
44
(contd.)
nonspecific; abundant: propyl, alicyclics, cycloalkanones, cycloalkylamines, cycloalkanols, butylaromatics methyl ketones, acetates, aromatic methyl ethers propylalkanes N,N-dimethylamines, N-ethylamines cycloalkanols, cyclic ethers, ethylene ketals, aliphatic aldehydes (McLaffem rearrangement)
2 Summary Tables
40
Mass Ion
Product ion and composition of the neutral particle lost
Substructure or compound type anhydrides, lactones, carboxylic acids
44 45
C2H50+, C2H7N+', CHS' (together with isotope signal for 34s) 0 indicator S indicator
ethyl esters, ethyl ethers, lactones, ethyl sulfonates, ethyl sulfones carboxylic acids N,N-dimethylamines, N-ethylamines
46
C~HSOH", N02+
ethyl esters, ethyl ethers, ethyl sulfonates primary alcohols carboxylic acids nitro compounds
47
CH3S+, C C P , C~HSOH~', CH(OH)2+, PO+ 2 x 0 indicator S indicator P indicator
methyl sulfides (together with isotope signal for 3%)
48
CH3SH+', CHCl+', SO+'
methyl sulfides sulfoxides, sulfones, sulfonates (together with isotope signal for 34s)
49
[M-49]+' (CH2C1)
chloromethyl (with corresponding signal for 37Cl)
50
[M-50]+'
trifluoromethylaromatics, perfluoroalicyclics
51
52 53
(CF2)
2.5 Mass Spectrometry
Mass Ion
Product ion and composition of the neutral particle lost
41
Substructure or compound type
54
cyclohexenes cyanoethyl
55
nonspecific; abundant: alicyclics, butyl esters, N-butylamides
56
butyl esters, N-butylamides, pentyl ketones, cyclohexenes, tetralins, pentylaromatics methylcyclohexenones, p-tetralones
57
nonspecific ethyl ketones
58
alkanes a-methylalkanals, methyl ketones, isopropylidene glycols
59
propyl esters, propyl ethers methyl esters amines, amides
60
propyl esters, propyl ethers acetates methyl esters
61 glycols, ethylene ketals ethyl sulfides (together with isotope signal for 343)
62
methoxymethyl ethers, ethylene glycols, ethylene ketals ethyl sulfides (together with isotope signal for 3%)
2 Summary Tables
42
Mass Ion
Product ion and composition of the neutral particle lost
63
[M-63]+' (C2H4C1) chloroethyl (CO + Cl) acid chlorides
64
CgH4+', SO,", S2+'
[M-64]+'
(SO2) (S2)
Substructure or compound type
sulfones, sulfonates disulfides (together with isotope signal for 34s)
65
[M-65]+'
(S2H) disulfides (together with ( S O ~ H ) isotope signal for 34s)
66
[M-66]+' (C5Hg)
cyclopntenes disulfides (together with isotope signal for 34s)
67
[M-67]+' (C4H30)
fury1 ketones
68
[M-68]+' (C5H8) (C4H40)
cyclohexenes, tetralins cyclohexenones, P-tetralones
69
M-69]+'
(CgHg) alicyclics, alkenes ( C F ~ ) trifluoromethyl
70
Mass Ion
alkanes, alkenes, alicyclics cycloalkanones pyrrolidines
Compound type alkanes, larger alkyl groups alkanones, alkanals, tetrahydrofurans alkanones, alkanals aliphatic amines perhalogenated benzenes
0 indicator N indicator
alcohols, ethers, esters acids, esters, lactones trimethylsilyl compounds
0 indicator
2.5 Mass Spectrometry
43
Mass Ion
Compound type
74
ethers methyl esters of carboxylic acids, a-methyl carboxylic acids
75
methyl acetals, glycols 2 x 0 indicator sulfides, thiols (together with isotope signal for 34s) S indicator trimethylsilyloxyl compounds
76
aromatics
77
aromatics chloro compounds
78
aromatics pyridines chloro compounds
79
aromatics with H-containing substituents pyridines, pyrroles bromo compounds (together with isotope signal for 81Br)
80
cyclohexenes, polycyclic alicyclics cyclopentenones bromo compounds pyrroles, pyridines
81
cyclohexanes, cyclohexenyls, dienes furans, pyrans bromo compounds (together with isotope signal for 79Br)
82
cyclohexanes cyclopentenones, dihydropyrans tetrahydropyridines pyrazoles, imidazoles chloro compounds (together with isotope signals at m/z 84 and 86)
83
alkenes, alicyclics, monosubstituted alkanes cycloalkanones
84
piperidines, N-methylpyrrolidines
44
2 Summary Tables
Mass Ion
Compound type
85
alkanes alkanones, alkanals, tetrahydropyrans,fatty acid derivatives chlorofluoroalkanes (with isotope signal at d z 87)
86
alkanones, alkanals aliphatic amines
N indicator 0 indicator
87
alcohols, ethers, esters esters, acids
88
ethyl esters of carboxylic acids, a-methyl-methyl esters, a-C2-carboxylic acids
89
2 x 0 indicator diols, glycol ethers sulfides (together with isotope signal for 34S)
90
disubstituted aromatics
91
aromatics alkyl chlorides
92
allcylbenzenes alkylpyridines
93
phenols, phenol derivatives anilines bromo compounds
94
phenol esters, phenol ethers pynyl ketones, pyridone derivatives
95
fury1 ketones
96
alicyclics
97
alicyclics, alkenes cycloalkanones alkylthiophenes (together with isotope signal for 34s)
98
N-alkylpiperidines
2.5 Mass Spectrometry
Compound type
Mass Ion ~~
99
alkanes alkanones ethylene ketals alkyl phosphates
104
tetralin derivatives, phenylethyl derivatives disubstituted a-ketobenzenes
105
alkylaromatics benzoyl derivatives diazophenyl derivatives
106
alkylanilines
111
thiophenoyl derivatives (together with isotope signal for 34s)
115
aromatics esters diesters
119
alkylaromatics tolyl ketones peffluoroethyl derivatives phenyl carbamates
120
y-benzopyrones, salicylic acid derivatives pyridines, anilines
121 hydroxybenzene derivatives 127
naphthalenes unsaturated diesters chlorinated N-aromatics iodo compounds
128
naphthalenes chlorinated hydroxybenzene derivatives iodo compounds
130
quinolines, indoles naphthoquinones
45
2 Summary Tables
46
Mass Ion
Compound type
131
tetralins thioethylene ketals (together with isotope signal for 34s) perfluoroalkyl derivatives
135
CqHgBr+
alkyl bromides
141
CllH9+
naphthalenes
142
CIOH8N+
quinolines
149
C8H503+
phthalates
152
12H8+'
diphenyl aromatics
165
13H9+
diphenylmethane derivatives (fluorenyl cation)
167
C8H704+
phthalates
205
12H1303+
phthalates
223
C12H 15O4'
phthalates
2.5.1 1 References G.P. Moss, Atomic weights of the elements, Pure Appl. Chem. 1999, 71, 1593. G. Audi, A.H. Wapstra, The 1995 update to the atomic mass evaluation, Nucl. Phys. 1995, A595, 409. Atomic Mass Data Center, world wide web site,
. K.J.R. Rosman, P.D.P.Taylor, Isotopic compositions of the elements 1997, Pure Appl. Chem. 1998, 70, 217. H. Kubinyi, Calculation of isotope distributions in mass spectrometry. A trivial solution for a non-trivial problem, Anal. Chim. Acta 1991, 247, 107.
2.6
UV/Vls Spectroscopy
47
2.6 UV/Vis Spectroscopy UV/Vis Absorption Bands of Various Compound Types ( A : alkyl or H; R: alkyl; sh: shoulder)
48
2 Summary Tables
a longest wavelength absorption maximum
3.1 Alkanes, Cycloalkanes
49
3 Combination Tables
3.1 Alkanes, Cycloalkanes Assignment CH3 CH2 CH C
CH3 CH2 CH CH st CH3 S a s CH2 6 CH3 6 SY CH2 Y
Range 5-35 5-45 25-60 30-60
ppm ppm ppm ppm
0.8-1.2 ppm 1.1-1.8 ppm 1.1-1.8 ppm 3000-2840 cm-l ~ 1 4 6 cm-l 0 ~ 1 4 6 cm-l 0 ~ 1 3 8 cm-l 0 770-720 cm-l
Molecular ion m/z 14n + 2 Fragments
Rearrangements
m/z 14n m/z 14n - 2
Comments CH3, CH2, CH, and C can be differentiated by 13C NMR multipulse experiments (DEPT, APT), offresonance decoupling, 2D CH correlation spectra, or based on relaxation times Lower shift values in three-membered rings 1H NMR
Lower shift values in three-membered rings Higher frequency in three-membered rings
IR
Doublet for geminal methyl groups In C-(CH*),-C with n 2 4 at ca. 720 cm-l Weak in n-alkanes Very weak in isoalkanes n-Alkanes: local maxima at 14n + 1, intensity variations: smooth, minimum at [M- 15]+ Isoalkanes: local maxima at 14n + 1, intensity distribution: irregular (relative maxima due to fragmentation at branching points with charge retention at the most substituted C) n-Alkanes: unspecific Isoalkanes: elimination of alkanes Monocycloalkanes: elimination of alkanes
Ms
No absorption above 200 nm
uv
50
3 Combination Tables
3.2 Alkenes, Cycloalkenes Assignment 13cNMR
l"MR
C-(C=C)
Range 100-150 ppm 10-60 ppm
H-(C=C)
4.5-6.5 ppm
c=c
CH3-(C=C) CH2-(C=C)
~ 1 . ppm 7 ~ 2 . ppm 0
Comments Considerable differences between Z and E:
Coupling constants, IJI: geminal 0-3 Hz, cis 5-12 Hz, truns 12-18 Hz Coupling constants, 3 J ~ ~ =7 2Hz ~ ~ In rings, IJI smaller: n=2 ~ 0 . 5Hz n=3 ~ 1 . Hz 5 n=4 = 4 . 0 H z
6
Long-range coupling constants 4JHC-C=CH0-2 Hz
IR
H-C(=C) st c=cst H-C(=C) 6 oop CH2-(C=C) 6
Ms
Molecular ion m/z 14n m/z 14n - 2 Fragments 14n - 1 14n - 3
3100-3000 cm-l 1690-1635 cm-l 1000- 675 cm-l 1440 cm-l
Rearrangements
Alkenes: moderate Monocycloalkenes: medium intensity Local maxima for alkenes Local maxima for monocyclic alkenes Usually, double bonds cannot be localized n-Alkenes: unspecific Specific for: 1 +*
1 +*
Cyclohexenes: retro-Diels-Alder reaction:
01+*uv
C=C n+n* (C=C), n+n*
e 210 nm (log E 3-4) 215-280 nm (loa E 3.54.5)
(=
+
I]+*
Isolated double bonds; for highly substituted double bonds often absorption tail
=
~
3.3 Alkynes
51
3.3 Alkynes Assignment CEC
c-(CEC) H-( C EC)
Range 65-85 ppm
Comments Coupling constant 2 J H ~ E i=50 3 ~ Hz; often leading to unexpected signs of signals in DEFT spectra
0-30 ppm 1.5-3.0 ppm
Coupling constants IJI 4 5
CH3-(C=C) CH~-(CEC) CH-(CEC) H-C(EC) st CEC st
J
~ J
~ =3 - Hz ~ E ~ C-CH ~ =3 - Hz ~
~ 1H~ N M R ~
=1.8 ppm =2.2 ppm =2.6 ppm 3340-3250 cm-l Sharp, intense 2260-2100 cm-l Sometimes very weak
Molecular ion Fragments and rearrangements C r C n+n*
13C N M R
e 210 nm (log E 3.7-4.0)
IR
Weak, for 1 -alkynes up to C7 often absent Vary in extent between alkanes and aromatics
Ms
absorption tail, often a few weak bands e 240 nm
W
3 Combination Tables
52
3.4
Aromatic Hydrocarbons -
~~~~~~~~
Assignment 13cNMR a r c ar CH a1 C-(C ar) l"MR
H-(Car)
CH3-(C ar) CH2-(C ZU) CH-(C ar)
IR
ar C-H st comb ar C-C st
ar C-H 6 oop
Ms
Molecular ion Fragments
~~
~
~
Range 120-150 ppm 110-130 ppm 10-60 ppm
6.5-7.5 ppm
-2.3 ppm ~ 2 . ppm 6 ~ 2 . ppm 9 3080-3030 cm-l 2000-1650 cm-l ~ 1 6 0 cm-l 0 ~ 1 5 0 cm-l 0 ~ 1 4 5 cm-l 0 900-650 cm-l
m/z 39, 50-53, 63-65,75-78 [M-26]+', [M-39]+ benzylic cleavage
Comments Same ranges for polycyclic aromatic hYh&ns
In polycyclic aromatic hydrocarbons up to =9 PPm Coupling constants: 3J0,h0 -7 Hz, 4J,,ta =2 Hz, 5Jpara <1 HZ Often line broadening due to long-range coupling with aromatic protons
Often multiple bands, weak Very weak Often split, sometimes not all three bands observable Strong, frequently multiple bands Strong, often base peak Often doubly charged fragment ions
OCH,.~ dZ 90-92
m$
m/z 127
<-
m/z 152, 153
eka
Rearrangements
uv
1
-200-210 nm (log E -4) -260 nm (log E ~ 2 . 4 )
m/z 152, 165
+.
In benzene and alkylbenzenes
1 f*
3.5 Heteroaromatic Compounds
53
3.5 Heteroaromatic Compounds Assignment ar c-x ar C-C
Range 120-160 ppm 100-150 ppm
H i C ar)
6-9 ppm
HiN ar)
7-1 4 ppm
ar C-H st ar N-H st ar c-c st ar C-H 6 oop Molecular ion Fragments
Comments 13c N M R
Coupling constants in 6-membered rings similar to those in aromatic hydrocarbons; in 5-membered heteroaromatic rings smaller Strongly solvent dependent, generally broad
IR
3100-3000 cm-l Often multiple bands, weak 3500-2800 cm-l 1600 cm-l Often split, sometimes not all three -1500 cm-l ~ 1 4 5 cm-l 0 bands observable 1000-650 cm-l Often strong, frequently multiple bands
-
m
Strong, often base peak m/z 39, 50-53, Often doubly charged fragment ions 63-65,75-78 [M-26]+', [M-39]+ benzyl-analogous cleavage
Rearrangements m/z 45 [CHS]+
1H N M R
Loss of HCN (N-heteroaromatics) Loss of CO (0-heteroaromatics) Loss of CS (S-heteroaromatics) S-Heteroaromatics l +
+. -RCH=CH2 * H
cf. UVNis Reference Spectra, Chapter 8.5.3.
uv
54
3 Combination Tables
3.6 Halogen Compounds Assignment ~ ~ C N Ma1 R C-F (C)=C-F C=(C-F) ar C-F ar C-(C-F)
l"MR
Range 70-100 125-175 65-115 135-165 105-135
ppm ppm ppm ppm ppm
a1 C-Cl (C)=C-cl C=(C-cl) ar c-Cl
30-60 ppm 100-150 ppm 100-155 ppm 120-1 50 ppm
al C-Br (C)=C-Br C=(C-Br) ax C-Br
10-45 ppm 90-140 ppm 9O-140 ppm 110-140 ppm
a1 C-I (C)=c-I C=(C-I) ar c-I
-20 to +30 ppm 6O-110 ppm 120-150 ppm 85-1 15 ppm
-CHz-F
4 . 3 ppm
~ 3 . 5ppm ~ 3 . ppm 4 ~ 3 . ppm 1
IR
C-F st C-cl st C-Br st c-I St
Comments CF3: ~ 1 1 ppm 5 Coupling with 19F (isotope abundance, 100%; I = 1/2): lJCF 100-300 Hz; 2 J 10-40 ~ ~Hz; 3 J 5-10 ~ Hz; ~ 4 J 0-5~ Hz~
Coupling with 19F (isotope abundance, 100%; I = 1/2): 2 J 40-80 ~ ~Hz; 3 J 0-50 ~ Hz; ~ 4 J 0-5~ Hz~
Alkenes: geminal protons strongly deshielded by all halogens; vicinal protons are shielded by F and deshielded by the other halogens Aromatics: shielding by F in 0-and ppositions, small effects for C1 and Br; deshielding by I in 0-and shielding in mposition
1400-1000 cm-l Strong c 850 cm-l c 700 cm-* e 600 cm-l
3.6 Halogen Compounds Assignment Molecular ion
Range
Fragments
d z 69
CF3
[M-50]+' or [Frag-50]+
CF2
55
Comments For saturated aliphatic halogen compounds often weak, for polyhalogenated compounds often absent Characteristic isotope patterns for C1 and Br
MS
1 1 -
R-C-
-ha1 >
R- -C-ha1
Rearrangements
[M-20]+' rM-361"
HF elimination HC1 elimination
ha1 n+z*
I280 nm
For C-I; for C-Br and C-Cl in general only absorption tail, for C-F no absorption
(log E ~ 2 . 5 )
uv
56
3 Combination Tables
3.7 Oxygen Compounds 3.7.1 Alcohols and Phenols
Assignment ~ ~ C N Ma 1R c - O ~
Range 50-100 ppm
a1 C-(C-OH) 10-60 ppm a1 C-(C-C-OH) 10-60 ppm ar C-OH 135-155 ppm ar C-(C-OH) 100-130 ppm
l"MR
IR
alC-OH ar C-OH -CHz-OH -CH-OH ar CH-(C-OH)
0-H st
C-O(H) st
Ms
0.5-5 ppm 5-8 ppm 3 . 5 4 0 ppm 3.8-4.2 ppm 6.5-7.0 ppm
For C-aromatics, shift with respect to CH-(C-H): ortho -0.6 ppm, metu -0.1 ppm, pura = - O S ppm
3650-3200 cm-l Position and shape depend on degree of association; often different bands for Hbonded and free OH 1260-970 cm-I Strong
Molecular ion
Fragments
Comments Shift with respect to corresponding C-H: =+50 ppm Hardly any shift with respect to C-(C-CH3) Shift with respect to C-(C-C-CH3) -5 ppm Shift with respect to C-H =+25 ppm Shift with respect to C-(C-H): ortho -13 ppm, meta =+1 ppm, para -8 ppm Position and shape strongly depend on experimental conditions
Aliphatic: m/z 31, 45, 59,. [M- 18]+' w-331' [M-46]+' Aromatic: [ar-O]+' [M-281" (CO) [M-29]+ (CHO)
Aliphatic: weak, often missing for primary and highly branched alcohols; in this case, peaks at highest mass are often due to [M-l8]+'or [M-15]+ Aromatic: strong Primary: m/z 31 > m/z 45 = m/z 59 Secondary, tertiary: local maxima due to acleavage: R -R* + R-CH-OH R-CH=OH
+.
-
Generally accompanied by rearrangement peaks
3.7 Oxygen Compounds Assignment
Range
57
Comments Aliphatic: elimination of H20 from M+' and from products of a-cleavage; elimination of H 2 0 followed by alkene elimination Unsaturated: vinylcarbinols: spectra similar to those of ketones allyl alcohols: specific, aldehyde elimination:
Rearrangements
Aromatic: ortho effect with appropriate substituents:
-Y-Z: -CO-OR, -C-hal, -0-R, and similar
Aliphatic: no absorption above 200 nm Aromatic: in alkaline solution, shift to longer wavelength and intensity increase due to deprotonation
uv
3.7.2 Ethers Assignment a1 C-0 a1 C-(C-0) a1 C-(C-C-O)
o-c-0
(C)=C-o C=(C-o) ar c-0 ar c-(c-0)
Range 50-100 ppm 10-60 ppm 10-60 ppm 85-1 10 ppm 115-165 ppm 70-120 ppm 135-155 ppm 100-130 ppm
Comments 1 3 c NMR Oxiranes: outside the normal range Hardly any shift with respect to C-(C-CH3) Shift with respect to C-(C-C-CH,) -5 ppm Shift with respect to (C)=C-C =+15 ppm Shift with respect to C=(C-C) -30 ppm Shift with respect to C-H =+25 ppm Shift with respect to C-(C-H): ortho -15 ppm, meta =+1 ppm, para = -8 ppm
58
3 Combination Tables
Assignment ~"MR~ ~ 3 - 0 CH2-0 0-CH2-0 CH-0 CH-03 H-C(O)=C H-C(=C-O) ar CH4C-O)
IR
H-C(-0) st
Range 3.3-4.0 ppm 3.4-4.2 ppm 4.5-6.0 ppm 3.5-4.3 ppm 4 - 6 ppm 5.7-7.5 ppm 3.5-5.0 ppm 6.6-7.6 ppm
2880-2815 cm-l
H-CH(-O):! st 2880-2750 cm-l C-O-C st as 1310-1000 cm-l
lcls
Shift with respect to H-C(H)=C =+1.2 ppm Shift with respect to H-C(=C-H) -1 ppm
For CH3-O and CH2-O; similar range for amines Two bands Strong, sometimes two bands Aliphatic: weak, tendency to protonate Aromatic: strong
Molecular ion Fragments
Comments Singlet
Aliphatic:
m/z 31, 45, 59, ...
[M- 18]+' [M-33]+ [M-46]+'
Base peak of aliphatic ethers, generally due to fragmentation of the bond next to the ether bond:
+.
Ri-C-O-R2]
-R1'
+
C=O-R2
or due to heterolytic cleavage of the C-0 bond, especially for polyethers:
Aryl alkyl ethers: preferential loss of the alkyl chain Diary1 ethers: preferential loss of CO (28) from M+' and/or [M-H]+ as well as: ar 1- D G r 2
Rearrangements
Aliphatic: elimination of alcohol Aromatic ethyl and higher alkyl ethers: alkene elimination to the phenol:
Y
W
1+*
Aliphatic: no absorption above 200 nm Aromatic: shift to higher wavelength and more intense due to the ether group
1+*
3.8 Nitrogen Compounds
59
3.0 Nitrogen Compounds 3.8.1 Amines Assignment a1 C-N a1 C-(C-N) a1 C-(C-C-N) (C)=C-N C=(C-N) ar C-N ar C-(C-N)
Range 25-80 ppm 10-60 ppm 10-60 ppm 120-170 ppm 75-125 ppm 130-150 ppm 100-130 ppm
Comments Shift with respect to C-H = +20 to +30 ppm 13C N M R Shift with respect to C-(C-C) =+2 ppm Shift with respect to C-(C-C-C) =-2 ppm Shift with respect to (C)=C-C =+20 ppm Shift with respect to C=(C-C) -25 ppm Shift with respect to C-H =+20 ppm Shift with respect to C-(C-H): ortho -15 ppm, meta =+1 ppm, para =-10 ppm
a1 C-NH ar C-NH a1 or ar N+H CH3-N CH2-N CH-N CH-N+ ar CH-(C-N)
0.5-4.0 ppm 2.5-5.0 ppm 6.0-9.0 ppm 2.3-3.1 ppm 2.5-3.5 ppm 3.0-3.7 ppm 3 . 2 4 . 0 ppm 6.0-7.5 ppm
1H N M R
ar CH-(C-N+)
7.5-8.0 ppm
N-H st
3500-3200 cm-l
N+-H st
3000-2000 cm-l
N-H 6 N+-H 6 H-C(-N) st
1650-1550 cm-l 1600-1460 cm-l 2850-2750 cm-l
Often broad Singlet
For C-aromatics, shift with respect to CH-(C-H): ortho -0.8 ppm, meta -0.2 ppm, para -0.7 ppm For C-aromatics, shift with respect to CH-(C-H): ortho =+0.7 ppm meta =+0.4 ppm, para =+0.3 ppm Position depends on extent of association, often different bands for H-bonded and free NH; always at least two bands for NH2 Broad, similar to COOH band but more structured Weak or absent Often weak For CH3(-N) and CH2(-N); similar range for ethers
IR
60
Ms
3 Combination Tables
Assignment Molecular ion
Fragments
Range
Comments Odd mass number for odd number of nitrogens Aliphatic: weak, tendency to protonate Aromatic: strong, no tendency to protonate [M+H]+ is often important Aliphatic: Base peak of aliphatic amines generally due to dZ 30, 44, 58,... fragmentation of the bond next to the amine bond:
Elimination of alkenes following amine cleavage:
Rearrangements
Aliphatic: no absorption maximum above 200 nm Aromatic: in acidic solution, shift to lower wavelength and decrease in intensity
W
3.8.2 Nitro Compounds Assignment Range 13CNMR alC-N02 55-1 10 ppm a1 C-(c-N02) 10-50 ppm a1 c-(ccN02) 10-60 ppm ar C-NO2 130-150 ppm ar C-(C-N02) 120-140 ppm
lH N M R
IR
a1 CH-NO2 ar CH-(C-NOz)
NO2 st as NO2 st sy
4.2-4.6 ppm 7.5-8.5 ppm
1660-1490 cm-l 1390-1260 cm-l
Comments Shift with respect to C-H =+50 ppm Shift with respect to C-(C-C) -6 ppm Shift with respect to C-(C-C-C) -2 ppm Shift with respect to C-H =+20 ppm Shift with respect to C-(C-H): ortho =-5 ppm, meta -+1 ppm, para =+6 ppm
For C-aromatics, shift with respect to CH-(C-H): ortho =+1.O ppm, meta =+0.3ppm, para =+0.4 ppm Strong to very strong Strong to very strong
3.8 Nitrogen Compounds
Assignment Molecular ion
Range
Fragments
[M-16]+', [M-46]+ m/z 30, [M-17]+, [M-30]+, [M-471"
Rearrangements
61
Comments Odd mass number for odd number of nitrogens Aliphatic: weak or absent Aromatic: strong
=275 nm (log E <2) Aliphatic -350 nm (log E =2) Aromatic
Ms
w
3.9 Thiols and Sulfides Assignment ~ ~ C N M a1 R C-s ar c-s
~HNMR ~ ~ C - S H cuC-SH a1 CH-S ar CH-S
IR
S-H st
Ms
Molecular ion
Fragments
Range 5-60 ppm 120-140 ppm 1.O-2.0 2.0-4.0 2.0-3.2 7.0-7.5
ppm ppm ppm ppm
Comments No significant shift with respect to C-C Vicinal coupling constant, J=5-9 Hz
2600-2540 cm-l
Frequently weak
m/z 47, 61, 75, ...
34S-isotope peak at [M+2]+' =4.5% Aliphatic: intensity higher than for corresponding alcohols and ethers Sulfide cleavage: RlSCH2-R;!]''
Rearrangements
uv
5R 1 S+€ H 2
m/z 34, 35,48
[M-33]+, [M-34]+' Alkene elimination after sulfide cleavage
In aliphatic c225 nm (log E 3-4) 220-250 nm (log E 2-3) ComPunds
3.1 0 Carbonyl Compounds
63
3.1 0 Carbonyl Compounds 3.1 0.1
Aldehydes Assignment Range CHO 190-205 ppm a1 C-(CHO) 30-70 ppm a1 C-(C-CHO) 5-50 ppm (C)=C-(CHO) 110-160 ppm C=(C-CHO) 110-160 ppm ar C-(CHO) 120-150 ppm H-(C=O) a1 CH-(CHO) CH=CH-(CHO) ar CH-(C-CHO)
comb
c=ost
9.0-10.5 2.0-2.5 5.5-7.0 7.2-8.0
2900-2700 cm-l 1765-1645 cm-l
Molecular ion Fragments
[M-I]+
Rearrangements
[M-29]+ m/z 44, [M-441"
n+n*
ppm ppm ppm ppm
Comments Coupling constant lJCH 172 Hz Coupling constant 2 J 20-50 ~ ~Hz Shift with respect to C-(C-CH3) -10 ppm
1 3 c NMR
1H NMR
3J" 0-3 HZ 3J" =8 Hz For C-aromatics, shift with respect to CH-(C-H): ortho: =+0.6 ppm, meta: =+0.2 ppm, para: =+0.3 ppm
IR
Two weak bands Aliphatic: -1730 cm-l Conjugated: =I690 cm-I
Ms
Aliphatic: moderate Aromatic: strong For aliphatic aldehydes, only significant up to c 7 Aliphatic aldehydes
270-310 nm (log E =1) 2 207 nm (log E "4) 2 250 nm (log E >3)
f.
Saturated aldehydes a$-Unsaturated aldehydes Aromatic aldehydes
f. W
64
3 Combination Tables
3.1 0.2
Ketones Assignment
Range '3cNMR c=o 195-220 ppm a1 C-(C=O) 25-70 ppm al C-(C-C=O) 5-50 ppm (C)=C-(C=O) 105-160 ppm C=(C-C=O) 105-160 ppm ar C-(C=O) 120-150 ppm
Comments
lH NMR
CH-CO-al2.0-2.6 ppm CH-CO-ar 2.5-3.6 ppm
al CH-(C=O)
2.0-3.6 ppm
CH=CH-(C=O) 5.5-7.0 ppm ar CH-(C-C=O) 7.2-8.0 ppm
IR
c=ost
MS
Molecular ion
1775-1650 cm-l
For C-aromatics, shift with respect to CH-(C-H): ortho =+0.6 ppm, meta =+O. 1 ppm, para =+0.2 ppm Aliphatic: ~ 1 7 1 cm-l 5 Cyclic: ring size 26: ~ 1 7 1 cm-l 5 ring size <6: 21750 cm-l Conjugated: ~1690-1665cm-l Aliphatic: moderate Aromatic: strong Ketone cleavages:
Fragments
uv
Shift with respect to C-(C-CH3) =-6 ppm
Aliphatic ketones
Rearrangements
dz44
K+K*
<200 nm (log E 3-4) 250-300 nm (log E 1-2) 2 215 nm (log E =4) 2 245 nm (log E >3)
n+n*
[M-44]+
Saturated ketones a,@-Unsaturatedketones Aromatic ketones
3.10 Carbonyl Compounds
65
3.10.3
Carboxylic Acids Assignment COOH a1 C-(COOH) a1 C-(C-COOH) (C)=C-(COOH) C=(C-COOH) ar C-(COOH) COOH
Range 170-185 ppm 25-70 ppm 5-50 ppm 105-160 ppm 105-160 ppm 120-150 ppm 10.0-13.0 ppm
a1 CH-(COOH) 2.0-2.6 ppm CH=CH-(COOH) 5.2-7.5 ppm ar CH-(C-COOH) 7.2-8.0 ppm
COO-H st c=ost CO-OH 6 OOP
3550-2500 cm-l 1800-1650 cm-l
-920 cm-l
Molecular ion
Comments In COO-, shift with respect to COOH: 0 to +8 PPm Shift with respect to C-(C-CH3) =-6 ppm
Position and shape strongly depend on experimental conditions
1H N M R
For C-aromatics, shift with respect to CH-(C-H): ortho =+0.8 ppm, metu -+0.2 ppm, para =+0.3 ppm
Broad Aliphatic: ~ 1 7 1 cm-l 5 Conjugated: ~ 1 6 9 cm-l 5 In COO- two bands: 1580 and 1420 cm-l For dimers Aliphatic: moderate, strong for long chains, tendency to protonate Aromatic: strong Strong for aromatic acids
Fragments
[M-17]+ [M-45]+
Rearrangements
m/z 60, 61
n+x*
<220 nm (log E 1-2) 2193 nm (log E -4) 2230 nm (log E >3)
[M- 181"
13C NMR
IR
Ms
Aliphatic acids Aliphatic acids Ortho effect with aromatic acids:
Saturated acids a$-Unsaturated acids Aromatic acids
w
66
3 Combination Tables
3.1 0.4 Carboxylic Esters and Lactones
Assignment Range 13CNMR COOR 165-180 ppm a1 C-(COOR) 20-70 ppm a1 C-(C-COOR) 5-50 ppm a1 C-(OCOR) 50-100 ppm (C)=C-(COOR) 105-160 ppm C=(C-COOR) 105-160 ppm (C)=C-(OCOR) 100-150 ppm C=(C-OCOR) 80-130 ppm ar C-(COOR) 120-150 ppm ar C-(OCOR) 100-160 ppm
lH NMR
a1 CH-(COOR)
2.0-2.5 ppm
al CH-(OCOR)
3.5-5.3 ppm
CH=CH-(COOR)
5.2-7.5 ppm
C=CH-(OCOR) CH=C-(OCOR)
6.0-8.0 ppm 4.5-6.0 ppm
ar CH-(C-COOR) 7.5-8.5 ppm
ar CH-(C-OCOR)
IR
c=ost
c-0 st
6.8-7.5 ppm
Comments Shift with respect to COOH: -5 to -10 ppm Shift with respect to C-(C-CH$ -6 ppm Shift with respect to C-(OH) +2 to +10 ppm
CH3COOR -2.0 ppm; CH2COOR ~ 2 . ppm 3 CHCOOR e2.5 ppm CH30COR -3.5-3.9 ppm CH20COR -4.0-4.5 ppm CHOCOR -4.8-5.3 ppm Shift with respect to CH=CH-H: geminal =+0.8 ppm, cis =+1.1 ppm, trans: -+OS ppm Shift with respect to CH=CH-H: geminal =+2.1 ppm, cis -0.4 ppm, trans -0.6 ppm For C-aromatics, shift with respect to CH-(C-H): ortho -+0.7 ppm, meta =+O. 1 ppm, para -+0.2 ppm For C-aromatics, shift with respect to CH-(C-H): ortho -0.2 ppm, meta -0 ppm, para -0.1 ppm
1745-1730 cm-l Strong; range for aliphatic esters Higher wavenumbers for ha1-C-COO, COO-C=C, COO-ar, and for small-ring lactones Lower wavenumbers for C=C-COOR and ar-COOR 1330-1050 cm-l Mostly two bands, at least one of them strong
3.1 0 Carbonyl Compounds
Assignment Molecular ion
Fragments
Range
[M - RO]+ [M - ROCO]+
Rearrangements
67
Comments Aliphatic esters: weak, tendency to protonate Aliphatic lactones: medium to weak, tendency to protonate Aromatic esters and lactones: strong Esters Esters Lactones: loss of a-substituents (attached to ether carbon), decarbonylation, for aromatic lactones also double decarbonylation Alkene elimination from the alcohol moiety:
Elimination of the alcohol side chain with double hydrogen transfer (for > C2 alcohols) +
Elimination of the alkyl chain of the acid moiety as an alkene
R'Yc0
1 +* I
- R I-CH=CH~ D
+ . u
9H
Alcohol elimination from ortho-substituted aromatic esters
[M- 181" n+n*
Lactones
c220 nm (log E 1-2) 2193 nm (log E =4) 2230 nm (log E >3)
Aliphatic esters a$-Unsaturated esters Aromatic esters
Ms
68
3 Combination Tables
3.1 0.5 Carboxylic Amides and Lactams
Assignment
Range 165- 180 ppm l3CNMR CONR2 a1 C-(CONR2) 20-70 PPm a1 C-(C
CONH
5-10 ppm
alCH-(CONR2) al CH-(NCOR)
2.0-2.5 ppm 2.7-4.8 ppm
CH=CH-(CONR2) 5.2-7.5 ppm
C=CH-(NCOR) CH=C-(NCOR)
6.0-8.0 ppm 4.5-6.0 ppm
ar CH-C(CONR2) 7.5-8.5 ppm
ar CH-C(NCOR) 6.8-7.5 ppm
IR
N-H St
3500-3100 cm-I
c=ost
1700-1650 cm-l
(amideI) N-H 6 and N-C=O st sy (amide II)
1630-1510 cm-l
Comments
Shift with respect to C-(C-CH3) --6 ppm Shift with respect to C-(NH) -1 to -2 ppm
Frequently broad to very broad; splitting due to H-N-C-H coupling often only recognizable in the CH signal CH3NCOR -2.7-3.0 ppm; CH2NCOR -3.1-3.5 ppm; CHNCOR ~3.8-4.8pprn Shift with respect to CH=CH-H: geminal =+1.4 ppm, cis =+1.O ppm, trans =+OS ppm Shift with respect to CH=CH-H: geminal =+2.1 ppm, cis -0.6 ppm, tram -0.7 ppm For C-aromatics, shift with respect to CH-(C-H): ortho =+0.6 ppm, meru =+O. 1 ppm, para - 4 . 2 ppm For C-aromatics, shift with respect to CH-(C-H): orrho =O ppm, meta =O ppm, para: = 0 to -0.3 ppm Position and shape depend on extent of association, often different bands for Hbonded and free NH,always at least two bands for NH2 Strong, range given for amides as well as for 6- and larger lactams, higher wavenumbers for p- and y-lactams Often strong, missing for tertiary amides and lactams
3.10 Carbonyl Compounds
Assignment
Range
Molecular ion
Comments Aliphatic amides: moderate, tendency to protonate Aromatic amides: strong Amides: cleavage on both sides of the carbonyl group followed by loss of CO; large number of fragments of even mass Lactams: loss of a-substituent, loss of CO
Fragments
Rearrangements [M- 18]+'
n+x*
69
e220 nm (log E 1-2)
Ms
Amides: elimination of the amine moiety, elimination of alkene from the amine or acid moiety in analogy to esters Lactams Aliphatic amides and lactams
uv
4.1 Alkanes
71
\
4 13C NMR Spectroscopy
4.1 Alkanes 4.1.1 Chemical Shifts 13C Chemical Shifts of Alkanes ( 6 in ppm relative to TMS) -2.3 CH4
7.3
15.9
13.0
24.1
- -n
H,C-CH,
M
15.4
22.8
34.8 14.2
32.2 14.2 23.1
24.8
32.0 22.3
1
x
-
0
C 0 \
30.1
29.5 23.1
32.4 14.1
32.1 14.1
29.5 22.8
72
4 13C NMR
13C Chemical Shifts of Methyl Groups (6 in p p m relative to TMS) 'A'
b
''
Substituent X -H C -CH3 -CH2CH3 -CH(CH3)2 -C(CH3)3 -(CH2)&H3 -CH2-phenyl -CH2F -CHZCl -CH2Br -CH21 -CHC12 -CHBr2 -CCl3 -CBr3 -CH20H -CH20CH3 -CH20CH2CH3 -CH20CH=CH2 -CH20-phenyl -CH2OCOCH3 -CH2NH2 -CH2NHCH3 -CH2N(CH3)2 -CH2NO2 -CH2SH -CH2S02CH3 -CH2S03H -CH2CHO -CH2COCH3 -CH2COOH -c yclopenty1 -cyclohexyl -CH=CH2 -CZCH -phenyl -1-naphthyl -2-naphthyl -2-pyridyl -3-pyridyl 4-pyridyl -2-fury1 -2-thienyl -2-pyrroly l -2-indolyl
kH3-X -2.3 7.3 15.4 24.1 31.3 14.1 15.7 15.8 18.7 19.1 20.4 31.6 31.8 46.3 49.4 18.2 14.7 15.4 14.6 14.9 14.4 19.0 14.3 12.8 12.3 19.7 6.7 8.0 5.2 7.0 9.6 20.5 23.1 18.7 3.7 21.4 19.1 21.5 24.2 18.0 20.6 13.7 14.7 11.8 13.4
Substituent X -3-indolvl -4-indoGl -5-indolyl -6-indolyl -7-indolyl H -F a -C1 1 -Br
kH3-X
9.8 21.6 21.5 21.7 16.6 71.6 25.6 9.6 -1 -24.0 0 -OH 50.2 -OCH3 60.9 -0CH2CH3 57.6 54.9 -OCH(CH3)2 49.4 4C(CH3)3 -OCH2CH=CH2 57.4 -0-cyclohexyl 55.1 -OCH=CH2 52.5 -0-phenyl 54.8 -0COCH3 51.5 -OCO-cyclohexyl 51.2 -OCOCH=CH2 51.5 -OCO-phenyl 51.8 -0COOCH3 54.9 -0S02-4-tolyl 56.3 -OS020CH3 59.1 N -NH2 28.3 -NH~+ 26.5 -NHCH3 38.2 -NH-cyclohexyl 33.5 -NH-pheny 1 30.2 47.5 -N(CH3)2 -N-p yrrolidiny1 42.7 -N-p yperidiny 1 47.7 -N(CH3)phenyl 39.9 -N-pyrrOlyl 35.9 -N-imidazolyl 32.2 -N-p yrazoly 1 38.4 -N-indol y 1 32.1 -NHCOCH3 26.1 -N(CH3)CHO 31.5; 36.5 -N(CH3)COCH3 35.0; 38.0 -NO2 61.2 -CN 1.7 -NC 26.8 -NCS 29.1
4.1 Alkanes
Substituent X S -SH -SCH3 -S-fl-CsH 17 -S-phenyl -SSCH3 -SOCH3 -S02CH3 -S02CH2CH3 -SO2Cl -SO3H -S03Na 0 -CHO 11 -COCH3 C -COCH2CH3 / \ - c oc c 13 -COCH=CH2 -CO-c yclohexyl -CO-phenyl -COOH
kH3-X
6.5 19.3 15.5 15.6 22.0 40.1 42.6 39.3 52.6 39.6 41.1 31.2 30.7 27.5 21.1 25.7 27.6 25.7 21.7
Substituent X
-coo-
-COOCH3 -COOCOCH3 -CONH2 -CON(CH3)2 -COSH -COSCH3 -COCOCH3
-coc1
-COBr -COSi(CH3)3
6CH,-X
24.4 20.6 21.8 22.3 21.5 32.6 30.2 23.2 33.6 39.1 35.7
73 \ /
/
C\
4 13C NMR
74
'c' ' \
13C Chemical Shifts of Monosubstituted Alkanes ( 8 in ppm relative to TMS)
Substituent
Methyl -CH3
-H C -CH=CH2 -CZCH -phenyl H -F a -C1 1 -Br
-I 0 -OH -OCH3 -0CH2CH3 -OCH(CH3)2 -OC(CH3)3 *phenyl -0COCH3 -0CO-phenyl -OSO~-4-tolyl N -NH2 -NHCH3 -N(CH3)2 -NHCOCH3 -NO2 -CN -NC S -SH -SCH3 -SSCH3 -SOCH3 -SO2CH3 -SO*Cl -S02OH 0 -CHO 11 -COCH3 C -CO-phenyl / \ -COOH -COOCH3 -CONH,
-coc1
I
-2.3 18.7 3.7 21.4 71.6 25.6 9.6 -24.0 50.2 60.9 57.6 54.9 49.4 54.8 51.5 51.8 56.3 28.3 38.2 47.6 26.1 61.2 1.7 26.8 6.5 19.3 22.0 40.1 42.6 52.6 39.6 31.3 30.7 25.7 21.7 20.6 22.3 33.6
Ethyl -CH2 -CH3
1-Propyl
-CH2
-CH2
-CH3
7.3 27.4 12.3 29.1 80.1 39.9 27.6 -1.6 57.8 67.7 66.0
7.3 13.4 13.8 15.8 15.8 18.9 19.4 20.6 18.2 14.7 15.4
15.4 36.2 20.6 38.3 85.2 46.8 35.6 9.1 64.2 74.5 72.5
15.9 22.4 22.2 24.8 23.6 26.3 26.4 27.0 25.9 23.2 23.2
15.4 13.6 13.4 13.8 9.2 11.6 13.0 15.3 10.3 10.5 10.7
56.8 63.2 60.4 60.8 66.9 36.9 45.9 53.6 34.4 70.8 10.8 36.4 19.1
16.4 14.9 14.4 14.4 14.7 19.0 14.3 12.8 14.6 12.3 10.6 15.3 19.7
69.4 66.2 66.4 72.2 44.6 54.0 61.8 40.7 77.4 19.3 43.4 26.4
22.8 22.4 22.2 22.3 27.4 23.2 20.6 22.5 21.2 19.0 22.9 27.6
10.6 10.5 10.5 10.0 11.5 12.5 11.9 11.1 10.8 13.3 11.0 12.6
31.8
14.7
48.2 60.2 46.7 36.7 35.2 31.7 28.5 27.2 29.0 41.0
6.7 9.1 8.0 5.2 7.0 8.3 9.6 9.2 9.7 9.3
56.3 67.1 53.7 45.7 45.2 40.4 36.2 35.6
16.3 18.4 18.8 15.7 17.5 17.7 18.7 18.9
13.0 12.1 13.7 13.3 13.5 13.8 13.7 13.8
48.9
18.8
13.0
4.1 Alkanes I 3 C Chemical Shifts of Monosubstituted Alkanes (contd.)
( 6 in ppm relative to TMS) Substituent -H C -CH=CH2 -C_CH -phenyl H -F a -C1 1 -Br -I -OH -OCH3 -0CH2CH3 -OCH(CH3)2 -0C(CH3)3 -0-phenyl -0COCH3 -0CO-phenyl N -NH2 -NHCH3 -N(CH3)2 -NHCOCH3 -NO2 -CN -NC S -SH -SCHZCH~ -S02CH3 -s02c1 -S020H 0 -CHO 11 -COCH3 C -CO-phenyl / \ -COOH -COOCH3 -CONHq -coc1 &
Isopropyl -CH -CH3 15.9 15.4 22.1 32.3 20.3 22.8 24.0 34.3 22.6 87.3 27.3 53.7 44.8 28.5 31.2 20.9 25.3 64.0 72.6 21.4 68.5 63.5 69.3 67.5 68.2 43.0 50.5 55.5 40.5 78.8 19.8 45.5 29.9 34.4 53.5 67.6 52.9 41.1 41.6 35.2 34.1 34.1 34.9 46.5
23.0 25.2 22.0 21.9 21.9 26.5 22.5 18.7 22.3 20.8 19.9 23.4 27.4 23.4 15.2 17.1 16.8 15.5 18.2 19.1 18.8 19.1 19.5 19.0
tert-Butyl -C -CH3 24.1 25.0 29.4 33.8 31.1 27.4 31.4 34.6 28.3 93.5 34.6 66.7 36.4 62.1 40.4 43.0 31.2 68.9 72.7 27.0 27.7 72.6 28.5 73.0 33.8 76.3 79.9 80.7 47.2 50.4 53.6 49.9 85.2 28.1 54.0 41.1
28.1 28.2 32.9 28.2 25.4 28.6 26.9 28.5 30.7 35.0
57.6 74.2 55.9 42.4 44.3 43.5 38.7 38.7 38.6 49.4
22.7 24.5 25.0 23.4 26.5 27.9 27.1 27.3 27.6 27.1
75
76
'c' / \
4 13C NMR
13C Chemical Shifts of 1-Substituted n - O c t a n e s ( 6 in ppm relative to TMS)
Substituent -H C -CH=CH2 -phenyl H -F a -C1 1 -Br -I 04 H -O-n-CgHI7 -ON0 N -NH2 -N(CH3)2 -NO2 -CN S -SH -SCH3 -SO-L'-CgH17 0 -CHO 11 -COCH3 C 40-phenyl / \ 4OOH -COOCH3 -CONHqA -COCl
*
1
2
3
4
-CH2
-CH2
-CH2
-CH2
14.1 22.8 34.5 -29.6 36.2 31.7 84.2 30.6 45.1 32.8 33.8 33.0 6.9 33.7 63.1 32.9 71.1 30.0 68.3 29.2 42.4 34.1 60.1 29.5* 75.8 26.2 17.2 25.5 24.7 34.2 29.0 34.5 52.6 -29.1 44.0 22.2 43.7 24.1 38.6 24.4 34.2 24.8 34.2 25.1 35.5 25.4 47.2 25.1 assignment uncertain
32.1 29.5 -29.6 -29.6 -29.6 -29.6 25.3 29.3 27.0 29.0 28.3 28.8 30.6 28.6 25.9 29.5 26.3 29.6 26.0 29.3 27.0 29.6 ~ 2 7 . 9 * e27.7" 27.9 -29.6 -29.9 -29.9 28.5 29.2 29.4 29.4 -29.1 ~ 2 9 . 1 -29.3 -29.3 -29.5 -29.5 29.5 29.5 -29.3 -29.3 29.3 29.3 29.1 29.1 28.5 29.1
5 -CH2
6
7
8
-CH2
-CH2
-CH3
29.5 -29.6 -29.6 29.3 29.2 29.2 29.1 29.4 29.4 29.3 29.4 29.7* =29.6 -29.9 29.1 29.4 ~29.1 -29.3 e29.5 29.5 -29.3 29.3 29.1 29.1
32.1 32.2 32.1 31.9 31.9 31.8 31.8 31.9 32.0 31.9 31.9 32.0 31.4 31.8 31.9 31.9 31.8 31.9 32.0 31.9 31.9 31.9 31.6 31.8
22.8 23.0 22.8 22.7 22.8 22.7 22.6 22.8 22.8 22.7 22.7 22.8 22.6 22.7 22.7 22.8 22.7 22.7 22.8 22.7 22.7 22.8 22.3 22.7
14.1 13.9 14.1 14.1 14.1 14.1 14.1 14.1 14.1 14.0 14.1 14.4 14.0 14.0 14.1 14.1 14.1 14.1 14.1 14.0 14.1 14.1 14.0 14.1
4.1 Alkanes
77
Estimation of I3C Chemical Shifts of Aliphatic Compounds (in pprn relative to TMS) The chemical shifts of sp3-hybridized carbon atoms can be estimated with the help of an additivity rule using the shift value of methane (-2.3 ppm) and increments for substituents in a-, p-, y-, and &position (see next pages). Some substituents occupy two positions. Thus, the quaternary carbon atom c in the example given below is in &position relative to the carbon atom a since the sp3-hybridized oxygen of the p-COO group occupies the y-position. This simple linear model needs corrections in case of strong branching of the observed C atom and/or its neighbors (steric corrections, S ) . Substituents for which such corrections are necessary are those with varying branching, Le., a varying number of directly bonded H atoms. They are marked with an asterisk (*) in the Table of Increments. Further correction terms are needed if y-substituents are in a sterically fixed position (conformational corrections, K). The chemical shifts estimated with this additivity rule differ in general by less than about 4 ppm from the experimental values. Larger discrepancies may be expected for highly branched systems (particularly for quaternary carbon atoms). For carbon atoms bearing several halogen, oxygen, and/or other strongly deshielding substituents, additional correction terms are needed [ 11. Without such corrections, deviations can be so large as to render the rule useless.
Example: Estimation of chemical shifts for N-terf-butoxycarbonylalanine
H a
1 S(tert,2) estimated exP
b base value 1 a-C 1 p-COOS 1 p-NH 1 r-coo 1 S(prim,3) estimated exP
-2.3 9.1 2.0 11.3 -2.8 -1.1 16.2 17.3
base value 3 a-C 1 a-OCO 1 y-NH 16-c 3 S(quat,l) estimated exP
-2.3 27.3 56.5 -5.1 0.3 -4.5 72.2 78.1
d base value 1 a-C 2 p-c 1 p-OCO 1 6-NH 1 S(prim,4) estimated exP
-2.3 9.1 18.8 6.5 0.0 -3.4 28.7 28.1
16-c
c
O
-2.3 9.1 20.1 28.3 2.0 0.3 -3.7 53.8 49.0
base value 1 a-C 1 a-COOH 1 a-NH 1 p-coo
\
/
C / \
4 13C NMR
78
‘c’ ‘ \
Estimation of I 3 C Chemical Shifts of Aliphatic Compounds (6 in ppm relative to TMS)
6 = -2.3 + CZi + CSi + E:Kk Substituent
-H -CC$ -c*=C
-c=c-phenyl
H -F a -Ci 1
-Br -1
0 -0-* -0CO*NOA N -Nb -N+L; 1
-NH3+ -NO2 -CN -NC
s -s*-scO-s*o-s*o2-s02c1 -SCN 0 -CHO
II -cO-
C -COOH / \
-coo-
-COO-CO-N<
-coc1
-C=NOH syn -C=NOH anti -CS-N< -S n
i j “ k Increment Zi for substituents in position a B Y 0.0 0.0 0.0 9.1 9.4 -2.5 19.5 -2.1 6.9 4.4 -3.4 5.6 22.1 -2.6 9.3 70.1 -6.8 7.8 -5.1 10.0 31.0 18.9 -3.8 11.0 -1.5 -7.2 10.9 49.0 -6.2 10.1 56.5 -6.0 6.5 54.3 -6.5 6.1 28.3 -5.1 11.3 30.7 -7.2 5.4 -4.6 26.0 7.5 -4.6 61.6 3.1 3.1 -3.3 2.4 31.5 -3.0 7.6 10.6 -3.6 11.4 17.0 -3.1 6.5 31.1 -3.5 7.0 7.0 30.3 -3.7 -3.0 3.4 54.5 9.7 23.0 -3.0 -0.6 -2.7 29.9 22.5 3.O -3.0 20.1 -2.8 2.0 3.5 24.5 -2.5 2.0 22.6 -2.8 -3.2 2.6 22.0 -3.6 2.3 33.1 0.6 11.7 -1.8 4.3 16.1 -1.5 7.7 33.1 -2.5 4.0 -5.2 -0.3
6 0.0 0.3 0.4 -0.6 0.3 0.0 -0.5 -0.7 -0.9 0.3 0.0 -0.5 0.0 -1.4 0.0 -1.0 -0.5 0.0 -0.4 0.0 0.5 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -0.4 0.0
0.0 0.0 0.6 0.0
4.1 Alkanes
79
'*L'
Steric Corrections, S S , for number of substituents at the &atoma
Observed 3C-center
0.0 0.0 0.0 -1.5
primary (CH3) secondary (CH2) tertiary (CH) quaternaxy (C)
-1.1 -2.5 -8.5 -10.0
0.0 0.0 -3.7 -8.0
-3.4 -6.0 -10.0 -12.5
a To be applied to each of the neighboring atoms, which may have a variable number of non-hydrogen substituents (marked with an asterisk (*) in the Table of Increments).
Conformational Corrections, K, f o r y-Substituents Conformation
K
synperiplanar
-4.0
synclinal
$ix
anticlinal
antiperiplanar
.1.0
0.0
&
2.0
X
not fixed
0.0
One can also use the chemical shifts of a reference compound as the base value if its structure is closely related to that assumed for the unknown. The increments corresponding to the structural elements missing in the reference compound are then added to the base value, while those of structural elements present in the reference but absent in the unknown are subtracted.
/
\
4 13C NMR
80
’
‘C’
Example: Estimation of the chemical shifts for the carbon atoms a and b in Nfeu-butoxycarbonylalanineusing the chemical shifts of valine as base values (a’, b’): Target: Reference:
a
base value 1 p-coo 1 6-c
1 S(tert3) - 2 p-c - 1 S(tert,3) estimated eXP
b base value
61.6 2.0 0.3 -3.7 -18.8 8.5 49.9 49.0
30.2 -2.8 -1.1 -18.2 8.5 16.6 17.3
1 y-coo 1 S(prim,3) - 2 a-C - 1 S(tert,3) estimated exP
4.1.2
Coupling Constants 1 3 C - I H Coupling Constants
Coupling through one bond ( I J C H in Hz) The 13C-lH coupling constant of 125 Hz in methane increases in the presence of electronegative substituents and can be estimated by using the following additivity rule:
Substituent -H -CH3 -C(CH3)3 -CH2C1 -CH2Br -CHzI -CHClZ -CCl3 -C=C -phenyl
-F -c1
Increments Z; 0.0
.o
1
-3.0 3 .O 3.0 7.0 6.0
9.0 7.0
.o
1
24.0 27.0
Substituent -Br -1
-0H -0-phenyl -NH2 -NHCH3 -N(CH3)2 -CN -SOCH3 -CHO -COCH? -COOHd
Increments Z; 27.0 26.0 18.0 18.0 8.0 7.0 6.0 11.0
Example: Estimation of 13C-l H coupling constant of CHC13: J = 125.0 + 3 x 27.0 = 206.0 Hz (exp: 209.0 Hz).
13.0 2.0 -1.0 5.5
4.1 Alkanes
81
Coupling through more than one bond (IJCHI in H z ) The coupling constants can be estimated from the corresponding IH-lH coupling constants [ 2 ] : JCH
2JcH 3
J
0.62 J"
1- 6 ~ 0-10 ~
H-CH2-l 3CH3 H-CH2-CH2-l 3CH3
4.5 5.8
The l3C-lH coupling constants for coupling across three bonds depend on the dihedral angle in the same way as the vicinal lH - lH coupling constants (see Chapter 5.1):
H 1 3 c - 1 3 ~Coupling Constants
( 1 ~ in~ HZ) ~ 1 b
H3C-CH3
l J 34.6
a
C
lJab 34.6
b d -aOH c
2Ja, 4.6 3Jad4.6 2Jbd <1
C
The 13C-13C coupling constants for coupling over three bonds depend on the dihedral angle in the same way as the vicinal lH-lH (see Chapter 5.1) and 13C-lH coupling constants. Maximum values of ca. 4-6 Hz are observed for dihedral angles of Oo and 180° and minimal values around 0 Hz at 90°. 4.1.3
References [l] A. Furst, E. Pretsch, W. Robien, A comprehensive parameter set for the
prediction of the 13C NMR chemical shifts of sp3-hybridized carbon atoms in organic compounds, Anal. Chim. Acta 1990,233, 213. [2] J.L. Marshall, Carbon-carbon and carbon-proton NMR couplings, Verlag Chemie International, Deerfield Beach, FL,1983.
' C ' /
\
4 13C NMR
82
4.2
Alkenes
c=c
4.2.1 Chemical Shifts
13C Chemical Shifts of Alkenes ( 6 in ppm relative to TMS) The I3C chemical shifts of the carbons of C=C double bonds typically range from ca. 80-160 ppm; a wider range of 40-210 ppm is observed with 0- and Nsubstituents. In unsaturated acyclic hydrocarbons, they can be predicted with high accuracy (see below). To estimate the I3C chemical shifts in all other substituted alkenes, one can use the substituent effects listed for chemical shifts in vinyl groups. However, since no configuration-dependent parameters are available, the values thus estimated are less accurate than those for unsaturated acyclic hydrocarbons. The 13C chemical shifts of sp3-hybridized carbon atoms in the vicinity of double bonds can be estimated using the additivity rule given on page 78. The conformational correction factors, K, for y-substituents of cis- vs. transdisubstituted alkenes differ by 6 ppm because the relative position of these substituents is fixed by the double bond.
Estimation of the 13C Chemical Shifts of sp2-Hybridized Carbon Atoms in Unsaturated Acyclic Hydrocarbons ( 6 in ppm relative to TMS)
c- c-c - C'= c-c -c - c Y' P' a' t ap Y Base value: 123.3 Incrementsfor C-substituents: at C-atom under consideration (C)
a
P
Y
at neighboring C-atom (C')
a'
-7.9
4.9
p'
-1.5
Y'
-1.8 1.5
10.6
Steric corrections: for each pair of cis-a,a'-substituents for a pair of geminal a,a-substituents for a pair of geminal a',a'-substituents if one or more P-substituents are present
-1.1 -4.8
2.5 2.3
4.2 Alkenes
83
Example: Estimation of chemical shifts of cis-4-methyl-2-pentene
a
a base value 1 a-C 1 a'-C 2 p-c cis-a,a' estimated eXP
c=c
b
b base value 1 a-C 2 p-c 1 a'-C cis-a,a' 1 P-substituent estimated exP
123.3 10.6 -7.9 -3.6 -1.1 121.3 121.8
123.3 10.6 9.8 -7.9 -1.1 2.3 137.0 138.8
Effect of Substituents on the 13C Chemical Shifts of Vinyl Compounds (in ppm relative to TMS)
CHXH, 1 2
Substituent X -H C -CH3 -CH2CH3 -CH2CH2CH3 -CH(CH3)2 -(CH2)3 -C(CH3)3 -CH2C1 -CH2Br -CH2I -CH20H -CH20CH2CH3 -CH=CH2 -C=CH -phenyl H -F a -C1 1 -Br -I
* estimated
values
6ci = 123.3 + Zi Z1 Z2 0.0 0.0 12.9 -7.4 17.2 -9.8 15.7 -8.8 22.7 -12.0 14.6 -8.9 26.0 -14.8 10.2 -6.0 10.9 -4.5 14.2 -4.0 14.2 -8.4 12.3 -8.8 13.6 -7.0 -6.0 5.9 12.5 -11.0 24.9 -34.3 2.8 -6.1 -8.6 -0.9 -38.1 7.0
Substituent X 0 -OH -OCH3 -0CH2CH3 -O(CH2)3CH3 -0COCH3 N -N(CH3)2 -N+(CH3)3 -N-pyrrolidonyl -NO2 -CN -NC S -SCH2CH3 -S02CH=CH2 0 -CHO 11 -COCH3 C -COOH / \ -COOCH2CH3 -COCl -Si(CH& -Sic13
z1 z2 25.7 -35.3 29.4 -38.9 28.8 -37.1 28.1 -40.4 18.4 -26.7 28.0* -32.0* 19.8 -10.6 6.5 -29.2 22.3 -0.9 14.2 -15.1 -3.9 -2.7 9.0 -12.8 7.9 14.3 15.3 14.5 13.8 4.7 5.0 9.8 6.3 7.0 8.1 14.0 16.9 6.7 8.7 16.1
4 13C NMR
04
The values listed on the preceding page can also be used to estimate the 13C chemical shifts of sp2-hybridized carbon atoms in alkenes with more than one substituent (note that the cis/truns configuration is not taken into account): 6q = 123.3 + Z Z i 1
Example: Estimation of chemical shifts of 1-bromo-1-propene a b Br- C= C- CH3 H H a base value 123.3 b base value 123.3 Z1(Br) -8.6 -0.9 Z2(CH3) -7.4 Zi(CH3) 12.9 estimated 107.3 estimated 135.3 eXP 108.9 (cis) eXP 129.4 (cis) 132.7 (trans)
104.7 (trans)
The following examples show some larger deviations between measured and estimated (in parentheses) chemical shifts. This is usually to be expected when several substituents are present that strongly interact with the n-electrons of the double bond: H b,N(CH3)2 a 69.2 NC\ a b,N(CH3)2 a 39.1
,c=c,
NC
N(CH3)2 ,,,NO2
c=c\ (H3C)2&
H
b a
b
(29.1) 171.0 (207.7)
aFC\
\
H
151.0 (150.4) 111.4 (113.6)
a
N( CH3) 2
b,oCH3
a
OCH3
b
,c= c,
H
b
(59.3) 163.0 (179.3) 54.7 (45.5) 167.9 (182.1)
13C Chemical Shifts of cis- and trans-l,2-Disubstituted Alkenes (6 in ppm relative to TMS) Substituent R -CH3 -CH2CH3 -c1 -Br -I -CN -OCH3 -COOH -COOCHq
R
R
R
H
H
H
H
R
H
123.3 131.2 118.1 116.4 96.5 120.8 130.3 130.4 130.1
H
124.5 131.3 119.9 109.4 79.4 120.2 135.2 134.2 133.5
13C Chemical Shifts of Enols (6 in ppm relative to TMS) The carbon atom bonded to the enolic OH group is strongly deshielded so that its shift is close to that of a carbonyl carbon. The other carbon atom is strongly shielded.
Enol:
a
Ketone: a
22.5
c
99.0 190a5
a
28.3 32.8 46.2 191.1 103.3
C
a
b c 0 d
e
a b c
28.5 201.1 56.6
a
28.3 31.0 54.2 203.6 57.3
JJ
a
C
e
b c d O e
13C Chemical Shifts of Aliphatic Dienes (6 in ppm relative to T M S ) Conjugated Dienes a
136.9 116.3
Allenes 213.5 74.8 CH2= C= CH2 Estimation of the chemical shifts of sp2-hybridized carbon atoms in substituted allenes: see [l].
c=c
4 13C NMR
06
13C Chemical Shifts of Substituted Allenes (6 in ppm relative to TMS) RI,~
C/R3 , c=c=c.,,,
R2 R1 -H -CH3 -CH3 -CH3 -CH2CH3 -C(CH3)3 -CH=CH2 -C=CH -phenyl -F -c1 -Br -1
-OCH3 -N(CH3)2 -CN -SCH3 -COOH
R2 -H -H -CH3 -H -H -C(CH3)3 -H -H -H -H -H -H -H -H -H -H -H -H
H
R3 -H -H -H -CH3 -H -H -H -H -H -H -H -H -H -H -H -H -H -H
b 213.5 210.4 207.3 207.1 208.9 207.0 211.4 217.7 210.0 200.2 207.9 207.6 208.0 202.0 204.2 218.7 206.1 217.7
a
74.8 84.4 93.4 85.4 91.7 119.6 93.9 74.8 94.4 129.8 88.8 72.7 35.3 123.1 113.1 67.4 90.0 88.1
C
74.8 74.1 72.1 85.4 75.3 75.8 75.1 77.3 78.8 93.9 84.5 83.8 78.3 90.3 85.5 80.7 81.3 80.0
4.2.2 Coupling Constants
13C-lH Coupling Constants ((J,-HI in Hz) Coupling through one bond
Coupling through two bonds (typical range: 0-16) H
H
H
H 2
+l3C
H
J -2.4 ~ ~
H 2
/L13C
c1
J 6.9 ~
H
Additivity rule for the estimation of 2J,-~ of alkenes: see [2].
~
4.2 Alkenes
87
Coupling through three bonds: The trans- lH-C=C-l 3C coupling constant of alkenes is always larger than the corresponding cis coupling constant so that an assignment is possible if both isomers are available: see [3]. a
a
C
H,
'3,CH3
H
c1
C
H
13,CH3
,c=c
H
H
3Jac
7.6 3Jbc 12.6
,c=c,
3Jac 4.1 3Jbc 8.1
b
b
a
a
C
H,
13/COOH
c =c,
H' b
c=c
H
3Jac
7.6
3Jbc
14.1
C
H,
13/COOH
c=c, H'
3Jac 7.6 3Jbc 14.1
CH3
b
a
C
H,
13/CooH
F =c
CH3
13CH3
C
3Jab
3Jac
CH?
7.7 7.4
13/COOH 3Jab 6.9 F =c, 3Jac 13.2 H 13CH3 a b
b
13C-13C Coupling Constants
(I'Jccl
in H z ) C
b,CH3 CH2= C H a
CH2= CH2
'Jcc
67.6
CH2=C=CH2
'Jcc
98.7
b
a@d
C
lJab 70.0 'Jbc 41.9 'Jab 68.8 'Jbc 53.7 2Jac c 1 3Jad 9.0
4.2.3
References [l] R.H.A.M. Janssen, R.J.J.Ch. Lousberg, M.J.A. de Bie, An additivity relation for carbon-13 chemical shifts in substituted allenes, J. R. Neth. Chem. SOC. 1981, 100, 85. [2] U. Vogeli, D. Herz, W. von Philipsborn, Geminal C,H spin coupling in substituted alkenes, Org. Magn. Reson. 1980, 13, 200. [3] U. Vogeli, W. von Philipsborn, Vicinal C,H spin coupling in substituted alkenes. Stereochemical significance and structural effects, Org. Magn. Reson. 1975, 7, 617.
88
4 13C NMR
4.3 AI kynes 4.3.1 Chemical Shifts
c=c
13C Chemical Shifts of Alkynes ( 6 in ppm relative to TMS) a b X-CE C- H
Substituent X -H
C -CH3 -CH2CH3 -CH2CH2CH3 -CH2CH$H2CH3 -CH(CH3)2 -C(CH3)3 -cyclohexyl -CH20H -CH=CH2 -C EC-CH3 -phenyl 0 -0CH2CH3 S -SCH$H3 0 -CHO 11 -COCH3
C -COOH / \ -COOCHq
a
b
71.9 80.4 85.5 84.0 83.0 89.2 92.6 88.7 83.0 82.8 68.8 84.6 90.9 72.6 81.8 81.9 74.0 74.8
71.9 68.3 67.1 68.7 66.0 67.6 66.8 68.3 73.8 80.0 64.7 78.3 26.5 81.4 83.1 78.1 78.6 75.6
Additivity rule for estimating the chemical shifts of sp-hybridized carbon atoms in alkynes: see El].
4.3 Alkynes
89
4.3.2 Coupling Constants 13C-lH Coupling Constants (IJcHI in H z ) [21 a
b
C
H- 13C, C- H a
b
c
de
H- CE C- CH3 a
b
'Jab
249 2Jbc 49.3 (in substituted acetylenes: 40-60) 2Jac 50.1 2Jc, -10.4
c=c
3.4 3Jbe 4.7
3Jad
c
C H ~ - C= C- C H ~2Jat, -10.3
3Jac 4.3
With acetylenes, the results of multipulse experiments (such as DEPT, INEPT, SEFT, or APT) to determine the number of protons attached to the carbon atoms must be interpreted with care. As a consequence of the unusually large 13C-lH coupling constants through one and two bonds, the sign of the signals may be opposite to the expected one.
1 3 c - 1 3 ~Coupling Constants ( 1 1 ~ in ~ HZ) ~ 1 H-CEC-H
lJCc
171.5
a b c H-CSC-C=C-H
'Jab 190.3 153.4
4.3.3 References [l] W. Hobold, R. Radeglia, D. Klose, Inkrementen-Berechnung von 13Cchemischen Verschiebungen in n-Alkinen, J. Prakt. Chem. 1976,318,519. [2] K. Hayamizu, 0. Yamamoto, 13C,lH Spin coupling constants of dimethylacetylene, Org. Magn. Reson. 1980, 13, 460.
4
90
NMR
4.4 Alicyclics 4.4.1
Chemical Shifts Saturated Monocyclic Alicyclics (6 in ppm relative to TMS)
0
v
-2.8
0
n 27.1
0 22.9
0
0
0
25.6
9 10 11 12 13
28.8
20 30 40 72
26.8
b 26.0 25.1 26.3 23.8 26.2 25.2 27.0 28.0 29.3 29.4 29.7
I3C Chemical Shifts of Monosubstituted Cyclopropanes (6 in ppm relative to TMS) [ 11 h
Substituent X -H C -CH3 -CH2CH3 -CH2CH2CH2CH3 -C(CH3)3 -CH2C1 -CH20H -CH=CH2 -phenyl H -c1 a -Br 1 -I 0 -OH N -NH2 -NO2 -CN 0 -CHO II -COCH3 C -COOH / \ -COOCHg
a -2.8 4.9 12.8 10.9 22.7 13.6 12.7 14.7 15.3 27.3 14.2 -20.1 45.7 24.0 54.3 -4.5 22.7 20.1 12.7 12.2
b -2.8 5.6 4.1 4.4 0.3 5.5 2.2 6.6 9.2 8.9 9.1 10.4 6.8 7.4 11.7 6.2 7.4 9.6 8.9 7.7
other CH3 19.4 CH2 27.8, CH3 13.6 1-CH2 34.7, 2-CH2 32.0 C 29.3, CH3 28.2 CH2 50.3 CH2 66.5 CH 142.4, CH2 111.5 C 143.9, CH 125.3-128.2
CN 121.5
co 202.1 CO 207.3, CH3 29.1 CO 181.6 CO 174.7, CH3 51.1
4.4 Alicyclics
91
13C Chemical Shifts of Monosubstituted Cyclopentanes ( 6 in ppm relative to TMS) [2] b
Substituent X -H C -CH3 -CH2CH3 -CH(CH3)2 -C(CH3)3 -CH20H H -F a -C1 1 -Br -I 0 -OH -0CH3 -0COCH3 N -NH2 -NO2 -CN S -SH -COOH
a 25.5 34.8 42.3 47.4 50.3 41.2 95.5 61.8 53.1 28.7 72.5 82.2 77.7 52.5 87.0 27.0 38.3 43.0
b 25.5 34.8 32.6 30.0 26.5 28.3 32.8 37.5 38.4 40.7 34.5 31.4 33.8 35.5 32.6 30.5 37.7 29.2
c 25.5 25.4 25.4 24.7 25.1 24.5 22.5 23.3 23.7 24.9 22.7 23.1 24.9 23.0 24.8 24.2 24.6 25.1
other CH3 21.4 CH2 29.2, CH3 13.2 CH 33.9, CH3 21.7 C 32.5, CH3 27.6 CH2 67.0 lJCF 173.5, 2JCF 22.1, 3JCF ~ 1 . 5
CH3 56.0 CO 170.8, CH3 21.7 CN 123.4 CO 183.8
0
92
4 13C
NMR
C Chemical Shifts of Equatorially and Axially Monosubstituted Cyclohexanes ( 6 in ppm relative to TMS)
W
X
d
pJxa
d
0
Substituent X a -H 27.1 C -CH3 33.2 -CH2CH3 40.1 -CH2CH2CH3 40.0 44.6 -CH(CH3)2 - C H Z C H ~ C H ~ C H38.4 ~ 48.8 -C(CH3)3 -cyclohexyl 44.3 -CH=CH2 42.1 -C=CH 28.7 -phenyl 45.1 91.0 H -F a -C1 59.8 1 -Br 52.4 -I 31.2 0 -OH 70.4 4CH3 79.2 -0COCH3 72.3 -OCO-phenyl 72.8 -OSi(CH3)3 70.5 N -NH2 51.1 -NHCH3 58.7 64.3 -N(CH3)2 -NH3+C151.8 -N=C=N-cyclohexyl 55.7 -NO2 84.6 59.5 -N3 -CN 28.0 -NC 51.9 -NCS 55.3 S -SH 38.3 0 -CHO 50.1 11 -COCH3 51.5 C -COOH 43.7 / \ -coo47.2 -COOCHq 43.4 -coc1 55.4 L
b 27.1 36.0 33.4 33.6 30.0 34.1 28.1 30.8 32.3 32.1 34.9 32.8 37.4 38.3 40.1 35.8 32.2 32.2 31.5 36.0 37.6 32.7 29.2 32.2 35.0 31.4 31.5 29.6 33.7 33.9 38.1 26.0 29.0 29.6 30.9 29.6 29.7
c 27.1 27.1 26.9 26.6 26.8 27.1 27.7 27.4 26.0 25.2 27.4 23.6 26.1 27.3 28.3 25.1 24.5 24.4 24.1 24.7 25.8 25.7 26.5 24.8 24.8 24.7 24.5 24.6 24.4 24.5 26.6 25.2 26.6 26.2 26.9 26.0 25.5
d 27.1 27.0 27.2 26.9 27.3 27.3 27.1 27.4 27.1 24.4 26.7 25.3 25.4 25.6 25.4 26.3 26.4 26.1 24.7 25.0 26.3 26.8 26.9 25.2 25.5 25.5 24.5 25.1 25.2 24.8 25.3 26.1 26.3 26.6 26.9 26.4 25.9
a b c d 27.1 27.1 27.1 27.1 28.4 32.4 20.6 26.9 35.5 30.0 21.4 27.1 41.1 30.2 21.6 27.1
37.0 30.0 21.2 27.1 28.0 30.0 21.2 25.7 88.1 60.1 55.4 38.3 65.5 74.9
30.1 33.9 34.9 36.0 33.2 30.0
19.8 20.4 21.5 22.8 20.5 21.1
25.0 26.0 26.4 26.1 27.1 26.6
69.0 29.3 20.3 24.7 66.1 33.1 19.8 25.0 47.4 33.8 20.0 27.1
56.8 26.4 50.3 50.3 35.9 46.4
29.0 27.4 30.5 30.5 33.1 24.7
20.1 21.9 20.1 20.1 19.4 22.7
25.2 25.0 25.2 25.2 25.7 -27.1
39.1 27.7 24.1 26.7
4.4
Alicyclics
93
Estimation of 13C Chemical Shifts of Alicyclic Compounds (in pprn relative to TMS)
The chemical shift of the parent compound (e.g., 22.9 for cyclobutane, 25.6 for cyclopentane, and 27.1 ppm for cyclohexane) and the same increments as for alkanes (see Chapter 4.1) can be used to estimate the chemical shifts of sp3hybridized carbon atoms of alicyclic compounds. Appropriate use of the conformational correction terms, K (page 79), is especially important with axial and equatorial substituents in cyclohexanes. The additivity rule is, however, not suitable for estimating chemical shifts of substituted cyclopropanes.
0
l 3C Chemical Shifts of Unsaturated Alicyclics
( 6 in ppm relative to TMS)
41.6
,
0 0 K 0'f.i0 124.9
127.4
1 \
134.3 152.6 123.4
25.4
124.5
26.0
23.0
134.1 129.8
123.3
29.8
0
130.2 25.7 26.4 29.5
cis
e'!::: 28.8
28.7 trans
cis, cis
0
126.1 124.6
22.3
4 13C NMR
94
13C Chemical Shifts of Condensed Alicyclics ( 6 in ppm relative to TMS)
2 027A . 2 16.7 0 5.8
21.5
@
22.9 B 3 3 .24.6 3
H
43.3
fI
28.0Ff 39.9 2 3 . 8 m e22.6 9
32.4 47.3 22.1 27.1 @la7
H
H
a
2
936.8 429.7.
5
44.0 f l 7 . 1
H
H
42.6
32.7 \ 37.6 22.0 27.5
9.9 48.8
75.2
&
:43.2
143.9
143.5 123*6 39.1
1
124‘5 133.8 126.1 \ 120.9 132*1 144.7
b z 6 . 7
136.8 125.5 J 29.5 1 2 9 , o m 23.6 \
4.4
Alicyclics
95
4.4.2
Coupling Constants 1 3 C - l H Coupling Constants
(1
Coupling through one bond
A 160
0
0 134
Coupling through two bonds
A 2.6
J C H ~in H z )
128
(I2Jc~I in
125
0
Hz)
0
03.5
Coupling through three bonds
0
3.0
0
3.7
(l3Jc~1 in H z ) H 2.1
'
A
M
H 8.1
' b c
~ J C C12.4
[>-CH3
lJab 13.4
'Jbc 44.0
0
' J c c 32.7
4.4.3
References [I] N.C. ~ 0 1 A.D.H. , Clague, 13c NMR Spectroscopy of cyclopropane derivatives, Org. Magn. Reson. 1981,16, 187. [2] H.-J. Schneider, N. Nguyen-Ba, F. Thomas, Force field and 13C NMR investigations of substituted cyclopentanes. A concept for the adaption of 3C NMR shifts to varying torsional arrangements in flexible conformers, Tetrahedron 1982,38, 2327.
'
4 13C NMR
96
4.5 Aromatic Hydrocarbons 4.5.1 Chemical Shifts z3C Chemical Shifts in Aromatic Hydrocarbons (6 in ppm relative to TMS) [ 11 133.7
131.8 128.1 126.2 125.3
+
128.0 \
\
/
125.5 126.3
135.2 124.6
130.1 124.6 143.9 125.9 J
143.5
123.9 137.4
\
141.6
1 2 4 . i 2 8 133.8
124.2@ \ 5:3.
126.1 120.9 132.1 144.7
1
136.8 125.5 J 29.5 1 2 9 . 0 0 3 23*6
143.2
137.3
29.2
37.7
128.0
&
128’7 129.7
@i;9,5 / 128.2 122.7
134.7
128.0
\
\
132.1
119.7
127.9 i4.3
128.4
1 7.4
-/-
137.3 123.9 127.5
4.5 Aromatics
97
Effect of Substituents on 13C Chemical Shifts of Monosubstituted Benzenes (in ppm relative to TMS)
C
Substituent X Zl -H 0.0 -CH3 9.2 -CH2CH3 11.7 -CH2CH2CH3 10.3 20.2 -CH(CH3)2 - C H ~ C H ~ C H Z C H ~ 10.9 18.6 -C(CH3)3 15.1 -cyclopropyl 17.8 -cyclopentyl 16.3 -cyclohexyl 22.2 -1-adamantyl -CH2F 8.5 2.5 -CF3 9.3 -CH2C1 -CHCl2 11.9 -CC13 16.3 -CH2Br 9.5 -CH2I 10.5 12.4 -CH,OH 8.7 -CH20CH3 14.9 -CH2NH2 12.6 -CH2NHCH3 7.8 -CH2N(CH3)2 2.2 -CH2N02 1.6 -CH2CN -CH2SH 12.5 9.8 -CH2SCH3 0.8 -CH2S (O)CH3 -CH2S02CH3 -0.1 7.4 -CH2CHO 5.8 -CH2COCH3 -CH$OOH 6.5 32.2 -CH2Li -CH=CH2 8.9 12.6 -C(CH+CH2 -6.2 -C=CH -phenyl 8.1 11.2 -2-pyridyl 9.6 4pyridyl
z2 0.0 0.7 -0.6 -0.2 -2.2 -0.2 -3.3 -3.3 -1.5 -1.8 -2.9 -0.7 -3.2 0.3 -2.4 -1.7 0.7 0.0 -1.2 -0.9 -1.4 -0.3 0.5 2.2 0.5 -0.6 0.4 1.5 2.1 1.3 0.8 1.4 -22.0 -2.3 -3.1 3.6 -1.1 -1.4 -1.6
z3 0.0 -0.1 -0.1 0.1 -0.3 -0.2 -0.4 -0.6 -0.4 -0.3 -0.5 0.4 0.3 0.2 0.1 -0.1 0.3 0.0 0.2 -0.1 -0.2 -0.3 -0.3 2.2 -0.8 0.0 -0.1 0.4 0.6 0.5 0.1 0.4 -0.4 -0.1 -0.4 -0.4 0.5 0.5 0.5
z4
0.0 -3.0 -2.8 -2.7 -2.8 -2.8 -3.6 -2.9 -2.8 -3.1 0.5 3.3 0.0 1.2 1.8 0.2 -0.9 -1.1 -0.9 -2.0 -1.8 -1.5 1.2 -0.7 -1.6 -1.6 -0.2 0.6 -1.1 -1.6 -1.2 -24.3 -0.8 -1.2 -0.3 -1.1 -1.4 0.5
4 I3C
90
NMR
Substituent X
H -F
-C1 -Br -I 0 -OH -ONa -OCH3 -OCH=CH2 -0-phenyl -0COCH3 -OSi(CH3)3 -OPO(O-phenyl)2 -OCN a
1
0
-NHCH3 -N(CH3)2 -"-phenyl -N(PhenYl)2 -NH3+ -NH2+CH(CH3)2 -N+(CH3)3 -N(O)(CH3)2 -NHCOCH3 -"OH -NHNH2 -N(NO)CH3 -N=CH-pheny 1 -N=NCH3 -NO -NO2 -CN -NC -NCO -NCS -N+=N -SH -SCH3 -SC(CH3)3 -S(CH3)2+ -SCH=CH2 -S-phenyl -S-S-pheny 1 -S(O)CH3 -S02CH3 -S020H -S020CH3 -S02F
"2-
S
Z1 33.6 5.3 -5.4 -3 1.2 28.8 39.6 33.5 28.2 27.6 22.4 26.8 21.9 25.0 18.2 15.0 16.0 14.7 13.1 0.1 5.5 19.5 26.2 9.7 21.5 22.8 13.7 24.7 22.2 37.4 19.9 -16.0 -1.8 5.1 3 .O - 12.7 4.0 10.0 4.5 -1.0 5.8 7.3 7.5 17.6 12.3 15.0 6.4 4.6
z2
-13.0 0.4 3.3 8.9 -12.8 -8.2 -14.4 -11.5 -11.2 -7.1 -8.4 -8.4 -12.7 -13.4 -16.2 -15.4 -10.6 -7.0 -5.8 -4.1 -7.3 -8.4 -8.1 -13.1 -16.5 -9.4 -6.5 -6.2 -7.6 -4.9 3.5 -2.2 -3.7 -2.7 6.0 0.7 -1.9 9.0 3.1 2.0 2.5 -1.3 -5.0 -1.4 -2.2 -0.6 0.0
z3 1.6 1.4 2.2 1.6 1.4 1.9 1.o
0.7 -0.3 0.4 0.9 1.2 2.6 0.8 0.8 0.9 0.9 0.9 2.2 1.1 2.5 0.8 0.2 -2.2 0.5 0.9 1.3 0.5 0.8 0.9 0.7 1.4 1.1 1.3 5.7 0.3 0.2 -0.3 2.2 0.2 0.6 0.8 1.1 0.8 1.3 1.5 1.5
z4
-4.4 -1.9 -1.0 -1.1 -7.4 -13.6 -7.7 -5.8
-6.9 -3.2 -7.1 -3.0 -1.0 -10.0 -11.6 -10.5 -10.5 -5.6 2.2 0.7 2.4 0.6 -4.4 -5.3 -9.6 -1.3 -1.5 -3.0 7.1 6.1 4.3 0.9 -2.8 -1.0 16.0 -3.2 -3.6 0.0 6.3 -1.8 -1.5
-1.1 2.4 5.1 3.8 5.9 7.5
4.5 Aromatics
0
II
C
/\
Si
P
Substituent X -s02c1 -S02NH2 -SCN -CHO -COCH3 -COCF3 -COC+CH -CO-pheny 1 -COOH -COONa -COOCH3 -CONH2 -CON(CH& -COF -coc1 -COSH -CH=NCH3 -CS-phenyl -CS-( l-piperidyl) -Li -MgBr -SiH3 -SiH2CH3 -Si(CH3)3 -Si(phenyl)3 -Sic13 -Ge(CH3)3 -Sn(CH3)3 -Pb(CH3)3 -P(CH3)2 -P(phenyl)2 -Pf(phenyl)2CH3 -PO(CH3)2 -PO(-phenyl)2 -PO(OH)2 -PO(OCH$H3)2 -PS(CH3)2 -PS(OCH2CH3)2
ASH^
-As(phenyl)2 -AsO(OH)2 -SeCH=CH2 -SeCN -Sb(~henyl)~ -Hg-phenyl -HCCl
99
Z1
22
23
z4
15.6 10.8 -3.7 8.2 8.9 -5.6 7.4 9.3 2.1 9.7 2.0 5 .O 6.0 4.2 4.7 6.2 8.8 18.7 15.0 -43.2 -35.8 -0.5 4.8 11.6 5.8 3.O 13.7 13.2 20.1 13.6 8.9 -9.7 2.5 5.8 -1.9 1.6 6.7 6.1 1.7 11.1 3.8 0.7 -5.3 9.8 41.6 22.5
-1.7 -3.0 2.5 1.2 0.1 1.8 1.o 1.6 1.6 4.6 1.2 -1.2 -1.5 1.6 2.7 -0.6 0.5 1.o -3.1 -12.7 -11.4 7.3 6.3 4.9 7.9 4.6 4.5 7.2 8 .O 1.6 5.2 5.2 1.1 3.9 3.6 3.6 2.0 2.8 7.9 5.0 1.6 4.7 5.1 7.7 9.3 8.0
1.2 0.3 2.2 0.5 -0.1 0.7 0.0 -0.3 -0.1 2.2 -0.1 0.1 -0.2 -0.7 0.3 0.2 0.1 -0.6 -0.2 2.4 2.7 -0.4 -0.5 -0.7 -0.6 0.1 -0.5 -0.4 -0.1 -0.6 0.0 2.0 0.1 -0.1 1.5 -0.2 0.2 -0.4 0.8 0.1 0.8 0.4 2.9 0.3 -0.9 -0.6
6.8 3.2 2.2 5.8 4.4 6.7 5.9 3.7 5.2 4.6 4.3 3.4 1.o
'
i:: 5.4 2.3 2.4 -0.2 3.1 4.0 1.3 1.o 0.4 1.1 4.2 -0.2 -0.4 -1.0 -1.0 0.1 6.7 3.O 3.O 5.6 3.4 2.9 3.4 0.0 -0.1 4.5 -1.4 2.1 0.0 -1.6 -0.9
0
100
4 13C NMR
Effect of Substituents in Position 1 on the 13C Chemical Shifts of Monosubstituted Naphthalenes (in ppm relative to TMS) for X: H
6c1= 128.0 6 c 2 = 125.9 6c9 = 133.6
0
Substituent X C -CH3 -C(CH3)3 -CHqBr -CH;OH
c-1 c-2 C-3 6.0 0.5 0.6 17.9 -2.8 -0.9 4.0 1.1 -0.9 8.2 -0.9 -0.6 -1.3 -1.8 H:;F3 31.5 -16.1 0.1 3.9 0.2 -0.2 a -c1 I -Br -5.4 3.6 -0.2 -I -28.4 12.3 1.7 0 -OH 23.5 -17.2 -0.1 -OCH3 27.3 -22.3 -0.2 -0COCH3 18.6 -7.9 -0.6 14.0 -16.5 0.3 N -NH2 -N(CH3)2 23.7 -11.2 0.6 -NH3+ -3.8 -4.6 -0.9 -NO2 18.5 -2.1 -2.0 -CN -19.2 5.1 -2.4 0 -CHO 2.9 10.8 -1.4 11 -COCH3 6.9 2.9 -1.7 -1.5 3.6 -2.4 C -COOH / \ -COOCH3 -0.9 4.5 -1.2 -CON(CH,)2 6.8 -2.1 -0.8 -COCl 1.2 10.6 -0.5 -Si(CH?)? 9.8 5.1 -0.4
C-4 -1.8 -0.6 1.3 0.1 5.0 -3.8 -0.9 -0.5 1.7 -7.3 -7.9 -2.1 -9.3 -4.6 3.4 6.5 3.8 6.7 4.9 4.3 5.4 0.9 9.3 1.7
C-5 0.3 1.6 0.5 0.5 1.0 0.1 0.2 -0.1 1.4 -0.4 -0.7 0.0 0.3 1.0 1.4 0.5 -0.7 0.2 0.3 -0.6 0.7 0.4 1.9 1.2
C-6 -0.7 -1.4 -0.1 -0.3 0.8 1.4 3.1 0.4 1.6 0.5 0.3 0.4 -0.3 0.4 2.1 1.3 0.2 0.6 0.4 -0.9 0.5 0.4 2.1 -0.8
C-7 -0.5 -1.4 0.3 0.1 2.0 0.7 0.8 1.0 2.6 0.3 -0.9 0.4 -1.3 -0.3 2.8 3.4 1.2 2.7 2.0 0.6 1.9 1.0 4.5 -0.7
C-8 C-9 -4.1 -1.1 -1.2 -1.6 -4.6 -2.8 -4.5 -2.6 -3.4 1.0 -7.1 -9.3 -3.6 -2.8 -1.3 -2.0 4.4 1.3 -6.6 -9.3 -6.1 -8.1 -6.9 -6.9 -7.3 -10.2 -3.2 -3.9 -9.0 -7.4 -5.1 -8.7 -4.5 -2.8 -3.5 -3.6 -2.0 -3.5 -3.2 -3.2 -1.8 -1.9 0.1 -4.1 -2.1 -2.1 0.1 3.8
C-10 -0.2 2.2 0.1 0.0 -3.9 2.1 1.0 0.6 1.3 1.0 0.8 0.9 0.6 2.1 1.2 0.6 -2.2 -0.3 0.2 -0.8 0.5 -0.2 1.0 0.2
4.5 Aromatics
101
Effect of Substituents in Position 2 on the 13C Chemical Shifts of Monosubstituted Naphthalenes (in p p m relative to TMS) for X: H
6 c 1 = 128.0 6 c 2 = 125.9 6 c 9 = 133.6
Substituent X C -CH?
J
H -F a -C1 1 -Br -I 0 -OH -OCH3 -0COCH3 N -NH2 -N(CH3)2 -NH3+ -NO2 -CN 0 -CHO 11 -COCH3 C -COOH / \ -COOCH3 -COCl -Si(CH?)q
*
C-1 -1.3 -3.3 -1.7 -2.7 -2.0 -17.0 -1.4 1.8 9.2 -18.6 -22.2 -9.5 -20.6 -21.1 -5.9 -3.4 5.8 6.2 1.9 2.7 3.0 2.5 5.8
assignment uncertain
C-2 C-3 C-4 C-5 C-6 9.3 2.0 -0.8 -0.5 -1.1 22.5 -3.0 -0.4 0.0 -0.7 9.0 1.9 -0.4 -0.5 0.7 12.3 -4.4 -0.1 -0.4" -0.2* -4.2 1.1" 0.1" 2.4" 34.9 -9.6 2.4 0.0 -0.7 5.7 0.8 1.5 -0.2 0.2 -6.2 3.1 1.5 -0.3 0.2 -34.1 9.0 2.3 0.5 1.3 27.3 -8.3 1.8 -0.3 -2.4 31.8 -7.1 1.5 -0.3 -2.2 22.5 -4.8 1.3 -0.4 -0.3 16.7 -8.9 -0.2 -1.6 -4.8 23.6 -8.8 1.2 0.0 -3.4 -0.3 -6.5 3.2 0.2 2.3 20.0 -6.7 1.7 0.1 4.0 -16.7 0.1 1.0 -0.2 3.0 7.9 -3.6 0.8 -0.3 2.9 8.3 -2.2 0.2 -0.4 2.3 2.4 -0.6 0.2 -0.3 2.4 1.8 -0.5 0.2 -0.1 2.4 9.1 -0.7 0.2* -0.4 2.2* 11.9 3.9 -1.0 0.1 0.3
C-7 -0.2 -0.2 0.3 0.1* 1.5 1.1 1.1 0.8 1.5 0.5 0.5 0.6 -0.9 0.7 2.0 2.2 1.6 0.9 0.7 0.9 0.9 0.8 -0.2
C-8 -0.6 -0.6 0.6 -0.2" 1.1 -0.6 -1.1 -1.1 -0.6 -1.7 -1.2 -0.4 -3.5 -1.1 0.2 2.1 0.2 1.8 1.4 1.3 1.4 1.2 0.1
C-9 -0.1 0.4 -0.6 -0.3 -1.1 0.7 0.7 -2.0 2.1 0.9 1.0 0.1 -0.1 2.4 0.1 -1.1 -1.6 2.4 1.8 -1.3 -1.0
C-10 -2.0 -1.3 -0.7 -0.8 1.3 -3.0 -1.9 0.7 -0.8 -4.7 -4.3 -2.2 -7.0 -5.9 -0.3 2.4 0.7 -1.4 -1.3 1.5 1.9 -1.4 -0.5 0.2
0
102
4 13C NMR
Estimation of 13C Chemical Shifts of Multiply Substituted Benzenes and Naphthalenes The 13Cchemical shifts of multiply substituted benzenes and naphthalenes can be estimated using the substituent effects in the corresponding monosubstituted hydrocarbons.
Example: Estimation of the chemical shifts for 3,5-dimethylnitrobenzene
P'"
4 CH3
2 Z3(CH3) estimated exP
-
C 3 base value
Zi(CH3) Z3(CH3) Zg(NO2) estimated exP
NO2
-
128.5 19.9 -0.2 148.2 148.5
C 2 base value Z2(N02)
128.5 9.2 -0.1 0.9 138.5 139.6
C 4 base value 2 Z2(CH3)
Z2(CH3) Z4(CH3) estimated exP
-
Z4(N02) estimated exP
128.5 -4.9 0.7 -3.0 121.3 121.7 128.5 1.4 6.1 136.0 136.2
Larger discrepancies between estimated and experimental values are to be expected if the substituents are ortho to each other or if strongly electron-donating and electron-accepting groups occur simultaneously. 4.5.2 Coupling Constants
13C- H Coupling Constants (IJI in H z )
4.5 Aromatics
6;
103
1 3 c . 1 3 ~Coupling Constants (IIJCCI in HZ)
2Jac
57.0 2.5
3Jad
10.0
'Jab
d
2Ja,
44*2 3.1
3Jad
3.8
4Ja,
0.9
lJab
e
4.5.3
References [l] P.E. Hansen, 13CNMR of polycyclic aromatic hydrocarbons. A review, Org. Magn. Reson. 1979,12, 109.
4 13C NMR
104
4.6 Heteroaromatic Compounds 4.6.1 Chemical Shifts 13C Chemical Shifts of Hetetoaromatic Compounds (6 in ppm relative to TMS)
150.60’?:841 0
136.2
N H N-N
4NJ147.9 H
135.9
Te
104.7 \ 133.3
147.4
N H
n130.4
K*.N
1 4 7 . 4Np N H
148.4
157‘ P 7 1 2 3 . 4 N, 147.8 S
I-
CH349.8 in ethanol
I
\
“,N H
H
146.0
n143.3
135.6
CTOH in DMSO
125.7
t.
0
4.6
Heteroaromatics
Effect of Substituents on the 13C Chemical Shifts substituted Pyridines (in ppm relative to TMS)
N Substituent in Dosition 2 or 6 -H C -CH3 -CH2CH3 -CH=CH2 -phenyl -
H -r a -C1 1 -Br -I 0 -OH
N
S
0
11
C /\
-OCH3 -&phenyl -0COCH3 -NH2 -NHCH3 -N(CH3)2 -NHCOCH3 -NO2 -CN -SH -SCH3 -S(=O)CH3 -S(=0)2CH3 -CHO -COCH3 -COOH -COOCH3 -CONH2 -Si(CH3)3 -Sn(CH3)3 -Pb(CH3)3
‘22 = ‘66
0.0 8.6 13.7 5.9 7.7 13.9 1.8 -7.5 -3 1.6 15.5 14.3 13.9 7.6 8.4 10.9 9.6 1.4 6.9 -15.8 30.4 10.2 16.2 8.5 3.0 3.8 -3.7 -1.7 -0.3 18.6 23.3 33.4
6c-2 = 6c-3 = 6 ~ -= 4 6c-5 = 6C-6 = ‘23 = ‘65
0.0 -0.5 -1.7 -1.3 -1.6 -14.0 0.8 4.6 11.3 -3.6 -12.7 -12.2 -7.3 -15.1 -16.2 -17.9 -9.8 -5.7 4.8 10.7 -4.6 -4.4 -2.6 -2.0 -2.1 0.0 1.5 -1.2 5 .O 7.6 9.2
105
of Mono-
149.8 + Zi,2 123.7 + Zi,3 135.9 + Zi,4 123.7 + Zi,5 149.8 + zi,6 ‘24
= ‘64
‘25 = ‘63
0.0 0.3 0.4 1.1 0.8 5.4 2.8 2.6 1.7 -1.1 2.6 3.5 3.4 1.8 1.5 1.2 2.6 3.9 1.1 2.1 0.0 2.2 2.4 1.2 0.9 2.5 1.1 1.4 -2.0 -2.7 -2.6
0.0 -3.0 -2.8 -2.5 -3.2 -2.5 -1.4 -1.1 -0.8 -17.0 -7.1 -5.3 -1.8 -9.7 -11.3 -12.3 -3.9 5.4 3.2 -10.6 -2.2 0.9 3.7 4.2 3.4 4.2 3.3 2.8 -1.1 -1.7 -2.3
‘26 = ‘62 0.0 -0.7 -0.6 -0.3 0.2
-2 Q
0.5 1.o -8.2 -2.9 -2.0 -1.6 -1.6 -1.3 -1.9 -2.1 -0.8 1.4 .12.1 -0.5 -0.2 0.3 0.4 -0.8 -1.7 0.0 -1.5 0.3 0.6 1.1
106
4 13C NMR
Substituent in position 3 or 5
-H C -CH3
0
-CH2CH3 -phenyl H -F a -C1 1 -Br -I 0 -OH -OCH3 -0COCH3 N -NH2 -NHCH3 -N(CH3)2 -CN S -SH -SCH3 0 -CHO 11 -COCH3 C -COOH / \ -COOCH3 -CONH2 -Si(CH3)3 -Ge(CH3)3 -Sn(CH3)3 -Sr~(n-CqHg)~ -Pb(n-CqHg)3
z32 = z56 '33
0.0 1.3 -0.4 -1.4 -11.5 -0.3 2.1 7.1 -10.7 -12.5 -6.5 -11.9 -13.6 -14.0 3.6 -12.8 -13.6 2.4 3.5 -6.4 -0.6 2.7 2.7 3.9 5.9 6.6 7.1
= ' 5 5 '34 = z54 '35 = '53
0.0 8.9 15.4 12.8 36.1 8.1 -2.7 -28.5 31.3 31.5 23.4 21.4 23.1 23.3 -13.8 26.1 24.6 7.8 8.5 13.0 1.o 5.9 9.1 12.8 13.0 12.6 21.7
0.0 0.0 -0.8 -1.8 -13.2 -0.4 2.7 8.9 -12.4 -15.9 -7.0 -14.4 -18.2 -17.1 4.2 -11.3 -11.7 -0.2 -0.7 11.1 -0.5 1.1 3.0 4.2 7.1 7.7 8.5
0.0 -0.9 -0.5 -0.3 0.8 0.6 1.1 2.3 1.2 0.1 -0.1 0.8 0.6 0.1 0.5 7.3 10.6 0.5 -0.2 4.3 -1.8 1.2 -2.3 -0.4 0.1 0.0 0.9
'36
= '52 0.0 -2.3 -2.7 -1.3 -3.9 -1.4 -0.9 0.3 -8.6 -8.4 -3.2 -10.8 -11.9 -11.6 4.2 -2.8 -3.0 5.4 0.0 -6.0 1.8 -1.5
-1.2 -0.1 -0.3 -0.4 -1.8
4.6
Substituent in position 4 -H C -CH3 -CH2CH3 -CH(CH3)2 -C(CH3)3 -CH=CH2 -phenyl H -F a -Br 1 -I 0 -OCH3 -0COCH3 N -NH2 -NHCH3 -N(CH3)2 -CN S -SH -SCH3 0 -CHO 11 -COCH3 C -COOCH3 / \ -CONH2 -Si(CH3)3 -Ge(CH3)3 -Sn(CH3)3 -Pb(CH3)3
z42 = z46 z43 = z45
0.0 0.5 -0.1 0.4 0.9 0.3 0.4 2.7 3.0 0.2 0.9 1.7 0.7 0.5 0.6 2.1 -16.9 0.1 1.7 1.6 1.o 0.4 -2.8 -1.1 -1.1 -0.5
0.0 0.7 -0.5 -1.9 -2.6 -3.0 -2.2 -11.9 3.3 9.1 -13.9 -6.7 -13.8 -15.9 -16.3 2.1 5.9 -3.3 -0.7 -2.7 -0.8 -0.9 2.4 4.4 7.3 9.1
Heteraaromatics
z44
0.0 10.6 16.8 21.2 23.9 8.4 12.2 32.8 -3.2 -30.8 29.0 23.9 19.3 19.8 19.2 -15.9 54.3 14.6 5.3 6.6 1.4 6.2 11.9 16.8 16.2 24.6
107
108
4 13C NMR
Estimation of 13C Chemical Shifts of Multiply Substituted Pyridines The 13C chemical shifts in multiply substituted pyridines can be estimated using the substituent effects in the monosubstituted parent compound.
Example: Estimation of the chemical shifts for 2-amino-5-methylpyridine
-
C 2 base value
estimated :Y
-
C 4 base value
estimated eXP
-
C 6 base value Z26("2) Z56(CH3)
estimated exP
-
149.8 8.4 -2.3 155.9 156.9
C 3 base value
135.9 1.8 0.0 137.7 138.6
C 5 base value
Z23("2) Z53(CH3)
estimated exP
-
Z25WH2) Z55KH3)
estimated exP
123.7 -15.1 -0.9 107.7 108.4 123.7 -9.7 8.9 122.9 122.5
149.8 -1.6 1.3 149.5 147.6
Larger discrepancies between estimated and experimental values are to be expected if the substituents are ortho to each other and if strongly electron-donating and -accepting groups occur simultaneously. Also, tautomerization and zwitterion formation have large effects on 13C chemical shifts.
4.6
Heteroaromatics
109
13C Chemical Shifts of Condensed Heteroaromatic Rings (6 in ppm relative to TMS)
.06.9 145.0
120.5 177*6102.1
123.8 ;39*8124.0
121.7 119'6 a\ i 2 4 . 1
1 2 4\ 124.4 ' 3 w 1 2 6 . 4
1
H 135.5
111e8 155.5
111.0
120.5 140.'
115.4 137'9
122.6 139.9
125'4@5 122*9&5 150.0 124.3 130.6 23 'O m\
141.5
0 152.6
124.4 \
122.9 \ 115.4
y2*2147.1 ,
t
N
€4
137.9
*qy> 122.1* 152.6
L 25.1
155.5
125.8" \ S 122.7* 133.2
122.8
N
109.9 162.7
139.9 122.1 134.5 i24.1@,?'~ 128.6 \
114*7 l"k6.1
111.2 144.4
121.6 155*2 129.0
1 2 7 . 2 s-3 2 0
15'6w 133.1
133.4 1 7 . i w 9 .114.1 5 110.5 \ 125.6
*
ll3so
assignment uncertain
120.7 129*0 { 100.5 125.5 142.1
H 148.9
154.9
4 13C NMR
110
128.0 135.5 126.2 J. 120.2 127.6 J. 135.7 \ 120.8 130.1 / \ 142.7 129.2 1 2 6\ ' 3 a i 5 ~ 1. ~ 2 7 . 0 a N 129.2 127.3 152.2 148.1 128.5
t
t
126.9 128.0 124.7 132.2 / \ 146.1 132.1129.5 & N
t
151.0
a ' 03n aAn rn
125.2 127.4 155.9 127.90':: 134.1 \ 3160.7 128.6 150.1
142.8 129.6 J. 129.4 N]
144.8
126.7 126.7 J. 152.0 133.1 \
t
\
124.2 120.6 122.6 / 127.0 \ f 111.6 156.2 142.7 \ 120.0
a
S
3 1b 112.8. 131.8 142.2
122.6 120.0 118.4 / 125.4 H 110.8 139.6
1
\
126.6 135.8 129.5 128.3
134.9 121.9 124.6 / 127.0 f 122.9 138.5 116.8 126.7* \ 121.3
0 : & t / 125.5 \
0 \
t' 130.3 149.1 144.0 130.9
/ 125.6* 113.8 141.7
119.9 127.4*
151.9
*
assignment uncertain
/N
4.6
4.6.2 Coupling Constants
13C-lH Coupling Constants (IJI in H z )
13C-13C Coupling Constants
((Jcclin
Hz)
Heteroaromatics
111
112
4 13C NMR
4.7 Halogen Compounds The additivity rules for estimating the 13C chemical shifts of various skeletons can be applied to those haloalkanes that do not have more than one halogen atom at a given carbon atom. In all other cases, the simple linear models fail but correction terms for non-additivity are available for halomethanes and derivatives (see [I, 21).
4.7.1 Fluoro Compounds Fluorine in nature occurs 100% as 19F, which exhibits a spin quantum number, I = 1/2. The signals of carbon atoms up to a distance of about four bonds are split by coupling to 19F.
13C Chemical Shifts and 19F-13C Coupling Constants of Fluoro Compounds (6 in ppm relative to TMS, IJI in H z ) 71.6 CH3F Jc, 161.9
109.0 116.4 CHzFz JCF 234.8 CHF3
JCF
274.3
118.5 CF4 JCF 259.2
Hal 15.8 \/F 80.1
2 J 19.5 ~ ~ 23.6 A F 9.2 85.2 3 J c 6.7 ~ 'JCF 163.3
4Jc~ = 0 2J ~ ~ 1 8 . 3 14.1 31.9 29.3 30.6 F22.7 29.3 25.3 84.2 3 J c 6.2 ~ 'JCF 164.8
2 J 22.4 ~ ~ 22.6
28.3
7;s
7 8 7 . 3
116.2 CF3-CF, 'JCF 271 2 J 48.1 ~ ~
2 J 24.8 ~ ~ 88.5 k F 147.7 'JCF 267.2
'JCF 177 78.9
JCF239 108.1
lJCF 283.2 115.0
CH2FYE.5 O 2~cF22
cHF2KE2 'Jc~28
C F 3 ~ z . 0 2J,, 43.6
4.7 Halogen Compounds
8
6
91.0; 'JCF 171
163.3; 'JCF 245.1
115.5; 2 J c 21.0 ~
32.8; 2 J ~ 22 p 23.6; 3 J c 5~
130.1; 3 J c7.8 ~ 124.1; 4 J c ~ 3.2
25.3; 4 J c ~ 0
6
C H 84.9; ~ 'JcF 166 ~ 1 3 7 . 02JcF ; 17 127.8; 3 J ~6F 128.9; 4 J c ~ 1 129.0; 5 J c 3~
-
N
3JcF4'3 @:8 .;
145.9: 4,J,
__
3.7
N
168.7; 'J,,
261.8
111.8; 2 J ~ F16.1 152.5; 3 J c 6.4 ~
141.3; 3 J c 7.5 ~
122.7; 2JcF 17.7 124'5:
113
121.2; 4 J c 4~ . 2 m . 7 ; 2 J 37.6 ~ ~
'JCF 255.1 138.3; 2 J 22.5 ~ ~
147.8; 3 J c 14.9 ~ N '
t F
163.7; ,J,'
236.3
Hal Estimation of 13C Chemical Shifts of Linear Perfluoroalkanes ( 6 in ppm relative to TMS) [3]
6 = 124.8 + CZi i
Increments Zi for the CF2- or CF3-substituent in position:
a
P
Y
-8.6
1.8
0.5
Example: Estimation of the chemical shifts in perfluorobutane ,CF2 ,CF3 F3C 'CF2 CF3
base value 1aCF2 1 P CF2 1 YCF3 estimated exP
124.8 -8.6 1.8 0.5 118.5 118.5
CF
base value 1aCF3 1a C F 2 1 P CF3
estimated eXP
124.8 -8.6 -8.6 1.8 109.4 109.3
114
4 13C
NMR
4.7.2 Chloro Compounds
I3C Chemical Shifts of Chloro Compounds ( 6 i n ppm relative to T M S ) 25.6
54.0
77.2
96.1
CH3C1
CHZClZ
CHC13
cc14
26.3
18.9
V C l 39.9
m
1
7
11.6 46.8
31.6
51.7
46.3
113.3
c1
126.1
c1
c1
119.9
w 118.1
127.1
Hal
c1
c1
c1
+Cl
c1
c1
c1
c1
c1&Cl
>=( 121.3
\=( 125.1 117.6 c1 63.7
40.7
88.9
CC13 CH2C1’fE7.
cHc12YE.4
0
FL59.8 25.4
126.6
128.5
135.5
__
124.3 n : ! 8 128.4 130.3
148.4
N
129.7 138.7
122.3 m 149.5
149.8
OH
y167.0 0
0
0;;:;
7
CCly-CC13
96.2
117.2
2
105.3
YcE 1 1
a-cl
c1
34.6
27.3
C
.
N
t
5
cl
151.6
4.7 Halogen Compounds
115
4.7.3 Bromo Compounds 13C Chemical Shifts of Bromo Compounds ( 6 in ppm relative to TMS)
9.6
21.4
12.1
-28.7
CH3Br
CH2Br2
CHBr3
CBr4 36.4
19.4
\Br 13.0
27.6
X Br.
1
Br-Br
53.4
CBr3--CBI~
31Y5 F r
Br
127.2
114.7
=( 97.0
Br.
Br
109.4
w
116.4
Br
Hal 25.9
"50.
112.4
B~
1
Br
122.4
+Br
E
49.4
32.4
31.8
Y
35.6
"k"g;.7 Br Br
31.3
0
0
128.7 138.5
Br
122.6 m 8 3 . 150.3
N
t
Br
142.3
4 13C NMR
116
4.7.4 lodo Compounds I3C Chemical Shifts of Zodo Compounds ( 6 in ppm relative to TMS)
-24.0 CH3I 20.6 -1 -1.6 3.O
&J
d31.2 40.1 28.3
-292.5 CI4 40.4
31.2
27.0 -1
I
I
130.1
25.4
127.4
I
144.8
Xi.0
y i . 9
15.3 9.1 130.3 -1 85.2
I1-
I. mi
-139.9 CHI3
-54.0 (33212
I
79.4
u 96.5
11-
@j mO .: 127.6
-
126*o0 / 6 5 . 2 150.1 N ‘ 156.9
137.6
122.9 150.8
N
t
118.2
4.7.5 References [l] G.R. Somayajulu, J.R. Kennedy, T.M. Vickrey, B.J. Zwolinski, Carbon-13 chemical shifts for 70 halomethanes, J. Magn. Reson. 1979,33, 559. [2] A. Furst, W. Robien, E. Pretsch, A comprehensive parameter set for the prediction of the 13C NMR chemical shifts of spjl-hybridized carbon atoms in organic compounds, Anal. Chim. Acta 1990,233, 213. [3] D.W. Ovenall, J.J. Chang, Carbon-13 NMR of fluorinated compounds using wide-band fluorine decoupling, J. Magn. Reson. 1977,25, 361.
4.8 Alcohols, Ethers, and Related Compounds
117
4.8 Alcohols, Ethers, and Related Compounds 4.8.1 Alcohols
13C Chemical Shifts of Aliphatic Alcohols ( 6 in ppm relative to TMS) 50.2 CH30H
18.2 \/OH 57.8
15.2 36.0 -OH 20.3 62.9
31.2
14.2 31.9 32.9 O H 23.0 25.8 62.1
25.9 /\/OH 10.3 64.2
YE
25.3
23.8 33.6 O -H 15.3 29.4 63.2
26.2 73.3 14.3 39.4 30.5 10.1 19.2 OH 72.2
7
1 4 s 6 7 . 2 23.2 39.2 23.5
13C Chemical Shifts of Aliphatic Glycols and Polyols (6 in ppm relative to TMS) HOWOH 63.4
HO\/\/OH 36.4
68.2
60.2
...........
7
2b OH . 7
18.7 ‘, 23.0 a
H
‘3
0
in CDCl,,
76.1
x
~
67.7 ’, 71.6 in D,O
72.9
HO 73.7
48.3 64*3 74.3
74.5
66.0 H O Y d ! ? H 91.2 OH
H Y % . 3 OH
~
~
4 13C NMR
118
13C Chemical Shifts of Alcohols ( 6 in p p m relative to TMS)
125.1
99.1
CF3-0H 61.4 '[Jlc~ 278 HZ *1J1,, 35 Hz
CC13-0H 75.9
OH
63.4 _TOH 114.9 137.5
8ti.8
73.8 83.0
OH
QH
121.1
108.5
50.0
25.1
26.3
13C Chemical Shifts of Enols ( 6 in ppm relative to TMS)
-pH 88.0
1 9 0 . a 9 0 . 5
149.0 22.5
0
32.8
1
46.2 103.3
99.0 22.5 31.0
A :::;
28.3 46.2
UFa6
0
57.3
J&Ol.l 56.6
28.5
4.8 Alcohols, Ethers, and Related Compounds
119
4.8.2 Ethers 13C Chemical Shifts of Ethers ( 6 i n p p m relative to TMS)
60.9 \
57.6 67.7
59.1
74.5 10.5
54.9 k . 6
/
0
\0-
\0-
14.7
23.2
59.1 73.4 20.5
\
27.0
49<0#
‘0-
‘ 0
O
W
21.4 9
72.3 58.4
32.9 15.0 72.7
52.5
152.7
‘0-
84.4 /
57.4 73.1 116.4 \0134.4
14.2
55.1 54’8 1 5 9 6 114.1
129.5 26.4
120.8
128.2 121.6
13C Chemical Shifts of Cyclic Ethers ( 6 in p p m relative to TMS)
145.6
0
98.4
68.6
28.5
1 4 4 . 1 0 6 4 : : 99.4 19.4
0I I
141.1 101.1
0
4 13C NMR
120
I3C Chemical Shifts of Acetals, Ketals and Ortho Esters (6 in ppm relative to TMS) 109.9
<
0-
53.7
95.0
u64.5
OAo
94.8
108.8
147*8
121.8 O-I.,100.7 ‘
0
ono
u
ono
99.9
Lo,
67.5
93.7 115.0
27.5
112.9 15.2
121.0
-0
10
-0 53:
0
50.4
4.9 Nitrogen Compounds
121
4.9
Nitrogen Compounds 4.9.1
Amines 13C Chemical Shifts of Amines ( 6 in ppm relative to TMS) as well as hydrochloride Shifts Induced by Protonation (in parentheses: 6aamine Samine,measured in D20)
The protonation of amines causes a shielding of the carbon atoms in the vicinity of the nitrogen. This shielding amounts to -2 ppm for an a-carbon atom, -3 to -4 for a P-carbon, and -0.5 to -1 .O ppm for a y-carbon. The most frequent exceptions occur in branched systems: Tertiary and quaternary carbon atoms in the a-position are generally deshielded by protonation of the nitrogen (A6 = +OS to + 9 ppm) PI. 28.3 (-1.8) CH3-NH2
38.2 (-2.0)
47.6 (-1.2)
\
\
27.4 (-5.4) 2"
11.5 44.6 (-0.4) (-1.8)
26.5 (-4.9)
N ;(
7
7
/
1 " 15.7 44.5 (-3.2) (-0.6)
L'NH
24.0
('2??52.4 1210 (-0.5)
(-1.4)
32.9 (-4.7) %4?
I'
P-
/" "2 19.0 (-5.0) 36.9 (-0.2)
56.5
' (+5.7)
12.0
10.9
54.4 9.5
4 13C NMR
122
14.3 (-2.6) H \N\ 45.9 35.2 (-0.4) (-1.8)
12.8 (-2.1) I \N\ 53.6 44.6 (+0.5) (-1.3)
23.2 (-2.9) H r c / N \ 12.5 54.0 36.1 (-0.9) (-2.1) (-2.0)
20.6 (-2.0)
22.5 (-3.1)
y"33.9 50.5 (-2.5) (+1*9)
18.7 (-1.3)
I
f i K 11.9 61.8 45.2 (-0.8) (-1.6) (-1.2)
28.2 (-1.2)
H
H
x"28.5 50.4 (+6.6) 25.4 (-0.8)
I
(-2.7)
1
y"40.9 KN\l8.7 55.5 (+0.2) (+3.8) (-0.8)53.6 (+8.9)
44.8 I"; 113.6 *doubly protonated form
td
64.2 (-5.4) H O m N H 2 44.6 (-1.9)
6
51.1 (+0.7) 37.6 (-5.4) 25.8 (-1.0) 26.3 (-1.1)
129.3
139.9
*doubly protonated form H 60.3
e,,,,
HO 33.5 (-1.5)
41.1 (-0.7)
6
58.7 (+0.6) 32.7 (-2.7) 25.7 (-0.3) 26.8 (-0.7)
6
64.3 (+2.4) 29.2 (-1.6) 26.5 (-0.9) 26.9 (-1.2)
30.2
39.9
\
\
NH
(jZ3
118.5
N
/
@:.l
129.3 116.9
129.4 117.0
4.9 Nitrogen Compounds
128.3
123
117.9
126.5
129.4 118.0
122.9
13C Chemical Shifts of Cyclic Amines ( 6 in p p m relative to TMS)
I 42.7
0
H
H
0::I CJ ::::
56.7
25.7
147.7
24.4
25.9
26.4
4.9.2 Nitro and Nitroso Compounds 13C Chemical Shifts of Nitro and Nitroso Compounds ( 6 in ppm relative to TMS)
61.2 CH3N02
12.3
21.2
k N 0 2
70.8
b
N
20.8 0
2
10.8 77.4
26.9 1
0 28.6
-
385.0
18.7
13.3 29.6 NO2 19.8 75.6 14.0 31.4 ~ 2 9 . 626.2 NO2 22.6 ~ 2 9 . 627.9 75.8
4 13C NMR
124
6 1 148.4 2 3 . 6 / 129.4
135.5
134.6
25.5
4.9.3 Nitrosamines and Nitramines
13C Chemical Shifts of Nitrosamines ( 6 in ppm relative to TMS) 11.5 38.4 I ? 7 //O
32.1 \
/-" 39.9
14.5 47.0
11.3 9 . 20.3
2
//o
19.14
"
,/o
y )*N
3
23.7 51.1
22.51 / 54.2 11.8
13C Chemical Shifts of Nitramines ( 6 in ppm relative to TMS)
N
4.9.4 Imines and Oximes
13C Chemical Shifts of Imines ( 6 in p p m relative to TMS) 22.6
29.3 163*4)=&r.6
29.7
17.8 129.8 130.2 137.4 122.0 129.8
128.6 129.0 137.3
P E W
130.8 -
1
3
2
.
4
w 153.2
E
a 127.0
4.9 Nitrogen Compounds
125
13C Chemical Shifts of Oximes ( 6 in p p m relative to TMS) /
147.8)”p” H
148*2/=N
OH
155.4)=N/
15.0
21.7
19’6y
13.6
OH
151.9 -N /OH
15.0
OH
11.2
2 0 . 31.5 7 ’
,OH
,OH
32.3 8 9 . 27.5 4 1 5 5 5\ y 6 126.0 .5
13.9 26.3
26.1
/ 128.5
24.6
129.1
4.9.5 Hydrazones and Carbodiimides
13C Chemical Shifts of Hydrazones ( 6 in pprn relative to TMS)
ydr.2 N
22.6\ 167.2
13a720.1
/
’
16e2
r46.5
13C Chemical Shifts of Carbodiimides ( 6 in pprn relative to TMS) 35.0 24.8 0
-
p
55.7
25.5
~
126
4 I3C
NMR
4.9.6 Nitriles and Isonitriles 13C Chemical Shvts of Nitriles
1.7 117.4 CH3CN
(6 in p p m relative to TMS)
10.6 120e8 \/CN 10.8
1 9 . y 119.9
28.5
assignment uncertain
125.1
110.5 NC-CN 8.6
122.4
137.5 117.2 +CN 107.8
123.7
13.3 19.3*
* 13.2 21.9 '19*' C -N 16.8 27.4
19.9
mCN
24.6 25.8
118.0 N m C N 14.6
6::; 118.7
132.8
13C Chemical Shifts of Isonitriles (6 in ppm relative to TMS, IJI C,J in Hz) Because of the symmetrical electron distribution around the nitrogen atom, the 13C-14N-coupling can be observed in the 13C NMR spectra of isonitriles: triplets with relative intensities of 1:1:1 (spin quantum number of 14N: I = 1, natural abundance 99.6%). 2J 7.5 'J 5.8 26.8 158.2 CH3NC
= o 'J 5.3 15.3 156.8 \NC 36.4 2J 6.5
35
= o 'J 5.0 120.6 165.7 b N C 119.4 2J 11.7
3J
165.7 'J 5.2
6
126.7 'J 13.2 126.3 2J=0 129.9 3J = 0 129.4 4J=0
4.9 Nitrogen Compounds
127
4.9.7 Isocyanates, Thiocyanates and lsothiocyanates 13C Chemical Shifts of Isocyanates ( 6 in pprn relative to TMS)
26.3 121.5 CH3NCO
13.6 34.2 125 (broad) -NCO 20.4 43.3
110.7
124*2 +NCO 124.7
13C Chemical Shifts of Thiocyanates and Zsothiocyanates (6 in ppm relative to TMS)
15.4 111.8 \SCN 28.7
133.3 S CN-
29’3 128*7 CH3NCS
13.3 32.3 131 (broad) -NCS 20.0 45.0
4.9.8
References [l] J.E. Sarneski, H.L. Surprenant, F.K. Molen, Ch.N. Reilley, Chemical shifts and protonation shifts in carbon- 13 nuclear magnetic resonance studies of aqueous amines, Anal. Chem. 1975,47, 2116.
N
4 13C NMR
128
4.1 0 Sulfur-Containing Functional Groups 4.10.1
Thiols 13C Chemical Shifts of Thiols ( 6 in p p m relative to T M S ) 6.5 CH3SH
19.7 V S H 19.1
12.0 35.7 -SH 21.0 23.7
27.6 b S H 12.6 26.4
35.0
27.4
22.2 33.9
Y’’
14.0 31.4 34.1 W S H 22.6 28.1 24.7
S H 14.0 30.6 24.6
H S W S H 28.7
28.1 38.8 64.2 HOwsH 27.3
1
6
28.8
130.6
\ 129.2
/ 128.8
25.9
125.3
126.8
S 4.1 0.2 Sulfides
13C Chemical Shifts of Sulfides ( 6 i n pprn relative to TMS) 19.3
‘S’
25.5
-S-
14.8
34.1 22.0
-S-
31.4 13.7
34.3 13.7
-sv
,l,k.4
23.2 A s k 4 5 . 6 33.2
23.6 r s y . 9 32.6
4.1 0 Sulfur-Containing Functional Groups
15.5
34.1 22.0
$‘9-
54.8
129
43.1
31.4 13.7 30.4
25.4 132.3
-s*
772.6
141.8
S
14.2
110.5
81.4
e
106.9
15.6
128.7
131.0
124.9 127.0
13C Chemical Shifts of Cyclic Sulfides ( 6 in p p m relative to TMS)
A 18.7
5
26.0
<’>
28.0 C=X_,.1 \-/128.8
;;:; 26.9
26.6 29.8
18.6
S
Q
38.1
c:,
34.4
S 29.1
4 13C NMR
130
4.10.3 Disulfides and Sulfonium Salts
13C Chemical Shifts of Disulfides and Sulfonium Salts ( 6 in ppm relative to TMS) 22.0
32.8
vs,s-. 14.5
13'*'0
\ /
127.4
127.2 129.3 27.5 \
-s+1/
4.1 0.4
Sulfoxides and Sulfones 13C Chemical Shifts of Sulfoxides and Sulfones ( 6 in ppm relative to TMS)
8
40.1 \ /
i?
54.3
0
123.5 43*9
14>&
25.4
129.6 130.9
42.6
s
39.3 48.2
\+
\ /
//Y\ 0 0
dq$-, 6.7
37.1 k 3 . 5 \ 04%0
133.2
34.2 \
15.2
141.6
40.3 56.3 13.0 \-
A\
0 0 16.3
x57*6
00 % 0 22.7
4.10 Sulfur-Containing Functional Groups
131
4.1 0.5 Sulfonic and Sulfinic Acids and Derivatives
13C Chemical Shifts of Sulfonic and Sulfinic Acids and Derivatives (8in pprn relative to TMS) 39.6 CH3S03H
8.0
18.8 m S 0 3 H 13.7 53.7
b S 0 3 H
46.7 52.6
9.1
CH3S02Cl
18.4
0
132.3
25.0
17.1
24.5
12.1 A 67.1O ' 2"
k 60.2 S o 2 "
42.7
143.5
16.8
7 6 ; y 1
yiyl
48.7 \s/S\ 13.7
6
134.9 127.9 / 130.0 134.4
o\\0
0
18.2
144.1
135.3
139.3
131.7
4 . 1 0.6 Sulfurous and Sulfuric Acid Derivatives
S
13C Chemical Shifts of Sulfurous and Sulfuric Acid Derivatives (6 in pprn relative to TMS)
n 26.0
57.1
9
8'0
0
4 13C NMR
132
4 . 1 0.7 Sulfur-Containing Carbonyl Derivatives 13C Chemical Shifts of Sulfur-Containing Carbonyl Derivatives (6 in ppm relative to TMS)
The chemical shifts of thiocarbonyl groups are higher by about 30 ppm than those of the correspondingcarbonyl groups:
6+,
1.5 6 p o - 57.5
Carbonyl groups of thiocarboxylic acids and their esters are deshielded by about 20 ppm with respect to the corresponding oxygen compounds.
32.6
il
39.2
Ad
278.4
28.4 22.2
30.1
194.1
s 32.7
32.1 13.6
195.4
194.5
234.1
202.1
199.4 1 42.3 132.1
11.3
30.2
SH
20.6
33.3
A
" 2
205.6
-
4.1 1 Carbonyl Compounds
133
4.1 1 Carbonyl Compounds 4.1 1.1 Aldehydes
Additivity Rule f o r Estimating the 13C Chemical Shifts of Aldehyde Carbonyl Carbon Atoms ( 6 in p p m relative to TMS)
6,=, = 193.0 + Z Z i 1
-Cp-CrCHO
Substituent i -Cf -CH=CH2 -CH=CH-CH3 -phenyl
z,
Z8
6.5 -0.8 0.2 -1.2
2.6 0.0 0.0 0.0
13C Chemical Shifts of Aldehydes ( 6 i n p p m relative to TMS)
197.0 CH2=O
15.5
31.3 200.5 CH3- CHO
204*6
194.4 CHO
4
13.8 24.3 201*3 -CHO 22.4 43.6
176.8 CHO 83.1 81.8
-
5.2 202.7 vCHO 36,7 23.4
205.6
204.7 CHO
15.7 201.6 m C H O 13.3 45.7 95.3 176.9 CC13-CHO
192.0 CHO
137.8 138.6 25.2 25.2
/
134.3
129.0
c=x
4 13C NMR
134 4.1 1.2
Ketones Additivity Rule for Estimating the 13C Chemical Shifts of Ketone Carbonyl Carbon Atoms ( 8 in ppm relative to TMS)
6,=, = 193.0 + CZi i
0
II
-cp-c,--c-c,(-pSubstituent i -CC
Za
-CH=CH* -CH=CH-CH3
-pheny 1
6.5 -0.8 0.2 -1.2
Zp 2.6
0.0 0.0 0.0
13C Chemical Shifts of Aliphatic Ketones ( 6 in ppm relative to T M S ) 206.7
0
207.6 30.7
29.3
0 27.5
45.2 13.5
213.5 29.4
43.5 23.8
26.5
24:hUa3
13C Chemical Shifts of Halogenated Ketones
(6 in ppm relative to TMS) 203.5
0
\x/F 25.1 84.9
187.5 23.1
0
115.6
4.1 1 Carbonyl Compounds
135
\q:l \qB:
186.3 27.2
193.6& \ a;2 22.1
49.4
203.5 27.0
\&
25.1
35.5
21.1
c1
Br
187.5
Br 84.9
23.1
c1 c1
Br
Br
1 7c15 . g ; : C
c1
c1
c1
13C Chemical Shifts of Unsaturated and Alicyclic Ketones ( 6 in ppm relative to TMS) 197S k U 8 . 0
207*9 29.9l h 0 . 3
25.7 137.1
81.9
21.1
78.1
209.4 \ 128.4
51.5
26.3
137.4
/ 132.9
132.2 137.8
13C Chemical Shifts of Diketones ( 6 in p p m relative to TMS)
Enol form: see Chapter 4.8
4 13C NMR
136
13C Chemical Shifts of Cyclic Ketones and Quinones (6 in ppm relative to TMS)
0
34.0
6
8
29.1
209.8 134.2
38.2
165.3
22.9
b
185.8 127.3
150.6
156.7
25.8 26.7 131.8
187.0 136.4 139.7
0
0
4.1 1.3
Carboxylic Acids and Carboxylates Additivity Rule f o r Estimating the 13C Chemical Shifts of Carboxyl Carbon Atoms ( 6 in ppm relative to TMS)
6,=,
= 166.0
+ X Zi i
-C+p-C,COOH
Substituent i -Cf
-CH=CH, -phenyl
za
ZB
Zr
11.0
3 .O
-1.0
5.0 6.0
1.o
37.9
4.1 1 Carbonyl Compounds
137
I3C Chemical Shifts of Carboxylic Acids (6 in pprn relative to T M S ) 166.3 H-COOH
18.8
21.7 176.9 CH3- COOH
184.1
9.6 180.4 k C O O H 28.5
14.2 27.7 -COOH
'r;:.Y
156.5
180.6
=/
8;:;
78.6 74.0
26.6 115.0 163.0 CF,-COOH
40.7 173.7 C HZC1-COOH 169.2
160.1
(
40.9 COOH COOH
172.6
182.1
- COOH _ .
133.1 128.3
FooH
13.7 36.2
22.7 34.8
171.7 COOH
COOH
18.7 179.4 a C O O H
63.7 170.4 CHC12-COO H
173.9 28.9O '('H
133.7 88.9 167.1 CC1, - C O O H
166.1
130.4 COOH
(,," COOH
166.6
134.2JC00H HOOC
13C Chemical Shifts of Carboxylate Anions ( 6in ppm relative to TMS; measured in water unless indicated otherwise) 171.3
-coo-
24.4 182.6 20.8* 177.6* CH3- COO-
*
11.1 185.1 10.6* 181.3"
\/coo-
solvent: CDCl,
31.5 28.4*
188.6
Tooc=x
* solvent: CDCl,/DMSO 174.5 =PO0126.7 134.3
0::; COO- 185.4
26.9 45.0 175.9CH2Cl-COO
65.6 171.8 CHClZ--COO
133.1 96.2 167.6 CCl, -COO-
4 13C NMR
138
4.1 1.4 Esters and Lactones Additivity Rule for Estimating the 13C Chemical Shifts of Ester Carbonyl Carbon Atoms (6 in ppm relative to TMS) = 166.0 + Z,Zi i
coo- Ca'-
- c r cp-c-
-
Substituent i
Zp 3.0
za 11.0 5 .O 6.0
-CL
-CH=CHz -phenyl
zct -5.0 -9.0 -8.0
-1.0
1.o
13C Chemical Shifts of Acetic Acid Esters ( 6 in ppm relative to TMS)
170x0) 20.9
14.4
1 6 9 3 22.3
28.1
21.0
17 O x 0 &
x>"" 24.4
O f 32.2
72.3
.5
21.3
1 6 9 3 20.8
21.9
0'""' 128.9
121.4 150.9
13C Chemical Shifts of Methyl Esters ( 6 in ppm relative to TMS)
161.6 .:
)(
H
173.3 9&0:1*5 20.6
23.9
27.2
172.2 f i 8 1 . 9 13.8 35.6
34.9
26.0 26.4
4.1 1 Carbonyl Compounds
139
167.8
cl
d
40.7
cl
c1 89.6
c1 64.1
&
166.5 1 3 0 . 4 a 0 / 5 1.5
16'.*
128.8
74.8
52*3
1676.)-:
51.8 130.5 129.7 / 128.4 132.8
2 ; , ; 03 y
41.2
51.3
O, 0
130.1 1
I
6
5 52.1~
$d ~
~
'
%
52.2
1521:~~'~
133.5 0
0
0
'0
13C Chemical Shifts of Lactones ( 6 in ppm relative to TMS)
&C
6
171.2 29.2
178.1 27.8
168.6 39.1 68.8
58.7
23.1*
28.9* 29.5"
*
assignment uncertain
19.1
22.3
6 1 . 117.0 6
6.:& :
69.2
69.3
22.3
152.1
' 142.9 106.0
c=x
4 13C NMR
140
4.1 1.5 Amldes and Lactams
Additivity Rule for Estimating the 13C Chemical Shifts of Amide Carbonyl Carbon Atoms ( 6 in ppm relative to T M S )
Substituent i
zp
za 7.7 3.3 4.7
-Cf
-CH=CH* -phenyl
4.5
-0.7
zaq
zp'
-1.5
-0.3
-4.5
13C Chemical Shifts of Amides ( 6 in ppm relative to TMS)
Fonnamides: 166.5
163.3 0
167.6
?!AN,24.8 -
H
H
H = 10%
161.8
\XNT -164c3t NH H H
-.x
14.6
= 90 %
- H
36.9k 1 6 . 8 = 10%
Primary and Secondary Acetamides: 173.4
171.7
22.3
* in water
'
I 28.2
= 90%
22.7
H
36.5
162.6
H
12.8
4.1 1 Carbonyl Compounds
169.8
168.6
H
22.5
22.5
141
169.0
22.6
H
22.3
H
23.6
t
49.9
Tertiary Aliphatic Amides:
169.6
gNK
,35.0 “03 21.5
N
I
21.4 38.0
13.1
42*9L 14.2
gN)1.4
170.1
21.5 50.65
2”:.;”
‘11.2
40.1
[-
14.0 35.1 42*0
13’2 14.4
13C Chemical Shifts of Lactams ( 6 in ppm relative to T M S )
175.5
179.4 42.4
20.8
49.5
34‘4\N.(z;3 49.9
21.6 23.3
171.9 42.0
147.6
22.3
“3::
m ( : & . 8 136.1
‘
106.6
42.0
142.0
*
29.9* 30.7* assignment uncertain
4 . 1 1.6 Miscellaneous Carbonyl Derivatives I3C Chemical Shifts of Carboxylic Acid Halides (6 in ppm relative to TMS)
A70.4 c1 33.6 1 3 7 3 65.6
'
131.4
k 8 . 9 I
A65.7 Br 39.1
9 0 7 4 . 7 c1 41.0
176.3
168.0
6
l% c/
c1
133.2 131.2 / 128.8 135.1
25.9 13C Chemical Shifts of Carboxylic Acid Anhydrides ( 6 in ppm relative to TMS)
HHO '' 158.5
167.4
AA0h 169.6
37.2 13.4
170.9-
&
0 %
/ 162.4
27.4
128.9 / *f28.9 134.5
4.1 1 Carbonyl Compounds
143
13C Chemical Shifts of Carboxylic Acid Imides ( 6 in ppm relative to TMS)
135*5(173*0
133.12@ 131S0 167.5
I ”
N-
0
23.2
0
l 3 C Chemical Shifts of Carbonic Acid Derivatives
(6 in ppm relative to TMS) CO 181.3
C02 124.2
lo, 54.9
\0
~
1 0 -
0 168.2 ~
~
-
(2%192.8
67.3 19.1
-0
156.5
155.9
30.9
13.6
226.2
lo)
68.1
27.4 \ N
21.7
157.8 165.4
k63.5 H2N
\
“2
N ‘”38.5
I
I
k61.3
“uN/ 31.2 45.0
22.5
14.7
NMR
4
144
4.1 2
Miscellaneous Compounds 4.12.1
Derivatives of Group IV Elements 13C Chemical Shifts and Coupling Constants of Derivatives of Group ZV Elements (6 in ppm relative to TMS, IJI in Hz)
-Si-
I I
0.0
128.3 129.6
129.1
4
4J 19
I -4.2 --.Pb -
+9*3
I
129.1 16.2
A
26.7
S
y>cl
1\
16.6
c1
129.6 I .i2*0 +S\ 138.7
128.5 136.3
f 'co4*7
MISC.
169.0
21.6
4.1 2.2 Phosphorus Compounds
13C Chemical Shifts and 31P-13C Coupling Constants of Aliphatic Phosphorus Compounds ( 6 i n ppm relative to TMS, IJI in Hz) 3J 11 'J12 24.5 32.6
'7-
3J 12.5 24.8
'J 16
13.9
126.0; 'J 12
-'- L
14.4
14.0 4J0
28.3 2J 14
450
'J -10.9 28.6
27.9 2J 15
/'< '
I-
10.7 \ 'J55
3J 10 2J 14 27.0 28.9
130.8 @pH2 2J20
12.3; 'J 49 6.3 TP+12 J 5 - L
'J 8 3J 15 ' J 48 24.1 1 8 . 7 y 1 4J 0
3 2J 4
z
c
'
3 J l l 'J44 23.4 42.9 -pc12 13.7 25.1 4J 0 2J 14
3J 11 'J20 24.7 33.6 /V-PMO, 14.0 24.8 4 J 0 2J 16
A,
3J 13 'J 66 24.4 2 7 . 8 y
'J 143 0
-PO 13.6 24.0 4J 0 2J 5
/
0,
'8
48.8 13.7 T 2 J 12 5 J 0
/o 3J 6 16.2 0k0-#=0 63.6 2 J 6 O4
33.4 3J5
19.1 61.9 4~~ *J 11
13.6 5J0
"Fko/
-0-yo-
4J 0 2J 6 18.9 67.2
2J 12
61.4;2J7 0-
6.6 2J 7
32.6 3J7
53.4
16.5 3J 6
I /N\
? -b
Misc.
3J 16 'J 54
'J 54
23.9 34.61 20.8 13.6
24.8 2J 4
4J 0
14.9 YN2J4
3J 16 'J 51 24*0
1
4J 0
30*9y 53.8/& FS
3 2J4
z
L
2J 5
%
13C Chemical Shifts and 3 1 P - 1 3 C Coupling Constants of Aromatic Phosphorus Compounds ( 6 in ppm relative to TMS, IJI in H z ) 2J 20 'J 12 137.2 /
'J 104 132.3 135.6
2J 10
3J 12
128.5
132.3
11.4; 'J 145
0
II
HO-P-OH
qPP- 120.5; 3J 4
0
0' ' 0
1 5 0 . 4 y 0 129*87 125.1 5J 4J0 2J 8
128.1; 3J 15 130.5; 4J 0
129.5 124.1 151.5
4J
3J
2J 8 150.4
-
129.7 120.1 5J0 O O - T - O G 5J 0 O ! - l - O G 125.5
Ja
P
Misc.
4.12 Miscellaneous Compounds
147
13C Chemical Shifts and 3 1 P - 1 3 C Coupling Constants of Phosphoranes ( 6 in ppm relative to TMS, (JI in Hz) 2~ 9
.\?
'J 83
3J 11132.9< 128.5130.6 4J 3
11.0 2J 4
'
24.1; 3J 6
3..2 'J 111
I
4.1 2.3
Miscellaneous Organometallic Compounds 3C Chemical Shifts and Coupling Constants of Miscellaneous Organometallics ( 6 in ppm relative to TMS, IJI in H z ) Li-
-BL
\ -6.3
6.2
Li+
/*
I
/B-
\
I
\ 14.8
-16.6
I 8.4
11.2
-AS+-
I
/As-
I-
4
\ / 136.8 129.4 d S b o 129.1 \ /
qB;p 1.o
139.3
2J 85 3J 104 137.4 128.3
128.3
131.1
170.3 'J 1275 (couplings with 199Hg)
Misc,
4 13C
148
NMR
4.1 3 Natural Products 4.13.1 Amino Acids
I3C Chemical Shifts of Amino Acids ( 6 i n ppm relative to TMS;solvent: water) 42.8 ' H 3 N 7 ' - 173.6
41.5 + ~ 3 ~ %0 ?2 (pH 0.45)
0
7:+ H N 3:*
(pH 0.49)
(pH 4.53)
46.0 H2NV0182.7 (pH 12.01)
11 179.4 0 (pH 5.03) 34.8
H 2 N 5 1 0y 2 . 7 (pH 12.56)
17.5
21.7
51.9 (pH 4.96)
52.7 (pH 12.52)
fH3Nf q O 174.0 H 50.1 (pH 0.43)
17.8
18.0 18.5
17.9
19.2
20.3
'H3N 30&75.40 59.8 0 (PH 3.0) 22.1
25/1
40.1
63.2 (pH 12.60)
61.9 (PH 5.64)
22.7
22.5
21.8
25/1
40.7
22.9
45.5 25$
23.7
Natural
Products +H3N 52.8 (pH 0.37)
+H34%6.3 0 54.4 (pH 7.00)
(pH 13.00)
4.13 Natural Products
12.1
149
12.4 2 . L $ . 6 1
H2Nf
58.7 (pH 0.28)
0
184.1
60.9 (pH 6.04)
62.3 (pH 12.84)
57.5 O (pH 6.05)
57.8 o (pH 9.28)
<
OH
60.4
56.0 6 (pH 1.12) 20.2 H o d
HO
66*3$0H
+H3Nf171.7 59.8 (pH 1.36) 25.1
61.5 0 (pH 5.87)
62.1 0 (pH 9.27)
56.7 (pH 5.14)
60.7 (pH 11.02)
rSH
55.9 0 (pH 1.75) /
15.2 HO' t N H 3 +
31 +H3Nf
55.3 0
175.3
9) 39.0fS
44.1 f s
+H3Nf 1 1 O 180.7 55.8 0 (in D20)
Natural Products
4 13C NMR
150
1 3 130.7 1 p 129.5 =145 37.5
,
1 3 0117.5 p z F 3 ~138 37.5
,
+H3N b ? 5 .O
57.3 0
P
174.4 35.0
181.3
178.7 OH
(pH 0.41)
0-
53.5 O (pH 6.73)
55.3 O (pH 12.73)
182.4 26.1/
30.7
33.0
28.2
0-
53.4 0 (pH 0.32)
56.0 (pH 6.95)
57.2 (pH 12.51)
33.3 0-
53.7 0 (pH 0.46)
Natural 30.5 Products + H 3 N h O H 173.2 54.0 (pH 0.50)
55.5 0 (pH 5.02)
57.2 0 (pH 13.53)
31.2
35.7 0-
55.9 0 (pH 6.03)
57.3 0 (pH 13.85)
151
4.1 3 Natural Products
'H2N
""e;
NH2 y157.9 41.6
"7 28.8
53.9 0 (pH 1.33)
/
") 42.1
25.0
32.7
56.6 (pH 11S 2 )
(pH 7.87)
24.4 29.4
24.8 173.3
(pH 1.27)
4
30.0 62.307 . 2 k 175.4 H2+ 0 (pH 7.26)
53.9
24.8 30.0 175.8 (PH 9.8)
174.9 H2+
0
133.1 55.7(pH 7.82)
127.7 53.6 (pH 1.74)
25'6
133.5 56.1 (pH 9.21) 56.1 "3'
174.4
74.8 \%108.7 125.8 119'3112.7 H ~137.3 (in D20, sat., 80 OC) 120.3
H
'2,
Natural Products
4 13C NMR
152
4.1 3.2 Carbohydrates l 3 C Chemical Shifts of Monosaccharides (6 in ppm relative to TMS)
Ribose
68.2 63.8
68.1 63.80 H 0 7 m 70.8 9 4 * 3
83.8
69.7 OH 71.9
'"/OH -.
Hdf
f'bH 70.8 71.7
Horn 70.4 OH 69.2
-
100.4
H d f f'bH 71.2 76.0
H0y>103.1 84.6 "'lo- 5 5.5
-.
56.7
H d f fibH 69.8 71.1
68.6 63.9
H o s Y57.0 OH 71.0
103.1
.H d f f"bH 70.9 74.3
Glucose
61.6 OH 72.3 7 HO 0 HO
.
e OH
92.9 72.5
76.7
OH 96.7 75.1
4.13 Natural Products
70.;%
100.0 74.1
153
70.6% HO
\ 58.1 76.8
72.2 o\55.9
OH 104.0 74.1
x(3: 69.4
Ac 0 Ac 0
70.5
Fructose
99.1 OH Ho-O
65.9
H 0 7 J 3 i y o H in water and in DMSO: traces
61.9
-
70.0 in water: 75%; in DMSO: 25%
105'5 63.8
Ho82.2 W
O 'OH H
77.0 82.9 in water: 4%; in DMSO: 20%
75.4 76.4 in water: 21%; in DMSO: 55%
in H z )
1 3 C - l H Coupling Constants through one Bond ('JCH
I
OR lJCH 169-171
I
H ~ J C H158-162
Natural Products
4 l3C
154
NMR
4.1 3.3
Nucleotides and Nucleosides 13C Chemical Shifts of Nucleotides and Nucleosides (6 in ppm relative to TMS) "2
164.4
(in DMSO/water, 1:2)
I
k 5 165*5 5.4 N O
e
(in D20)
(in DMSO)
"2
93.8?% 141.4
H
H
H
10 1.7 140.6
I
NAg0.7
109.5 136.2
:y;;:q;; I
69.3
I I
I
69.8
OHOH
OHOH
(in D20)
(in D20)
70.5 OH (in D20)
tpJ 119.1 2"
H
140.3
153.4
#
\ N 151.7
(in DMSO)
Natural Products
168.8
156.4
162.2 (in D20)
4.13 Natural Products
155
86.2 OHOH
7 0 . 6 1 73.9 OHOH
(in DMSO)
(in DMSO)
Hq62.5
I
ky
88.3 OH (in DzO)
152.0
84.8 88.0 7 2 . 0 v 39.6 OH (in D20)
Natural Products
4 13C NMR
156
4.1 3.4
Steroids 13C Chemical Shifts of Steroids ( 6 in p p m relative to TMS)
38.0
21.2 26.8
27.4
38.8 26.6
32.3 28.9 H 28.9
11.0
197.7 123.9 32.5
197.4 124.0 32.3
12.0 39.2 22.7 32.6 23.1
N iit t I ra I
P!odllc:s
23.8
18.8 I
4.1 4 Spectra of Solvents and Reference Compounds
157
4.14 Spectra of Solvents and Reference Compounds 4.1 4.1
13C NMR Spectra of Common Deuterated Solvents (125 MHz, 6 in ppm relative to TMS) Acetone-dg
I 206.0
-
29.8
A
31 1
'
1
200
'
1
180
'
1
160
I
9
140
,
120
I
30
.
100
I
'
80
I
1
29
~
60
I
L
I
I
I
1 -
40
.
1
20
0
Acetonitrile-d3
I 118.3
2
I
'
200
1
180
~
160
1
140
~
1
120
~
100
1
1
80
~
60
1
40
~
I
~
0
20
Benzene-dg
129
I
2bO
1
128 127
180
'
I
160
I
'
140
l
'
120
l
~
100
1
80
~
,
60
*
,
40
.
0
20
I
.
I
Bromoform-d
~
200
I
'
180
l
160
~
1
140
, '
120
I
I
-
I
100
T
I
80
I
io
1'1 I
.
1
60
I
3
40
.
I
20
0
Chloroform-d
I . . . . ( I . . I I
78
- I
200
'
I
180
'
I
160
'
I
140
'
77 ,
120
.
76 I
100
.
l
80
.
I
60
.
l
40
~
1
20
,
L 0
l
Solvents
4 13C NMR
158
Cyclohexane-dl2
27 l
'
1
200
'
180
1
'
160
1
140
'
1
120
'
'
80
100
1
26
1
1
~
60
1
'
40
1
~
~
'
~
0
20
Dimethyl sulfoxide-dg
40
1
~
200
1
'
180
1
-
160
1
140
-
1
120
39
'
1
~
80
100
1
L 1
~
60
1
40
1
''
1
20
0
Methanol-dl
R -
I
I \
50
51 I
'
I
200
'
180
I
'
160
I
140
'
~
120
49
'
I
100
49.9
'
80
I
'
60
l
~
40
I
~
I
'
I
0
20
Methanol-d4
50 I
.
200
I
180
'
160
1
'
140
1
'
120
100
1
48
49 1
~
80
1
~
60
L 1
,
40
1
20
~
1
~
1
0
Pyridine-dg
1149' L 123.5
135.5
151
150
149
1
136.0 135.0
124.0 123.0
A - 6k 25.3
68
67
26
25
I
4.14 Spectra of Solvents and Reference Compounds
159
4.1 4.2 3C NMR Spectra of Secondary Reference Compounds Chemical shifts in 13C NMR spectra are usually reported relative to the peak position of tetramethylsilane (TMS), which is added as an internal reference. When TMS is not sufficiently soluble in the sample, use of a capillary containing TMS as external reference is recommended. Owing to the different volume susceptibilities, the local magnetic fields differ in the solvent and reference. Therefore, the position of the reference must be corrected. For a D2O solution in a cylindrical sample and TMS in a capillary, the correction amounts to +0.68 and -0.34 ppm for superconducting and electromagnets, respectively. These values must be subtracted from the shifts relative to external TMS if its position is set to 0.00 ppm. Alternatively, secondary references with (CH3)3SiCH2 groups may be used. The following spectra of two secondary reference compounds in D 2 0 were measured at 125 MHz with TMS as external reference. Chemical shifts are reported in ppm relative to TMS upon correction for the difference in the volume susceptibilities of D20. As a result, the peak for the external TMS appears at 0.68 PPm.
0.68 TMS (external reference) - .9 55.1 19.8 15.8
H3C, FH3 Si.,-.-SO3Na
H3C' 1
'
1
'
I
'
I
'
2,2,3,3-D~-3-(Trimethylsilyl)-propionic acid sodium salt -2.0
A 186.3 260
180
e
r
n
a
-l----l--
187 186 33
1bO
140
1O ;
32
31
100
12
13
sb
I
60
0.68 TMS lreference) 31.9
'
I
40
12.7 '
20
I
11
'
0
I
~
Solvents
160
4 13C NMR
4.1 4.3
3C NMR Spectrum of a Mixture of Common Nondeuterated Solvents This broad band-decoupled I3C NMR spectrum of a CDC13 sample with 20 common solvents (0.05-0.4 ~ 0 1 % )is shown as a guide for the identification of solvent impurities (125 MHz, 6 in ppm relative to TMS). Chemical shifts of signals marked with an asterisk (*) may change up to a few ppm if the sample contains solutes with functional groups that can form hydrogen bonds. DMF: dimethyl formamide; THF tetrahydrofuran; EGDME: ethylene glycol dimethyl ether. 149.9* pyridine 206.8* acetone
192.6 CS,
ethyl acetate 171.1
DMF 162.5
210 205 200 195 190 185 180 175 170 165 160 155 150 145 140 pyridine 129.1 toluene 136.0 128.4, 128.3 toluene, benzene toluene 137.9
123.8 pyridine
dimethyl sulfoxide 41.1
25.6 DMF36.4
THF
5.1 Alkanes
161
5 l H NMR Spectroscopy
5.1 AI kanes 5.1.1 Chemical Shifts I H Chemical Shifts of Alkanes ( 6 in ppm relative to TMS, J in H z ) CH4 0.23
Jgem -12.4
FH3 0.89 Jvic 6.8 CH 1.74 I \
CH3 CH3
fH3 0.86
FH3 0.91
CH3
FH2 1.33 CH3
FH3 a 0.91 7H2 b 1.31 7H2 c CH3
3J,b
Jvic 7.4
7.3
2Jbb' -12.4
3Jbc 3Jbci
5.7 8.5
In long-chain alkanes, the methyl groups at ca. 0.8 ppm typically show distorted triplets because of second order effects:
\
/
/
C\
5 'H NMR
162
Chemical Shifts of ,C, IH ( 6 in ppm relative to TMS)
Monosubstituted Alkanes
1 ,
Substituent -H
C -CH=CH2 H a
1
0
N
S
0
11
C / \
-C=CH -phenyl -F -C1 -Br -I -OH -0-alkyl -OCH=CH2 *phenyl -0COCH3 -OCO-phenyl -0S02-4-tolyl -NH2 -NHCH3 -N(CH3)2 -NHCOCH3 -NO2 -CN -NC -SH -S-alkyl -SS-alkyl -SOCH3 -S02CH3 -CHO -COCH3 -CO-phenyl -COOH -COOCH3 -CONH, * -coc1
Methyl -CH3 0.23 1.71 1.80 2.35 4.27 3.06 2.69 2.16 3.39 3.24 3.16 3.73 3.67 3.88 3.70 2.47 2.3 2.31 2.79 4.29 1.98 2.85 2.00 2.09 2.30 2.50 2.84 2.20 2.09 2.55 2.10 2.01 2.02 2.66
-CH2 0.86 2.00 2.16 2.63 4.36 3 -47 3.37 3.16 3.59 3.37 3.66 3.98 4.12 4.37 4.07 2.74
Ethyl -CH3 0.86 1.oo .15 .21 .24 .33 .66 .88 1.18 1.15 1.21 1.38 1.26 1.38 1.30 1.10
2.32 3.26 4.37 2.35 3.39 2.44 2.49 2.67
1.06 1.14 1.58 1.31 1.28 1.31 1.25 1.35
2.94 2.46 2.47 2.92 2.36 2.32 2.23 2.93
2.80 1.13 1.05 1.18 1.16 1.15 1.13 1.24
-CH2 0.91 2.02 2.10 2.59 4.30 3.47 3.35 3.16 3.49 3.27
Propyl -CH2 -CH3 1.33 0.91 1.43 0.91 0.97 SO 0.95 .65 0.97 .68 1.06 .81 1.06 .89 1.03 .88 0.93 1.53 0.93 1.55
3.86 4.02 4.25 3.94 2.61
1.70 1.65 1.76 1.60 1.43
1.05 0.95 1.07 0.95 0.93
3.18 4.28 2.29
1.55 2.01 1.71
0.96 1.03 1.11
2.50 2.43 2.63
1.63 1.59 1.71
0.99 0.98 1.03
2.42 2.32 2.86 2.31 2.22 2.19 2.87
1.67 1.56 1.72 1.68 1.65 1.68 1.74
0.97 0.93 1.02 1.oo 0.98 0.99 1.00
5.1 Alkanes
163
H Chemical Shifts of Monosubstituted Alkanes (contd.)
(6 in ppm relative to TMS) Substituent -H C -CH=CH2 -C_CH -phenyl . . H -F a -C1 1 -Br -I -OH -0-alkyl -OCH=CH2 -0-phenyl -0COCH3 -0CO-phenyl -0S02-4-tolyl N -NH2 -NHCOCH3 -NO? -CNL -NC S -SH -S-alkyl -SS-alkyl -SO~CHQ 0 -CHb 11 -COCH3 C -CO-phenyl / \ -COOH
-coc1
Isopropyl -CH -CH3 1.33 0.91 2.59 2.89
1.15 1.25
4.14 4.21 4.24 3.94 3.55 4.06 4.51 4.99 5.22 4.70 3.07 4.01 4.44 2.67 3.87 3.16 2.93
1.55 1.73 1.89 1.16 1.08 1.23 1.31 1.23 1.37 1.25 1.03 1.13 1.53 .35 .45 .34 .25
3.13 2.39 2.54 3.58 2.56
.4 1 .13 1.08 1.22 1.21
356
117
2.97
1.31
Butyl tert-Butyl -CH2 -CH2 -CH2 -CH3 -CH3 0.89 0.91 1.31 1.31 0.91 1.02 2.06 ~ 1 . 5 ~ 1 . 2 .0.90 1.22 2.18 1.52 1.41 0.92 1.32 2.61 1.60 1.34 0.93 0.95 1.34 4.34 1.65 1.60 3.42 1.68 1.41 0.92 1.76 3.20 1.80 1.42 0.93 1.95 1.22 3.63 1.53 1.39 0.94 1.24 3.40 1.54 1.38 0.92 3.68 1.61 1.39 0.94 3.94 1.76 1.47 0.97 1.45 4.06 1.60 1.39 0.94 1.58 4.03 1.62 1.36 0.88 1.15 2.68 1.43 1.33 0.92 1.28 3.21 1.49 1.35 0.92 1.59 4.47 2.07 1.50 1.07 .63 1.50 0.96 1.37 2.34 1.44 1.43 .59 1.43 0.92 2.52 1.39 .56 1.42 0.92 2.49 1.32 .64 1.42 0.93 2.69 1.44 .59 1.35 0.93 1.07 2.42 1.12 2.95 1.72 1.41 0.96 1.23 2.35 1.62 1.39 0.93 1.20 2.31 1.61 1.33 0.92 1.22 2.22 1.60 1.37 0.93 2.88 1.67 1.40 0.93
\
/
C / \
5 'H NMR
164
\
/
C / \
Estimation of IH Chemical Shifts of Aliphatic Compounds (6 in ppm relative to TMS)[ l ]
CH,
~ C H ~= 0.86 X + Z, ~ C H ~ C X Y=Z0.86 + i
CH2
~ C H ,= 1 . 3 7 + Z Z a i i
CH
6CH=1.50+xZ,i
-c c-phenyl H -F a -C1 1 -Br -I 0 -OH
-0-c
-0c=c -0-phenyl -o(C=Ot N -N -N+ -N(C=Ot -NO2 -CN -NCS
s -s-sco-
S(=O)-S(=0)2-SCN 0 -CHO
II
-co-
C -COOH / \
-coo40-N -coc1
j
+xzpj
CH3
z, -C -c=C
+ZZpj j
i
Substituent (X, Y, Z)
zpi
0.00 0.85 0.94 1.49 3.41 2.20 1.83 1.30 2.53 2.38 2.64 2.87 2.81 1.61 2.44 1.88 3.43 1.12 2.51 1.14 1.41 1.64 1.98 1.75 1.34 1.23 1.22 1.15 1.16 1.94
For other approaches: see [2]
CH2
q3 0.05 0.20 0.32 0.38 0.41 0.63 0.83 1.02 0.25 0.25 0.36 0.47 0.44 0.14 0.39 0.34 0.65 0.45 0.54 0.45 0.37 0.36 0.42 0.66 0.21 0.20 0.23 0.28 0.28
z,
CH
q3
0.00 0.63 0.70 1.22 2.76 2.05 1.97 1.80 2.20 2.04 2.63 2.61 2.83 1.32 1.91 1.63 3.08 1.08 2.27 1.23 1.54
-0.04 0.00 0.13 0.29 0.16 0.24 0.46 0.53 0.15 0.13 0.33 0.38 0.24 0.22 0.40 0.22 0.58 0.33
2.08 1.62 1.07 1.12 0.90 0.92
0.52
1.51
0.26 0.63
0.29 0.24 0.23 0.35
z,
zP
0.17 0.68 1.04 1.28 1.83 1.98 1.94 2.02 1.73 1.35
-0.01 0.03
2.20 2.47 1.13 1.78 2.10 2.31 1.oo 2.14 1.06 1.31 1.25 1S O 1.64 0.86
0.50 0.59 0.23 0.56 0.62
0.87 0.83 0.94
0.38 0.27 0.3 1 0.41 0.15 0.08 0.32
0.3 1 0.19
0.22 0.32 0.63
5.1 Alkanes
165
H Chemical Shifts of Aromatically Substituted Alkanes (6 in ppm relative to TMS)
'C/ / \ C H 3 2.65
d
mCH3 2.46
3
CH3 2.05
d
2.16
2.42
<'a3H
N
H
3.50
2.27
H
pJ
P
N H
,CH3 2.79
1.94
0
pa3
0 r a
d3
2.17
QCH3
N
Y'
3.80
a
3
3
2.37
CH3 2.05
P N I?
H CH3 2.21
QCH3
2.41
0
2.18 CH
2.47 CH3 qLCH3
tJ
2.74
om' 2.32
2.30
-CH3 (333
3.60
H
,CH3 2.30
or";, H
166
'c /
\
5 'H NMR
5.1.2 coupIing constants Geminal Coupling Constants (25"
in HZ)
2 J ~ ~-8 H to -18 Hz
Electronegative substituents cause a decrease in IJI while a double or triple bond next to the CH2 group causes an increase. The fzKr effect is strongest if one of the C-H bonds is parallel to the K orbitals:
Compound CH4 CH3Cl CH2C12 CH30H
Jgern -12.4
Compound CH3COCH3 CH3COOH CH3CN CH2(CN)2
-10.8
-7.5 -10.8 -14.3
O C - C N H2
Vicinal Coupling Constants (35"
Jgem
- 14.9 -14.5 -16.9 -20.3 -18.5
in HZ)
conformation not fixed: 3J" = 7 fixed: 3 J = 0~- 18 ~
Influence of Substituents on the Vicinal Coupling Constant
5.1 Alkanes
167
Vicinal coupling constants strongly depend on the dihedral angle, @ (Karplus equation):
J = Jo COS:! @ - 0.3 J = J180 cos2 @ - 0.3
/
C / \
Oo I Q I 90° 90° I @ 5 180°
The same relationship between torsional angle and vicinal coupling constant holds for substituted alkanes if appropriate values are used for Jo and J180. These limiting values depend on the electronegativity and orientation of substituents, the hybridization of carbon atoms, bond lengths, and bond angles. J/Hz 15 -
-
10 -
5-
0I
,
I
0
I
I
(
30
I
I
I
I
I
(
I
I
,
60
I
I
(
J
I
I
I
I
I
120
90
I
I
I
I
(
I
150
I
I
I
I
180
4 I degrees Long-Range Coupling Constants
(IJl"
in Hz)
Coupling constants through more than three bonds (long-range coupling) in alkanes are generally much smaller than 1 Hz and thus not visible in routine 1D NMR spectra. They are, however, much larger than 1 Hz for fixed conformations (e.g. in condensed alicyclic systems, see Chapter 5.4) and in unsaturated compounds (see Chapter 5.2). They are also significant when electronegative substituents are present between the coupling partners, as e.g.: ~
Ro
0
CH3
4J"
0.7 ~
~
~
5.1.3 References [l] R. Burgin Schaller, C. Arnold, E. Pretsch, New parameters for predicting 'H NMR chemical shifts of protons attached to carbon atoms, Anal. Chim. Acta 1995, 312, 95. [2] E. Friedrich, K.G. Runkle, Empirical NMR chemical shift correlations for methyl and methylene protons, J. Chem. Educ. 1984, 61, 830.
3
5
168
‘H NMR
5.2 Alkenes
c=c
5.2.1 Substituted Ethylenes
IH NMR Chemical Shifts and Coupling Constants of Alkenes ( 6 in ppm relative to TMS, J in Hz) 2.5
H
trans
H
19.1
-1.7 3Jac 15.1 3Jad 6.5 CH31.58 5Jbd 1.6
cH&H15*55 b
4J,b
Hc
4.87 HwH:5.7:
4.94Hc
CH2-CH3 2.00 1.00
4.88 H ~ H ; 5 . 7 3
3Jab 10.3 3Jac 17.2 3Jad 6.2 2Jbc 2.0
4.97Hc
CH31.72
3Jab 3Jac 3Jad 2Jbc 4Jbd 4Jcd
10.0 16.8 6.4 2.1 -1.3 -1.8
HkHa5*3 3Jab 10.9 4Jac -1.8
CH3 C
CH31.54 d
3Jad 5Jcd
6.8
1.2
4Jbd -1.3 4Jcd -1.7
Geminal and Vicinal Coupling of Alkenes (J in Hz) The coupling constants strongly depend on the electronegativity of the substituents (see Table on pp 170, 171). They decrease with increasing electronegativity and number of electronegative substituents. The same trend holds for the signed values of geminal coupling constants but not for the absolute values because Jgem can be positive or negative. Although the total ranges of cis and trans vicinal coupling constants overlap, JtranS> Jcis always holds for given substituents. Typical ranges: Jgem -4 to 4 Jcis 4 to 12 JtranS 14 to 19
Coupling Over More than Three Bonds in Alkenes (Long-Range Coupling) ( J in H z ) Allylic
Coupling
c=c
l @
n
: Ha
b H
4'
=,-?:\
CiSOid
Jab -3.0 to +2.0
transoid: Jac -3.5 to +2.5
c-:
H C
In acyclic systems, lJlcisoid > IJ(transoid usually holds. The magnitudes of the coupling constants depend on the conformation. Largest absolute values are observed if the C-H bond of the substituents overlaps with the n-electrons (@= 0):
@
Jab
00
-3.0
90°
+1.8
1800
-3.0 0.0
270° Homoallylic
Coupling
tfb ra .*
: '
i"
Jac -3.5
+2.2 -3.5 0.8
cisoid
IJlab 0-3
transoid lJlac 0-3
Hc
Allylic and homoallylic couplings with methyl groups are often comparable: 4JH-C=C-CH3 5JCH3-C=C-CH3 In acyclic systems, IJlcisoid < lJltransoid usually holds. Large homoallylic coupling constants are generally observed in cyclic systems:
Jab 5-11
x
x HxR b
X: CH, N R: any substituent
X: 0, NH R: any substituent
170
5 'H NMR
H Chemical Shifts and Coupling Constants of Monosubstituted Ethylenes ( 6 in ppm relative to TMS, J in Hz)
HRHa
c- c
Hb
Substituent X -H C -CH3 -CH2CH=CH2 -CH2-phenyl -c yclopropyl -cyclohexyl -CH2F -CF3 -CH2C1 -CH2Br -CH$ -CH20H -CH2NH2 -CH2N02 -CH=C=CH2 -C=C-CH3 -phenyl -2-naphthyl -2-m-xyl yl -2-nitrophenyl -3-nitrophenyl -4-nitrophenyl -2-pyridyl -4-pyridyl H -r a -C1 1 -Br -I 0 -OH -OCH3 -0CH2CH3 -OCH=CH, -0-phenyl -0CHO -0COCH3 -OCOCH=CH2 -0CO-phenyl -OPO(OCHiCH3)2
Ha 5.28 5.73 5.71 5.89 5.32 5.79 5.89 5.90 5.93 5.99 6.04 5.98 5.97 6.11 6.31 5.62 6.72 6.87 6.65 7.19 6.74 6.77 6.84 6.61 6.17 6.26 6.44 6.53 6.45 6.44 6.46 6.49 6.64 7.33 7.28 7.39 7.52 6.58
Hb
5.28 4.97 4.95 5.01 5.04 4.95 5.24 5.85 5.30 5.29 5.23 5.26 5.15 5.46 5.19 5.39 5.72 5.86 5.22 5.68 5.86 5.90 6.22 5.91 4.37 5.48 5.84 6.57 4.18 4.03 4.17 4.52 4.74 4.96 4.88 4.96 5.04 4.91
Hc 5.28 4.88 4.92 5.00 4.84 4.88 5.12 5.56 5.17 5.11 5.95 5.12 5.04 5.49 4.99 5.24 5.20 5.32 5.48 5.45 5.42 5.48 5.45 5.42 4.03 5.39 5.97 6.23 3.82 3.88 3.96 4.21 4.40 4.66 4.56 4.62 4.67 4.59
Other
19.1 16.8 16.9 17.0 17.1 17.6 17.2 17.5 16.9 16.8 16.5 17.4 17.3 16.7 17.2 17.0 17.9
Jac 11.6 10.0 10.3 10.0 10.4 10.5 10.6 11.1 10.1 10.0 9.7 10.5 10.4 10.7 10.1 11.1 11.1
2.5 2.1 2.2 1.9 1.8 1.9 1.5 0.2 1.3 1.2 1.3 1.7 1.7 0.8 1.6 2.3 1.0
17.9 17.4 17.5 17.4 18.5 17.6 12.8 14.5 14.9 15.9
11.4 10.7 10.9 10.9 11.3 10.8 4.7 7.5 7.1 7.8
2.1 1.1 0.4 0.8 1.4 0.7 -3.2 -1.4 -1.9 -1.5
CH3 2.27
14.1 14.4 14.0 13.7 13.9 14.1 14.2 13.8 13.8
7.0 6.9 6.4 6.1 6.4 6.3 6.4 6.3 6.0
-2.0 -1.9 -1.8 -1.6 -1.7 -1.6 -1.6 -1.7 -2.1
CH3 3.16
Jab
Jbc
CH3 1.72 CH2 2.72 CH2 3.19 CH2 4.69 CH2 3.91 CH2 3.87 CH2 3.82 CH2 4.12 CH2 3.29 CH2 4.93
CHO 8.07 CH3 2.13
5.2 Alkenes
Substituent X N -NH2 -N+(CH3)3Br-NHCOCHq -NO2 -CN -NC -NCO S -SCH3 -%phenyl -S(O)CH3 -S02CH3 -S02CH=CH2 -S020H -SO2OCH3 -S02NH2 -S02NH-phenyl -SFg -SCN 0 -CHO 1 1 -COCH3 C -COCH=CH2 / \ 40-phenyl -COOH -COOCH3 -CONH2 -CON(CH3)2 -COF -coc1 P -P(CH3)2 -P(CH=CH2)2 -PC19 J
Ha
Hb
Hc
26-05 24.04 23.99 6.50 5.76 5.54 -1.33 -4.53 24.68 7.12 6.55 5.87 5.73 6.20 6.07 5.90 5.58 5.35 6.12 5.01 4.77 6.35 4.84 5.08 6.53 5.32 5.32 6.77 6.08 5.92 6.76 6.43 6.14 6.67 6.41 6.17 6.73 6.41 6.13 6.57 6.43 6.22 6.93 6.17 5.98 6.56 6.18 5.86 6.63 5.96 5.64 6.19 5.66 5.70 6.26 6.11 6.26 6.30 6.27 5.90 6.67 6.28 5.82 7.20 6.52 5.81 6.15 6.53 5.95 6.14 6.40 5.83 6.48 6.17 5.71 6.64 6.12 5.55 6.14 6.60 6.25 6.35 6.63 6.16 6.23 5.39 5.51 6.16 5.59 5.64 7.48 6.64 6.68 6.72 6.25 6.21 6.42 6.13 5.90 6.60 6.26 6.14 6.82 6.34 6.17
-L1
-MgCl -MgBr -Si(CH3)3 -Sn(CH=CH2)3 -Pb(CH=CH2)3 -HgBr
6.68 6.67 6.11 6.39 6.70 6.45
5.57 5.51 5.63 5.75 5.46 5.52
6.20 6.15 5.88 6.21 6.19 5.92
Jab
15.1
Jac
Jbc
171
Other
8.2 -4.3
14.6 17.9 15.6 15.2 16.4 16.7 16.7 16.5 16.4 16.8 16.9 16.3 16.7 16.6
7.0 11.8 8.6 7.6 10.3 9.6 9.8 10.0 10.0 10.2 10.1 10.0 10.1 9.8
1.4 0.9 -0.5 -0.1 -0.3 -0.2 -0.6 -0.5 -0.6 -1.2 -0.6 0.0 -0.3 0.4
17.4 18.7 17.9 17.7 17.2 17.4 17.3 17.0 17.3 17.4 18.3 18.4 18.6 18.9 17.5 17.9 17.9 23.9 23.0 23.3 20.2 20.7 19.8 18.7
10.0 10.7 11.0 9.9 10.5 10.6 7.9 9.8 10.7 10.6 11.8 11.8 11.7 12.9 11.0 11.8 11.7 19.3 17.6 17.7 14.6 13.4 12.2 11.9
1.0 1.3 1.4 2.3 1.8 1.5 5.0 3.4 0.8 0.2 2.0 2.0 0.4 1.8 0.3 1.8 1.6 7.1 7.5 7.6 3.8 3.1 2.1 3.1
c=c CH3 2.12 CH3 2.61 CH3 2.96 CH3 3.85 NH2 6.7 NH 9.07 CHO 9.51 CH3 2.25 COOH 12.08 CH3 3.76 NH2 7.55
CH3 0.95
CH3 0.06
172
5 'H NMR
Estimation of IH Chemical Shifts of Substituted Ethylenes (6 in ppm relative to TMS)
Substituent R -H C -alkyl -alkyl ring' -CH2-aromatic -CH2X, X: F, C1, Br -CHF2 -CF3 -CH20 -CH2N -CH2CN -CH2S -CH2CO -C=C -C=C conjugated2
-c=c
H a 1
0
-aromatic -aromatic, fixed3 -aromatic, o-substituted -F -C1 -Br -I -0c (sp3) -0c (sp2)
-0co-
-NCO-R -N=N-pheny 1 -NO2 -CN
zgem
0.00 0.45 0.69 1.05 0.70 0.66 0.66 0.64 0.58 0.69 0.7 1 0.69 1.oo 1.24 0.47 1.38 1.60 1.65 1.54 1.os 1.07 1.14 1.22 1.21 2.1 1 1.33 0.80 1.17 2.08 2.39 1.87 0.27
%is 0.00 -0.22 -0.25 -0.29 0.11 0.32 0.6 1 -0.01 -0.10 -0.08 -0.13 -0.08 -0.09 0.02 0.38 0.36 0.19 -0.40 0.18 0.45 0.81 - 1.07 -0.60 -0.35 -0.34 - 1.26 -0.53 -0.57 1.11 1.30 0.75
Ztrans 0.00 -0.28 -0.28 -0.32 -0.04 0.21 0.32 -0.02 -0.08 -0.06 -0.22 -0.06 -0.23 -0.05 0.12 -0.07 -0.05 0.09 -1.02 0.13
0.55 0.88 -1.21 -1.00 -0.64 -0.66 -1.21 -0.99 -0.72 0.67 0.62 0.55
5.2 Alkenes
Substituent R
%em I
s -s-so402-sco-
1.11 1.27 1.55 1.41 0.94 1.68 1.02 1.10 1.06 0.97 0.80 0.80 0.78 1.37 1.11 0.66
-SCN -SFg 0 -CHO
11 -co-
C -CO- conjugated2 / \ -COOH -COOH conjugated2 -COOR -COOR conjugated2 -CON -coc1 -PO(OCH2CH3)2
Zcis
Ztrans
-0.29 0.67 1.16 0.06 0.45 0.61 0.95 1.12 0.91 1.41 0.98 1.18 1.01 0.98 1.46 0.88
-0.13 0.41 0.93 0.02 0.41 0.49 1.17 0.87 0.74 0.71 0.32 0.55 0.46 0.46 1.01 0.67
173
C=C
1) The increment for "alkyl ring" is to be used if the substituent and the double bond are part of a cyclic structure. 2) The increment "conjugated" is to be used if either the double bond or the substituent is conjugated to other substituents. 3) The increment "aromatic, fixed" is to be used if the double bond conjugated to an aromatic ring is part of a fused ring (such as in 1,2-dihydronaphthalene).
H Chemical Shifts of Substituted Isobutenes
(6 in ppm relative to TMS) 1.70
CH3 cH&H
4.63
1.68 CH3
H
1.62 C H
5.13 H
1.80
5.17
i 1.88
1.75
5.78
CH3 cH$==(H Br 1.75 1.86
5.97
1.65
6.79
cHf4H OCOCH3
CH3 1.65 1.84
5.62
1.91
5.63
c CH3 H k CHO H 2.11 1.97
6.01
cHkH cHkH cHkH CH3 2.06
COCH3
CH3
2.12
COOCH3
CH3
2.12
COCl
5
174
'H NMR
IH Chemical Shifts of Enols ( 6 in ppm relative to TMS, J in Hz) =16
=16
Hb
Hb
5.60
5.04
5.2.2 Dienes I H Chemical Shifts and Coupling Constants of Conjugated Dienes
( 6 in pprn relative to TMS, J in Hz) 3Jab 3Jac 3Jad 4Jae 4Jaf 2Jbc 5Jbe 5Jbf 5Jcf
5.06 6*27 #'bHe
5.16
6.59
1.72
5.03 Hc Hd 5.11 5.92
10.2 17.1 10.4 -0.9 -0.8 1.8 1.3 0.6 0.7
3Jab 3Jac 3Jad 5.45 H e 4Jae
4.86
10.2 16.9 10.9 -1.1
5Jaf 0.2
6.21 5.61
Hc
Hd
4.98
5.98
2Jbc 2.1
3Jab10.2 3Jac 16.9 3Jad 10.3 5Jae 0.4 1.71 4Jaf -0.8 2Jbc 1.9 4Jbd -0.8 6Jbe -0.7
4Jbd -0.8 5Jbe -0.7 6Jbf 0.7
5Jc, 6Jcf 3Jde 4Jdf
4J,d
3Jef 7.0
-0.8
0.7 -0.6 10.8 -1.8
IH Chemical Shifts and Coupling Constants of Allenes ( 6 in pprn relative to TMS, J in Hz)
5Jbf 0.7 4Jcd -0.8 6Jce -0.7 5Jcf 0.7 4Jde -1.6 3Jdf 15.1 3Jef 6.6
5.3 Alkynes
175
5.3 Alkynes 5.3.1 Chemical Shifts and Coupling Constants
I H Chemical Shifts and Coupling Constants of Alkynes (6 in ppm relative to TMS, J in Hz) 1.80 I: - H
1.80
1.91 2.15 1.12 H-CHz-CH3 a
1.80
- CH3
b
c
4Jab 2.6 5 ~ a c0
=
I:
3Jbc 7.4
1.15 2.59 ,CH3
1.77 CH3
2.13 1.11 CH2-CH3 5 b I Jlab 2.5
-
7.42 7.23 5Jab 0.28 d 7.24 6Jac -O.ll 7Jad 0.22
a
4Jab
2.0
5 ~ a c 1.0
i&ci:9
3Jbc 10.5 6~~~ 0.6
CH3 d 1.85
cy
CH3
1.74
5.34
4JH,CH3 2.9
2.93 a
4 J b ~ 1.6 3Jcd 6.5
b
1.7-2.4 H = - R
2.7-3.4 H-mR
1.3 H+
2.1-3.3
c
0-alkyl alkyl
C=C
5 'H NMR
176
5.4 Alicyclics H Chemical Shifts and Coupling Constants of Saturated Alicyclic Hydrocarbons ( 6 in ppm relative to TMS, J in H z ) 0.20
0 0
2Jgem -4.3 3Jcis 9.0 3~trans5.6
In derivatives: 2Jgem -3 to -9 3Jcis 6 to 12 3~trans2 to 9 Throughout: Jcis > Jtrans
b 7'01 a 0.92
0
At-lOO'C: Ha, 1.1
In derivatives: 3Jab 1.5 to 2.0 3Jbc 0.5 to 1.5
io
ed0~5*66 2Jgem,a -12.8 b 2.27 3Jab,cis 9-3 a 3Jab,trans 5*7 1.79 2Jgem,., -16.1 3Jbc 2.3
a 6-53 b 6.22
3Jab 5.1 5Jac 0.5 5Jad 1.4 5.85 4Jae 1'3 3Jaf 2.0
01.94
In derivatives: 2Jgem -10 to -17 3J,is 4 to 12 3Jp,, 2 to 10 4Jcis =O 4Jpans -1
.44 In derivatives:
In derivatives:
lS1 2Jgem -8 to -18 3Jcis 5 to 10 3Jtrans 5 to 10
c
*
4Jbd 5Jbe,cis -2'3 2*1 5Jbe,trans 3*0 5.8 3Jcd
4Jbc -0.2 4Jbd -0.4 4Jbe 2.0 2Jcd O''
2Jgem -11 to -14 3J,x,ax 8 to 13 3 Jeqm 2 to 6 3~e9,eq 2 to 5 Generally: Jeq,ax Jeq,eq + 1
b 5.95
,13.7 1.o -0.3 1.8 4.6 2.8
a 2.57
3Jab
1.3
edoc;;3i8 a
2.80
4Jbd 1.1 5Jbe 2.0 3Jcd 1.9
5.59 3Jab =lo 1.96 3Jbc d
1.65
1.5
5.4 Alicyclics b 5.71
0 C
177 3Jab=10
2.11 3Jbc 3*7
d 2.62
e
2.49
6 6 . 5 0 3Jab 11.2 5J,g -0.6 c 6.09 4Jac o.8 3Jde 0 3Jbc 5.5 4Jdf f e d 5.26 3Jcd 8.9 5Jdg 0 2.22 5Jcf 0 2Jgem,e -13.0
a
b5.56 3Jab=10 C 2.1 1 3Jbc 5.3
0
0.5
1.47 f
e 2.14
1.44
4J1,4 1.2 4J1,5n -0.3 4 J i , 5 ~ 0.2 3 ~ 1 , 6 n 0.1 3 ~ 1 , 6 x 4.7 J I ,7a 1*2 3J1,7s 1.6 2J3n,3x -17.6 3J3n,4 0 4J3n,7a 4.2 ~ 3 n , 7 a 4.2 3J3x,4 4.8 4J3x,5x 2.3 3 ~ 4 , 5 n 0.1 3J4,5x 4.3
-0.5 4J4,6x 0.7 3 ~ 4 , 7 a 2.1 3J4,7s 1.6 2J5n,5x -12.8
4J4,6n
3J5n,6n 9*1 3J5n,6x 4.7 ~5 n ,7a -0.1 ~5 n ,7 s 2.1 3J5x,6n 4.6 3J5x,6x 12e1 2J6n,6x -12.3 J6n,7 a 4J6n,7s 2.3 2J7a,7s -10.2
5 'H NMR
178
In condensed alicyclics, couplings over four or more bonds are often observed. Such long-range couplings are particularly large if the arrangement of the bonds between the two protons is w-shaped: 4Jac = 7 =0 4 J a ~4Jbd ,
H H CH3 signal broadened due to longrange coupling
HC
0
H Chemical Shifts and Coupling Constants of Monosubstituted Cyclopropanes (6 in ppm relative to TMS, J in Hz)
Substituent X -H C -CH=CH2 -phenyl H -F a -C1 1 -Br -1 0 -OH N -NH2 -CN 0 -CO-cyclopropyl 11 -COOH C -COOCH3 / \-COF -coc1 -Li -B(cyclopropyl)2 -Hg-cyclopropyl
Ha
0.20 2.36 1.71 4.32 2.55 2.83 2.31 3.35 2.23 1.36 1.70 1.59 1.95 1.66 2.11 -2.53 -0.25 0.00
Hb,d 0.20 0.64 2.65 0.69 0.87 0.96 1.04 0.59 0.32 0.94 0.56 0.91 0.81 1.20 1.18 0.43 0.66 0.75
H ~ , e 3Jab 3Jac 2Jbc 0.20 9.0 5.6 -4.3 0.34 8.2 4.9 -4.5 2.83 9.5 6.3 -4.5 0.27 5.9 2.4 -6.7 0.74 7.0 3.6 -6.0 0.81 7.1 3.8 -6.1 0.76 7.5 4.4 -5.9 0.34 6.2 2.9 -5.4 0.20 6.6 3.6 -4.3 0.93 8.4 5.1 -4.7 1.02 7.9 4.6 -3.5 1.05 8.0 4.6 -4.0 0.85 8.0 4.6 -3.4 1.11 8.0 4.6 -4.5 1.28 7.9 4.4 -4.5 -0.12 10.3 9.1 -1.6 0.61 8.9 5.8 -3.3 0.47 9.6 6.9 -3.7
3Jbd
9.0 9.3 9.5 10.8 10.3 10.2 9.9 10.3 9.7 9.2 9.1 9.3 8.8 10.1 9.2 7.7 8.2 8.5
3Jbe 5.6 6.2 5.2 7.7 7.1 7.0 6.6 6.8 6.2 7.1 7.0 7.1 6.9 7.5 7.6 3.2 5.9 4.8
3Jce 9.0 9.0 8.9 12.0 10.6 10.5 10.0 10.9 9.9 9.5 9.5 9.7 9.6 9.3 10.0 6.5 8.4 7.9
5.4 Alicyclics
179
H Chemical Shifts of Axially and Equatorially Monosubstituted Cyclohexanes (6 in p p m relative to TMS)
Substituent R
-D C -CHq -pheiyl H a -Br 1 -I 0 -OH -0COCH3 N -NH2 -NHCH3 -NO2 S -SH
2e
3a
3e
la
2a
1.12 1.27 2.47 3.63 3.81 3.98 3.38 4.46 2.52 2.08 4.23 2.57
1.12 1.60 1.12 1.60 0.81 1.57 1.15 1.60
1.09 1.78 1.19 1.61
2.2 0.7
1.9 1.3
le
2a
2e
3a
3e
1.60 1.93 2.98 4.34 4.62 4.72 3.89 4.98 3.15 2.70 4.43 3.43
1.12 1.60 1.12 1.60 1.37 1.40 1.39 1.34 1.7 1.35 1.58 1.58 1.33 1.47 2.3 1.6 2.6 1.5 1.9
0
180
5 'H NMR
5.5 Aromatic Hydrocarbons IH Chemical Shifts and Coupling Constants of Aromatic Hydrocarbons ( 6 in ppm relative to TMS, J in Hz) In derivatives: 0 7 . 2 6 3~0d0 6.5-8.5 4J,eta 1.O-3.0 5Jpara 0.0-1 .O
7.67 g~ f \
e
7.98
e 8.40
d
d
In derivatives: 3Jab 8-9 5Jae ~ 0 . 9 87.32 4Jac 6Jaf =-Oal 5Jad 5Jag =0.2 35bc 5-7 4Jah=-0.5 7Jbf ~ 0 . 3 6Jbg ~ 0 . 1
In derivatives: 7.44 3Jab 8*5-9*5
;
4Jac 0.8-1.5 5Jad 0.6-0.9 5Ja, 10.8 3Jbc 6.5-8.0 4Jde 10.4
b7.61
3Jab
8.4
f
In derivatives: 3Jef 4
In routine spectra, the small long-range couplings between aromatic protons and aliphatic substituents are not resolved. Nevertheless, they are diagnostically highly relevant because the line broadenings caused by them are easily detected (if there is a reference line in the spectrum, e.g. from another methyl group, or in an AA'XX' spin system of the aromatic protons). As a confirmation, a decoupling experiment may be useful (line sharpening on weak irradiation of the frequency of the coupling partner) or a COSY experiment is recommended.
5.5 Aromatics
181
CH3 ,CH31.25
FH31.32 CH3-C-
CH3
6
7.28 7.18
7.08
7.09
7.05
& 6*99a 7.08
c 3.33
2.91
2.04
\
3Jab 5.8
7.01 2.85
b 6.50 4Jac 'Jad 0.7 2.0 6
.
9
3
a 1.60
\
8
6*82
3Jbc 2.0
3.91 7.31 7.38 \
7.19
3.87 \ 7.55 7.28 A
7.75 2 -\7.29 7.22 3
- a 7.15 ad
d 7.46
d 7.79
4Jbd 0.6 3Jcd
182
5
'H NMR
Effect of Substituents on H Chemical Shifts of Monosubstituted Benzenes (in ppm relative to TMS)
Substituent X -H C -CH3 -CH2CH3 -CH(CH3)2 -C(CH3)3 -CF3 -CC13 -CH20H -CH=CH2 -CH=CH-phenyl (trans) -CZCH -C eC-phenyl -phenyl -2-pyridyl -
H -r
a -C1
I -Br -I 0 -OH -OCH3 -OCH2CH=CH2 -0-phenyl -0COCH3 -0CO-phenyl -0SO2CH3 N -NH2 -NHCH3 -N(CH3)2 -N+(CH3)31-NHCOCH3 -NHNH2 -N=N-phenyl -NO -NO2 -CN -NCS
z2
z3
z4
0.00 -0.20 -0.14 -0.13 0.03 0.19 0.55 -0.07 0.04 0.16 0.16 0.20 0.22 0.73 -0.29 0.01 0.17 0.38 -0.53 -0.49 -0.45 -0.34 -0.19 -0.1 1 -0.05 -0.80 -0.83 -0.67 0.72 0.38 -0.60 0.67 0.55 0.93 0.25 -0.11
0.00 -0.12 -0.05 -0.08 -0.08 -0.07 -0.07 -0.07 -0.05 0.00 -0.03 -0.04 0.06 0.09 -0.02 -0.06 -0.11 -0.23 -0.17 -0.11 -0.13 -0.04 -0.03 0.07 0.07 -0.25 -0.22 -0.18 0.40 -0.02 -0.08 0.20 0.29 0.26 0.18 0.04
0.00 -0.21 -0.18 -0.18 -0.20 0.00 -0.09 -0.07 -0.12 -0.15 -0.02 -0.07 -0.04 0.02 -0.23 -0.12 -0.06 -0.01 -0.44 -0.44 -0.43 -0.28 -0.19 -0.10 -0.01 -0.64 -0.68 -0.66 0.34 -0.26 -0.55 0.20 0.35 0.39 0.30 -0.02
5.5 Aromatics
Substituent X S -SH -SCH3 -,%phenyl -S-S-phenyl -SOzCH3 -S020CH3 -s02c1 -S02NH2 0 -CHO 11 -COCH3 C -COCH2CH3 / \ -CO-phenyl -CO-(2-~yridyl) -COOH -COOCH(CH3)2 -COO-phenyl -CONH2 -COF -coc1 -COBr -CH=N-phenyl -Li -MgBr -Mg-phenyl -Si(CH& -Si( phenyl)&l -Sic13 P -Pb(phenyl)2Cl -P(PhenY 112 -PO(OCH3)2 -Zn-phenyl . -Hg-phenyl
z2 -0.08 -0.08 -0.06 0.24 0.68 0.68 0.68 0.59 0.61 0.60 0.63 0.44 0.86 0.87 0.73 0.88 0.69 0.71 0.81 0.77 0.64 0.77 0.40 -0.49 0.19 0.32 0.52 0.68 -0.02 0.46 -0.36 0.00
z3
-0.16 -0.10 -0.20 0.02 0.35 0.34 0.23 0.32 0.25 0.11 0.08 0.10 0.1 1 0.21 0.1 1 0.15 0.18 0.21 0.21 0.21 0.24 0.26 -0.19 0.18 0.00 0.07 =0.2 0.28 -0.33 0.14 0.02 0.00
z4 -0.22 -0.24 -0.26 -0.06 0.39 0.36 0.34 0.32 0.35 0.19 0.18 0.19 0.20 0.34 0.20 0.25
0.25 0.38 0.37 0.38 0.24 -0.29 -0.26 0.25 0.00 0.12 =0.2 0.11 -0.33 0.22 0.05 -0.20
183
184
5
'H NMR
Effect of Substituents in Position 1 on the IH Chemical Shifts of Monosubstituted Naphthalenes (in ppm relative to TMS)
0
Substituent X C -CHq -CH;CH3 -CH2CtCH -CH$1 -CF3 -
H -r a -C1 1 -Br
-I 0 -OH -OCH3 -0C0CH3 N -NH2 -N(CH3)2 -NHCOCH3 -NO2 -NCO -CN 0 -CHO 11 -COCH3 C -COOH / \ -COOCHq-
-coc1
*
H-2 -0.22 0.01 0.25 0.13 0.67 -0.22 0.17 0.38 0.10 -0.68 -0.68 -0.15 -0.77 -0.30 0.40 0.80 -0.29 0.48 0.44 0.38 1.11 0.80 1.17
Assignment uncertain
H-3 -0.13 0.08 -0.07 0.01 0.15 0.01 -0.04 -0.09 -0.48 -0.15 -0.09 0.11 -0.17 0.03 0.17 0.14 -0.15 0.12 0.10 -0.07 0.23 0.05 0.17
H-4 -0.16 0.03 -0.06 0.09 0.18 -0.11 -0.02 0.03 0.18 -0.36 -0.38 -0.10 -0.51 -0.19 0.05 0.19 -0.19 0.30 0.21 0.10 0.42 0.22 0.37
H-5 -0.03 0.17 0.00 0.13 0.23 0.13 0.07 0.05 -0.20 0.01 -0.01 0.03 -0.06 0.11 0.26 0.33 -0.03 0.16 0.06 0.01 0.24 0.08 0.17
H-6 -0.03 0.14 0.03 0.14 0.23 0.15" 0.11 0.11 -0.07 0.03 0.04 -0.07 -0.02 0.13 0.20 0.21 0.05 0.22 0.14 0.04 0.25 0.10 0.21
H-7 H-8 -0.01 0.10 0.17 0.38 0.13 0.69 0.20 0.42 0.29 0.52 0.17* 0.42 0.16 0.54 0.19 0.51 -0.02 0.27 0.06 0.41 0.03 0.50 0.07 0.16 -0.01 -0.01 0.10 0.55 0.24 0.44 0.32 0.72 0.03 0.24 0.29 0.51 0.23 1.52 0.13 1.08 0.34 1.43 0.20 1.30 0.30 1.04
5.5 Aromatics
185
Effect of Substituents in Position 2 on the lH Chemical Shifts of Monosubstituted Naphthalenes (in ppm relative to TMS)
Substituent X C -CH3 -CH2CH3 -CH(CH3)2 -CH=CH2 -CF3
-c1
-Br 0 -OH -OCH3 -0COCH3 N -NH2 -N(CH3)2 -NHCOCH3 -NO2 -CN 0 -CHO 11 -COCH3 C -COOH /\-COOCH3
-coc1
H-1 -0.21 -0.05 -0.07 0.06 0.45 0.13 0.23 -0.69 -0.70 -0.19 -0.88 -0.90 0.50 0.98 0.51 0.62 0.76 1.00 0.83 1.02
H-3 -0.14 0.02 0.01 0.30 0.30 0.08 0.14 -0.35 -0.28 -0.14 -0.56 -0.33 0.14 0.82 0.25 0.61 0.69 0.73 0.66 0.74
H-4 -0.06 0.09 0.05 0.11 0.23 0.07 -0.09 -0.05 -0.07 0.01 -0.16 -0.13 0.07 0.18 0.20 0.23 0.19 0.37 0.09 0.39
H-5 0.01 0.12 0.07 0.11 0.12 -0.08 -0.04 -0.03 0.06 -0.12 -0.12 0.06 0.18 0.19 0.21 0.17 0.36 0.09 0.49
H-6 -0.04 0.08 0.04 0.10 0.25 0.13 0.05 -0.11 -0.11 -0.04 -0.23 -0.23 0.07 0.28 0.31 0.30 0.25 0.36 0.15 0.32
H-7 -0.01 0.12 0.06 0.12 0.22 0.15 0.07 -0.02 0.00 0.11 -0.09 -0.08 0.10 0.24 0.26 0.24 0.21 0.32 0.11 0.37
H-8 -0.03 0.10 0.07 0.11
0.05 0.01 -0.14 -0.07 0.08 -0.23 -0.16 0.08 0.26 0.19 0.29 0.26 0.48 0.17 0.37
5 ’H NMR
186
5.6
Heteroaromatic Compounds 5.6.1
Non-Condensed Heteroaromatic Rings ‘ H Chemical Shifts and Coupling Constants of Non-Condensed Heteroaromatic Compounds ( 6 in ppm relative to TMS, IJI in H z )
4Jb, 2.3 b7.09 3Jab 0.8 b7.13 3Jab 1-2 a 7.70 4Jac c n a 7.69 4Jac O S c a7.13 4Jac 1-2 4Jbc 0.0 7.70 N 3Jbc Se 4Jad 2.5 7.95 0 3Jbc 3.6 Hd 13.4 (J values in derivatives) b 7.12 3Jab 5.4
‘0
d
0
l a 1
;gba ‘qb
8.15
3Jab 1.7 7.55 6.25 3Jab 2.1 4Jac 0.3 4Jac 0.0 4Jbc 1.8 y N a7.55 3Jbc 2.1 0 8.39 H d 13.7 (in CS,)
8.56 19b7.26 S
6.28
3 :abJacc0.4 4.7
a8.72 3Jbc 1.7
H 12
N-N
c(
8.27 N H 13.5 -12 (in H2S04)
5.6
In DMSO:
7.64 b 7.25
(in CDCl3)
7.32
a 8.59 7*38 7'75
3Jab 6.5
C
d e
b 7.40 4JaC 5Jad 0.6 'a 8 * l 9 4Jae 1.9 3Jbc 7.7 f 4Jbd 2.1 0
In denvatives: 3Jab 6.0 4-6 4Jac 1.9 0-2.5 5Jad 0.9 0-2.5 4Jae 0.4 0-0.6 3J13c7.6 7-9 4Jbd 1.6 0.5-2
'9 N,
/
Heteroaromatics
187
'6 9.04
3Jab 6.0 b8.50 4JaC 1'6 5Jad 0.8 e a9.23 45 ae 1.0 N 3Jbc 7.9 H 4Jbd 1.4 (in CD3CN)
7.22 1.o
b7'55 a9.24
0
5 'H NMR
188
Effect of Substituents on the IH Chemical Shifts substituted Furans (in ppm relative to TMS)
of Mono-
6H-2 = 7.38 + zi,2 6H-3 = 6.30 + zi,3 6H-4 = 6.30 + zi,4 ~ H - S= 7.38 + Zi,5
Substituent
in position 2 or 5 : '23 z54
-H
'25 z52
'32 z45
'34 z43
z35 z42
0.00
0.00
0.00
0.00
-0.42 -CH20H -0.11 -CH2NH2 -0.24 -CH=CHCHO 0.70 -Br -0.02 0.12 0&H3 -1.34 N -NO2 1.21 -CN 0.85 S -SCH3 -0.12 -SCN 0.40 0 -CHO 0.93 II -COCH3 0.81 C -COCF3 1.34 / \ -COOH 0.94 -COOCH3 0.85 -coc1 1.20
-0.12
-0.17 -0.08 -0.10 0.42 -0.01 -0.01 -0.68
-0.27
0.00 -0.17
0.00 -0.15
-0.13 -0.46
0.04 -0.28
-0.22 -0.37
0.45 -0.18 0.19 0.48 0.46
0.22 -0.05 0.19 0.37 0.36
-0.02 -0.15 0.03 -0.07 -0.12
0.89 0.45
0.54 0.33
0.36 -0.14
C -CH3
0
'24 z53
in position 3 or 4:
-0.05 -0.06 0.35 0.03 -0.13 -0.23 0.55
0.51
0.32 -0.06 0.06 0.31 0.23
0.28 -0.09 0.10 0.34 0.19 0.64 0.41 0.25 0.48
0.50 0.33 0.22 0.39
5.6
Heteroaromatics
Effect of Substituents on the I H Chemical substituted Pyrroles (in ppm relative to TMS)
Substituent in position 1 -H -CH3 -CH2CH3 -CHz-phenyl -phenyl -COCH3 -CO-phenyl
Substituent
C N
S 0
11
C
'15
z13 z14
0.00 -0.25 -0.16 -0.12 0.33 0.56 0.57
0.00 -0.13 -0.12 -0.04 0.14 0.12 0.18
in position 2 or 5: z23 254
-H -CH3 -NO2 -CN -SCH3 -SCN -CHO -COCH3 -COOCHq
212
0.00 -0.33 1.06 0.83 0.18 0.48 0.93 0.78 0.79
z24
253 0.00 -0.16 0.24 0.23 0.05 0.10 0.27 0.10 0.13
Shifts
189
of Mono-
in position 3 or 4: z25 z5 2
z32 z45
z34 z43
z35
0.00 -0.26 0.43 0.5 1 0.10 0.28 0.61 0.44 0.29
0.00 -0.34 1.04
0.00 -0.20 0.70
0.00 -0.20 0.13
0.79 0.90
0.63 0.73
0.15 0.16
z42
5
190
'H NMR
Effect of Substituents on the I H Chemical Shifts substituted Thiophenes (in p p m relative to TMS)
4032
5
Substituent
-H
C -CH3 -C%CH
H -c1 a -Br
N -NH2 -NO2 -CN S -SH -SCH3 -S02CH3
-soy21 -SCN
0 -CHO
11
-COCH3
C -COOH / \ -COOCH3
-coc1
S
Mono-
5H-2 = 7.20 + zi,2 6 ~ -= 3 6.96 + Zi,3 6 ~ -= 4 6.96 + Zi,4 6 ~ =~7.20 5 + Zi,5
in position 2 or 5:
in position 3 or 4:
z23 z54
z24 z53
z25 z52
0.00 -0.36 0.15 -0.25 -0.05 0.13 -0.72 -0.94 -0.95 0.82 0.47 0.00 -0.03 1.03 0.73 0.30 0.65 0.57 0.80 0.70 0.88
0.00 -0.24 -0.16 -0.22 -0.27 -0.33 0.59 -0.43 -0.45 -0.03 0.00 -0.20 -0.18 0.20 0.06 -0.05 0.10 0.00 0.08 -0.05 0.06
0.00 -0.29 -0.12 -0.22 -0.11 0.01 -3.10 -0.82 -0.85 0.30 0.28 -0.07 -0.05 0.79 0.45 0.28 0.45 0.28 0.40 0.20 0.44
* Present in the keto form
of
z45
z34 z43
z35 z42
0.00 -0.45
0.00 -0.22
0.00 -0.14
-0.22 -0.12 0.06
-0.11 -0.08 0.00
-0.03 -0.10 -0.19
-1.10 -1.25 0.95 0.63 -0.22 -0.33 0.96
-0.38 -0.53 0.60 0.20 -0.20 -0.10 0.48
-0.20 -0.25 0.03 0.15 -0.10 -0.03 0.46
0.25 0.79 0.68 0.99 0.78 1.05
0.05 0.45 0.47 0.48 0.47 0.50
0.05 0.03 -0.02 0.24 -0.05 0.03
z32
5.6
Heteroaromatics
Effect of Substituents on the I H Chemical Shifts of substituted Pyridines (in p p m relative to TMS; solvent: DMSO) 6H-2 = 8.59 + zi,2 6H-3 = 7.38 + zi,3
4
6H-6 = 8.59 + zi,6 Substituent in position 2 or 6 -H C -CH3 -CH2CH3 -CHz-phenyl -CH20H -CH2NH2 -CH2S-n-C3H7 -CH2S02-phenyl -CH=CH2 -phenyl -2-pyridyl .. H SF a -C1 1 -Br 0 -OH -0-n-CqHg N -NH2 -NHCOCH3 -NHCOOCH2CH3 -"NO2 -NO2 -CN S -SCH3 0 -CHO 11 -COCH3 C -CO-phenyl / \ -COOH -COO-n-CqHg -CONH2 -CSNH2 -CH=NOH
z23 z65 0.00 -0.11 -0.09 0.12 0.37 0.20 0.04 4 0.1 1 0.16 1.12 -0.10 0.32 0.41 -0.7 -0.53 -0.68 0.94 0.59 0.34 1.09 0.88 -0.09 0.93 0.82 0.62 0.97 0.86 1.05 1.41 0.40
z24 z64 0.00 -0.01 -0.08 -0.08 0.30 0.07 -0.08 =-0.3 -0.14 -0.28 -0.09 0.40 0.29 0.17 0.0 -0.03 -0.3 1 0.16 0.07 0.31 0.67 0.38 -0.11 0.42 0.37 0.55 0.43 0.39 0.47 0.37 0.28
z25 z63 0.00 -0.16 -0.15 -0.20 0.02 -0.09 -0.26 4 -0.1 1 -0.40 -0.26 0.12 0.29 0.19 -1.0 -0.49 -0.78 -0.20 -0.24 -0.03 0.74 0.55 -0.29 0.50 0.39 0.32 0.48 0.35 0.43 0.33 0.01
z26 z62 0.00 0.08 0.03 0.02 0.06 0.05 -0.06 -0.2 0.04 -0.03 0.00 -0.13 0.20 0.02 -0.9 -0.32 -0.48 -0.10 -0.21 -0.41 0.26 0.39 -0.11 0.44 0.28 0.28 0.42 0.35 0.30 0.25 0.16
191
Mono-
192
5
'H N M R in position 3 or 5:
Substituent
-H C -CH3 -CH2-phenyl -CH20H -CH2NH2 -CH2S-n-C3H7 -CH2S02-phenyl -CH=CH2 -CH=CH-COOH H -F a -C1 1 -Br 0 -OH -OCH3 -CN S -SCHz-phenyl -S-phenyl -SO3H 0 -CHO I t -COCH3 C -CO-phenyl / \ -COOCH3 -COO-n-CqHg -CSNH2 -CH=NOH
in position 4:
z32 z56 0.00 -0.02
z34
z35
z36
z54 0.00 -0.06
z53
0.00 -0.09
z52 0.00 -0.02
0.11 0.16
0.15 0.13
0.04 0.04
-0.04 0.00
-0.24
-0.15
-0.22
0.01
0.45 -0.01 0.20 0.20 -0.03
0.52 0.00 0.24 0.43 -0.37
0.34 0.14 0.19 0.34 0.15
0.17 -0.10 0.09 0.18 -0.24
-0.06 0.37 0.63
-0.49 0.50 0.72
0.02 0.06 0.43
-0.36 -0.16 0.50
0.70 0.45 0.72 0.47 0.62
1.14 0.42 0.68 0.54 0.60
0.81 0.12 0.30 0.37 0.23
0.70 0.20 0.37 0.34 0.34
0.68 0.39
0.67 0.43
0.24 0.19
0.26 0.15
z42 z46
z43 z45
0.00 0.01 0.00 0.07 0.01 -0.06 -0.09 0.12
0.00 -0.10 -0.15 0.14 0.03 -0.13 -0.18 0.13
-0.07 0.00 0.09
-0.03 0.05 0.35
0.02 -0.15 -0.05 0.46 -0.02 0.05
-0.29 -0.74 0.3 1 0.62 0.04 -0.16
0.47 0.40 0.36
0.58 0.58 0.40
0.34 0.35 0.24
0.54 0.68 0.37
5.6.2
Condensed Heteroaromatic Rings H Chemical Shifts of Condensed Heteroaromatic Rings (6in ppm relative to TMS, IJ( in Hz) 7.49 7.13d
a
7.52
7.19e \
f
7.42 7.55 6.99 d
@ 7.26 a
7.09 e \ f
Hs 10.1
7.40
7.83
@4:L'
7.36 d 7.34e \
f
7.88
7.41~
a 8.42
7.41d \ e 7.67 7.70
7.70
0
3Jab 2.5 5Ja,, 6Jad, 6Jae, 5Jaf: 0 4Jbc, 5Jbd, 6Jbe: 0 5Jbf 0.9 3Jcd 7.9
4Jce 1.2 5Jcf 0.8 3Jde 7.3 4Jdf 0.9 3Jef 8.4
3Jab 3.1 5Ja,, 6Jad, 6J,e, 5Jaf: 0 3Jag 2.5 4Jbc, 5Jbd, 6Jbe: 0 5Jbf 0.7 4Jbg 2.0 3Jcd 7.8
4Jce 1.2 5Jcf 0.9 5Jcg 0.8 3Jde 7.1 4Jdf 1.3 3Jef 8.1 6Jdg, 5Jeg, 4Jfg: 0
3Jab 5.5 5Jac, 6Jad, 6Jae,5Jaf:0 4Jbc, 5Jbd, 6Jbe: 0 5Jbf 0.8 3Jcd 8.0
OJaC -0.1 6Jad 0.4 5 -ae 1 n -.-n 3Jbc 8.2
4Jce 1.1 0.9 3Jde 7.2 4Jdf 1.0 3Jef 8.0
5Jc.
4J,e 1.2 3Jde 8.3
194
5 'H NMR
8.08
5Jab 0.1
7.50d \ e 8.14
6Jac -0.2 6Jad 0.4 5J,e 0.1 3Jbc 8.2
a
9.26
s
4Jbd 1.1 5Jbe 0.6 3Jcd 7.2 4Jce 1.1 3Jde 8.2
7.60
7.96
3Jab 9.2
LT')
9.06
H =11
d
Wa2' 7.25
6.50 e 6.31f \ N
b 6.64
/
a 7.14
7.76
N 8.34
3Jab 2.7 4Jac 1.2
5Jcg 1.0 3Jde 9.0 4Jdf 1.0 5Jdg 1.2 3Jef 6.4 4Jeg 1.0 3Jfg 6.8
5.6
a() 6.52
6*71
Heteroaromatics
5'77
0
c \
3Jab 7.9 4Jac 1.5 5 Jad 0.4 3Jbc 7.9
d
7.63 7.80
3Jab 9.8
3Jcd 8.5
4Jce 2.0 5Jcf 0.0
3Jde 8.6 4Jdf 1.8 3Jef 8.5
f 7.20
7.43d /
b 6.34
7.68e \ f 7.47
a 7.88
7.19 7 . 1 2 b u 1 )
6.42
c \
3Jab 6.1 3Jcd 8.0 4Jce 1.8 5JCf0.5
3Jde 7.0 4Jdf 1.1 3Jef 8.4
'Jab 7.8 4J,c 1.3 5Jad 1.1 3Jbc 7.1
d
7.68 8.00 7.43e /
\ b 7.26
7.61 f @a \
8.81
g
8.05
3Jab 4.3 4Jdf 4Jac 1.8 5Jdg 3Jbc 8.3 3Jef 5Jcg 0.8 4Jeg 3Jde 8.2 3Jfg
1.6 0.5 6.8 1.1 8.2
195
5 'H NMR
196
7.74
g
J
3Jab 6.0 4Jac 1.1 3Jbc 8.5
.
8.75 0 7.71 7.50
g
a
7.87 9.15
4J,b 5Jac 5Jad 3Jbc 5Jcg
0.8 0 ~0.5 6.0 0.8
3Jde 8.7 4Jdf 1.1 5Jdg 0.9 3Jef 7.0 4Jeg 1.3 3Jfg 8.2
8.77 7.57 7.73
f
8.30 7.84 9.29
3Jab 5Jbf 3Jcd 4Jce 5Jcf
5.7 3Jde 6.9 0.8 4Jdf 1.3 7.8 3Jef 8.6 1.5 0.8
4Jab 0 5Jbf 0.5 3Jcd 7.9 4Jce 1.2 5Jcf 0.8
;:;::$yJ f 8.01
8.07
f
'a 9.23
3Jab 3Jc-j 4J,e 5Jcf 3Jde
1.8 8.4 1.6 0.6 6.9
3Jde 6.9 4Jdf 1.2 3Jef 8.5
5.6 Heteroaromatics
7.93 9.44
f
a d 7.84
H
a
7.48
e
8.08
b7.49
5Jac 3Jcd 4Jce 5Jcf 3Jde
0.4 8.2 1.2 0.6 6.8
3Jab 8.5 4Jac 0.9 5Jad 0.6
3Jbc 7.3 4Jbd 1.3 3Jcd 7.6
5Jae 0.7 3Jbc 8.2 4Jbd 0.9 5Jbe 0.7
3Jcd 7.2 4Jce 1.2 3Jde 7.8
3Jab 9.0 4Jac 1.2 5Jad 0.6 5Ja, 0.9
3Jbc 6.6 4Jbd 1.4 3Jcd 8.2 4Jde 0.4
3Jab 8.4 4Jac 1.1 5Jad 0.5
3Jbc 7.1 4Jbd 1.8 3Jcd 8.0
5Jae 0.4 3Jbc 8.6 4Jt,d 1.0 5Jbe 0.4
3Jcd 7.0 4Jce 1.4 3Jde 8.2
a 10.3
9.09 d
y
7
./ 6b7.89 4 a 8.22
d 8.36
a 7.50
e
H
8.27
b7.57 a11.70
197
5.7
Halogen Compounds 5.7.1 Fluoro Compounds Fluorine in nature occurs 100% as 19F, which exhibits a s in quantum number I = 1/2. The signals of 'H atoms are split by coupling to F up to a distance of about four bonds.
B
IH Chemical Shifts and Coupling Constants of Fluoro Compounds (8in ppm relative to TMS,J in Hz) 4.10 CH3F 2JHF 46.4 1.24 b \/F
Ha'
a
4.36
2J,F 46.4 3 J b ~25.2 3J,b 6.9
\-p
4.37 H b 4.03 Hc
H,6.17
0.69
a
e Hd
4.32
5.45 CH2 5 2 1.7
J 50.2 ~ ~ ~ J , F57.3
6.25 CHF3 2
J 79.2 ~ ~
1.34
b y a F 6.1 3JbF F 3J,b 4.5 2009
2 J a ~84.7 3J,b 12.8 3Jb~ 20.1 3Jac 4.7 3 J c 52.4 ~ 2Jbc -3.2 3J,b 5.9 3Jac 2.4 2Jbc -6.7 3Jbd 10.8 3Jbe 7.7 3Jc, 12.0
1.57 H =
6
3
J 15.0 ~ ~
F
3 J , ~ 8.9 3J,b 8.4 4 J t , ~5.7 4J,c 1.1 de / b7.24 a 6.97 'J,F 0.2 'J,d 0.4 C 4J,c 2.7 7.03 3Jbc 7.5 4Jbd 1.8
5.7 Halogen Compounds
199
5.7.2 Chloro Compounds l H Chemical Shifts and Coupling Constants of Chloro Compounds ( 6 in ppm relative to TMS,J in H z ) 3.06 CH3Cl
5.33 CH2C12
2.07
3.67 a/\/Cl
Y
c1E
9 3J 6*1
3J 6.4
1.55
1.33 \Cl
7.24 CHC13
3J 6.8
3J 7.2
3.47
1.81 m C 1 1.06 3.47
0.92 1.68 -Cl 1.41 3.42
1.60 5.39 Hc
Ha6.26
3Jab 14.5 3Jac 7.5 2Jbc -1.4
1.78 H-Cl
0.87 0 . 7 4 Hb :vl H i "a e Hd
F'
'Jab 7.0 3Jac 3.6 2Jbc -6.0 2.55 3Jbd 10.3 3Jbe 7.1 3Jc, 10.6
'::
3Jab 8.1 e o a 7 . 2 7 2.3 1.1 5Jad 0.5 d / b7.20 4 C
7.14
3Jbc 7.5 4Jbd 1.7
Hal
&::
d H 4 . 3 4
e 6 i/ 3 7b7'19 .81 C
7.17
3Jab 8.1 4Jac 1.1 4Jac 5Jad 0.5 2.4 3Jbc 7.5 4Jbd 1.4
5 ' H NMR
200 5.7.3
Bromo Compounds
H Chemical Shifts and Coupling Constants of Bromo Compounds ( 6 in p p m relative to TMS,J in Hz) 4.94 CH2Br2
2.69 CH~BI
2.47 \r?ig3J
6.4
3.63 B r w B r
Br 1.76
yBr Hal
5.97Hc
0.96 Hb 0.81 F y B r
3Jab 7.1 3Jac 3.8 *JbC -6.1 H H a 2.83 3Jbd 10.2 e Hd 3Jbe 7.0 3Jc, 10.5
e
d
a 7.43 / b7.15 C
3Jab 8.0 4Jac 1.1 5Jad 0.5 4J,c 2.2 3Jbc 7.4
1.66 \Br 3.37
6.82 CHBr3
1.89 b B r 1.06 3.35
1.73
7 4 % 2.33 HB -r
3Jab 14.9 3Jac 7.1 Ha 6.44 2jbC -1.9
&H
4.62
5.7 Halogen Compounds
201
5.7.4
lodo Compounds I H Chemical Shifts and Coupling Constants of Zodo Compounds ( 6 in ppm relative to TMS, J in Hz)
2.16
3.90
CH3I
CH212
2.96
-
3J 7.0
3.70
1.95
6.57HhI
Y'
y:.24
1.88 \/I 3.16
1.88 11.03 3.16
1T-
y lI . 2 4
1.89
4.91 CHI3
0.93 1.80 11.42 3.20
% 1;:;;:
-
I: - I 2.06
Ha *JbC -1.5 6.53
6'23HC
Hal
0.76H
1.04 Hb
3Ja13 3Jac 2Jbc a 2.31 3Jbd
cy: H :
e Hd
de b / a 7 b7.03 . 6 4 C
7.25
7.5 4.4 -5.9 9.9 3Jbe 6.6 3Jc, 10.0
3Jab 7.9 4Jac 1.1 5Jad 0.5 4Ja, 1.9 3Jbc 7.5 4Jbd 1.8
8 & :
d H 4 . 7 2
202
5 'H NMR
5.8 Alcohols, Ethers, and Related Compounds 5.8.1 Alcohols
H Chemical Shifts and Coupling Constants of Alcohols
(6 in ppm relative to TMS, J in Hz) Aliphatic and alicyclic alcohols: 0.5-3.0 (in DMSO: 4-6) Phenols: 4.0-8.0 (in DMSO: 8-12)
0
Hydrogen bonds strongly deshield hydroxyl protons. The position of the signal may depend heavily on the experimental conditions. If a compound contains several kinds of hydroxyl protons (-OH, -COOH, H20), in general only one signal at an average position is observed because of rapid exchange. In dimethyl sulfoxide (DMSO) as solvent, this exchange in most cases is so slow that isolated signals are observed. In this case, the chemical shifts of hydroxyl protons are characteristic. However, if the sample contains strong acids or amine bases, the exchange rate increases, and also in DMSO, a signal at an average position is observed. Frequently, intermediate exchange rates lead to very broad signals extending over several ppm and, therefore, sometimes not discernible in routine spectra. As a consequence of fast intermolecular exchange of the hydroxyl protons, their coupling with the protons on the adjacent carbon atoms is usually not observed. However, in very pure (acid-free) solutions or in DMSO, the exchange is sufficiently slow so that the H-0-C-H couplings become visible. Their dependence on the conformation is analogous to that shown by the H-C-C-H couplings (Chapter 5.1). In case of fast rotation: 3 J = 5 Hz. ~ In cyclohexanols, ~ ~ the~ vicinal coupling constants for axial hydroxyl protons (3.0-4.2 Hz) are lower than those of equatorial ones (4.2-5.7 Hz). 3.39 3.9 CH30H, b
(in CDCl,)
in DMSO: 3J,b 5.2
1.18 2.61 liquid: in DMSO: 1.53 2.26 c\oHa 6, 5.27 6,4.5 -OH 6, 3.66 0.93 3.49 3.59 6, 1.19 (in CDCl3) (in CDcl3) ,Jab 4.8 ,JbC 6.9
5.8 Alcohols, Ethers, and Related Compounds
1.16
2.16 3Jab 6.2 OH liquid:
(in CDCl3)
O H-H 2cJ=(
1.22
2.01 cl&OH 2.96 cl 4.15 (in CDC13) 60, in DMSO: 6.8
Y O H (in CDCl3)
6 , 1.23
203
(a2
5.2
5.6 CH-OH
(in DMSO)
(in DMSO)
(in DMSO)
3.40 For derivatives inDMSO:
For derivatives
0
4.0-4.5 3Ja,0H 4.2-5.7
1.45
6.82 4Jbd 1.7 (in CC14) * in DMSO: 6 0 ~ 9 . 3
1.17
NO2
(in DMSO)
7.00 (in CDCl3)
5 'H
204
NMR
I H Chemical Shifts of Enols ( 6 in ppm relative to TMS,J in H z )
=16
-16 3Jab 9.7 3Jbc =8
5.04
3Jab5.1
Q
Ha CH3 7.90 H b 2.11 5.60
2.00
0
(in CDC13, partly enolized)
5.8.2
Ethers H Chemical Shifts and Coupling Constants of Ethers
(6 in ppm relative to TMS,J in Hz) 3.21
2Jgem -10.6
f i 0%
\ 0/
3.27 0.93
3.37
*y)-
b 3J& 1.15
1.55
3.40 1.38
*,O
1.54 0.92
3.16 Hb6.44 Hc 3.88 a\o+ Hd 4.03 (in TMS)
0.3 7.0 3Jbd 14.1 2Jcd -2.0
4Jab 3Jbc
.
V.
3.74
a&o'
1.27
6
A
1.24
7.0 0.4 3Jcd 6.9 3Jce 14.4 2Jde -1.9 3Jab
Hd 3.96 4Jbc
Y He 4.17
H Chemical Shifts and Coupling Constants of Cyclic Ethers
( 6 in ppm relative to TMS,J in Hz)
A
2.54
In derivatives: 2Jgem 5 - 6 3Jcis 4.5 3~trans3.1 Throughout: Jcis > Jtrans
5.8 Alcohols, Ethers, and Related Compounds
e a 4.73
c
b 2.72
31Jlac
c
8*3 Jab,trans 0.7 3Jbc 2.5
b
4.82 2.53
0;65; c
1.98
c
7.56
d
0
a 4.63 3Jab
4J
-2.5 ad,& 7.1 4Jad,trans 4*6 3Jbc 6.3
b 5.89 4JaC
c
2.6 2.6
4Jbd 3Jcd
6.38
1.59
6.6 <0.3
o 4.20 3Jab,cis
6.22 d
3.96 1.85 de
6
2Ja,gem -5.8 2Jb,gem- 11.o 3jCis 8.7
trans
3Jab 6.2 4Jac 2.0 3Jbc 3.8 4Jbd 0.6
3Jab 4Jac 5Jad 3Jbc 4Jbd 3Jcd
205
5.0 2.4 1.2 6.3 1.5 9.4
a 6.17
2.66
7.89 3Jab 5Jac 0.3 6'o
;Qa
I
I b 6.34 4J,d 0
2.7 4Jbc 1.1
5 'H NMR
206
I H Chemical Shifts and Coupling Constants of Aromatic Ethers (6 in ppm relative to TMS, J in Hz) a
5Jab~ 0 . 8 3*73 3Jbc 8.3 f b 6.77 4Jbd e \ c 7.15 5Jbe 0.4 4Jbf 2.7 d 6.82 3Jcd 7.4 3Jce 1.8
0 p'
C
6.98
I H Chemical Shifts and Coupling Constants of Acetals, Ketals, and Ortho Esters ( 6 in ppm relative to TMS, J in Hz) 0- 3.20
J
4.44< 05.1
- J fO-(O O
3.53
5*03 7 1 . 1 3 4.9
0
2Ja,gem -7.5
b a 3.9 3Jab,cis '~ab,trans 7*3 6.0
nt5). 0
00
4.70 0 3 . 8 0 1.68
5.9 Nitrogen Compounds
207
5.9 Nitrogen Compounds 5.9.1 Amines
Amine and Ammonium Protons (6 in ppm relative to TMS, IJI in H z ) Chemical shifts of amine protons lie around 0.5-5 ppm depending on solvent, concentration, and hydrogen bonding. Those of ammonium protons are found between ca. 6 and 9 ppm: alk-NH2
0.5-4.O (W2-W
'
2.5-5.0
@ H 2 + - a l k
. 6-9
N
Coupling of amine protons with vicinal H atoms is usually not seen in aliphatic amines because of their rapid intermolecular exchange. However, for =C-NH-CH moieties (enamines, aromatic amines, amides, etc.), the exchange rate is slower and splitting is often observed. The H-C-N-H coupling depends on the conformation in a similar way as the H-C-C-H coupling (see Chapter 5.1). For N-CH3 and N-CH2 groups: 3 J = 5-6.~ ~ ~ ~ In acidic media (e.g., in trifluoroacetic acid as solvent), the exchange of the ammonium protons is slowed down to such an extent that the vicinal coupling H-N+-C-H generally becomes observable. In other media, signals are usually broad owing to intermediate exchange rates. The signals of amine and especially of ammonium protons are often broadened additionally because the 14N-lH coupling is only partly eliminated by the quadrupole relaxation of I4N (spin quantum number, I = 1; natural abundance, 99.6 %; ~ J N H= 60). This line broadening has no effect on the vicinal H-C-N-H coupling so that sharp multiplets can be observed for neighboring H atoms. In
5 ‘H NMR
208
ammonium compounds of high symmetry, the quadrupole relaxation is slow and the coupling with 14N leads to triplets of equal intensity for all three lines. NHq+ lJNH 52.8
H Chemical Shifts and Coupling Constants of Amines
(6 in ppm relative to TMS,J in Hz) 2.47 CH3NH2 1.10
H 3.06 \N,/
\/“2
1.00 2.86
2.74
3.27 1.27
-r
-L a b
1-
1.43
2 J a =OS 3 J b ~1.9
/\/“2
0.93 2.61
(in D20)
N 1.50 H 1.90 A N 0.91 2.56
1.04
H 1.0
1
2.43
1.15
1.03 \“2
3.07
1
-
0.92 1.43
1.77
“2
1.33 2.68
5.9 Nitrogen Compounds
&.8i 1.62 H
2.42 HNH 0.91
1.16H~ H 1r73 1.24
1.'78 1.18
3J,b 8.0 5Jad 0.5 1.1 e 6 a 6 . 4 6 4Jac d
/
,2.94
/
2*78 3J,b 8.2
6.58
4Jbd 1.7
3.55 HN
b7.01 4
J,, 2.5 3Jbc 7.4 4Jbd 1.6
C
6.62
C
6" 3J,b 8.4 4J,c 1.0 e b a 6 . 5 9 5Jad Os4 d / b7.08 4Jae 2.8 C 3Jbc 7.3 6.60 4Jbd 1.8 \
209
/
2.85
3.09
NO2
in DMSO: 7.32 \
I
/
3.72
C
NO2
7.57
I H Chemical Shifts and Coupling Constants of Cyclic Amines (6 in ppm relative to TMS, J in Hz)
H 1.84
H 0.9 N b a 1.61 2Jgem=1 3Jab.cis =6
I 2.25
N
1.59
2.23
H 1.92 (N)2.87 3.67 0
CJz4 1.5
I
I 2.27
(Nl;:8387 N H2.12
5 'H NMR
210
5.9.2 Nitro and Nitroso Compounds
H Chemical Shifts and Coupling Constants of Nitro and Nitroso Compounds ( 6 in ppm relative to TMS, J in Hz)
-
2.01 f i NO2 1.03 4.28
1.58 \ NO2 4.37
4.29 CH3N02
1.07 2.07
1.53
72
1.59
NO2 1.50 4.47
H 4.22
6 J
4.91 2.26, 2.12
4 5 4 . 4 3
1.88, 1.70
6.55 '"-<"a Hc 5.87
bi
6
7.12 3Jab11.8 3Jac 17.9 e / 2Jbc 0.9 NO2 d \
c
H 1.6
H 2.2
3Jab a 8.21 4Jac 5Jad b 7.52 4Jae
7.64
8.4 la2 : 0.4 2.4 3Jbc 7S 4Jbd 1.5
6
a
C
3Jab 7.84 4Jac 5J,d b 7.57 4Jae
7.9 1.3 0.6 2.0 3Jbc 7.4 4Jbd 1.4
7.63
5.9.3 Nitrosamines, Azo and Azoxy Compounds I H Chemical Shifts of Nitrosamines, Azo and Azoxy Compounds ( 6 in ppm relative to TMS)
Generally: ZCis < Ztrans for a-CH3, a-CH2, and P-CH3 protons &is > Ztrans for a-CH protons
2.96 \
/?
FN
3.76
1.15 4 1.52
3
4.26
,p
q N-N
5.9 Nitrogen Compounds
4.16 / N+=N 0'
21 1
N+=N
\ 3.16
O-/
h1.28
5.9.4
Imines, Oximes, Hydrazones, and Azines I H Chemical Shifts and Coupling Constants of Imines, Oximes, Hydrazones, and Azines ( 6 in ppm relative to TMS) 7.50 7.90
O C p F 3.4
7.50
8.40
7.2-8.6
6.8-7.9 YN-OH
-
H F W O H 7-10 ar
7-10
alk
6a,syn
6a,syn > 6a,anti
7.52 HplOH
> 6a,anti
1.86 k N / O H 9.9
9.9
6.92 H
1.83
In aldoximes and ketoximes, the chemical shift difference between syn and anti protons at the a-CH groups, A 6 = Gsyn - Ganti, depends on the dihedral angle, @H-c-c=N:
@ 00 60° 115O
A6 1 0 -0.3
N
5 'H NMR
212
6.1-7.7 H
)=Ff
PFf
alk
"-a
H 7.89 2.03
2.00
sa,syn > aa,anti
5.9.5 Nitriles and Isonitriles I H Chemical Shifts and Coupling Constants of Nitriles (6 in ppm relative to TMS, J in Hz)
1.98 CH3CN
1.31
bCN J,ic 7.6 2.35
2.29
0.96 1.63 -CN 1.50 2.34
?v
6.07 5.73 3Jab11.8 0.94 3Jab 8.4 H h H a 3Jac 17.9 0*93 Hb 3Jac 5 * 1 2Jbc 0.9 2Jbc -4.7 Hc CN H i 'Ha 3Jbd 9.2 6.20 e 1.36 3Jbe 7 * 1 3Jc, 9.5
3Jab
a
C
1.11
1.35
7.0 7.4 4Jac -0.05
1.71 b -CN3Jbc
1.37
e6
YCN 3Jab 7.8
a 7.51 4Jac 1.3
\
5Jad 0.7 7'44 4Ja, 1.8
C
7.56
3Jbc 7.7 4Jbd 1.3
IH Chemical Shifts and Coupling Constants of Isonitriles (6 in ppm relative to TMS, J in Hz) Because of the symmetrical electron distribution around the N atom, the quadrupole relaxation of the nitrogen nucleus is so slow that the 14N-lH coupling becomes observable and leads to triplets with relative intensities of 1:l:l (spin quantum number of 14N: I = 1; natural abundance, 99.6 %): b a -C-C-"NC H2 H2
l J l a 1.8-2.8 lJlbN 1.5-3.5
5.9 Nitrogen Compounds
2.85
2JaN 2.3
CH3NC a
3Ja1, 7.3 2 J , ~2.0 3 J b ~2.4
1.28 b\NC a
21 3
1.45 b y N C a 3'87 3 J b ~2.6
$:
i::
3.89
5.9.6
Cyanates, Isocyanates, Thiocyanates, and lsothiocyanates H Chemical Shifts and Coupling Constants of Cyanates, Isocyanates, Thiocyanates, and Zsothiocyanates ( 6 in ppm relative to TMS,J in Hz) 1.45 \OCN 4.54
3.02 CH3NCO
1.63 f i NCO 0.99 3.26
1.29
2.61 CH3SCN
1.52 2.98
3.37 CH3NCS
'c NCS 3.64
1.20 \NCO 3.37 4.77 6.12 3Jab 7.6 3Jac 15.2 'WHa 2Jbc -0.1 Hc NCO 5.01
N
5 'H NMR
214
5.1 0
Sulfur-Containing Functional Groups 5.10.1 Thiols
1H Chemical Shifts and Coupling Constan (6 in ppm relative to TMS,J in Hz)
I
f Thiols
Typical ranges of SH chemical shifts: &-SH
1-2
O
S
H 2-4
The exchange with other SH, OH, NH, or COOH protons is generally so slow that the chemical shift is characteristic and the vicinal coupling with SH protons becomes visible (5-9 Hz in aliphatic systems with fast rotation). 2.00 1.26 CH3SH b
3Ja1, 7.4
a
(in benzene)
1.31 1.39 V S H 2.44
1.63 1.33 -SH 0.99 2.50 3Ja1, 5.7
0.92 1.59 1.32 -SH 1.43 2.52
S
1.43
H
YSH
S
1.88 1*35 d H 2.68
1.2 0.6 4Ja, 2.1 3Jbc 7.5 4J,c 'Jad
C
7.04
5.10 Sulfur-Containing Functional Groups
215
5.10.2 Sulfides
I H Chemical Shifts and Coupling Constants of Sulfides (6 in ppm relative to TMS, J in Hz)
2.12
‘S/
2.10 2.51 \S1.26
2.09 2.49 1.42 ‘S1.56 0.92
2.43 0.98 & - . S V 1.59
/I(1.39
&,S
a k s
k 9 3 1.25
a 6.35 3Jab 10.3 H b 5.08 3Jac 16.4 \ 2Jbc -0.3 , H c 4.84 (in TMS)
2a12 q
\s
7.16 7.02 7.20 I H Chemical Shifts and Coupling Constants of Cyclic Sulfides ( 6 in ppm relative to TMS, J in Hz)
2Jgem 0 L1 2*27 3Jcis 7.2 3 ~ t r a n s5.7 S
S c ()a b
2.94
3.21 2Ja,gem -8-7 2Jb,gem -11.7 8.9 6.3 4~ac,cis 1.2 ‘~ac,trans -0.2 3Jab,cis 3Jab,trans
0 2 . 7 5 1.88
S
5
216
'H NMR
5 . 1 0.3 Disulfides and Sulfonium Salts
H Chemical Shifts and Coupling Constants of Disulfides and Sulfonium Salts ( 6 in ppm relative to TMS,J in Hz) 2.30
2.67 &+/\ 1.35
,&As/
0
e
&/S'S-/
:::: l::
7.50 7.28
2.63 1.03 1.71
0 2 . 7 1.9
4Jae 0.5 5Jad 2.0
d
*/s\
2.94 \
-s+ /
,
1-
3Jbc 7.2
5.10.4 Sulfoxides and Sulfones I H Chemical Shifts and Coupling Constants of Sulfoxides and Sulfones (6 in ppm relative to TMS,J in Hz)
qs00 / \
2.84
+'
/u 0 '
1.47
2.80 2.94
3Jbc 10.0 3Jbd 16.5
2'96
b6.14 2Jcd -0.5 Hb6.76
qSQo 1.41 2.85 ' x 1 3
% eo
1.44
ysy
%go O=
- 3.06
Q63t
7.94 7.61 7.65
5.10 Sulfur-Containing Functional Groups
21 7
5.10.5 Sulfonic, Sulfinic, Sulfurous, and Sulfuric Acids and Derivatives
H Chemical Shifts and Coupling Constants of Sulfonic, Sulfinic, Sulfurous, and Sulfuric Acids and Derivatives ( 6 in ppm relative to TMS, J in H z ) 11-12 alk-SOz-OH
3.0
2.5
-/3.7(
3J,b 4Jac 5J,d, 7.94 4Ja, e \ a 7. , / hb e-l o/ a 77.60 3Jbc d C 4Jbd 7.62
2.68 ,cH3
8.0 1.2 0.6 2.0 7.6 1.4
3.6
J,, c
7.60
4Jbd 1.3
6 sJH2
7.37
7.85 / 7.58 7.58
5 . 1 0.6 Thiocarboxylate Derivatives
H Chemical Shifts of Thiocarboxylic Acids and Derivatives
(6 in ppm relative to TMS, I JI in Hz)
3J,b 5.9 2.41S H' 2.30
5.09
s/
a 6*47 4J,c 2.0
7.84 2.27
2.2
3Jbc 2*8
6.4
5 'H NMR
218
5.1 1
Carbonyl Compounds 5.1 1.1 Aldehydes
' H Chemica Shifts and Coupling Constants of ..,.#ehyi es (6 in ppm relative to TMS,J in Hz) Typical ranges for chemical shifts and coupling constants of aldehyde protons: alk-CHO 9.0-10.1
O
C
H
3J,ic 0-3
alken--CHO 9.0-10.1
cHO
O 9.5-10.5
R 9.60 CH2=O 'IJIgem 42.4
1.67
9.74
6.26
C=X
6.26
H=i="
Hd 6.11
0
ycfo
1.13 3Jab 2.0
0.97 2.42
2.20 9.80 b a C H r C H O 3Jab 3.0
9.57
3Jab 1.1
2.39
3jVic
10.2-10.5 m , p : 9.5-10.2 0:
1.13 9*79 +CHO 2.46
1.07
Z8
8
3Jab 1.4
9*48
YCHO
3Ja1, ~ 8 . 0 4Jac ~ 0 . 3 4Jad 10.1
Ha 9.51 7.61
4Jce 1.3
5.1 1 Carbonyl Compounds
219
5.1 1.2
Ketones I H Chemical Shifts and Coupling Constants of Ketones ( 6 in ppm relative to TMS, J in Hz)
%:
k . 0 5 a J 1 4 & 4Jab 0.5 2.14 2.14 2.47 1.98 2.32 0.85
2.09
(in benzene) in CDC13: c 1.56 d 0.93
6.27
5.90
6.30
6.67
2.55 7.45
2.92
2.86 1.02
7.44
3.58 d
ae 1.8 3Jbc 7.5 4Jbd 1.3 '='
5 'H NMR
220 7.74
Qni
? I
7*57
2.68 7.47
?!
fs
7.46*
( J
2.63
6-78
.--
II
7.21 2.93
j.13
*
0
assignment uncertain
I H Chemical Shifts of Diketones ( 6 in ppm relative to TMS)
2.34
3.62
2.17
For the enol form, see Chapter 5.8.1 Long-Range Coupling in Ketones (IJI in Hz) Coupling over the C=O group is often detectable for fixed conformations in Warrangement of the coupling path:
Br
5.1 1.3 Carboxylic Acids and Carboxylates
' x A
I H Chemical Shifts of Carboxyl Protons ( 6 in ppm relative to TMS, J in Hz) The position of the COOH signal depends on the solvent, the concentration, and the presence of other exchangeable protons. Intermediate rates of exchange with other protons may induce very broad lines, which are sometimes not even detected. 8.06
11.0 H-COOH
2.10 11.42 CH3-COOH
11.73 1.16 vCOOH 2.36
1.06
VCOONa 2.18
(in D20)
1.68 11.51 m C O O H 1.00 2.31
1.23
1.21
0.93 1.62 -COOH
11.88
11.96
1.39 2.35
11.19 COOH
11.49
y'"""
3.45
12.2 COOH
Coo,
(
COOH
2*43
(in DMSO)
OOH-12.5 3Jab 7.9 3Jab 10.5
5.95 Ha 6.15
OH12.8 3Jac 17'2 2Jbc 1.8 C
3Jbc 7.5 4Jbd 1.3
7.60
5.1 1.4
Esters and Lactones H Chemical Shifts and Coupling Constants of Aliphatic Carboxylic Acid Esters ( 6 in ppm relative to TMS, J in H z )
,f,o,:z b
41Jlab 0.8
l o q ! c 4 . 6 9 Ha 8.03 Hd 5.01
Ha 8.07
4Jab -0.7 3Jbc 6.4 5J,c 1.6 3Jbd13.9 5.Jad 0.8 2Jcd -1.7
c=x &67 2.01
2.04
1.26
2.05
1.65
4.06 1.39 2.02
1.23
2.04
0-
1.60
0.94
J O k 1.45
5 'H NMR
222
C
7.07
0.98
2.32
0
.
9
l*?Q7 2.56
2.22
w $66
1.33 2.31
For esters of boronic, nitric, and sulfuric acid, see Chapter 5.12. I H Chemical Shifts and Coupling Constants of Alkyl Esters (6 in ppm relative to TMS)
qoT40
5
F
4 b
y
Hc 0 6.40
%
3Jab 10.6 3Jac 17.4 2Jbc 1.5
do% 1.30
3.76
nK22 .37 1.77
I.4U
C
7.46
7.37
5.1 1 Carbonyl Compounds
223
H Chemical Shifts and Coupling Constants of Lactones
(6 in ppm relative to TMS, J in H z )
&C
3.56 4.29
4.28
2Jab -17.5 Ha 2.41 3J,, 9.5 3Jad 6.9 4J,, 0.3 Hf Hd 2.23 4jaf -0.5
*J,d -12.7 3Jce 7.9 3Jcf 6.3 2Jef -8.8
5 . 1 1.5 Amides and Lactams
Amide Protons ( 6 i n ppm relative to TMS, J in Hz)
1
R
"2
5-7
R: alk, ar
1
R N H 6-8.5
R: alk, ar
1 /o R N H
R: alk, ar
7.5-9.5
Line Widths The signals of the NH protons are often broad because the 14N-lH coupling is only partly eliminated by the quadrupole relaxation of 14N (spin quantum number, I = 1; ~ J N H = 60). In primary amides, the hindered rotation around the CO-N bond is another reason for line broadening. At slow rotation, the chemical shifts of the two primary amide protons differ by about 0.5-1 ppm. Vicinal Coupling H- C-N-H Due to the slow intermolecular exchange of amide protons, their coupling to neighboring hydrogen atoms is usually detectable. The splitting of the C-H signal is clearly observed even in those cases where the signal of the NH proton is broad and featureless. The H-C-N-H coupling depends on the conformation in a similar way as the H-C-C-H coupling (see Chapter 5.1). For N-CH3 and N-CH2 groups: 3 J sz 7. ~ ~ ~ ~
C =X
5 'H NMR
224
Tertiary Alkylamides The rotation around the CO-N bond is usually so slow that, with different Nsubstituents, two separate signals are observed for the two conformers. In general, the following relationships hold: for NCH3, NCH2CH3, and NCH(CH3)2 for NCH(CH& and NC(CH3)3 for NCH,
Gcis to 0 5 Gwans to 0 &ram to o 5 %is to o %is to o Gtrans to o
-
Formamides ( 6 in ppm relative to TMS, IJI in Hz) In the more stable conformer of monosubstituted formamides, the substituent occupies the cis position relative to the carbonyl oxygen. In the more stable conformer of asymmetrically disubstituted formamides, the larger substituent occupies the trans position relative to the carbonyl oxygen.
H
- '*' ii' H
,kN/2*:8
8.1
H7.9 90 %
Ha 8.02
'
Ha
"7.9
2.88 = 10%
8.2-8.7
N
B
R
7.5-9.5
1 2.71
4J,b -0.3
4Ja, -0.7
b 2.97
A 1 2 2.83
1.19
= 30 %
= 70 %
Acetamides ( 6 in ppm relative to TMS,J in Hz) In monosubstituted acetamides, the substituent of the only observable conformer ; ; -. X is cis to the carbonyl oxygen. In disubstituted acetamides, the more stable conformer has the larger substituent cis to the carbonyl oxygen.
0
3.26
3J,b 4.8
1.98
Hb 6.4
1.98
H b 1.14 6.7
3Jab 5.9
AN)96 -2.0
H
1.55
5.1 1 Carbonyl Compounds
225
3.21 1.35 3Jab 8.4
~ 2 . 0 H b 1.13 8.1
1.98
4 '
2.08
.
N H 1.49 0.92 7.05
=2.O
-
N/ 3.02 5Jab 0.1 5Jac 0.5 2.94
A N L y 2
I 2.83
1.15
= 60 %
= 40 %
JNb;::: L
-2.1
H
a
7.64
1.03
0
f N/2'70 l 2
3Jab 8.2 4Jac 1.2 5Jad 0.5 4Jae 2.4
H 1.28 7.3
3.36
3.46 1.97
l H Chemical Shifts of Lactams ( 6 in ppm relative to TMS)
C=X
0
5.1 1 . 6 Miscellaneous Carbonyl Derivatives H Chemical Shifts of Carboxylic Acid Halides (6 in ppm relative to TMS, J in Hz)
A
2.66
DF
3Jab 10.7 3Ja, 17.3 2Jbc 0.8
2.82 A B ,
6.25 Ha
6.14
6.16
3Jab 10.6
3Jab 8.0
3Jac 17.4 2Jbc 0.2
1.2 8.07 5Jad o-6 7.47 4 ~ a e 2.0 3Jbc 7.5 4Jbd 1.4
k, 6.35
4Jac
de&;
C
7.63
H Chemical Shifts of Carboxylic Acid Anhydrides
(6 in ppm relative to TMS)
5.1 1 Carbonyl Compounds
227
H Chemical Shifts of Carboxylic Acid Imides
( 6 in ppm relative to TMS)
0
2.62 2.06
3.83
2.50
l H Chemical Shifts of Carbonic Acid Derivatives ( 6 in ppm relative to TMS)
4.13 1.2-1.7
o+O- 0- 3.8 1.2-1.7 0.93
3.94
5.5
[>s
2.78 \ l N H 5.16
o z 1.23
c=x
5 'H NMR
228
5.1 2
Miscellaneous Compounds 5.12.1 Silicon Compounds I H Chemical Shifts and Coupling Constants of Silanes and Silanols ( 6 in ppm relative to TMS, J in H z )
a R-?i-H R
For R: H, SiX3: 2-4 2-6 other: 3-6
H a 3.20 H-Ai-H I
H 'J,si -202.5
b
FH3 0.19 'Jasi-202.5 I t y i - H 3.58 35 4 7 a ab . H
0.42
0.79
YH3
CH3-g iC1 CH3 5.88
6.11
'Jasi -150 to -380 (4.7% natural abundance of 29Si, "Si satellites")
Cl-
YH3
i C1
I$-
CH3
3 'aD 1. ldh 3Jac 20.2 2Jbc 3.8
1.14 YH3
Cl-7x1 c1
I-."
4Ja, 5Jad 3Ja, 3Jbc 4Jbd
1.4 0.7 1.4 7.5 1.2
5.1 2 Miscellaneous Compounds
229
The silanol hydrogen is exchangeable with D20. Slow intermolecular exchange is observed in dimethyl sulfoxide as solvent so that the vicinal coupling in H-Si-OH is detectable.
(in DMSO)
5.1 2 . 2 Phosphorus Compounds H Chemical Shifts and Coupling Constants of Phosphines and Phosphonium Compounds ( 6 in p p m relative to TMS, IJI in Hz) 1.79 a
PH3
lJap 184.9
0.98 2.63 lJap 186.4 b a 2Jbp 4.1
CH3-PH2
3Jab
8.2
1-06 'Jap 191.6 2Jbp 3.6 H 3Jab 7.7
CH3\p/CH3 a
3.13
I H Chemical Shifts and Coupling Constants of Phosphine Oxides and Sulfides ( 6 in ppm relative to TMS, IJI in H z )
5 'H NMR
230
H 6.60
2Jap 13.5 3Jbc 11.8 2Jbp 25.9 3Jbd 17.9 Hc6.14 3Jcp 45.3 2Jcd 1.8 3Jdp 25.4
"$k
6.26
\
Ha6.82 2Jap 24.9 H b 3Jbp 47.0 6.17 3Jcp 25.5 3Jab 11.7 6*34 3Jac 17.9 2Jbc 1.6
H Chemical Shifts and Coupling Constants of Phosphonous Acid Derivatives ( 6 in ppm relative to TMS, IJI in H z ) c 1.20 2Jap 9.7 y q r y 4 . 2 0 a 1.10
3JbP 9*5 4Jcp 6.0
\N\
q ' xa 3.49 \/sr,9' bl .25 /o 3Jap 10.8
-0
a 3.85
f
2Jap 8.7 8.0 4Jcp ~ 1 . 0 3Jbc 7.0
fvc 1.01 3Jbp "
b 2.96 a 1.18 (in CCl4) 3 J a ~ 8.0
4Jbp 0.6 3Ja1, 7.1
Ia
I "\Q"' /
N\
3Jap 8.9
2.43
5.12 Miscellaneous Compounds
231
IH Chemical Shifts and Coupling Constants of Phosphonic and Phosphoric Acid Derivatives (6 in ppm relative to TMS, J in Hz) 3.66 O’b a -$=O 1.43 I 0,
3.78 a
\oI
&’
3.65 2JaP-18.O 7.40 7.72 1.72 OI G 3Jbp 19.5 2JaP 17*3 a p d = O 3Jcp 10.0 \ 3Jbp 11.o 3J,b 7.5 7’48 d e b \ 1.06
-o-P=o
1.29
4.04
1.28
3J,p 13.3 4Jbp 4.1 h=o 5Jcp 1.2 3Jab
4Jac 5Jad 4J,, 3Jbc 4Jbd
7.7 1.4 0.6 1.6 7.6 1.4
4.06
b a -0
9I
Lo+o
J,p 11.0
b
I H Chemical Shifts and Coupling Constants of Phosphorus Ylids (6 in ppm relative to TMS, J in H z )
2Jab 12.7 2J,c -1.2
Misc.
5 'H NMR
232
5.12.3 Miscellaneous Compounds
H Chemical Shifts and Coupling Constants of Miscellaneous Compounds ( S i n ppm relative to TMS)
Li- CH3 -1.32(in benzene) -1.74(in ether)
0-
,o-i
3.5
0-
6.80 (in DMSO)
o."-o+
4.78
e\ / 4.2 N-0 d'
1.39
0.71
R / 4*3 o=c1-0 II
0
6.67
H, 5.51
MnBr
6.19
6.70
3~~~17.7 3J,c 23.3 2Jbc 7.6
3Jab 12.2
3Jac 19.8
FH3
CHrTb-CH3 CH3 (in DMSO)
6.15
2Jbc 2.1
0.72
7.40 7.44
0.4
7.24
5.13 Natural Products
233
5.1 3 Natural Products 5.13.1
Amino Acids I H Chemical Shifts and Coupling Constants of Amino Acids ( 6 i n ppm relative to TMS; J in Hz, solvent: tripuoroacetic acid (TFA) or D20)[ 11
7.47 4.28 a b
3.58 'H3N)K0-
3Jab 5.7
0
0
(in D20)
(in TFA)
?(.-
1.86
d 1-25 3Jab 5.7
1.49
+H3Nf 3.79
4.49 O
(in TFA)
7.i3
'H3N b 4.32 0 (in TFA)
(in D20)
g
a c,d4: 7.38 'H3N b 4.28 0 (in TFA)
3Ja1, 5.5 f 1.10 3Jbc =6.7 3Jeg ~6.1 3Jbd 6.7 5.7
4.51 3Jab 6 4.0* OH 3Jbd 4.0" 2J,d -13.5
c'd 4.56 3Jbc
a 4.650 7.70 (in TFA)
3Jef
* average value
3Jbc 4.2 OH 3Jcd 6*9
1.10
3Jab
5.5
1.21 d
a 4.410 7.35 (in TFA)
d1.67 3J,b 5.5 4.82 3Jbc 4.5 7.63aH0&oH 'H3N b 3Jcd 6.5 C
4.44 0 (in TFA)
Nat ?Ir ;i I Products
e
a 4.680 7.58 (in TFA) * average value
3Jab 5.3 3Jbc 5.0* 3Jbd 5.0" 2Jcd -15.5 3Jce 9.1* 3Jde 9.1"
f
a
7.73
2.27'Jab
5.5
4.670
(in TFA)
* average value
z7.45
7.03
p
7.27
7.3 0 =7'45 3Jbc 8.5 3Jbd 4.5 2Jcd -14.5 3.64 cd 3.37 7.4 a
+H3N*OH a 4.68 0 7.33 (in TFA)
7.73
OH
OH
6
4.64 (in TFA)
3Jab 5.1 3Jbc 4.7
2 2.63 . 5d. 4 7.71 a
4.76 0 (in TFA)
3Jab 5.8 3Jbc 5.6* 3Jbd 5.6" f 2.00 2Jcd -15.0 ~ 1 . 8 3Jce 6.0* 2.35 d 3Jde 6.0" OH 3Jfg ~ 6 . 0 3Jgh e6.0 4.52 0 h
r!rirl ! i R I til
l,Jt!;'lS
6.97
(in TFA) * average value
+H3N b
OH 3Jab 5.5 3-01 ::bcbd 5.6* OH
4.60 0
2Jcd -15.5 3Jce 6.2* 3Jde 6.2*
(in TFA) * average value i 6.19
i 6.19
3Jab 5.5 3Jbc 5.3* 3Jbd 5.3* 2Jcd z-15.0 3Jce =6* 3Jcf =6* 3Jde =6* 3Jdf r6* 3Jeg 6.5" 3Jfg 6.5* 'Jgh 5.3
+HzIY"2 4.46 0 (in TFA) * average value
5.1 3 Natural Products
2.06 d 2.04 e
I
b2.42 c 2.14
4.33 (in D20, pH 2.0)
1.07 d 1.05 e
-
b 1.45 c
1.04
2.81 (in D20, pH 13.0)
a
1.63 d 1.60 e
3Ja1, 8.5 3Jac 6.5 2Jbc -13.5 3Jbd 7.5 3Jbe 5.5 4Jbf -0.4 4Jbg 0.0 3Jcd 5.5 3Jce 7.5 2Jde -13.0 3Jdf 5.5 3Jdg 7.5 3Jef 7.5 3Jeg 5.5 2Jfg -11.0
7.205
H (in TFA)
OH
3.9* e
3'9*f H2'\ 0 8.60 g 4 8.00 h (in TFA)
3Jab 8.4 3Jac 6.2 2Jbc -13.5 3Jbd 7.6 3Jbe 5.4 4Jbf -0.4 4Jbg 0.0 3Jcd 5.6 3Jce 7.8 2Jde -13.0 3Jdf 5.7 3Jdg 7.9 3Jef 7.9 3J,g 5.7 2Jfg -11.0 3Jab 8.2 3Jac 10.4 2Jbc -15.0 3Jbd <2 3Jcd 4.2
* average value
7.05
a
b 1.96 c 1.68
3.74 (in D20, pH 7.0)
3J,b 8.6 3Jac 6.6 2Jbc -12.0 3Jbd 8.1 3Jbe 5.9 4Jbf -0.6 4Jbg 0.0 3Jcd 6.7 3J,e 8.5 2Jde -11.0 3Jdf 5.5 3Jdg 8.1 3Jef 7.7 3Jeg 5.7 2Jfg -10.5
(w4H 7.66
2Jbc 4.0 3Jbd 8.0 2Jcd -15.5
I
235
d
8'73
7.82 N H ~ + 4.91
3.87 0 (in TFA)
3Jab 6.4 4J,d 1.4
Nat 11 ra I
Products
5 'H NMR
236
5.13.2 Carbohydrates [2-41
z3.7 ~ 3 . 7H
3.93
H% =3.7
i.r t OH
5.20
t 3.52 OH
3.32
z3.7
(in D20)
(in D20)
Glucose
-* a
3.75j 3.60
.
1 4.45*
InD20 7.8 9.5 9.5 9.5 2.8 5.7 ,12.8
OH a 6.54*
4.81*h 3.30gHOHO
OH b4.51 4.81* 3.37 3c13 4.81* f
(in D20, relative to internal acetone at 6 = 2.12) * in DMSO 3.725
,
1
4.34"
InD20 3Jbc
3J,e
4.42* (in D20, relative to internal acetone at 6 = 2.12) * in DMSO
3J,g 3Jgi 3J.. J' 3Jik 2Jjk
InDMSO 3J,b 6.5 3Jcd 4.5-6
3Jef 4.5-6 3Jgh 4.5-6 3Jj1 5.5 3Jkl 6.0
InDMSO
3.6 3J,t, 9.5 3Jcd 9.5 3Jef 9.5 3Jg., 2.8 3Jjl 5.7 3Jk1 -12.8
4.5 6.8 4.8 5.5 5.7 6.2
5.13 Natural Products
237
Fructose
3.77, 3.41
5.14
3.62 h
a
n
4.38 3-58 (in DMSO, 25% p-D) 3.52, 3.40
Z
In DMSO (at 25 OC)
6 in D20 (75% p-D)
2Jbc -11.3 3Jdf 10.1 3Jfi 4.0 3Jhk 1.9 3Jh1 1.6 2Jk1 -12.1
3J,b 7.4 3Jac 5.4 3Jde 6.8 3Jfg 5.8 3Jhi 3.8
b 3.68 c 3.53 d 3.76 f 3.86 h 3.96 k 4.00 1 3.68
3.48, 3.37
W HOJ
In DMSO (at 70 OC)
O
H 3Jde 3Jef
"'OH !OH
2J,b -11.0
3
2Jfg -11.6 3.79 3.80
3.72 3.77
(in DMSO, 55% p-D) Coupling constants: at 70 OC
(in DMSO, 20% a - D ) Coupling constants: at 70 OC, tentative values
5.13.3 Nucleotides and Nucleosides 0
"2
' NAO
5.97 ?N 7.50 H
(in D20)
7.41 b Hc 10.82
(in DMSO) 3Jat, 7.5 3Jbc 5.7
H 10.6 (in DMSO) Nat 11ra I Prodiicts
5 'H NMR
238
"2
7.71 "yIH'l.3
I
5.04
c 5.91
3Jef 5.1
OHOH (in D20)
6.18 4 . 2 6 y 2.08 OH 5.25 (in DMSO)
NH2 7.09
I
8 . l l t y 0J 8.14 N H N 12.8 (in CDC13) "2
I
R
7.41
8 . 1 7 t x J 8.38
-"?rj
5.48
5.91 3.70 3.58 3.99 4.17H4.64 OHOH 5.24 5.51 (in DMSO)
4.11H 4 . 4 3 OHOH 5.20 5.45 (in DMSO)
5.13 Natural Products
5.10
OH 2.64 5.3 1 (in DMSO)
239
6.50
4.36 OH 2.22 5.31 (in DMSO)
5.1 3.4 References B. Bak, C. Dambmann, F. Nicolaisen, E.J. Pedersen, N.S. Bhacca, Proton magnetic resonance at 220 MHz of amino acids, J. Mol. Spectrosc. 1968, 26, 78. B. Gillet, D. Nicole, J.-J. Delpuech, B. Gross, High field nuclear magnetic resonance spectra of hydroxyl protons of aldoses and ketoses, Org. Magn. Reson. 1981, 17, 28. M. Jaseja, A.S. Perlin, P. Dais, Two-dimensional NMR spectral study of the tautomeric equilibria of D-fructose and related compounds, Magn. Reson. Chem. 1990, 28, 283. C. Altona, C.A.G. Haasnoot, Prediction of anti and gauche vicinal protonproton coupling constants in carbohydrates: a simple additivity rule for pyranose rings, Org. Magn. Reson. 1980,13, 417.
Natural Products
240
5 'H NMR
5.1 4 Spectra of Solvents and Reference Compounds 5 . 1 4.1 H NMR Spectra of Common Deuterated Solvents (500 MHz; =1'000 data points per 1 ppm; 6 in ppm relative to TMS) Acetone-dg
Benzene-d6
1 7.16 10 9 Bromoform-d
7
8
6
5
4
3
2
1
Chloroform-d
I
7.26
1.55 (yo)
0
5.14 Spectra of Solvents and References
24 1
Cyclohexane-dl2
JL
1.38
11111111111
1.40 1.35 I
-
a
'
*
,
~
-
'
*
,
"
'
~
"
~
'
'
"
'
'
I~ ' ' ~I
'
'
'
.
-
I
~
'
'
'
l
~'
'
*
'
I
.
'
'
'
'
'~
l
Methanol-dl
Methanol-d4
I " . . r . " I
3.35 3.30 3.25 1
.
'
~
"
'
"
'
1
"
~
~
1
"
"
J
'
"
'
I
'
'
"
I
"
~
~
~
~
'
~
'
~
'
~
"
~
~
Pyndine-dg 8.73
~
"
A '
~
~
7.21
7.58
I,
'
"
4.91 (50) I '
~
"
~
'
l
"
"
~
"
-3.60 3.55
I
'
.
'
~
I
'
"
I
'
"
I
1.75 1.70
'
~
'
'
1
'
"
"
~
"
~
~
"
"
~
. I~
~
~
'
~
1.72
3.58
,
~
"
L
'
"
~
~
"
"
~
"
~
'
~
'
'
~
~
'
'
''
SOIV~!171s
~
5 'H NMR
242
Water-d2 4.80
0.68 TMS
(external reference)
5.1 4.2 H NMR Spectra of Secondary Reference Compounds
Chemical shifts in l H NMR spectra are usually reported relative to the peak position of tetramethylsilane (TMS) added to the sample as an internal reference. If TMS is not sufficiently soluble, a capillary with TMS may be used as external reference. In this case, owing to the different volume susceptibilities, the local magnetic fields in solvent and reference differ, and the peak position of the reference must be corrected. For a D20 solution in a cylindrical sample and neat TMS in a capillary, the correction amounts to +0.68 and -0.34 ppm for superconducting and electromagnets, respectively. These values must be subtracted from the chemical shifts relative to external TMS if its position is set to 0.00 ppm. Alternatively, secondary references with (CH3)3SiCH2 groups may be used. The following spectra of two such secondary reference compounds in D20 were measured at 500 MHz with TMS as external reference. Chemical shifts are reported in ppm relative to TMS upon correction for the difference in the volume susceptibilities of D 2 0 and TMS. As a result, the peak for the external TMS appears at 0.68 ppm. 3-(Trimethylsily1)-1-propanesulfonic acid sodium salt (sodium 4,4-dimethyl-4silapentane-1-sulfonate; DSS)
0.68 TMS DD H3c~,si8COONa H3C D D
(external reference)
H3F
4.80HDO
0.00
5.14 Spectra of Solvents and References
243
5.1 4.3 l H NMR Spectrum of a Mixture of Common Nondeuterated Solvents The following l H NMR spectrum (500 MHz, 6 in ppm relative to TMS) of CDC13 containing 18 common solvents (0.05-0.4 ~ 0 1 % is ) shown as a guide for the identification of possible impurities. Where the signals of several solvents overlap, insets show signals for the individual compounds from separate spectra. Peaks in these insets are labeled with the corresponding chemical shifts from the main spectrum but their values may differ by up to 0.03 ppm. Signals that are particularly prone to vary in their position are marked with *. THF: tetrahydrofuran; EGDME: ethylene glycol dimethyl ether. pyridine 8.61
J 1
r "
8.8
"
1
'
"
8.7
'
,
1
:E>
dimethyl formamide 8.01
I1
L
"
~
pyridine 7.67
r
'
1
~
8.6
'
'
~
8.5
I
3
'
"
8.4
~
I
8.3
17.35* benzene
'
'
'
I
~
8.2
*
'
8.1
pyridine llj'28*
.
I
'
~
.
8.0
'
I
'
7.9
'
~
'
I
7.8
dimethyl sulfoxide 2.60
'
I
7.1
5.3
5.2
3.47* methanol
toluene 2.35
acetone ethyl 2.16 acetate 2.04
I
ether m?
'
'
.
'
7.6
-1
dimethyl formamide 2.88
~
CW!? 5.29
5.4
dimethyl formamide 2.96
~
7.7
toluene
7.2
ethyl acetate 4.11
'
--r
-F
0.88 hexane
I
'
"
~
I
6.1 Alkanes
245
6 IR Spectroscopy
\CY / \
6.1
Alkanes %T
1 1
CH38 as
i
C-H st
CH28 I
I
1
Typical Ranges ( V in crn-l) Assignment C-H st
Range Comments 3000-2840 Intensity variable, often multiplet Beyond n o m 1 range: 2850-2815 CH3-0, methyl ethers 2880-2830 CH2-0, ethers 2880-2835, 0-CH2-0, methylenedioxy 2780-2750 O-CH-O, acetals: weak ~2820 3050-3000 2900-2800, 2780-2750 2820-27 80 3 100-3050, 3035-2995 ~2700 3080-2900
CH=O, aldehydes: Fermi resonance CH3-N, CH2-N; amines
D
0
CH-ha1
comb for cyclohexanes (CH2 as st ~2930)
246
\
/
c / \
6 IR
Assignment C H 3 6 as
Range Comments 1470-1430 Medium, coincides with CH2 6 Beyond n o m 1 range: 1440-1400 CH3-C=0, methyl ketones, acetals CH3-C=C
CH2 6
Medium, coincides with CH3 6 as 1475-1450 Beyond normal range: =1440 CH2-C=C ~1425
C H 3 6 SY
CH2-CrC CH2-C=O, CH~-CZN, CH2-X (X: hal, N02, S, P)
Medium. Doublet in compounds with geminal methyl groups: ~ 1 3 7 0 CH(CH3)2, equal intensity (y 1175-1 140, d) C(CH3)2, 1385 weaker than 1365 (y 1220-1 190, often d) C(CH3)3, of equal intensity, sometimes triplet (y 1250-1200, d) N(CH3)2, no doublet
1395-1 365 -1385, -1385, -1365 -1390, -1365
Solid-state spectra: sometimes doublet also in the absence of geminal methyl groups Beyond normal range: 1325-1310 S02-CH3 1330-1 290 S-CH3, sulfides 1310-1 280 P-CH3 1275-1260 Si-CH3, strong, sharp CH3 Y
1250-800
Intensity variable, of no practical significance Strong band in compounds with geminal methyl groups: 1175-1 140 CH(CH3)2, doublet 1220-1 190 C(CH3)2, generally doublet 1250-1200 C(CH&, doublet, often not resolved Beyond normal range: 1765 SiCH3 1855, -800 Si(CH3)2 ~ 8 4 0-765 , Si(CH3)3
6.1 Alkanes
Assignment
CH2
Y
C-D st
Range
247
Comments
770-720
Medium, sometimes doublet C-(CHZ)~-C for n > 4 at ~ 7 2 0 ; for n c 4 at higher wavenumbers; in cyclohexanes at 4 9 0 , weaker Beyond n o m 1 range: 1060-800 Cycloalkanes, numerous bands, unreliable 2200-2080
In general, substitution of L by isotope L':
\ /
/
C\
6 IR
248
6.2 Alkenes
c;,:..-c 6.2.1 Monoenes
c=cst
t
C=C-H 6 OOP
Typical Ranges (v in c m - l ) Assignment = C H 2 st
Range 3095-3075
=CH st
3040-3010
Comments Medium, often multiple bands
Medium, often multiple bands CH st in aromatics and three-membered rings fall in the same range In cyclic compounds: ~3075
D
-3020
0
=CH 6 ip
1420-1290
=CH 6
1005-675 A number of bands In the same range also: ar CH 6 oop, C-0-C 'y, and C-N-C y in saturated heterocyclics, OH 6 oop in carboxylic acids, NH 'y, NO st, SO St, CH2 y, CF st, CCl st
OOP
Of no practical significance
6.2 Alkenes
Assignment Subranges:
Range
Comments
c=c CH=CH2
C=CH2
249
C=C-C=O 1005-985 ~980 920-900 =960 (with overtone -810 at 1850-1800) 900-880 -940 (with overtone 4 1 0 at 1850-1780) 990-960 -975
C=C-OR =960 415
C=C-O-C=O 2950 470
=795 -960
-950
H%H "H
HH c=c s t
725475
-820
840-800
-820
1690-1635 Subranges: 1650-1635 1660-1 640 1690-1665
Of variable intensity, weak for highly symmetric compounds, strong for N-C=C and O-C=C CH=CH2 C=CH2
%H
H
Weak
1665-1635
'HH
1690-1660
HH
1690-1650
Weak, often absent
Weak, often absent
Beyond noma1 range: down to C=C-X with X: 0, N, S ; of higher intensity; in vinyl ethers often doublet due to rotational 1590 isomers
-
c=c
6 IR
250
At lowerfrequency if conjugated with: c=c =1650 ~1600 czc =1600 CzN
~1620
c=o
~1630
4
~1630
4
=1640
Examples (v in crn-I) 1645 994 912
=L
\ g'76:
1575 826 76 1
c1
liquid: CC14: 1610 1634 1608 987 964 810 943
7
1
< cI=/Cl
/ 0-
1663
1647 889 669
1682 972 963
1650 709
1667 825
1595 848 714
1587 929 835 780
E 958 793
1670 1652 937 925
1660
1673
-Ido
1663
3O 7
=\
1650
6.2 Alkenes
w-N-
1640
1662
1652 1612
1830 1621 987 818
251
/
<
c=c
1607 (2270)
&
CHO
1618 (1704)
COOCH3 4
1637 (1735)
w
=\=L,
1800 1621 94 1 899
CN
1645 1612
==/
1636
COOH 1635 d 1615 (1730) ( 1706)
6.2.2 Allenes
Assignment (C=C)=C-H st C=C=C st as
Range 3050-2950 1950-1930
Comments
c=c=cst
1075-1060
Weak, absent with highly symmetric substitution Strong, overtone at ~ 1 7 0 0weak ,
sy
( C = C ) = C H z 6 OOP 4 5 0
Strong, doublet in X-C=C=CH2 if X other than alkyl Ring strain increases frequency: l)cC=CH2 ~ 2 0 2 0
6 IR
252
6.3 AI kynes %T overtone
C=C
zC-H
St
EGH6
CEC st
zGH6 I
f
3600
2800
2000
1600
1200
800
400
Typical Ranges ( v in crn-l) Assignment =C-H st
Range 3340-3250
C E C st
2260-2100
Comments Strong, sharp; in the same region also OH st, NH st Weak, sharp
Beyond normal range: R-CZC-H; at the lower end of the cited range R-CEC-R; usually 2 bands (Fermi resonance), often missing if symmetrical Subranges: =2 120
C-C
=2220
c-c =c-c
~2240
C-CGC-CN C-CzC-COOH C-C=C-COOCH3
~2240 =2240, -2140
IC-H
In the same range: C z Z st, X=Y=Z st, Si-H st
EC-H 6
700600
Strong,broad; overtone at 1370-1220 (broad, Weak)
6.4
Alicyclics
253
6.4 Alicyclics Cyclic Alkanes
%T
\
I
CH2 6 \
CH st
Cyclic Alkenes
%1
V
c=cst 3600
2800
2000
1600
1200
800
I
400
The other vibrations are similar to those in noncyclic alkenes and cyclic alkanes.
Typical Ranges ( v in crn-l) Assignment Range Comments C-H st 3090-2860 Strong H-C-H 6 1470-1 430 Weak c=c st 1780-1610 Varies with ring size and substitution Twisting and wagging CH2 as well as C-C st do not significantly differ from the corresponding vibrations in noncyclic compounds and are of limited diagnostic value.
Examples (v in crn-l)
D
0
3090 3019 2933 1434 2920 2860 1447
2974 2896 1450
0
0
d-
K
-1570
1690
1
-1660
A b
11570
0"
~1650
d
295 1 2871 1455
2933 2865 1462
-1780
I7
0 &
11680
=1640
0
6 0 0"
-1650
11610
B
~1670
li
-1650
1665
1
@
OJ-
1660
=1690
-1675
=1670
6.5 Aromatics
255
6.5
Aromatic Hydrocarbons %T
\
C-H st
C-H C=C6 6 oop
skeletal vibrations 3600
2800
2600
1600
1200
800
400
Typical Ranges ( v in c m - l ) Assignment arc-H st
arc-C
Range 3080-3030
@+
Comments Often numerous bands; in the same range also CH st of alkenes and small rings Medium, often 1625-1 575 doublet: generally weak in benzene derivatives having a center of symmetry in the ring In the same range also: C=C st, C=N st, C=O st, N=O st, C-C in heterocyclics, NH 6 Weak in: 1525-1475 Medium, often doublet:
p-e & 0
In the same range: C=O st, N=O st, C-C in heterocyclics, B-N st, CH3 6, CH2 6, NH 6
comb
Very weak; useful for determining substitution patterns in 6-membered aromatic rings In the same range also: C=O st, B-H*.*B st, N+-H st, H20 6 2000-1650
256
6 IR
Assignment arc-H 6 ip
Range 1250-950
Comments Numerous bands of variable intensity; of no practical significance arc-H 6 oop 900650 One or more strong bands; useful for determining substitution patterns in 6-membered aromatic rings In the same range also: =C-H 6 oop, C-O-C y and C-N-C y in .saturated heterocyclics, OH 6 oop in carboxylic acids, NH 6, N-O st, S-0 st, CH2 y, C-F 6, C-C1 st
Determination of Substitution Patterns in 6-Membered Aromatic Rings: Position and Shape of Bands Related to the Number of Adjacent H-Atoms ( v in cm-l) Not to be used for ring systems with strongly conjugated substituents such as C=O, N02, C s N . Comb, overtones Substitution type; Comb, overtones Substitution type; CH 6 oop, ar C-C y CH 6 oop, ar C-C y mono400
770-730 710-690 2000
2000
1600
-
2000
1600
m-di-
vic-tri-
900-860 865-8 10 8 10-750 725-680
800-770 720-685 780-760
1600
2000
1600
2000
1600
1,2,4-tri900-860 860-800 730-690 2000
1600
6.5 Aromatics
Comb, overtones
257
Substitution type; Comb, overtones Substitution type; CH 6 OOP, C-C y CH 6 OOP, C-C y 1,3,5-tri900-840 850-800 730-675
2000
2000
1600
1600
1,2,4,5-tetra900-840
2000
1600
2000
1600
2000
1600
2000
1600
Examples
0
(V
in m i 1 )
3080 3040 1968 1818
acl
3080
a Q( I
302 1 1945 1862 1808 1739 3040 1915 1845 1775
0"
3086
aoH OH
1927 1887 1764
6 IR
258
6.6 Heteroaromatic Compounds Characteristic Absorption Bands (v in cm-l ) Furans
skeletal vibrations I
C-O-C st t
I
3600
2800
2000
N-H st
1600
1200
skeletal vibrations
800
400
C-H 6
I
3600
2800
2000
1600
1200
800
400
Typical Ranges ( v in cm - l) Assignment
Range
N-H
3450-3200
st
Comments Medium, narrow; shifted by formation of hydrogen bonds Weak, characteristic Strong, sharp bands
Overtones Ring skeleton
2100-1800 1610-1360
C-H 6 C-H st
1oOCL700
3 100-3000
Strong, broad; difficult to identify Medium, sharp
co-c
1190-990
Medium or strong; of variable intensity
st
6.6 Heteroaromatics
5-Ring-Heteroaromatics:
0 0
0 N
9
H
NH st free NH st H-bonded CH st =3 100 Ring skeleton: intensity 1610-1560 variable, generally multiplets 1510-1475 CH 6 oop: generally strong 990-725
3500-3400 3400-2800 ~3100 1590-1560 1540-1500 770-7 10
=3 100 1535-15 15 1455-1410 935-700
259
6 IR
260
6.7 Halogen Compounds 6.7.1 Fluoro Compounds
C-F st 3600
2800
2dOO
1600
1200
800
I
400
Typical Ranges (v in ernm1)
I-hl
Assignment C-F st
CF2 CF3 S-F P-F Si-F B-F
Range 1400-1000
Comments Strong, often more than one band (rotational isomers), often not resolved
Subranges: 1100-1000 a1 CF2 (FC-H st: 3080-2990) a1 CF2 1150-1000 1350-1100 a1 CF3 1350-1 150 C=CF =1745 C=CF2 st 1250-1 100 ar CF In the same range: strong bands for C-0 st, NO2 st sym, C=S st, S=O st 780-680 Medium or weak,assignment uncertain 780-680 (C-F S?)
st st st st
815-755 1110-760 980-820 1500-800
Strong
6.7 Halogen Compounds
261
6.7.2 Chloro Compounds %T
c-c1 st 3600
2800
2000
,
I
1600
1200
800
400
Typical Ranges ( v in crn-l) Assignment c-Cl st
Range 1100-1020 830- 4 0 0
c-Cl 6 P-Cl st Si-Cl st B-Cl st
400-280 <600 <625 1100-650
Comments Strong, narrow or of medium width; chloroaromatics Strong, often broad (rotational isomers), absent in chloroaromatics Of medium strength and width
In disubstituted halobenzenes, characteristic skeletal vibrations: R,ex
x
ortho
meta
p.an
c1 Br I
1055-1 035 1045- 1030
1080-1075 1075-1 065
1095-1 090 1075-1 070 1060- 1055
Hai
262
6 IR
6.7.3 Bromo Compounds
C-Br st 3600
2800
2000
1600
1200
1
800
400
Typical Ranges ( v in crn-l) Assignment C-Br st
Range 1080-1000
700-500
iiai
C-Br 6
350-250
Comments Strong, narrow or of medium width; bromoaromatics Strong, of medium width; absent in bromoaromatics Of medium strength and width
6.7.4
lodo Compounds
c-I st 3600
2800
2600
1600
1200
800
Typical Ranges ( v in c m - l ) Assignment c - I st c-I 6
Range 650-450 300-50
Comments Strong, two or more bands Of medium strength and width
I
400
6.8 Alcohols, Ethers, and Related Compounds
263
6.8
Alcohols, Ethers, and Related Compounds 6.8.1 Alcohols and Phenols
Alcohols
C-0-H 6
c-0 st I
3600
2800
2000
1600
1200
800
400
Phenols
0 I
I
3600
2800
2000
1600
1200
800
400
Typical Ranges ( v in crn-l) Assignment 0 - H st
Range Comments 3650-3200 Of variable intensity Subranges: 3650-3590 Free OH; sharp 3550-3450 Hydrogen bonded OH; broad 3500-3200 Polymer OH; broad, often numerous bands Beyond noma1 range: 3200-2500 Enols, chelates; often very broad In the same range also: NH st, zCH st (~3300,sharp), H20
0 - H 6 ip
1450-1200
Medium, of no practical significance
6 IR
264
Range 1260-970 Subranges: 1075-1000 1125-lo00 1210-1100 1275-1 150 In the same
Assignment
c-0
st
0-H 6
<700
OOP
Comments Strong, often doublet CH2-OH CH-OH C-OH C-OH range: bands for C-F st, C-N st, N-O st, P-0 st, C=S st, S=O st, P=O st, Si-0 st, Si-H 6 Medium, of no practical significance
Examples (v in crn-l)
-OH
3250 1430 1075 1050
8
3215 1368 1220
OH
0
6
(OH
0:
OH
OH
3290 1430 1020
3450 1370 1260 1195
6.8.2 Ethers, Acetals, Ketals
%T
C-0-C st as 1
3600
2800
2600
1600
li00
800
400
In acetals and ketals, the C-0 stretching vibrations are split into 3, sometimes even 4 to 5 bands. Acetals have an additional band due to a special C-H 6 vibration. The C-H st vibration frequency is especially low: OCH3 st, 2850-2815; OCH2 St, 2880-2835.
6.8 Alcohols, Ethers, and Related Compounds
Typical Ranges Assignment C-0-C st as
(V
265
in crn-l)
Range Comments 1310-1000 Strong, sometimes split Subranges for non-cyclic ethers: 1150-1085 CH2-O-CH2 1170-1 115 CH-0-CH, often split 1225-1 180 C=C-O-alC 1275-1200 arC-0-alC Subranges for cyclic ethers: 1280 sym 870 as -1030 sym -980 as
A
0
=lo70 sym -915 as ~123.5 -1100 as -815 sym
-950
0
=925
0
1024, 1086 as =880 sym
-800 C-0-C
st sym
1055-870
ketals, acetals: 4 to 5 bands
ao)
eo
in acetals: st CH, ~ 2 8 2 0weak ,
Strong, sometimes multiple bands Subranges for non-cyclic ethers: 1125-1080 C=C-O-alC, medium 1075-1020 arC-0-alC, medium In the same range: strong bands for C-0 st, C-F st, C-N st, N-0 st, P-0 st, C=S St, S=O st, P=O st, Si-0 st, Si-H 6
0
266
6 IR
Examples (v in cm-l)
/9/4 1188 1138 1111 1046
ep
1172 1132 1077 1057 1038
6.8.3 Epoxides %T
V C-H st ring st sy
Typical Ranges (v in cm-l) Assignment C-H st
Range 3050-2990
ring s t as ring st sy ring def
1280-1230 950-815 880-750
Examples (v in cm-1)
Comments Frequency higher than normally found in alkanes Variable intensity Variable intensity Variable intensity
6.8 Alcohols, Ethers, and Related Compounds
267
6.0.4 Peroxides and Hydroperoxides
c-0-0 I
3600
2800
2000
1600
8
1200
st
,
800
1
400
Typical Ranges (v in c m - l ) Assignment 0-0-H st
Range 3450-3200 Subranges: -3450
Comments Of variable intensity
Free OOH; H-bonded: -30 cm-l higher than in corresponding alcohols In the same range: OH st, NH st, zCH st, H20
c-0-0
st
Strong, about =20 cm-l lower than in corresponding alcohols In the same range: strong bands for C-0 st, C-F st, C-N st, N-0 st, P-0 st, C=S st, S=O st, P=O st, Si-0 st, Si-H 6 1200-1000
0-0 st
1000-800
Also:
1760-1745 1820-1770
Examples (V in cm-l)
Medium or weak, often doublet, assignment uncertain C=O st in peracids C=O st in diacylperoxides(two bands)
0
6.9
Nitrogen Compounds 6.9.1 Amines and Related Compounds
r\r
'
, Fermi
C-H st C-N st
Secondary Amines
N
I
3800
2800
I
2600
1600
1200
800
400
2000
1600
1200
800
400
Ammonium
I
N+-H st and comb
I
I
3600
2800
6.9 Nitrogen Compounds
Typical Ranges
(V
269
in c m - ] )
Assignment N H 2 st
Range 3500-3300
NH st
Of variable intensity, only one band At lower wavenumbers (<3200) and broader if H-bonded. Free and H-bonded forms often simultaneously observed In the same range: OH st, ECH st, H20
NH; st
NH2 6 NH 6
3000-2000 Medium, broad, highly structured 3000-2700 Major maximum, comb: ~ 2 0 0 0 3000-2000 Medium, broad, highly structured 3000-2700 Major maximum 3000-2000 Medium, broad, highly structured 2700-2250 Major maximum In the same range: OH st, NH st, CH st, SH st, PH st, SiH st, BH st, X=Y=Z st, XEY st 1650-1 590 Medium or weak 1650-1550 Weak
NH; 6
1600-1 460
NH+Z
6
1600-1460
NH+ 6
1600-1460
C-N st NH2 6 NH 6 P-N-C st
1400-1000 850-700 850-700 1110-930, 770-680
N H ~st N H + st
Comments Of variable intensity, generally 2 sharp bands, AV = 65-75 At lower wavenumbers (<3200) and broader if H-bonded. Free and H-bonded forms often simultaneously observed In primary aromatic amines additional combination band at -3200 In the same range: OH st, ECH st 3450-3300
Medium, often more than one band; weak in aliphatic amines Medium, often more than one band; weak in aliphatic amines Medium, often more than one band; weak in aliphatic amines Medium, of no practical significance Medium or weak; 2 bands in primary amines Medium or weak
N
6 IR
270
Examples ( v in crn-l)
CH3-NH2
3470 3360 1622
3356 3274 3175 1650
L N H 2 H2N
6.9.2 Nitro and Nitroso Compounds
Nitro Compounds
I
Nitroso
I
I
3600
2800
2000
1600
1200
800
400
800
400
Compounds
I
N=O st N=O st
1
3600
2800
2000
1600
1200
I
6.9 Nitrogen Compounds
271
Typical Ranges ( v in crn-l) Assignment N O 2 st as
N O 2 st
Ring 6 N=O st
SY
Range 1660-1490 Subranges: 1660-1625 1570-1540 1560-1490 1630-1530
Comments Very strong, of medium width
1390-1260 Subranges: 1285-1270 1390-1340 1360-1 3 10 1315-1 260 In nitrates also: 470 =760 =700 760-705 1680-1450 1420-1 250 Subranges: 1680-1650 1585-1540 1510-1490 ~1450 In nitrites also: 3300-3 200,
Strong, of medium width
0-NO2, C-NO2, C-NO2, N-NO2,
0-NO2, C-NO2, C-NO2, N-NO2,
nitrates a1 nitro compounds ar nitro compounds nitramines
nitrates a1 nitro compounds ar nitro compounds; often 2 bands nitramines
N-0 st, strong NO2 Y NO2 6 Strong; modified deformation of aromatic ring Very strong, in monomers Very strong, in dimers 0-NO C-NO, C-NO, N-NO,
(nitrites) trans; 1625-1610: cis a1 C-nitroso compounds ar C-nitroso compounds N-nitroso compounds
comb
~2500,
C-N st
2300-2250 =800 =600 450
N-N st
=1100 =lo40
N-0 st trans; cis: very weak 0-NO 6 trans; cis: =650 C-NO, a1 C-nitroso compounds: coupled with other vibrations C-NO, ar C-nitroso compounds N-Nitroso ComDounds
N
6 IR
272
Examples (v in crn-l) 1564 842
CH3-NO
1524 1359 85 I
I
YO
1506
1497
NO
8'E; aNo2 1506 1351 1261 873 748
"7
720
6.9.3
Imines and Oximes
Oximes %T O-H st 0-H st free H-bonded C=N st 1
3600
2800
2000
1600
1200
800
400
6.9 Nitrogen Compounds
273
Typical Ranges (v in c m - l ) Assignment C=N st
Range 1690-1520 Subranges: 1670 21645 21630 -1655 -1645 -1635
-
21555 21645 =1625
Comments Generally strong R-CH=N-R R, R : a1 R-CH=N-R R or R : conjugated R-CH=N-R R, R : conjugated R R, R , R':a1 R: conjugated R" R' R, R : conjugated
kY
PW
\ / additional band: -1655 C=O
R
)=m
R, R': a1 R, R : conjugated
R R 1685-1580
)=q
1670-1 600
H2N R CH=N-NSH
1690-1 645
"YNH RO
Additional band at 1540-1515 in:
R
)=N
R"
R
Additional bands: NH st: ~ 3 3 0 0 , C-0 st: 21325, 21100 Additional bands:
1680-1635 2050-2000
OH st
OH 6 N - 0 st
1580-1520 1685-1650 1645-1650 1690- 1645 1640-1605 1640-1 580 3600-2700 Subranges: 23600 3300-3100 2 22700 1475-1 3 15 1050-400
NH2+ st: -3000 RO 6: 1590-1540 C=C=N; Ketimines, very strong, sometimes doublet Quinone oximes: C=O st 1680-1620 Aliphatic oximes Aromatic oximes oC=N S-C=N S-S-C=N Strong R>h2
Free H-bonded, broad Quinone oximes, more than one band Of no practical significance Of no practical significance
N
6 IR
274
Examples (v in crn-l)
/-+-
I
1667
1637
1603 \ N,
OH
1675
1672 (solid) Y N - O H 1662 (gas)
9, N=N st
I
I
3600
2800
2000
1600
1200
800
400
Typical Ranges (v in erne1) Assignment
N N=N
st
Range 1500-1400
1480-1450 1335-1315 ~1450 =lo50 1410-1175
Comments Very weak, missing in compounds of high symmetry \ N=N
r”
\
\
st as st sy
fls
N=Y
\ ,N=Y
P
Dimers of C-nitroso compounds
0
Subranges: 1290-1 175 1425-1385, 1345-1 320 1300-1250 ~1410, ~1395
Aliphatic trans Aliphatic cis Aromatic trans Aromatic cis
6.9 Nitrogen Compounds
275
6.9.5 Nitriles and Isonitriles
Nitriles
I
i
3600
2800
2000
1600
1200
800
400
1600
1200
800
400
Isonitriles
-NEC st I
3600
2800
2000
Typical Ranges (v in ernq1) Assignment CEN st
Range 2260-2240
Comments Medium to strong, sharp; for O-CH2-C=N, N-CH~~EN of: low intensity or absent Beyond normal range: 2240-22 15 C=C-C=N
2240-2230 e2275 2225-2175
-N+=C'
X: C1, Br, I XC-CIN -CF~-CEN \
\+
/
/
N-GN-
2210-2185 2200-2070
>N-C=C-CrN CEN-
2150-21 10
Strong
WGN-
N
6 IR
276
Assignment -NkN
Range Comments Medium, frequency depends on anion 23 10-2130 In the same range: C=C st, X=Y=Z st as, NH+ st, PH st, POH st, SiH st, BH st
Examples (v in c m - l ) 2222
N b C N
2273
NC
CN
NC
CN
2257 2222
)=(
NaCN, KCN 2080-2070
wcN 2252
-CN
2235
NC-CN
2235
NC+CN
2252
2245
CN
2220
CN
Q AgCN
&OH
2178
NH2-CN
2268
6.9.6 Diazo Compounds
r\i Assignment N k N st
Range 23 10-2130
C=N+=N-
2050-2010 Very strong Subranges: 2050-2035 R-CH=N+=N- R: a1 or ar 2035-2010 R+=N+=N- R: al or ar Beyond n o m 1 range: 2 100-2050 R-CO-C=N+=NC=O st ~ 1 6 4 (R: 5 al) C=O st ~ 1 6 1 (R: 5 ar) C=N+=N- st sy: -1350, strong 2180-20 10
Comments Medium, frequency depends on anion
O e-% N -
C=O St 1655-1560
6.9 Nitrogen Compounds
277
6.9.7 Cyanates and Isocyanates
Cy an a tes
I
t
3600
2800
2000
1600
1200
800
400
1600
1200
800
400
Isocyanates
3600
Typical Ranges
-N=C=O st as 2800 2000
(V
I
in crn-l)
Assignment
Range
Comments
OC=N st
2260-2 130
Medium to strong
2220-21 30
(WEN)(OCEN)~ st SY
1335-1290
c-0 st 1200-1080 N=C=O st as 2280-2230 ~2300
Strong Strong,sharp -CF2NCO
N=C=O st sy 1450-1380 Weak Beyond n o m 1 range: 2220-21 30 (N=C=O)-
N
6 IR
278
Examples (v in crn-l) CH3NCO
\NCO
2265
2280
YNCO
2270
bNCO
2256 (1629 C=C)
li
2246
NCO
6
O
2267
6.9.8 Thiocyanates and lsothiocyanates
Thiocyanates
I
I
3600
2800
2000
1600
1200
800
400
N Zsothiocyanates %T C-N
st
-N=C=S
st SY
-N=C=S st as 1
I
3600
2800
2600
1600
1200
800
400
6.9 Nitrogen Compounds
Typical Ranges Assignment S C = N st
c-s
(v
279
in crn-l)
Range 2 170-2 130 2090-2020
Comments Medium, sharp (SC=N)'
750-550 N=C=S st as 2200-2050
Often doublet Very strong, generally doublet, Fermi resonance
st
N=C=S s t sy 950-650 =950 a1 -N=C=S 700-650 -N=C=S Beyond n o m 1 range: 2090-2020 (N=C=S)-
C-N s t
1090-1075
Examples (v in crn-l) CH3NCS
neat: 2206 21 14
uNCS
2105
in CCl,: 2221 2106 2077
eNCS
/\rNCS
2062
6s
2173 2097 2068
neat: 2090 in CCl,: 2065 in CHC13: 21 12
N
6 IR
280
6.1 0
Sulfur-Containing Functional Groups 6.10.1 Thiols and Sulfides
I
I
3600
2800
2000
1600
1200
800
400
Typical Ranges ( v in c m - l ) Assignment S-H st S-H 6
c-s s-s Also:
st
st
Range 2600-2540 915-800 710-570 400 ~2880
~2860 =1430 1330-1290 ~1425 815-755 =630 725-550
S
Comments Often weak, narrow Weak, of no practical significance Weak, broad, of no practical significance Weak, of no practical significance (S-)CH3 st as (S-)CH2 st as (S-)CH3 6 as (S-)CH3 6 SY (S-)CH2 6 S-F st, strong S-N st in S-N=O S-C in S-CsN, often doublet
Examples ( v in cm-l) -SH
2950
\S,s/\
698 668 64 1
Hs/\/’SH
2525
566
esH 2585
662
6.10 Sulfur-Containing Functional Groups
28 1
6.1 0.2 Sulfoxides and Sulfones
Sulfones
I
I
3600
Typical Ranges Assignment
s=o st
2800
(V
2000
1600
1200
800
400
in c m - l )
Range 1225-980 Subranges: 1060-10 15 =1100
Comments Strong, sometimes multiple bands R-SO-R R-SO-OH
e1135 1225-1 195 ~1135 ~ 1 0 3 0~, 9 8 0 ~ 1 1 0 0=lo50 ,
R-SO-OR RO-SO-OR R-SO-C1 R-SO2RSO
S-0 st 870-810 OH st free ~ 3 7 0 0 , H-bonded ~ 2 9 0 0~, 2 5 0 0 S-0 st 740-720,710-690
N=SO: ~ 1 2 5 0~, 1 1 3 5
S
6 IR
282
Assignment
‘go /
st as 0 st sy
Range 1420-1000
Subranges: 1370-1290, 1170-1 110 1375-1350, 1185-1 165 ~1340,~ 1 1 5 0 1415-1 390, 1200-1 185 1365-13 15, 1180-1150
s-0 S
st
Comments Very strong
R-S02-R R-S 02-OR
R-S 02-SR RO-S02-OR R-S02-N N-H St: 3330-3250; N-H 6: ~1570; S-N st: 910-900
1410-1375, 1205-1 170 1355-1340, 1165-1 150
R-SO2-hal
1250-1 140, 1070-1030 1315-1 220, 1140-1050
R-SO3-
870-690
Of variable intensity, weak in sulfites
R-SO2-OH
0-H st, H-bonded: =2900, ~2400 hydrated: 2800-1650, broad
RO-SO~-
6.10 Sulfur-Containing Functional Groups
283
6.1 0.3 Thiocarbonyl Derivatives
S-H st
1 3600
2800
2000
1600
1200
8bO
4bO
Typical Ranges ( v in crn-l) Assignment
Range
c=s s t
1275-1030 Subranges: 1075-1030 1210-1080 -1215
Comments Strong, narrow Thioketones Thioesters Dithioacids
1125-1075
Thioacid fluoride
1100-1065
Thioacid chloride
1140-1090
Thioamides and thiolactams P=S st
SH st: ~2550 SH 6: =860 perfluorinated: 1130-1 105 perchlorinated:
1 loa-1075
Also:
750-580
C-N st: 1535-1520 NH 6: 1380-1300
S 6.1 0.4 Thiocarbonic Acid Derivatives
Trithiocarbonates
c=sst I
3600
2800
2000
1600
1200
800
400
6 IR
284
Xu n t h a tes
%T
V S-H st COC st sy 3600
2800
2dOO
1600
I
1200
800
I
400
Thiocarbonates
%T c=sst
I
3600
2800
6
2000
1600
1200
800
I
400
c=sst
% T
,
Typical Ranges ( v in crn-l) Assignment S-H st
c=s st
COC st as COC st sy
Range 2560-2510 2600-2500 1100-1020 1070- 1000 1250-1 180 1400-1 100 1260-1140 1150-1090
Comments Weak, narrow Weak, narrow Very strong Strong Strong Strong Strong Strong to medium
trithiocarbonates xanthates trithiocarbonates xanthates thiocarbonates thioureas xanthates xanthates
6.1 0 Sulfur-Containing Functional Groups
285
Examples (v in c m - ] )
in CCI,: 1718 1677 1640
Lo ‘s .f,
neat: 1076
s/
in ~ ~ 1 4 : 1083 1079 gas: # 2593 HSKO’2548 neat: 2470
in CC14: 1662
in CS,: 2562 2522
J , ;7;7C14:
in CC14:
in CC14: 1719
,k0’ ‘0
solid: 1212
,k0‘ 0
solid: 1234
solid: 1400
I
I
I
I
S
6 IR
286
6.1 1 Carbonyl Compounds 6.1 1.1 Aldehydes
%T C-H comb
c=ost 7-
3600
2c00
2doO
1600
1200
800
400
Typical Ranges ( v in c m - l ) Assignment C-H comb
c=o st
c=x
C-H 6
Range 2900-2800 2780-2680
Comments Weak, Fermi resonance with C-H 6 at =1390 For extreme position of C-H 6 only one band
Subranges: 2830-2810, Aliphatic 2720-2690 Aromatic, for o-substitution often higher 2830-28 10, 2750-2720 In the same range: cyclohexanes at ~2700,weak 1765-1645 Strong Subranges: 1740-1720 Aliphatic 1765-1730 &Halogenated aliphatics 1710-1685 Aromatic 1695-1660 a$-Unsaturated aromatic 1670-1645 With intramolecular H bonds 1390 Weak, of no practical significance
6.1 1 Carbonyl Compounds
287
Examples (v in mi1) CH3CHO
1748
CC13CHO
1760
x1c7c14:
CHO
b"
1696
in CHC13: 1710 AN,
NO2
6.1 1.2 Ketones
Typical Ranges (v in c m - l ) Assignment
c=o st
Range 1775-1650 Subranges: ~1715
c=x Comments Strong Aliphatic, branching at a-position causes shift to lower frequencies:
\8-
~1775-1705
-1695
-1685
Cyclic, v decreases with increasing ring size [contd.]
2aa
6 IR
Assignment
Range
Comments
8 Conjugated:
-1675
-1775
e;
-1750
1650-1600
a$-Unsaturated, often 2 bands (rotational isomers) c=cst
-
a,p;y,&Unsaturated; a ,p;a',p'-unsaturated
=1695
1665
d
a
=
l
-1670
&
C
-1690 -1675
Aryl ketones
&a Diary1 ketones, with N or 0 in p-position: down to -1600 Shifted toward higher wavenumbers depending on dihedral angle cp between C=O and C-hal; largest effect for cp = Oo, no effect for cp = 90° Maximal shifts:a-chloro -25 a-bromo =20 a,a-dichloro 4 5 a-iodo 4 a,a'-dichloro 4 5 a,a-difluoro -60 perfluoro 40
-1665 &Halogenated ketones:
a-Diketones:
c; x 2
p-diketones:
-1720 -1775, -1760 ~1760 -1730 1675 =I680 1675 1720 -1650 -1615
--
Aliphatic Aliphatic 5-ring Aliphatic 6-ring Aliphatic enolized, C=C st: ~ 1 6 5 0 Aromatic o-Quinones, withperi-OH: -1675, =I630 Keto form, sometimes doublet Enol form Enol with intramolecular H bonds, C=C st: -1600 strong
6.1 1 Carbonyl Compounds
Assignment y-diketones:
Range =1675
C=C=O st as
2155-2130
289
Comments As monoketones p-Quinones, with peri-OH: ~ 1 6 7 5~, 1 6 3 0 ; C=C st: ~ 1 6 0 0 Verystrong
Examples ( v in c m - l )
6
&
1691
&
/
s-trans
1672 1660
& l
d
1664
(rotamers) 1726
s-trans 1690 S-cis 1707
s-cis
(2222)
1639 ‘N
1648
N’
I
I
1752 C
A &
1697
1
Cl3C
ca3
1780 1751
c1
1722
c=x
1724 (keto form) 0 1608 (enol form) 1635 1590
6 IR
290
6
1669
&
1675
1669
& &
1623
1662
OH 0
1678
0
0-H 6 ip
O-H 6 OOP
(free) 0-H st
Carboxylate Anions
%T
I
3600
2800
2000
1600
1200
800
400
6.11 Carbonyl Compounds
291
Typical Ranges ( v in c m - l ) Assignment COO-H st
Range Comments 3550-2500 intensity variable Subrunges: 3550-3500 Free, sharp, only in highly diluted solutions 3300-2500 H-bonded, broad, often more than one band In the same range also OH st, NH st, CH st, SiH st, SH st, PH st 1800-1650 Strong 1800-1740 Free (also in dicarboxylic acids) 1740-1650 H-bonded (dimer, also in dicarboxylic acids) Subrangesfor H-bonded C=O: 1725-1700 al-COOH 1715-1 690 CS-COOH 1700-1680 ar-COOH 1740-1720 hal-C-COOH 1670-1650 Intramolecular H bond 1440-1210 Of no practical significance
c=o st
OC-OH st, C-OH 6 OC-OH 6 OOp960-880
( C O O ) -st as 1610-1550
( C O O ) -st sy 1450-1400
(coo)-6
Examples
1
OH
-775 -925 =680 =600 (V
Medium, generally broad (only in dimers), in the same range: =CH 6, ar CH 6 , NH 6 Very strong; in a-halogen carboxylates near the higher value, with more than one a-ha1 beyond the normal range; in polypeptides at -1575 Strong, of no practical significance, in polypeptides at ~ 1 4 7 0 Formates, weak Acetates Benzoates CF3COO'
in crn-l)
E;
in CCI,: 1756 1724
J O H
neat: 1759 1718 in CC1,: 1768 1717
OH
in CC14: 1704 solid: 1686
c=x
6 IR
292
neat:
neat:
in CC14:
+ ' OH
a q O H
neat: 1725
1730
1694
in CC14:
solid:
solid 0-
1605
';bOH NH3+
"3'
1740
)$OH
1788 1725
0
solid:
solid:
1735
$O ''H 0
solid: H o d o H 1724
0
doHgoH solid:
solid:
OH 1690
!{?&4:
0
in CHC13: 1706
0
solid:
OH
OH
in CC14:
1696
1696
in CHC13:
9
1661
6.1 1.4 Esters and Lactones
C-X
C=O st 3600
2800
2000
1600
C 0 - 0 st as 1200
I
800
400
6.1 1 Carbonyl Compounds
293
Typical Ranges (v in c m - l ) Range 1790-1650 Subranges: 1750-1 735 Conjuguted esters: 1730-17 10 1730-1715 1690-1670 17961740 ~1760 ~1760 ~1735 Diesters: Keto esters: 1755-1725 =1750 (ketone) ~ 1 7 3 (ester) 5 1650
Assignment c=o st
-
Lactones:
Comments Strong Aliphatic esters a$-Unsaturated esters Aromatic esters With intramolecularH bonds a-Halogenated esters Vinyl esters, C=C st: 1690-1650, strong Phenol esters Phenol esters of an aromatic acid As the corresponding monoesters a-Keto esters, generally one band 0-Ketoesters,keto form P-Ketoesters, enol form, C=C st: ~ 1 6 3 0strong , y-Ketoesters, pseudoesters: -1770
~1840
-0 0
co Go -1770
~1800
0
9 0
~ 1 7 5 (additional 0 band at ~ 1 7 8 if 0 a-position free)
oo oo oo -1760
c-0
st
C - 0 st as:
1330-1050
~1720
2 bands: st as, very strong and at higher frequency; st sy, strong, at lower frequency
Subrunges: Formates, propionates, higher aliphatic esters ~1185 =1240 Acetates Z1210 Vinyl esters, phenol esters -1180 y-Lactones, &lactones Methyl esters of aliphatic acids -1165 In the same range: Strong bands for C-F st, C-N st, N-0 st, P-0 St, C=S St, S=O st, P=O st, Si-0 st, Si-H 6
c=x
6 IR
294
Examples (v in c m - l ) 1743
cq,f. 0-
1787
Br 1758 (1690)
1726
1730 (1658) (1638)
Ao/Si: I
0 % ’
40,
1725
1752 (1675)
1725
0
mo/
ester: 1704 ketone: 1690 \-O,)!.oq enol: 1645
0-
;7: 0
1760 1742
0
0
0
do/ 1737
O2N
0
1766
1743
6.1 1 Carbonyl Compounds
295
6.1 1.5 Amides and Lactams Primary Amides
V
NH2 st 3600
c=ost 2800
2000
1600
I
1200
800
400
1200
800
400
1200
800
400
Secondary Amides
c=ost I
3600
2800
2000
3600
2800
2000
%
1600
c=oS t 1600
I
Typical Ranges (v in m i 1 ) Assignment N-H st
Range 3500-3 100
Comments Medium, in primary amides two bands, in proteins m d p l e t
Subranges: 3500-3400 Free 3350-3 100 H-bonded ~ 3 3 5 0=3 , 180 In primary amides generally two bands
c=x
296
6 IR
Assignment
Range Comments -3200, -3 100 In lactams generally two bands -3200 Monohydrazides -3 100 Dihydrazides -3250 Imides In the same range: OH st, fCH st (-3300, sharp), H20 C=O st (amide I) 1740-1630 Generally strong Subrunges: NH,C=O free amides, H-bonded: 1650 1690 -1685 NHC=O free amides, H-bonded: -1660 NC=O free amides, H-bonded: -1650 1650 ~1745 4-Ring lactams -1700 5-Ring lactams =1650 6-, 7-Ring lactams =1670 Monohydrazides -1600 Dihydrazides 1740-1670 Imides -1750, 1700 5-Ring imides, 2 bands 1655-1630 Polypeptides ~1690 Isocyanurates, with aromatic substitution at ~1770 1720 1755 sh Trifluoroacetamides NH 6 and 1630-15 10 Generally strong, absent in lactams st SY Subrunges: (amiden) -1610 NHzC=O free, H-bonded: -1630 -1530 NHC=O, H-bonded: -1540 1560-1510 Polypeptides -1555 Trifluoroacetamides C-N st (?) -1400 "2C=O -1250 "C=O -1330 Lactams NH 6 ip -1150 "2C=O 1465 Lactams NH 6 oop 750-600 NH2C=O -700 "C=O -800 Lactams
-
-
-
:":
x
-
-
6.1 1 Carbonyl Compounds
297
Examples (v in crn-l) neat: 1672 in CHC13: 1709
H
solid:
AyOH
1631 in CHC13: 1679
1
H
H
I
JvvH
H
'
in CHC13: 1673
in cc14: 1690
JN-
1650
JNo
0
3
dm2 in 1678 CHC13:
H
N'
H solid: 1656
neat:
neat: 1672
L
in CC14: 1647
in cc14:
in CHC13: 1691 in CC14: 1705
1667
L
c x
solid
H
1505
1689
-z
in CCl4: 1753 1727
6 IR
298
solid: 1760 1690
p {
in CC14: 1721 1705
0
<:
solid: 1718 1670
in CC14: 1729, 1686
0
in CHC13: 1783 1733
(WBr 0
0
Go;?% 1
NH
1749 1724
in CHC1,: 1778 1735
solid: 1790 1735
@LO 0
6.1 1.6 Acid Anhydrides
f\. ' - X
in CC14:
C=O st sy C=O st as
1718
4 'I
in CHC13
N- 1772 1712
0
6.1 1 Carbonyl Compounds
299
Typical Ranges (v in crn-l) Assignment c=o st sy C=O st as
c-0-c
st
Range Comments 1870-1770 Strong 1800-1720 Strong Subranges: ~ 1 8 2 0~, 1 7 6Linear 0 anhydrides,higher band stronger -1850, -1775 5-Ring, lower band stronger -1800, ~ 1 7 6 6-Ring, 0 lower band stronger 130O-9OO Strong, several bands =lo40 Linear anhydrides =920 Cyclic anhydrides
Examples ( v in crn-l)
AoL
1045 1040
1859 1789
go% 1803 1743
1845 1780 900
0
0
p
@ 0
1840 1810 1760 912
0
6.1 1.7 Acid Halides
c-c= st
c=ost 3600
2800
2600
1600
1200
800
1
400
Typical Ranges ( v in crn-l) Assignment
c=o st
Range 1820-1750 1900-1870
c-co s t
1000-800
C-ha1 st
1200-500
Comments chlorides, strong,of narrow or medium width, for bromides and iodides at lower frequency fluorides, strong, of narrow or medium width, additional band at ~ 1 7 2 5in aromatic acid chlorides and bromides 1000-900 al, assignment uncertain 900-800 ar, assignment uncertain 1200-800 F 750-550 C1 700-500 Br 600-500 I
6.1 I Carbonyl Compounds
301
6.1 1.a Carbonic Acid Derivatives
Carbonic Acid Derivatives %T
C-0 st as
c=ost 3600
2800
2000
1600
I
I
1200
800
400
1200
800
400
1200
800
400
Carbamates
c=ost I
3600
2800
2000
1600
Ureas
%T N-H st
c=ost #
3600
Typical Ranges Assignment
c=o s t
C - 0 st as
2800 (V
2000
1600
in cm-l)
Range 1820-1740 1750-1680 1690-1620 1260-1 150
Comments Strong Strong Strong Strong
carbonic acid derivatives carbamates ureas carbonic acid derivatives
6 IR
302
Assignment
Range
Comments
N-H
3500-3250
Medium, two bands for "2, one for NH Medium, two bands for
St
3500-3200
carbamates
ureas
"2
N-H 6 NH2 6
1650-1500 1650-1600
Medium Medium
carbamates ureas
N-CO-0 st as N-CO-0 st SY C-N-H 6
1270-1210 1050-850 1600-1500
Medium Weak Weak
carbamates carbamates ureas
Examples (v in crn-l) in CHC13:
in CCl4:
\N
l
H
a
J,
in C C ~ ~ : 'N 0 1822
e,
in CC14: 1719
in CC14: 1718 1677 1640 solid: 1679
\s x s' \s
\
1748 in CCl4: 1653
1s'
neat: 1076
1
solid: 1645 1567 1418
"2
in CHC13: 1684
0-
J, I
'S
in C C ~ : 1662
1
f7gC7Cl4:
Lo
1
solid: 1058 in ~ ~ 1 4 : 1083 1079 solid: 1656
I
1511
6.1 1 Carbonyl Compounds
solid: 1622 1580 1530 in CHC13: 1663 1548
CHC13: 1675
a
solid: 1667 1634
in CCl4: 1735 muNH 1718
solid: 1712 1676
”,fN’
30
neat: 1600
in CS2: 2562 2522 solid: 1400
303
‘0
‘N
0 ’
N’
I
solid: 1776 1697
solid: 1767
gas: 2593 2548 neat: 2470
HS~O/
solid: 1234
solid: 1212
1 :?$ I
U0
solid: 1748 1706
solid: 1767 1681 1621
1
”a”
01 0 Y Y
solid: 1131
c=x
6 IR
304
6.1 2
Miscellaneous Compounds 6.12.1 Silicon Compounds
%T Si-H st Si-H 6 1
3600
2800
2000
1600
1200
800
400
Typical Ranges ( v in cm-l) Assignment Si-H st
Range 2250-2090 Subranges: 2160-2090 -2250 2220-2120 Si-H 6 1010-700 (Si-)CH3 6 as -1410
Comments Medium
(Si-)CHS 6 sy 1275-1260
Very strong, sharp, typical for SiCH3, not split for Si(CH3)2
’
biilSC.
(Si-)CH3 y
860-760 -765 -855, -800 -840, -765
Si-0 s t
1110-1000, 900- e600 1110-1000, 850-800 1090-1 030, e 650 900-800 3700-3200 -1030
R3Si-H; also for R as H,for SiH3 2 bands hal-Si-H (Si-0)Si-H Strong, broad, generally 2 bands Weak
Si-0-C Si-0-Si Si-OH Si-OH st Si-OH 6
6.12 Miscellaneous Compounds
Assignment Si-C st Si-N st
Si-F
Si-Cl
st
st
Range
305
Comments
850-650
1250-830 Subranges: 950-830 Si-N-Si =3400 Si2NH st 950-830 N-Si-N 1250-1 100 Si-NH2 ~ 3 5 7 0~, 3 3 9 0SiN-H2 st ~1540 Si-NH2 6 980-820 Subranges: 920-820 945-870 980-860
Si-F Si-F2, 2 bands Si-F3, 2 bands
< 625
6.12.2 Phosphorus Compounds Phosphorous Compounds
1
P-H st
3600
2800
2000
1600
7
P=O st 1200
800
400
Phosphines
%I
P-H st
-C&and -CH2CH3
P-H6
P-Cst I
I
3600
2800
2000
1600
1200
800
400
Typical Ranges ( v in crn-*J
Assignment P-H st
Range
PO-H st POH comb
270-2650 2300-2250 1740- 1600
P - 0 st
1260-855 Subranges: 1050-970, 830-740 1260-1 160 995-9 15 875-855 1100-940 980-900 1300-960 Subranges: 1190-1150
P=O st
2440-2275
1265-1200 1280-1 240 1300-1 260 1220-1150 1250-990 1125-970, 1000-960 1205-1090 1200-1090, 1090-995 = 1250 1230-1210, 1030-1 020 1140-1050, 1010-970 1250-1210 1285-1 120, 1120-1050 1220-1 170 1245-1 150, 1110-1050
Comments Weak to medium, generally one band, in R3PH+ very broad Weak,very broad Weak, very broad Additional band in O=P-OH (dimer?)
P-O-C a1 st; strong and often weak for upper and lower band, respectively P-0-c ar st P(V> P(W P-OH st, broad, for P(OH)2 often two bands P-0-P st Strong R3P=0, also for R: H R2(RO)P=0, also for R: H R(R'0)2P=0, also for R: H (RO)3P=O R(H0)2P=O R(HO)P02-, more than one band ~ ~ 0 ~ 2 R2(HO)P=O R2PO2RO(H0)2P=O RO(HO)P02~ 0 ~ 0 ~ 2 (R0)2(HO)P=O (R0)2P02R(RO)(HO)P=O R(RO)P02-
6.12 Miscellaneous Compounds
Assignment
Range 1240-1205
Comments R 9 9 R R.‘P, ,P<
-1195
HO.9 R P.
= 1275
R2N.P. RO’.
1265-1 250
RO’P.oP;OR R.9 9 R
307
o’PP:oOR H .E ‘OR 0
NR2
9NR2 ~ 1 3 0 0~, 1 2 4 0 R0.OP, ,P,‘ RO’ 0 NR2 -1250
RO,f HO”0’
O !,R ‘OH
-1235 1265-1240 1365-1 260 1330-1280 1365-1 260 P=N P-OH 6 P-c st
1500-1 170 = 1280 800-700
P-H 6
1090-910
R2(X)P=0, X: F, C1, Br R(X)2P=O, X: F, C1, Br (R0)2(X)P=0, X: F, C1, Br RO(X)2P=O, X: F, C1, Br We’&, of no practical significance Intensity varies widely, of no practical significance Strong, for (RO)2HP=O very strong
1110-930, 770-680 1500-1230 P=N-a1 s t 1390- 1300 P=N-ar st P=N-C=O st 1370-1 3 10 P=N-PRz s t 1295-1 170 P-N-C
st
P=S s t P-s s t (P-)CH3 6
SY
750-580 <600 1310-1280
Misc.
Intensity varies widely
Assignment P-F st PF2
Range 905-760 1110-800
P-Cl st
e600
Comments More than one band
6 . 1 2.3 Boron Compounds
%T
B-H St 3600
2800
2000
B-0 st 1600 1200
I
800
Typical Ranges (v in crn-l) Assignment B-H st
Range 2640-2200 2200-1540
B-0
1380-1310 =1500
St
BO-H st B-N s t B-C st
3300-3200 1550-1330 1240-620
B-F st B-Cl S t
1500-800 1100-650
Comments Strong B-H-oB, more than one band Very strong Haloboroxines Very broad Very strong Strong, 2 bands if substitution highly asymmetric
I
400
6.13 Amino Acids
309
6.1 3 Amino Acids
\I m;s
st and comb
3"
3600
2800
w
-
6
rocking
c=ost 2000
1600
1200
800
400
Typical Ranges (v in c n i l ) ~~~
~
Assignment N-H S t
Range 3400-2000
Comments Generally strong, broad, very structured
Subranges: 3 100-2000 3350-2000 3400-3200
Zwitterions, distinct side band at 2200-2000 Hydrochlorides N ~ salts +
1660-1590
Weak, for hydrochlorides near the lower limit
1550-1480
Medium
1760-1595 Subranges: = 1595 1755-1700 ~1595
Strong
0-H st
"+3 "+3
6 as 6 sy
C O O - st as
Zwitterions Hydrochlorides, in a-amino acids: 1760-1730 Na' salts
Natural Products
6 IR
310
6.1 4 Solvents, Suspension Media, and Interferences 6.1 4 . 1 Infrared Spectra of Common Solvents The low transmission in regions where the solvent absorbs may lead to artifacts. For the interpretation of spectra, these regions should be disregarded. In the following, they are indicated by bars. Chloroform: 0.2 mm cell
Chloroform: 1 mm cell I
-
g
80-2 6040200-
v
.C
.C
5
e9
" " , " " , , " ' , , . . , ' , . , . . , , . , . , . . .
Carbon tetrachloride: 1 mm cell 801 60 40 -
-
v-
20 0- , , , , , , , , , , , 4000 3500 3000 25
6.14 Solvents, Suspension Media, Interferences
31 1
"i:q-\, ,/----rq
Carbon disulfide: 0.2 mm cell
1
,
9 20
$ -s 0
4000 3500 3000 2500 2000 1800 1600 1400 1200 1000 800
600
Carbon disulfide: 1 mm cell 100 I 8 80'g 60-
'E 40-
\
9 20-
Et; 8 0-
, , , , ( , , , , I
, , , ,
, ,
,
, ,
6.1 4.2 Infrared Spectra of Suspension Media
As it is difficult to prepare pellets and thin mineral oil films of reproducible thickness, the bands of these suspension matrixes are always found superimposed on the sample spectra. Mineral oil (nuiol): 10 um thickness
8
2 60
'E
40 20
;ir-;x--1---
-s 'g+ o4000 3500 3000 2500 2000 1800 1600 1400 1200 1000
800
600
4000 3500 3000 2500 2000 1800 1600 1400 1200 1000 800
600
Potassium bromide: Dellet
1
9 20
& o b?
Solvents
312
6 IR
6.1 4.3
Interferences in Infrared Spectra Traces of water in carbon tetrachloride or chloroform may give rise to two bands in the vicinity of 3700 and 3600 cm-l as well as one around 1600 cm-l. At higher concentrations, a broad band at 3450 cm-l is found. Water in the vapor phase exhibits many sharp bands between 2000 and 1280 cm-l. If present in high concentrations, they may temporarily block the detector and appear as shoulders if occumng at a steep side of a strong signal. Dissolved carbon dioxide shows an absorption band at 2325 cm-l. In solutions that contain amines and traces of water, C02 can form carbonates, which lead to the appearance of unexpected bands of protonated N-containing groups. In improperly balanced double beam instruments, gaseous C 0 2 can give rise to two signals at approximately 2360 and 2335 cm-l as well as a signal at 667 crn-l. Chloroform, saturated with water: 0.2 mm cell
Water vapor with carbon dioxide 60
'E 40 $ 20 i *G; o4000 ''
3500 3000 2500 2000 1800 1600 1400 1200 lo00 800
600
Commercially available polymers often contain phthalates as plasticizers, which can be found in apparently pure samples and give rise to a band at 1725 cm-l. The presence of such phthalates can be confirmed by MS ( d z 149). In the course of chemical reactions, phthalates may be transformed into phthalic anhydride, which shows a band at 1755 cm-l. Other frequently encountered contaminants are silicones, which generally exhibit a band at 1625 cm-l, together with a broad signal in the region from 1100 to 1000 cm-1.
7.1 Alkanes
31 3
7 Mass Spectrometry
7.1 Alkanes [ i ] 7.1.1 Unbranched Alkanes [2,3] Fragmentation: Larger alkyl fragments (with Cn,4) are chiefly formed by direct cleavage. They dehydrogenate and undergo substantial H and skeleton rearrangements. Smaller alkyl fragments (C, to C,) are mainly formed by secondary decomposition of higher alkyl fragments. Eliminations of groups from within the chain (and recombination of its ends) also occur. Zon series: Consecutive peaks corresponding to CnH2n+l ( d z 29,43, 57, 71, ...), accompanied by CnH2n-l ( d z 27, 41, 5 5 , 69, ...) and CnH2n ( d z 28, 42, 56, 70,. . .) of lower intensity. Intensities: Maximum intensity at m/z 43 or 57; with increasing masses, intensity of local maxima smoothly decreasing to a minimum at [M-15]+. Molecular ion: Medium intensity.
7.1.2 Branched Alkanes Fragmentation: In most cases, apparently simple bond cleavages, preferably at branched C atoms. The positive charge remains mainly on the branched C atom. Mechanistically, many H and skeleton rearrangements take place. This is reflected by the fact that no specific localization of heavy isotopes is possible.
H
R3
Zon series: Consecutive peaks corresponding to CnH2n+l ( d z 29,43, 57, 71, ...), accompanied by CnH2,,-1 ( d z 27, 41, 5 5 , 69, ...) and CnH2., ( d z 28, 42, 56, 70,. . .) of lower intensity.
'C' / \
314
\C’
’
\
7 Mass Spectrometry
Intensities: Local intensity maxima at those masses that result from cleavage at branched C atoms if the charge is localized there. Both CnHzn+l and (often more characteristically) CnHzn show this tendency. Molecular ion: Intensity decreasing with increasing degree of branching. No M+’ is observed in highly branched systems.
7.1.3 References [ 11 J.T. Bursey, M.M. Bursey, D.G. Kingston, Intramolecular hydrogen transfer
in mass spectra. 1. Rearrangements in aliphatic hydrocarbons and aromatic compounds, Chem. Rev. 1973, 73, 191. [2] K. Levsen, H. Heimbach, G.J. Shaw, G.W.A. Milne, Isomerization of hydrocarbon ions. VIII. The electron impact induced decomposition of n-dodecane, Org. Mass Spectrom. 1977,12, 663. [3] A. Lavanchy, R. Hounet, T. Gaumann, The mass spectrometric fragmentation of n-alkanes, Org. Mass Spectrom. 1979, 14, 79.
7.2 Alkenes
31 5
7.2 Alkenes [i-4] 7.2.1
Unbranched Alkenes Fragmentation: Dominant loss of alkyl residues and neutral alkenes. The position of highly substituted double bonds can be localized because in this case alkene eliminations are specific McLafferty-type reactions. Otherwise, double bonds can be localized in derivatives, such as epoxides and glycols, or by means of low energy ionization techniques. Branching effects are less characteristic than in isoalkanes. Alicyclic compounds exhibit very similar spectra. Zon series: Consecutive peaks corresponding to C,H2,-1 ( d z41,55, 69,83,...), accompanied by alkyl and alkene ions, CnH2,+l ( d z 43, 57,71, 85,...) and CnH2, ( d z 42,56,70,84,...), mostly of lower intensity. Intensities: Dominant maxima in the lower mass range, peaking around Cq. Local even-mass maxima due to alkene eliminations if the double bond is highly substituted. Molecular ion: Significant, but not necessarily strong.
7.2.2 Branched Alkenes Fragmentation: Highly substituted double bonds are less easily displaced than the unsubstituted ones and give rise to specific alkene eliminations of the McLafferty type, resulting in significant local maxima corresponding to C,H,, (cf. scheme). The latter may allow to localize the double bond. With unsubstituted double bonds, no reliable localization is possible and only moderateIy useful branching effects can be observed. The branching position is more easily determined after reduction to an alkane (in situ in GC/MS with H2 as carrier gas and heated Pt wool as catalyst).
Zon series: Maxima of the alkene type (CnH2,-1; m/z 41, 55, 69, 83,...), accompanied by weaker alkyl fragments, CnH2,+1 ( d z 43,57,71,85,...), in the low mass range and more significant alkene ions, C,H2, ( d z 42,56,70, 84,.. .). Intensities: Intensive peaks in the lower mass range. Diagnostically important local maxima of even mass, frequently also in the higher mass range. Molecular ion: Usually significant.
C=C
316
7 Mass Spectrometry
7.2.3 Polyenes and Polyynes , ; ;
c;
~..
Fragmentation: The spectra of aliphatic compounds with several triple and/or double bonds are similar to those of aromatic hydrocarbons. Zon series: Very similar to those of aromatic hydrocarbons, but fragments with higher hydrogen contents than in aromatics (m/z 54, 55; 66, 67; 79, 80) are usually found in polyenes and polyynes. Intensities: Very similar distribution of peak intensities as for aromatic hydrocarbons. Molecular ion: Usually strong, as in aromatic hydrocarbons.
7.2.4 References [ 13 A.G. Loudon, A. Maccoll, The mass spectrometry of the double bond. In: The
Chemistry of Alkenes; J. Zabicky, Ed.; Interscience: London, 1970; p 327. [2] J.T. Bursey, M.M. Bursey, D.G. Kingston, Intramolecular hydrogen transfer in mass spectra. 1. Rearrangements in aliphatic hydrocarbons and aromatic compounds, Chem. Rev. 1973, 73, 191. [3] N.J. Jensen, M.L. Gross, Localization of double bonds. Muss Spectrom. Rev. 1987, 6, 497. [4] C. Dass, Ion-molecule reactions of [ketene]+' as a diagnostic probe for distinguishing isomeric alkenes, alkynes, and dienes: A study of the CqH8 and CgHg isomeric hydrocarbons, Org. Muss. Spectrom. 1993,28, 940.
7.3 Alkynes
31 7
7.3 Alkynes [ i ] 7.3.1 Aliphatic Alkynes
Fragmentation: Tendency to lose a non-acetylenic H' from M+'. Extensive rearrangements (including consecutive McLafferty rearrangements to the triple bond) result in uncharacteristic degradation:
/
d z 54 (base peak for 5-decyne)
Rearrangement products at m/z 82 and 96 are dominant in nonbranched alkynes with cn,g. Consecutive loss of methyl radical occurs. In general, no reliable localization of the triple bond is possible except in derivatives (as in ethylene glycol adducts [I], see scheme).
R'
-
6 HOCH2CH20H 111
C I R2
(OxR' 0 CH2R2
-[
O+ F R 1 0
O+
+
[0\)-CH2R2
Zon series: Prominent peaks for CnH2n-3 (rdz 25, 39, 53, 67, 81,...), accompanied by CnH2n-1 ( d z 41, 55, 69, 83,...) and alkyl ions CnH2n+l (m/z 43, 57, 71, 85, ...). Occasionally even-mass maxima for CnHzn-2 ( d z 26, 40, 54, 68, 82,...). Intensities: Intensive peaks mainly in the lower mass range. Molecular ion: Weak or missing in spectra of smaller molecules, significant in those of larger ones. Generally, [M-l]+ is present. In terminal acetylenes, it is normally more abundant than M+'. 7.3.2 References
[l] C. Lifshitz, A. Mandelbaum, Mass spectrometry of acetylenes. In: The Chemistry of the Carbon-Carbon Triple Bond; S. Patai, Ed.; Wiley: New York, 1978; p 157.
c c
7 Mass Spectrometry
31 8
7.4
Alicyclic Hydrocarbons
[i]
7.4.1 Cyclopropanes [2,3] Fragmentation: Generally, spectra of cyclopropanes and alkenes are very similar because at 70 eV ionization, the ring readily isomerizes to corresponding alkene radical cations.
A
U
kJ/mol
I+,
42 Reaction coordinatePreferred primary fragmentation by bond cleavage at branched C atoms. Loss of alkyl residues and of neutral alkenes dominates. The ring of monosubstituted cyclopropanes is opened exclusively at the 1,2- and not the 2,3- bond. The primarily formed double bond is predominantly (for R: OCH3) or exclusively (for R: H, alk, COOCH3) found in the P,y-position (even for COOCH3, where the a$-unsaturation is thermodynamically more stable).
1 - ",)o;'
1''
+*
2 3
H H
H
H
P -
e
R
Y
a
Molecular ions of cyclopropyl cyanide, allyl cyanide, methacrylonitrile, and pyrrole rearrange to one common radical ion, most likely that of pyrrole [4]. Ion series: Consecutive maxima corresponding to C,H2n-~ ( d z 41, 55, 69, 83,. ..), accompanied by alkyl and alkenyl ions of the type CnH;?,+l ( d z 4 3 , 5 7 , 71, 85 ,...) and C,H2, ( d z 42, 56, 70, 84,...), mostly of lower intensity. Intensities: Dominant peaks in the low mass range, peaking around C,. Local even-mass maxima due to alkene eliminations if the resulting double bond is highly substituted. Molecular ion: Significant, but not necessarily strong.
7.4 Alicyclic Hydrocarbons
319
7.4.2
Saturated Monocyclic Alicyclics [5] Fragmentation: Preferred primary fragmentation by bond cleavage at branched C atoms, followed by loss of alkyl residues and alkenes. Ion series: Consecutive maxima corresponding to CnH2,-1 ( d z 41, 55, 69, 83,...), accompanied by CnH2n+l ( d z 43, 57, 71, 85,...) and CnH2n ( d z 42, 56, 70, 84,. , .) of lower intensities. In general, the maxima are so similar to those of alkenes that no clear distinction is possible. Intensities: Overall distribution of peaks maximizing in the lower mass range, around C4 or C5. Local maxima can result from branching effects. Molecular ion: Significant, mostly of medium intensity.
7.4.3 Polycyclic Alicyclics Fragmentation: Most important primary cleavage at highly branched carbon atoms, followed by H rearrangements and complex fragmentations. Ion series: With increasing number of rings, the position of unsaturated hydrocarbon fragments in the upper d z range shifts from CnHzn-l ( d z 41, 55, 69, 83 ...) to C,H2n-3 ( d z 39, 53, 67, 81,...) and to C,Hzn-5 ( d z 51, 65, 79, 93, ...). Typically, maxima in the lower d z range have a lower degree of unsaturation than those in the upper d z range. Intensities: Major maxima evenly distributed, somewhat more intense in the high mass or M+' range. Molecular ion: Strong.
7.4.4 Cyclohexenes Fragmentation: Loss of larger ring substituents as well as retro-Diels-Alder reaction, yielding even-mass maxima with one or two double-bond equivalents, CnH2, ( d z 42, 56, 70, 84,...) and CnH2,-2 ( d z 40, 54, 68, 82,...), unless the retro-Diels-Alder product corresponds to ethylene. Somewhat unexpectedly, the base peak of cyclohexene is at [M-15]+. The retro-Diels-Alder reaction often accounts for prominent fragments of cyclohexenes and 1,4-cyclohexadienes:
However, double-bond migration may or may not occur beforehand. Also, other fragmentation pathways may dominate. Therefore, a reliable localization of the
0
320
7 Mass Spectrometry
double bond in cyclohexene derivatives of unknown structure is not necessarily possible. For example, the base peak of 1,2-dimethylcyclohexene is at m/z 68 rather than at the expected m/z 82. Zon series: Unsaturated hydrocarbon fragments in the upper m/z range are shifted, relative to cyclohexane fragments, by two mass units to CnH2n-3 (m/z 39, 53, 67, 8 1,...). Typically, maxima in the lower m/z range have a lower degree of unsaturation than those in the upper m/z range. Intensities: Intensive peaks evenly distributed over whole mass range. Molecular ion: Medium intensity (ca. 40% in cyclohexene).
0
7.4.5 References [13 J.T. Bursey, M.M. Bursey, D.G. Kingston, Intramolecular hydrogen transfer
[2]
[3] [4] [5]
in mass spectra. 1. Rearrangements in aliphatic hydrocarbons and aromatic compounds, Chem. Rev. 1973, 73, 191. H. Schwarz, The chemistry of ionized cyclopropanes in the gas phase. In: The Chemistry of the Cyclopropyl Group; Z . Rappoport, Ed.; Wiley: Chichester, 1987; p 173. J.R. Collins, G.A. Gallup, Energy surfaces in the cyclopropane radical ion and the photo-electron spectrum of cyclopropane, J. Am. Chem. SOC. 1982, 104, 1530. G.D. Willet, T. Baer, Thermochemistry and dissociation dynamics of stateselected C4H4X ions. 3. CqHgN+, J. Am. Chem. SOC. 1980,102, 6774. E.F.H. Brittain, C.H.J. Wells, H.M. Paisley, Mass spectra of cyclobutanes and cyclohexanes of molecular formula C10H16, J. Chem. SOC.B 1968, 304.
7.5 Aromatic Hydrocarbons
32 1
7.5 Aromatic Hydrocarbons [MI 7.5.1 Aromatic Hydrocarbons
Fragmentation: Weak tendency of fragmentation. Elimination of H' and successive H2 eliminations, yielding [M-l]+, [M-3]+, and [M-5]+ of decreasing intensities. In condensed aromatics, [M-2]+' can be a dominating fragment. Further typical fragmentation reactions are the eliminations of acetylene (Am 26) and C3H3 (Am 39). Some CH3 elimination frequently occurs in pure aromatic compounds. In the case of diphenyl compounds, biphenylene ( d z 152) and, if a CH2 group is available, fluorene (m/z 165) ions are typically observed. Zon series: C,H, and C,H,&l ( d z 39, 51-53, 63-65, 75-77,. , .), for polycyclic aromatics gradually changing to more highly unsaturated ions. Doubly charged ions frequently occur, increasingly with increasing number of 7c-electron systems. Intensities: Weak fragments. The intensity pattern of doubly charged ions does not follow that of the corresponding singly charged ions. Molecular ion: Strong. 7.5.2 Alkylsubstituted Aromatic Hydrocarbons Fragmentation: Dominant loss of alkyl residues by benzylic cleavage, followed by elimination of alkenes.
At low resolution, ethylbenzyl and P-phenylethyl are isobaric with benzoyl ( d z 105). In contrast to benzoyl, dehydrogenation products ( d z 104, 103) as well as protonated benzene (m/z 79) are also present if m/z 105 is a hydrocarbon rest. Zon series: Aromatic hydrocarbon fragments, C,H, and C,H,,1 ( d z 39, 51-53, 63-65, 75-77,. ..), in the lower mass range. Intensities: Intensive peaks mainly in the higher mass range. Maxima by benzylic cleavage. Molecular ion: Strong or medium.
0
322
7 Mass Spectrometry
7.5.3 References
J.T. Bursey, M.M. Bursey, D.G. Kingston, Intramolecular hydrogen transfer in mass spectra. 1. Rearrangements in aliphatic hydrocarbons and aromatic compounds, Chem. Rev. 1973, 73, 191. W. Schonfeld, Fragmentation diagrams for elucidation of decomposition reactions of organic compounds. 1. Aromatic hydrocarbons (in German), Org. Mass. Spectrom. 1975,10, 321. C . Lifshitz, Tropylium ion formation from toluene: Solution of an old problem in organic mass spectrometry. Acc. Chem. Res. 1994,27, 138. M.V. Buchanan, B. Olerich, Differentiation of polycyclic aromatic hydrocarbons using electron-capture negative chemical ionization, Org. Mass. Spectrom. 1 9 8 4 1 9 , 486.
7.6 Heteroaromatic Compounds
323
7.6 Heteroaromatic Compounds [1,2] 7.6.1 General Characteristics Fragmentation: Mostly fragments of aromatic character with specific eliminations including heteroatoms, e.g., elimination of HCN, CO, CHO, CS, and CHS from M+' and of HCN, CO, and CS from fragments. In the case of alkylsubstituted heteroaromatics, occurrence of benzylic-type cleavage and McLafferty rearrangements of substituents with C,, 1, as well as specific rearrangements including heteroatoms, especially in N aromatics. Ion series: Aromatic hydrocarbon fragments C,H, and CnH,,l (m/z 39, 51-53, 63-65,. ..) in the lower mass range if the necessary number of C atoms is present (no such fragments, e.g., in pyrazine). Ions including heteroatoms like HCN+' (m/z 27), CH3CNH+ ( d z 42), and CS+' (m/z 44). Intensities: Intensive peaks mainly in the higher mass range. Molecular ion: Generally strong. [M- 1]+ is often relevant in alkylsubstituted heteroaromatics. 7.6.2 Furans [3] Fragmentation: Oxygen can be lost from M+' together with the neighboring C as CHO (Am 29). In 2- or 6-methyl-furans, CH3CO+ (m/z 43) can be seen (base peak in 2,5-dimethylfuran). As in aromatic methyl ethers, [M-43]+ is a product of a two-step reaction: (M+'-CH3'-CO). Furans substituted with an alkyl group (Cn,l): benzylic-type cleavage (to pyrylium ion CgH50+, m/z Sl), followed by loss of co. Zon series: Mainly aromatic hydrocarbon fragments C,Hn and C,Hn,l (m/z 39, 5 1-53, 63-65,. ..). Intensities: Intensive peaks mainly in the higher mass range. The fragments are usually stronger than in purely aromatic hydrocarbons. Molecular ion: Strong. No pronounced tendency to protonate. Usually, [M-l]+ is very strong in methylfurans. 7.6.3 Thiophenes [4] Fragmentation: Sulfur can be lost from M+' together with the neighboring C as CHS (Am 45) or CS (Am 44). Typical for thiophenes substituted with an alkyl group (C,,,) is benzylic-type cleavage followed by loss of CS (Am 44). Protonated thiophene (m/z 85) is a characteristic product of monoalkylated thiophenes.
324
7 Mass Spectrometry
Ion series: Aromatic hydrocarbon fragments CnHn and CnHn*l (m/z 39, 51-53, 63-65,. . .). Besides the isotope peak (M+2), the signals at d z 44 and 45 (CS+' and CHS+) are indicators for sulfur. Intensities: Dominant peaks for M+' and products of benzylic-type cleavage. Molecular ion: Strong. Characteristic S isotope signal ([M+2]+' corresponds to 4.4% of M+'). No pronounced tendency of protonation. Usually, [M-l]+ is very strong in methylthiophenes.
7.6.4 Pyrroles [5] Fragmentation: HCN elimination from M+' and from fragments. In methylpyrroles, [M- 1]+ is dominant. Benzylic-type cleavage in C- and N-alkylpyrroles with or without (non-specific) H rearrangements. Zon series: Aromatic hydrocarbon fragments CnHn and CnHnkl (m/z 39, 51-53, 63-65,. ..). Intensities: Dominant peaks for M+' and products of benzylic-type cleavage. Molecular ion: Strong (odd mass for odd number of N in the molecule). No tendency to protonate. In methylsubstituted pyrroles, [M- 1]+ is dominant. 7.6.5
Pyridines Fragmentation: HCN elimination (Am 27) from fragments and the ion H$N+ (m/z 28) are characteristic. Additional reactions in 2- or 6-methylpyridines are CH3CN elimination (Am 41) and the formation of CH3CNH+ (m/z 42). Benzylic cleavage is dominant for 3-alkyl-, strong for 4-alkyl-, and weak for 2alkylpyridines. Typical rearrangements with participation of the N atom in 2- and 6-alkylpyridine derivatives. Intramolecular N-alkylation in 2-alkyl derivatives:
m/z 106
m/z 120
m/z 134
7.6 Heteroaromatic Compounds
325
McLafferty rearrangements are important in 2- and 4-alkylpyridines: R'
R2
- w
-
CYH2 \
N.H
Ion series: Aromatic hydrocarbon fragments, C,H,, C,H,,l and C,H,*lN ( d z 39-41, 51-54, 63-67, 75-80 ,...). Intensities: Dominant peaks for M+' or, if possible, for products of benzylic-type cleavage. Molecular ion: Strong except when benzylic-type cleavage is possible. Odd mass for an odd number of N in the molecule. No tendency to protonate. [M-l]+ is usually present and is strong in alkylsubstituted pyridines.
7.6.6 N-Oxides of Pyridines and Quinolines Fragmentation: The [M-O]+' ion, with variable intensity, is probably due to thermal decomposition. The fragments [M-CO]+' and, if an alkyl group is present on the neighboring C atom, [M-OH]+ are relevant for quinoline N-oxides. Rearrangements with ring formation including the N-0 moiety if alkyl or aryl groups are present in the neighboring positions. Ion series: As for the corresponding heteroaromatics, too, aromatic hydrocarbon fragments C,H,, C,H,*1 and C,HnklN ( d z 39-41, 51-54, 63-67, 75-80, ...) are observed. Intensities: Dominant peaks for M+' and products of benzylic-type cleavage. Molecular ion: Strong, except when [M-O]+' dominates due to experimental conditions or when benzylic-type cleavage is possible. Odd mass for odd number of N atoms in the molecule. No tendency to protonate.
7.6.7 Pyridazines and Pyrimidines Fragmentation: Loss of N2 and CH2N' from pyridazines to yield M-28. Also, loss of N2H' (especially important in methylpyridazines) to give [M-29]+. In pyridazine N-oxides, consecutive loss of NO' and HCN. Consecutive loss of two HCN (Am 27) molecules from pyrimidines. In 2-, 4-, and 6-methylpyrimidines, CH3CN is eliminated (Am 41) and the ion CH&NH+ (m/z 42) occurs. Ion series: Aromatic hydrocarbon fragments (C,H,, C,Hnk 1) and, for pyrimidines, C,H,,lN, at low masses ( d z 39, 51-53). Intensities: Dominant peak for M+'. Molecular ion: Strong. No tendency to protonate. For pyrimidines, [M-l]+ is usually observable.
326
7 Mass Spectrometry
7.6.8 Pyrazines
Fragmentation: Consecutive losses of two HCN (Am 27) molecules. For methylpyrazines, elimination of CH3CN (Am 41) and formation of CH$NH+ ( d z 42). Zon series: No aromatic character of the spectra. Intensities: Dominant peak for M+'. Molecular ion: Strong. No tendency to protonate. Usually, [M-l]+ is observable; it can be stronger than M+' in alkylsubstituted (C,,,) pyrazines.
7.6.9 Indoles Fragmentation: Analogous to pyrrole; HCN elimination (Am 27) from M+' and from fragments. From M+' also H2CN' (Am 28) elimination (in one or two steps). In methylsubstituted indoles, [M-1]+ is dominant. In N-methylindoles, [M- 15]+ is significant. Benzylic-type cleavage in C- and N-alkylindoles with or without (non-specific) H rearrangements. Zon series: Aromatic ion series. Intensities: Dominant maxima in the higher mass range. Molecular ion: Strong. No tendency to protonate. In methylsubstituted indoles, [M-l]+ is strong. 7.6.1 0
Quinolines and lsoquinolines Fragmentation: Similar to pyridine: HCN elimination (Am 27) from M+', [M- I]+, and fragments. In methylquinolines and isoquinolines also CH3C N eliminations (Am 41). In alkylsubstituted (C,,,) quinolines, benzylic cleavage dominates except when neighboring effects of N can play a role. For 2- and 8alkylquinolines, as well as 1- and 3-alkylisoquinolines, see rearrangements in pyridines. Zon series: Aromatic hydrocarbon fragments, C,H,, C,H,+l, and C,H,*lN ( d z 3941, 51-54, 63-67, 75-80,. ..). Intensities: Dominant peak for M+' or, if possible, for products of benzylic-type cleavage. Molecular ion: Strong, except when benzylic-type cleavage is possible. Odd mass for odd number of N atoms in the molecule. No tendency to protonate. [M-l]+ is usually present and is strong in alkylsubstituted quinolines.
7.6 Heteroaromatic Compounds
327
Rearrangements in 8-alkylquinolines:
mc m/z 156
m/z 170
'CH2 H
m/z 143
7.6.1 1
Cinnoline, Phthalazine, Quinazoline, Quinoxaline Fragmentation: Same as for the corresponding monocyclic heteroaromatics pyridazine, pyrimidine, and pyrazine. Characteristic for pyridazine, cinnoline, and phthalazine is the elimination of N2 (Am 28) and of NzH' (Am 29) from their alkyl derivatives. Phthalazine loses HCN (Am 27) twice. Zon series: Aromatic hydrocarbon fragments (C,H,, C,H,,l) and C,H,+lN (m/z 3 9 4 1, 5 1-54, 63-67, 75-80,. . .). Intensities: Dominant maximum for M+' or, if possible, for products of benzylictype cleavage. Molecular ion: Strong, except when benzylic-type cleavage is possible. Odd mass for odd number of N atoms in the molecule. No tendency to protonate. [M-l]+ is usually present and is strong in alkylsubstituted compounds. 7.6.12
References [l] Q.N. Porter, Mass Spectrometry of Heterocyclic Compounds, 2nd ed.; Wiley:
New York, 1985. [2] D.G.I. Kingston, B.W. Hobrock, M.M. Bursey, J.T. Bursey, Intramolecular hydrogen transfer in mass spectra. 111. Rearrangements involving the loss of small neutral molecules, Chem. Rev. 1975, 75, 693. [3] R. Spilker, H.-F. Grutzmacher, Isomerization and fragmentation of methylfuran ions and pyran ions in the gas phase, Org. Mass. Spectrom. 1986, 21, 459. [4] W. Riepe, M. Zander, Mass-spectrometric fragmentation behavior of thiophene benzologs. Org. Mass. Spectrom. 1979,14, 455. [5] H. Budzikiewicz, D. Djerassi, A.H. Jackson, G.W. Kenner, D. J. Newmann, J. M. Wilson, Mass spectra of monocyclic derivatives of pyrrole, J. Chem. SOC. 1964, 1949.
328
7 Mass Spectrometry
7.7 Halogen Compounds [ M I 7.7.1 Saturated Aliphatic Halides
Fragmentation: Loss of halogen radical (I > Br > C1> F) followed by elimination of alkenes. Loss of alkyl radical followed by elimination of acid HX. Loss of acid HX to give an alkene radical cation.
9 alkene" -3R-CH2 +
-
1
- CHzX'
+*
R-CH2-X
Important for F and C1.
R+
- R'
- RCH2'
CH2=X+
x+
With successive alkene elimination; important for Br and I. Relevant for F and Cl compounds of intermediate chain length and for a-branching. Weak but characteristic halogen indicators. Weak but characteristic halogen indicators.
Zon series: The dominant hydrocarbon fragments are mainly alkenyl fragments (CnH2n-1) for F and C1, mixed alkyl ( C , H Z ~ + ~and ) alkenyl fragments (CnH2n-1)for Br, and mainly alkyl fragments (CnH2n+l)for I. Intensities: Intensive peaks mainly in the lower mass range. Characteristic maxima for C1 and Br at CqHgX ( d z 91/93 and 135/137, respectively), which has a cyclic structure: +.
+
Ru 0 P X
m/z 91,93 for X = C1 m/z 135, 1 3 7 f o r X = B r
Alkyl substituents on the chain reduce the intensity of this fragment. If it is strong, [M-X]+ is weak. In the case of iodoalkanes some I+ and HI+'at m/z 127, 128 is usually detectable. Molecular ion: Strong for the smallest alkanes, with increasing intensity in the sequence F, C1, Br, I. Decreases rapidly with increasing mass and with increasing branching. It is negligible for F and C1 if the n-alkyl chains are longer than pentyl, and for Br and I if they are longer than heptyl and nonyl, respectively. Low tendency to protonate. Characteristic isotope patterns for C1 and Br. Iodine can be detected because of its high mass; the 13C signals of M+' and its fragments are conspicuously weak.
7.7 Halogen Compounds
329
7.7.2 Polyhaloal kanes Fragmentation: Preferred fragmentation of the C-C bond if several halogen atoms are bonded to one of these carbon atoms. CF3 (m/z 69) is often the base peak in terminally peffluorated alkanes, and so is CHC12 (m/z 83, 85, 87) in terminally dichlorinated compounds. Often, X2 is eliminated besides the usual fragmentation of X' and HX. Interchange of halogens may occur. For example, m/z 85 (CF2C1) is a dominant signal (ca. 60%) for CF3CFC12. Zon series: Most fragments are halogenated alkyl and alkenyl groups, easily detectable on the basis of the isotope signals in the cases of C1 and Br. Intensities: Intensive peaks mainly in the lower mass range. Molecular ion: Weak, decreasing with increasing number of halogen atoms. Absent from the spectra of many polyhalogenated compounds. 7.7.3 Aromatic Halides Fragmentation: Consecutive losses of halogen radicals andlor acid HX. In perhalogenated aromatics, decomposition down to C,+, with x from 1 to 6 (m/z 12, 24, 36, 48, 60, 72). If alkylsubstituted (Cn,l), the base peak is mostly the result of benzylic cleavage. In an otherwise aromatic environment, m/z 57 is a F indicator (C3H2Ff). Elimination of CF2 (Am 50) from CF3 groups attached to the aromatic ring (from M+' or from fragments). Zon series: Aromatic hydrocarbon fragments, CnHn, CnHn-l, and CnHn-2 (m/z 39, 5 1-53, 63-65, 75-77,. , .). In the higher mass range: C,(H,X),. Intensities: Dominant peaks in the M+' region. Molecular ion: Usually very strong. Characteristic isotope signals for C1 and Br. 7.7.4 References
[l] A.G. Loudon, Mass spectrometry and the carbon-halogen bond. In: The Chemistry of the Carbon-Halogen Bond; S. Patai, Ed.; Wiley: New York, 1973; p 223. [2] D.G.I. Kingston, B.W. Hobrock, M.M. Bursey, J.T. Bursey, Intramolecular hydrogen transfer in mass spectra. 111. Rearrangements involving the loss of small neutral molecules, Chem. Rev. 1975, 75, 693. [3] J.M. Miller, T.R.B. Jones, The mass spectra of azides and halides. In: The Chemistry of Functional Groups, Suppl. D ; S. Patai, Z. Rappoport, Eds.; Wiley: New York, 1983; p 75.
Ha
7 Mass Spectrometry
330
7.8 Alcohols, Ethers, and Related Compounds [1,2] 7.8.1 Aliphatic Alcohols [3]
Fragmentation: Elimination of water from M+' and from fragments. Strong for primary alcohols. If an aliphatic H atom can be transferred in a 6-ring process, it is involved in the water elimination in 90% of the investigated cases. If a CH2CH2 group is attached to the 0-bearing C atom, water elimination is often followed by loss of ethylene. Water elimination is dominant for long-chain alcohols, making their spectra similar to those of alkenes.
Cleavage of bonds next to the OH-bearing C atom to form oxonium ions, then elimination of water and of alkenes. The a-cleavage is often dominant. Usually, its importance increases with increasing branching at the a-carbon atom. The larger substituent is lost most readily.
0
-
R ~R'- ) C ~ ~ H-k3 R3
R' \C=OH +
R2
[CH20H]+( d z 3 1) for primary alcohols (R', R2 = H) [30 + R']' ( d z 45,59,73, ...) for secondary alcohols (R2 = H) E29 + R' + R2]+( d z 59,73, 87, ...) for tertiary alcohols
Consecutive H20 and alkene eliminations in longer chain primary alcohols lead to [M-46]+', [M-74]+', [M-102]+',.... The series of fragments at [M-15]+, [M-18]+', and m-33]+ is frequently observed for branched alcohols. Zon series: Dominant consecutive alkene ions corresponding to CnH2n-l ( d z 41, 5 5 , 69,...), CnH2n ( d z 42, 56, 70,...), accompanied by weaker fragments, CnH2n+10( d z 31, 45, 59, ...), with one or more local maxima in the latter senes ( d z 3 1 dominates in primary alcohols). Intensities: Major peaks in the lower mass range from alkyl- and alkene-type ions with weaker maxima from ions of the sort CnH2n+10. Molecular ion: Mostly weak, often missing, especially in tertiary and long-chain alcohols. Indirect determination of M+' is often possible from the fragments at [M-15]+, [M-18]+' and [M-33]+. [M+1]+ is often significant. In primary and secondary alcohols also [M-1]+ can usually be seen. Sometimes, [M-2]+' is formed because of oxidation to carbonyl compounds during sample introduction.
7.8 Alcohols, Ethers, and Related Compounds
33 1
7.8.2 Alicyclic Alcohols [3]
Fragmentation: Elimination of water from M+', followed by loss of alkyl or alkenyl residues. Ring cleavage at the 0-bearing C atom, followed by loss of alkyl residues after H rearrangement.
Zon series: Alkene hydrocarbon fragments C,HZ,-~ (m/z 41, 55, 69, ...), C,H2,-3 ( d z 39, 53, 67, 81, ...), and unsaturated 0 fragments, C,H2,-10 (m/z 43, 57, 71,. .,), as well as acetaldehyde and its homologues (m/z 44, 58, 72,. ..). Intensities: Local maxima evenly distributed over whole mass range. Molecular ion: Usually weak but in contrast to aliphatic alcohols practically never missing. [M+l]+ usually contains a significant amount of protonated molecule ion. 7.8.3 Unsaturated Aliphatic Alcohols 131
Allyl alcohols: The spectra are similar to those of the corresponding carbonyl compounds, which are (partly) formed by double H rearrangement of M+'.
y,&Unsaturated alcohols: Aldehyde elimination through a McLafferty-type rearrangement:
7.8.4 Vicinal Glycols
Fragmentation: Cleavage of bonds next to the OH-bearing C atom (a-cleavage) dominates. Preferable fragmentation of the C-C bond between the two oxygens, the charge remaining mainly on the larger fragment. Water elimination from these fragments, but scarcely from M+'. Zon series: Saturated and unsaturated aliphatic ions ( d z43, 57, 71, ... and 41, 55, 69,. . .) and intense peaks from 0-containing saturated rests ( d z45, 59, 73,. ..). Intensities: Dominant peaks for the products of a-cleavages and their dehydrated derivatives. Molecular ion: Weak.
0
332
7 Mass Spectroscopy
7.8.5 Aliphatic Hydroperoxides [4] Fragmentation: Most pronounced is the loss of the hydroperoxy radical H02' (Am 33), especially when a tertiary alkyl cation is formed. Important, in decreasing order, is loss of H202 (Am 34), H20 (Am 18), HO' (Am 17), and 0 (Am 16). Zon series: Mainly saturated and unsaturated alkyl fragments, CnH2n+l (m/z 43, 57, 71, ...) and CnH2n-1 (m/z 41, 5 5 , 69, ...). The oxygen-indicating fragments at m/z 3 1 and its homologues are always present. Intensities: Intensive peaks mainly in the lower mass range. Molecular ion: Weak.
7.8.6 Phenols
'
Fragmentation: Decarbonylation (Am 28) and loss of CHO' (Am 29) followed by elimination of acetylene. In alkyl derivatives [M-l]+ and, if at least two alkyl carbons are present (dimethyl or ethyl), [M-15]+ become important. Elimination of CO from the primary fragments. [M-18]+' mainly with ortho-alkylphenols. In derivatives with a longer alkyl chain, benzylic cleavage and alkene elimination (McLafferty rearrangement) are the dominant primary fragmentation processes. The fragments then lose CO (Am 28). Zon series: Aromatic hydrocarbon fragments C,Hn and C,H,,l (m/z 39, 51-53, 63-65,75-77,. ..). The presence of some m/z 55 (C3H3O) is common. A peak at d z 69 (O=CCH=C=O) is characteristic of 1,3-dihydroxy substitution. Intensities: Dominant peaks in the higher mass range. Molecular ion: Dominant, no tendency to form [M+H]+. [M-l]+ is weak.
7.8.7 Benzyl Alcohols Fragmentation: Loss of H' and consecutive elimination of CO (Am 28) to give a protonated benzene molecule, which further loses H2.
- co + C6H7'
Q+IH 2!i M" (80%)
[M-11' (65%)
m/z 79 (100%)
- H2
+ C6HS' m/z 77 (65%)
Elimination of OH' (Am 17) to yield the tropylium cation is the second important fragmentation path:
7.8 Alcohols, Ethers, and Related Compounds
eo. -0" (=J= +
e
333
@
+ [M-17]+,C7H7+, m/z 91 (25%)
M+' (80%)
Zon series: Aromatic hydrocarbon fragments corresponding to C,H, and C,H,1 (mlz 39, 51-53, 63-65, 75-77 ,...). Intensities: Dominant peaks for the products described under Fragmentation. For benzyl alcohol decreasing in the sequence of [M-29]+, M+', [M-l]+, [M-311+, [M17]+. Molecular ion: Strong. 7.8.8 Aliphatic Ethers [5,61 Fragmentation: Homolysis of the C-C bond next to the 0 atom to yield oxygencontaining fragments. Preferably, the bond at the highest substituted C atom breaks and the larger alkyl group is lost.
-R3 CnH2,,+10+,m/z 3 1,45, 59,... This homolysis is followed by the elimination of alkenes, carbonyls, or, less importantly, of water.
- R~CH=O
\ +
R'
CO=CH-R~
+ R'CH2CH2 m/z 29,43, 57,...
As a competing process, especially with increasing molecular weight, heterolysis at the 0 atom takes place to yield strong alkyl ion signals. The larger as well as the branched alkyl rests are fragmented preferably. The base peak often arises from heterolysis of the C-0 bond.
- R'CH2CH20'
R R3
R2 H<+ R3 m l z 29,43, 57, ...
0
7 Mass Spectroscopy
334
In contrast to the H,O elimination from alcohols, the H transfer involved in the elimination of RCH2CH20H from ethers is non-specific. U *
R2
+
- R'CH2CH20H
1+*
R3CH=R2
m/z 28,42,56,...
Ion series: Alkyl fragments, CnH2n+l (m/z 29, 43, 57, ...), with maxima due to cleavage of the C-0 bond. Alkene ion series, CnH2n (m/z 28,42, 56,...), due to elimination of alcohol. Oxygen-containing fragments C,H2n+ 1 0 (m/z 3 1, 45, 59,. ..) with maxima due to cleavage of the C-C bond next to oxygen. Intensities: Intensive peaks mainly in the lower mass range. Molecular ion: Significant or weak. Decreasing with increasing chain length and branching. 7.8.9 Unsaturated Ethers [7]
Q
Fragmentation of vinylic and acetylenic alkyl ethers: Dominant homolysis of the alkyl C-C bond next to the 0 atom on the saturated side, leading to C3H50+ ( d z 57) for vinylic and C3H3O+ (m/z 5 5 ) for acetylenic ethers of primary aliphatic alcohols. For alkyl (C,,,) vinyl ethers, ethanol elimination after triple H transfer. [M-15]+ in vinyl ethers predominantly by elimination of the vinyl CH2 after H rearrangement.
+.
+
f.
[84+Alk]+ Fragmentation of allylic ethers: Heterolysis of both C-0 bonds, leading to strong C3H.g+ (m/z 41) and alkyl ( d z 29, 43, 57, ...) cations. Formation of ionized allylic alcohol (m/z 5 8 ) by non-specific H transfer from the alkyl rest. In allylic and propargylic ethers, no cleavage of the C-C bond next to the 0 atom of the alkenyl group occurs. Hence, loss of vinyl or acetylenyl cannot be observed. Zon series: C,HznO (m/z 44, 58, 72, ...) for alkenyl alkyl ethers and CnH2n-20 (m/z 42, 56, 70, ...) for dialkenyl ethers. Unsaturated aliphatic (C,Hzn-l; m/z 41, 55, 69,., .) as well as saturated aliphatic and unsaturated oxygen-containing fragments (C,Hzn+l and CnH2,-10; m/z 43, 57, 71, ...). Intensities: Intensive peaks mainly in the lower mass range. Molecular ion: Weak to medium, very weak for acetylenic ethers.
7.8 Alcohols, Ethers, and Related Compounds
335
7.8.1 0 Alkyl Cycloalkyl Ethers
Fragmentation of methyl ethers of cycloalkanols with > 3 C atoms: After primary cleavage of the ring C-C bond next to the 0 atom, the prominent fragments formed are CH3OCH=CH2+' (m/z 58) and, for alicyclics with > 4 C atoms, CHqO=CHCH=CH?+ (m/z 71, rearrangement in analogy to that observed for cycioalkanols). Loss-of methanol to give hydrocarbon fragments, CnH2n-2 (m/z 54, 68, 82,...). Fragmentation of ethyl and higher alkyl ethers of cycloalkanols with > 3 C atoms: Alkene elimination to yield the protonated cycloalkanol (m/z 72, 86, 100,. ..) and heterolytic cleavage of the C-0 bond to give dominating cycloalkyl ions (m/z 69, 83, ...). Ion series: Besides the fragments already mentioned, mainly unsaturated hydrocarbon fragments (CnH2n-1, m/z 27, 41, 55, 69,.. .). Intensities: The above mentioned fragments dominate the spectrum. Molecular ion: Weak or intermediate. 7.8.1 1 Cyclic Ethers
Fragmentation: Primary ring cleavage at C-C bonds next to the 0 atom, followed by loss of CH2O (Am 30), H20 (Am 18), or alkyl (Am 15, 29, ...). Elimination of H' to give [M-l]+, followed by CO elimination (Am 28) to [M-29]+. When a-substituted, dominant loss of substituents, followed by water elimination. Formation of acyl if two a-substituents are present.
+
+
Ion series: Mainly ions of the alkene type. Weak saturated, oxygen-containing fragments ( d z31, 45, ...). Intensities: Intensive peaks evenly distributed over whole mass range. Molecular ion: Often significant but sometimes weak, especially when a-substituted. Intensity of [M-l]+ usually comparable to that of M+' if no a-substituent is present.
0
336
7 Mass Spectroscopy
7.8.1 2 Aliphatic Epoxides [8] Fragmentation: The most important primary fragmentation is the cleavage of C-C bonds next to the 0 atom (a-cleavage), resulting in complex degradation due to the related multiple choice and extensive secondary rearrangements. The products allow mass-spectrometriclocalization of double bonds after epoxidation. Due to ring opening prior to fragmentation, P-cleavage is as relevant as the a-cleavage.
y-Cleavage is the most important fragmentation mechanism, especially in terminal epoxides:
m/z 71
0
Mainly in terminal epoxides, rearrangement with alkene elimination, formally leading to alkene-OH-+' (CnH2n0, m / i 44, 58, 72,. ..) and alkene+' (CnH2,-,, dz 28, 42, 56,...):
Mainly in nonterminal epoxides, transannular cleavage with H transfer and elimination of an alkenyl radical, leading to CnH2,,+10 fragments ( d z 45, 59, 73,. ..):
Ion series: Mixed, not characteristic. Intensities: Intensive peaks mainly in the lower mass range. Molecular ion: Usually weak.
7.8 Alcohols, Ethers, and Related Compounds
337
7.8.1 3 Methoxybenzenes Fragmentation: Loss of methyl radical, followed by decarbonylation to give [M-43]+; elimination of formaldehyde (Am 30) from M+' or from primary fragments. Ion series: Aromatic hydrocarbon fragments corresponding to C,H, and C,H,+ 1 ( d z 39, 51-53, 63-65, 75-77 ,... ). Intensities: Intensive peaks in the M+' region. Molecular ion: Strong. 7.8.1 4 Alkyl Aryl Ethers [91 Fragmentation: Commonly dominating alkene elimination to give the corresponding phenol ion (non-specific hydrogen migration), followed by decarbonylation. In the case of aryl methyl ethers, loss of CH20 from M+' or from primary fragments as well as CH3' elimination followed by decarbonylation. Ion series: Mostly aromatic hydrocarbon fragments, C,H, and C,H,+1 ( d z 39, 5 1-53, 63-65, 75-77,. ..). Intensities: Usually maximum at the mass of the corresponding phenol. Otherwise, intensive peaks mainly concentrated in the high and medium mass range. Molecular ion: Strong. 7.8.1 5 Aromatic Ethers Fragmentation: Loss of H' (Am l), CO (Am 28), and CHO' (Am 29) from M+'. Cleavage at the C-0 bond and decarbonylation of the resulting product, followed by dehydrogenation. Ion series: Aromatic hydrocarbon fragments corresponding to C,H, and C,H,*l ( d z 39, 51-53, 63-65, 75-77 ,...). Intensities: Intensive peaks mainly in the M+' region. Molecular ion: Strong. 7.8.1 6 Aliphatic Peroxides [4] Fragmentation: Alkene elimination to give hydroperoxide radical cations and hydroperoxide elimination to yield alkene radical cations (dominating if larger alkyl groups are present). Alkene elimination can be followed by loss of OH', resulting in products that formally correspond to those obtained by 0-0 cleavage, which probably is not a one-step process (see scheme).
0
338
7 Mass Spectroscopy
- CH2=CHR2 ___._)
"l@@H H
- OH'
+
+
R'-CH=OH [30 + R1]+
Elimination of 0' or 0 2 may occur in cyclic peroxides. tert-Butyl peroxides predominantly eliminate tert-butyl-00' to give [M-89]+. Zon series: Saturated or unsaturated alkyl groups (CnH2,+l, m/z 29, 43, 57, ...; C,H2,-1, m/z 27, 41, 55 ,...) and alkenyl ions (CnH2n, m/z 28, 42, 56,...) dominate. The fragment at m/z 31, and sometimes its homologues, indicate the presence of oxygen. Intensities: Intensive peaks mainly in the lower mass range. Molecular ion: Weak to moderate. 7.8.1 7 References [11 D.G.I. Kingston, J.T. Bursey, M.M. Bursey, Intramolecular hydrogen transfer
'
[2] [3] [4] [5]
[6] [7] [8] [9]
in mass spectra. II. The McLafferty rearrangement and related reactions, Chem. Rev. 1974, 7 4 , 215. D.G.I. Kingston, B.W. Hobrock, M.M.Bursey, J.T. Bursey, Intramolecular hydrogen transfer in mass spectra. 111. Rearrangements involving the loss of small neutral molecules, Chem. Rev. 1975, 75, 693. R.B. Cooks, The mass spectra of hydroxyl compounds. In: The Chemistry of the Hydroxyl Group, Part 2 ; S . Patai, Ed.; Wiley: New York, 1971; p 1045. H. Schwarz, H.M. Schiebel, Mass spectrometry of organic peroxides. In: The Chemistry of Functional Groups, Peroxides; S . Patai, Ed.; Wiley: New York, 1983; p 105. C.C. van de Sande, The mass spectra of ethers and sulfides. In: The Chemistry of Ethers, Crown Ethers, Hydroxyl Groups and Their Sulfur Analogues, Suppl. E ; S . Patai, Ed.; Wiley: New York, 1980; p 299. S.L. Bernasek, R.G. Cooks, The P-cleavage reaction in ethers, Org. Mass Spectrom. 1970, 3, 127. J.P. Morizur, C. Djerassi, Mass spectrometric fragmentation of unsaturated ethers, Org. Mass Spectrom. 1971, 5 , 895. Q.N. Porter, Mass Spectrometry of Heterocyclic Compounds, 2nd ed.; Wiley: New York, 1985. G. Sozzi, H.E. Audier, P. Morgues, A. Millet, Alkyl phenyl ether radical cations in the gas phase: A reaction model, Org. Mass Spectrom. 1987, 22, 746.
7.9 Nitrogen Compounds
339
7.9
Nitrogen Compounds [1,2] 7.9.1 Saturated Aliphatic Amines [3]
Fragmentation: Dominating loss of alkyl residues by cleavage of the C-C bond next to the N atom (“N-cleavage”). Larger substituents are eliminated preferably. When a y-H is available, subsequent elimination of alkenes by McLafferty-type reactions.
Otherwise, unspecific H transfer onto the N atom.
“3, RNH2, and RR’NH eliminations from primary, secondary, and tertiary amines, respectively, are negligible except from some multifunctional compounds (e.g., diamines and phenyl-phenoxy-substituted amines). Zon series: Even-mass fragments of the type CnHzn+2N (m/z 30, 44, 58, 72, 86,.. .). Intensities: Mainly peaks in the low mass range. Dominating base eak from “N-cleavage” at [28 + m(R1) + m(R2) + m(R4) + m(R5)]+ for R1R2R CNR4R5 (e.g., m/z 30 for RCH2NH2, m/z 44 for RCH2N HCH 3, m/z 58 for RCH2N(CH3)2, and d z 86 for R C H ~ N ( C H ~ C H ~ )Local Z ) . maximum at d z 86 (C5H 2N+) for n-alk-NH2 (protonated piperidine, 6-membered ring). Molecular ion: Usually weak or absent, especially if the a-C atom is substituted. Decreasing intensity with increasing molecular weight. Tendency to protonate to [M+H]+. 7.9.2 Cy c Ioa Iky Iam ines
Fragmentation: The most important primary reaction is the ring cleavage next to the N atom, followed by H rearrangement and loss of an alkyl residue. Some elimination of amine, RlR2NH.
N
340
7 Mass Spectrometry
R.GH
R.
+
$"
[55 + R]+
Zon series: Even-mass fragments of the type CnH2,-,N (m/z 42,56,70, 84,. ..). Intensities: Intensive local maxima evenly distributed over whole mass range. Molecular ion: Usually significant. 7.9.3 Cyclic Amlnes
Fragmentation: Dominating primary reaction is the cleavage of C-C bonds next to N, resulting in loss of substituents next to N or in primary ring cleavage. Primary ring cleavage is followed by H rearrangement and loss of alkenes or alkyl groups. The most important primary fragmentation for substituted cyclic amines is the loss of substituents at C atoms next to N. Piperidine:
N m/z85(43%)
\
m/z 84 (100%)
*
I
I
<;4 H m/z 57 (57%)
H
-CH3;I wi=CH2 m/z 70 (14%)
\-C3H6
+* CH3-N=CH2 m/z 43 (34%)
CH3-&=CH2 H m/z 44 (43%)
NHi=CH2 m/z 30 (52%)
Zon series: Even-mass fragments of the type CnH2nN (m/z 42, 56, 70, 84,. ..) and CnH2n+2N (m/z 30, 44, 58, ...) as well as odd-mass fragments of the type CnH2n+lN (m/z 43, 57, 71, 85, ...).
7.9 Nitrogen Compounds
341
Intensities: Intensive local maxima evently distributed over whole mass range if no substituent is bonded to the C atom next to N. Otherwise, dominating maxima by loss of such substituents. Molecular ion: Significant or strong if no substituent is bonded to the C atom next to N; otherwise weak. Tendency to form [M-HI+.
7.9.4 Piperazines Fragmentation: As for cyclic amines, enhanced primary ring cleavage at C-C bonds next to the N atom. Zon series: Even-mass fragments of the type CnH2nN ( d z 42, 56, 70, 84,. ..) and CnH2n+2N(m/z 30, 44, 58,. ..) as well as odd-mass series of the type C,H2n+lN ( d z 43, 57, 71, 85,...). Intensities: Intensive local maxima evently distributed over whole mass range if no substituent is bonded to the C atom next to N. Otherwise, dominating maxima by loss of such substituents. Molecular ion: Significant or strong if no substituent is bonded to the C atom next to N; otherwise weak. Tendency to form [M-HI+.
7.9.5 Aromatic Amines Fragmentation: Dominating cleavage of alkyl bond at N-bearing C atom (“Ncleavage”) followed by alkene elimination if aliphatic substituents with 2C2 are present. Otherwise, loss of H’ from primary and secondary anilines and benzylic amines. Loss of HCN from M+’ or from fragments. A local maximum at m/z 42 is typical of an aromatically bonded dimethylamino group. Zon series: Aromatic hydrocarbon fragments (CnHn and CnH,,l; d z 39, 51-53, 63-65, 75-77,. ..). Intensities: Dominating maxima by “N-cleavage” and following alkene loss if aliphatic substituents with Cn,l are present. Molecular ion: Abundant if no aliphatic substituents with more than one carbon atom are present, otherwise medium or weak. No tendency to protonate. In primary and secondary aromatic and benzylic amines, [M-H]+ is important.
7.9.6 Aliphatic Nitro Compounds Fragmentation: Loss of NO’ (Am 30), NO2’ (Am 46), and HNO? (Am 47) as well as the formation of some m/z 30 as N indicator. Spectra with only few characteristic features. Zon series: Mixed alkyl and alkenyl fragments, CnH2n+l ( d z 43, 57, 71, ...) and CnH2n-1 ( d z41, 55, 69,...).
N
342
7 Mass Spectrometry
Intensities: Dominant peaks in the lower mass range. Molecular ion: Weak or missing.
7.9.7 Aromatic Nitro Compounds Fragmentation: Loss of 0 (Am 16), NO' (Am 30, followed by elimination of CO, Am 28), and N02' (Am 46) from M+' or from a major primary cleavage product. Extensive rearrangement of the functional group to a nitroso ester. Ion series: Aromatic hydrocarbon fragments corresponding to C,H, and C,H,* 1 (m/z 39, 51-53, 63-65, 75-77 ,...). Intensities: Intensive peaks mainly in the upper mass range. Molecular ion: Strong.
7.9.8 Diazo Compounds [4,5] Diazonium: Because of the low volatility of diazo compounds, their electron impact mass spectra show thermal decomposition products. These are formed by loss of N2 (e.g., an aromatic chloro compound is formed from the corresponding diazonium chloride). From a phenyl diazonium ortho-carboxylate zwitterion, biphenylene is formed as dimerization product. Diazomethane and derivatives: M+' is strong except when catalytic decomposition occurs on metal surfaces of the inlet system. Loss of N2 is a dominant reaction of diazomethane and diazoketones.
N
7.9.9 Arobenzenes Fragmentation: Cleavage at the azo group followed by loss of N2, giving rise to the dominant base peak. Zon series: Aromatic hydrocarbon fragments corresponding to C,H, and C,H,+l (m/z 39, 51-53, 63-65, 75-77 ,...). Intensities: Dominant M+' and azo cleavage products. Molecular ion: Strong.
7.9.1 0 Aliphatic Azides [6] Fragmentation: [M-42]+ (N3' elimination) or [M-28]+' (N2 elimination) is dominant in most cases. The spectra have the character of the corresponding aliphatic compounds. Ion series: Aliphatic hydrocarbon series.
7.9 Nitrogen Compounds
343
Intensities: Dominant peaks in the lower mass range, as in aliphatic compounds. Molecular ion: Absent or weak. Odd mass for odd number of N atoms in the molecule. 7.9.1 1 Aromatic Azides [7]
Fragmentation: In most cases, [M-28]+' (N2 elimination) is the base peak. The next step is the elimination of HCN (Am 27) or acetylene (Am 26), or, if there is a substituent X on the ring, of X' or HX.
I
mlz64
m/z 63
m/z 64
$. -HCN
or C2H2
m/z 37-39
Ion series: Aromatic hydrocarbon fragments (C,H, and C,Hnkl; m/z 39, 5 1-53, 63-65, 75-77,. ..). Intensities: Dominant peaks in the higher mass range: [M-28]+' (N2 elimination) and [M-55]+' (N2 and HCN elimination) are the most intense peaks. Molecular ion: Weak. Odd mass for odd number of N atoms in the molecule. 7.9.1 2 Aliphatic Nitriles [4]
Fragmentation: Elimination of alkyl radicals to give (CH,),CN+ ions (mlz 40, 54, 68,. . .). McLafferty rearrangement yielding CR2=C=NH+' ( d z 41 for R: H). In most cases, C-CN cleavage and HCN elimination are not significant reactions. Complex rearrangements in unsaturated cyanides if other functional groups are present.
N
344
7 Mass Spectrometry
Zon series: Saturated and unsaturated alkyl ions mainly in the lower mass range (CnH2n+l and CnH+l; m/z 29, 43, 57,... and 27, 41, 55 ,...). Rearrangement products corresponding to CnH2n-1Ncontribute, to a significant extent, to the ion series m/z 41, 55, 69, ... For alkyl chains with C,,5, dominating (CH2)nCN+ (i.e., CnH2,-2N, m/z 82, 96, 110,.. ., probably with a cyclic structure). Intensities: Lntensive peaks due to the above mentioned ions. Molecular ion: Weak or missing. Both [M+H]+ and [M-H]+ are usually more intense than M+'. In some aliphatic nitriles, [M+2H]+' is as intensive as M+'. Odd mass for odd number of N atoms in the molecule.
7.9.13 Aromatic Nitriles Fragmentation: Consecutive elimination of HCN and acetylene. Zon series: Aromatic hydrocarbon fragments corresponding to C,H, and C,H,+ (m/z 39, 51-53, 63-65, 75-77 ,...). Intensities: Intensive peaks in the M+ region. Molecular ion: Dominant intensity, often base peak. In contrast to aliphatic and benzylic nitriles, [M-l]+ is usually not important. Odd mass for odd number of N atoms in the molecule.
7.9.14 Aliphatic lsonitriles (R-NC)
t\i
Fragmentation: In general, the spectra are similar to those of the corresponding nitriles. The most important difference lies in the loss of CN' (Am 26) and the higher probability of losing HCN (Am 27). Further important fragmentations are the elimination of alkyl radicals to give (CH2),CN+ ions and the McLafferty rearrangement to yield CR2=N=CH+' (m/z 41 if R: H). Zon series: Saturated and unsaturated alkyl ions mainly in the lower mass range (C,H2,+1, m/z 29, 43, 57,... and CnH2n-1, m/z 27, 41, 55 ,...). Rearrangement products corresponding to CnH2,- IN contnbute, to a significant extent, to the ion series of m/z 41, 55, 69,.. .. Intensities: Intensive peaks in the lower mass range. Molecular ion: Weak, decreasing with increasing chain length and degree of branching. Both [M+H]+ and [M-H]+ can be stronger than M+'. Odd mass for odd number of N atoms in the molecule.
7.9.15 Aromatic Isonitriles (R-NC) [4] Fragmentation: Dominant loss of HCN ([M-27]+'). In methylphenyl and benzyl isocyanides also formation of isocyanotropylium ion, [M-l]+, followed by loss of HCN to [M-28]+.
7.9 Nitrogen Compounds 7.9 Nitrogen Compounds
345 345
Ion Ion series: series: Aromatic Aromatic hydrocarbon hydrocarbon fragments fragments (CnHn (CnHn and and CnHn+l; CnHn+l; m/z m/z 39, 39, 55 1-53, 1-53, 63-65, 75-77,. . .). 63-65, 75-77,. . .). Intensities: Intensities: Intensive Intensive peaks peaks in in the the higher higher mass mass range. range. Molecular ion: Dominant; base peak for phenyl Molecular ion: Dominant; base peak for phenyl isocyanide. isocyanide. Odd Odd mass mass for for odd odd number of N atoms in the molecule. number of N atoms in the molecule. 7 7 .. 9 9 .. 1 16 6 Aliphatic Aliphatic Cyanates Cyanates (R-OCN) (R-OCN) [8] [8]
Fragmentation: Fragmentation: Spectra Spectra often often very very similar similar to to those those of of the the corresponding corresponding isocyanates. Cleavage of the C-C bond next to 0, with the charge isocyanates. Cleavage of the C-C bond next to 0, with the charge remaining remaining on on 'CH20CN 56) for for short-chain short-chain cyanates cyanates and and preferably preferably on on the the alkyl alkyl 'CH20CN (m/z (m/z 56) substituent substituent if if it it has has aa Cn>2 Cn>2 chain chain (( dd zz 29, 29, 43, 43, 57, 57, ...). ...). Cleavage Cleavage of of the the C-0 C-0 bond bond with H rearrangement to give HCNO+' ( d z 43) or alkene+' ( d z 42, 56, with H rearrangement to give HCNO+' ( d z43) or alkene+' ( d z42, 56, 70,. 70,. ...). .). For 99. For cyanates cyanates with with Cn>5 Cn>5 substituents, substituents, alkene alkene elimination elimination to to yield yield m/z m/z 99. Ion 29, 43, 57,. .. Ion series: series: Saturated Saturated and and unsaturated unsaturated alkyl alkyl cations cations (C,H2n+l, (C,H2n+l, m/z m/z 29, 43, 57,. .. and CnH2n-1, m/z 27, 41, 5 5 , ...). Alkene radical cations (CnH2n, m/z 42, 56, and CnH2n-1, m/z 27, 41, 5 5 , ...). Alkene radical cations (CnH2n, m/z 42, 56, together with isobaric ions of the composition CnH2,NC0. 70,. .) together with isobaric ions of the composition CnH2,NC0. 70,. ...) Intensities: Intensities: Intensive Intensive peaks peaks mainly mainly in in the the lower lower mass mass range. range. Molecular ion: Usually weak or absent. [M-H]+ is often Molecular ion: Usually weak or absent. [M-H]+ is often more more intense. intense. Odd Odd mass mass for odd number of N atoms in the molecule. for odd number of N atoms in the molecule. 7 7 .. 9 9 .. 1 17 7 Aromatic Aromatic Cyanates Cyanates (R-OCN) (R-OCN) [8] [8]
Fragmentation: Fragmentation: Loss Loss of of OCN' OCN' (Am (Am 42) 42) or, or, to to aa lesser lesser extent, extent, of of CO, CO, with with subsequent HCN elimination (Am 28 and 27). subsequent HCN elimination (Am 28 and 27). Ion Ion series: series: Aromatic Aromatic hydrocarbon hydrocarbon fragments fragments corresponding corresponding to to CnHn CnHn and and CnHn, CnHn, 11 ( m / z 39, 51-53, 63-65, 75-77 ,...). ( m / z 39, 51-53, 63-65, 75-77 ,...). Intensities: Intensities: Intensive Intensive peaks peaks in in the the higher higher mass mass range. range. Molecular ion: Strong. Odd mass for odd number Molecular ion: Strong. Odd mass for odd number of of N N atoms atoms in in the the molecule. molecule. 7 7 .. 9 9 .. 1 18 8 Aliphatic Aliphatic lsocyanates lsocyanates (R-NCO) (R-NCO) [8] [8]
Fragmentation: Fragmentation: Spectra Spectra often often very very similar similar to to those those of of the the corresponding corresponding cyanates. cyanates. Cleavage of the C-C bond next to N, the charge remaining Cleavage of the C-C bond next to N, the charge remaining on on the the 'CH2NCO 'CH2NCO ( (d dz z 56) 56) for for short-chain short-chain isocyanates isocyanates and and preferably preferably on on the the alkyl alkyl substituent substituent for for compounds with a Cn,2 chain (m/z 29, 43, 57, ...). Cleavage of the C-N bond compounds with a Cn,2 chain (m/z 29, 43, 57, ...). Cleavage of the C-N bond with with H H rearrangement rearrangement to to give give HCNO+' HCNO+' ( ( dd zz43) 43) or or alkene+' alkene+' (( dd zz 42, 42, 56, 56, 70,. 70,. ...) .) ions. For isocyanates with Cn,5 alkyl chains, alkene elimination, yielding ions. For isocyanates with Cn,5 alkyl chains, alkene elimination, yielding d d zz 99. 99.
N N
346
7
Mass Spectrometry
+' m/z 99
Zon series: Saturated and unsaturated alkyl cations (CnH2n+l, d z 29, 43, 57,. .. and CnH2n-1, m/z 27, 41, 55, ...). Alkene radical cations (CnH2n, m/z 42, 56, 70,. . .) together with isobaric ions of the composition of CnH2,0CN. Intensities: Intensive peaks mainly in the lower mass range. Molecular ion: Usually weak or absent. [M-H]+ is often more intense. Odd mass for odd number of N atoms in the molecule. 7.9.1 9 Aromatic Isocyanates (R-NCO) [8]
N
Fragmentation: Consecutive elimination of CO (Am 28) and HCN (Am 27). In contrast to aromatic cyanates, practically no elimination of NCO' (Am 42). Zon series: Aromatic hydrocarbon fragments corresponding to CnHn and CnHnk1 (m/z 39, 51-53, 63-65, 75-77 ,...). Intensities: Intensive peaks in the higher mass range. Molecular ion: Dominating; base peak for phenyl isocyanate. Odd mass for odd number of N atoms in the molecule. 7.9.20 Aliphatic Thiocyanates (R-SCN)
[8]
Fragmentation: Elimination of HCN (Am 27) followed by loss of an alkyl group. The cleavage of the C-C bond next to SCN is unimportant except in short-chain thiocyanates. Zon series: Saturated and unsaturated alkyl cations (CnH2n+l,m/z 29, 43, 57,. .. and CnH2n-1, m/z 27, 41, 55 ,...>. Intensities: Intensive peaks in the lower mass range. Molecular ion: Weak. Decreasing with increasing chain length and degree of branching; absent from the spectrum of hexyl thiocyanate. Odd mass for odd number of N atoms in the molecule. Both [M+H]+ and [M-H]+ are detectable.
7.9 Nitrogen Compounds
347
Characteristic 34S isotope peak at [M+2]+' and [Frag+2]+ for S-containing fragments (per S atom 4.4% relative to M+'). 7.9.21 Aromatic Thiocyanates (R-SCN) [8]
Fragmentation: The most important fragmentation is the elimination of SCN' (Am 58). Further elimination reactions are loss of CN' (Am 26), HCN (Am 27), and CS (Am 44). Zon series: Aromatic hydrocarbon fragments corresponding to CnHn and CnHn+l (m/z 39, 51-53, 63-65, 75-77,...). Weak signal at m/z 45 (CHS+) indicates sulfur. Intensities: Intensive peaks in the higher mass range. Molecular ion: Dominant; base peak in phenyl thiocyanate. Odd mass for odd number of N atoms in the molecule. Characteristic 34S isotope peak at [M+2]+' and [Frag+2]+ for S-containing fragments (per S atom 4.4% relative to M+'). 7.9.22 Aliphatic lsothiocyanates (R-NCS) [8]
Fragmentation: Cleavage of the C-C bond next to NCS, leading to m/z 72 (CH2NCS) or to its homologues if the a- C atom is substituted. Loss of the alkyl residue with concomitant double hydrogen rearrangement to yield the protonated functional group (m/z 60). With a Cn>4 alkyl chain, loss of SH' (Am 33). With Cn>5 alkyl chain, loss of alkene leading to m/z 115, probably according to the mechanism shown for isocyanates. Zon series: Mainly saturated and unsaturated alkyl cations (CnHp+1, m/z 29, 43, 57,... and CnH2n-1, m/z 27, 41, 55,... ). Signal for CHzNCS (m/z 72) or its homologues (m/z 86, 100, 114,., .) if the a - C atom is substituted. Intensities: Intensive peaks mainly in the lower mass range. Molecular ion: Medium to weak, decreasing with increasing chain length and degree of branching. More intense than in the corresponding thiocyanates; 1% for hexadecyl isothiocyanate.Both [M+H]+ and [M-H]+are relevant. Odd mass for odd number of N atoms in the molecule. Characteristic 34S isotope peak at [M+2]+' and [Frag+2]+ for S-containing fragments (per S atom 4.4% relative to M+'). 7.9.23 Aromatic lsothiocyanates (R-NCS)
[8]
Fragmentation: Dominant loss of NCS' (Am 58). In contrast to aromatic thiocyanates, the loss of HCN (Am 27) or CS (Am 44) leads to very weak fragments only. Zon series: Aromatic hydrocarbon fragments corresponding to CnHn and CnH,* 1 (m/z 39, 51-53, 63-65, 75-77,...). Weak signal at m/z 45 (CHS+) indicates sulfur.
N
Next Page 348
7 Mass Spectrometry
Intensities: Intensive peaks in the higher mass range. Molecular ion: Dominant; base peak in phenyl isothiocyanate. Odd mass for odd number of N atoms in the molecule. Characteristic 34S isotope peak at [M+2]+' and [Frag+2]+ for S-containing fragments (per S atom 4.4% relative to M+'). 7.9.24 References
H. Schwarz, K. Levsen, The chemistry of ionized amino, nitroso and nitro compounds in the gas phase. In: The Chemistry of the Amino, Nitroso and Nitro Compounds and Their Derivatives; S . Patai, Ed.; Wiley: New York, 1982; p 85. D.G.I. Kingston, B.W. Hobrock, M.M. Bursey, J.T. Bursey, Intramolecular hydrogen transfer in mass spectra. 111. Rearrangements involving the loss of small neutral molecules, Chem. Rev. 1975,75, 693. R.D. Bowen, The chemistry of CnH2,,+2N+ ions. Mass Spectrom. Rev. 1991,IO, 225. K.-P. Zeller, Mass spectra of cyano, isocyano and diazo compounds. In: The Chemistry of Functional Groups, Suppl. C ; S . Patai, Z. Rappoport Eds.; Wiley: Chichester, 1983; p 57. C.W. Thomas, L.L. Levsen, Electron-impact spectra of 2-diazoacetophenones, Org. Mass. Spectrom. 1978,13,39. J.M. Miller, T.R.B. Jones, The mass spectra of azides and halides. In: The Chemistry of Functional Groups, Suppl. D; S . Patai, Z. Rappoport Eds.; Wiley: Chichester, 1983; p 75. R.A. Abramovitch, E.P. Kyba, E.F. Scriven, Mass spectrometry of aryl azides, J. Org. Chem. 1971,36,3796. K.A. Jensen, G. Schroll, Mass spectra of cyanates, isocyanates, and related compounds. In: The chemistry of Cyanates and Their Thio Derivatives; S . Patai, Ed.; Wiley: Chichester, 1977, p 274.
Previous Page 7.1 0 Sulfur-Containing Functional Groups
349
7.10 Sulfur-Containing Functional Groups [ i ] 7.10.1 Aliphatic Thiols [2]
Fragmentation: Elimination of H2S (Am 34; or SH, Am 33, from secondary thiols) followed by loss of alkenes; consecutive losses of ethylene from unbranched thiols. Cleavage of the a,P-C-C bond (next to the SH group) leads to CH2SH+ ( d z 47). Note that this fragment also occurs in secondary and tertiary thiols. The S atom is poorer than N, but better than 0, at stabilizing such a fragment. Cleavage at the next C-C bonds leads to signals at m/z 61, 75, and 89. In secondary and tertiary thiols, prominent fragments are formed by loss of the largest a-alkyl group. Zon series: Dominant consecutive alkenyl fragments (C,H2,-1, m/z 41, 5 5 , 69, ...) and smaller aliphatic fragments (CnH2n+l, m/z 43, 57, 71, ...). Sulfurcontaining aliphatic fragments: C,H2,+1S (m/z 47, 61, 75, 89, ...). Often significant sulfur-indicating fragments: HS+, H2S+', H3S+, and CHS+ ( d z 33, 34,35, and 45). Intensities: More intensive peaks in the lower mass range; mostly of the alkene type. Characteristic local maxima from S-containing fragments, CnH2,+1S (m/z 47, 61, 75, 89, ...). In n-alkyl thiols, the intensity of m/z 61 is roughly half that of m/z 47; the signal at m/z 89 is more intense than that at m/z 75, presumably because it is stabilized by cyclization. Molecular ion: Relatively strong except for higher tertiary thiols. Characteristic 34S isotope peak at [M+2]+' and [Frag+2]+ for S-containing fragments (per S atom 4.4% relative to M+'). 7.10.2 Aromatic Thiols [2]
Fragmentation: CS elimination from M+' and [M-l]+, yielding [M-44]+' and [M45]+. SH elimination from M+' to give [M-33]+. Zon series: HCS+ (m/z 45) is characteristic besides the aromatic fragments, C,H, and CnHnkl (m/z 39, 51-53,6345, 75-77 ,...). Intensities: Intensive peaks in the higher mass range. Molecular ion: Usually dominating; base peak in thiophenol. [M-l]+ is usually strong. Characteristic 34S isotope peak at [M+2]+' and [Frag+2]+ for S-containing fragments (per S atom 4.4% relative to M+').
S
350
7 Mass Spectrometry
7.1 0.3 Aliphatic Sulfides [ l ] Fragmentation: Loss of alkyl radicals by cleavage of the C-C bond next to S (the largest group being lost preferably) and of the C-S bond, followed by alkene and H2S elimination. Alkene elimination from M+' to form the corresponding thiol ions. In contrast to thiols and cyclic sulfides, no H2S or HS' elimination from M+'.
m/z 61
In general, the H rearrangements are non-specific. Secondary H transfer predominates over primary H transfer. Zon series: Sulfur-containing aliphatic fragments, CnH2n+lS (m/z 47, 61, 75, 89,. ..). The hydrocarbon fragments may dominate in long-chain sulfides. Intensities: Intensive peaks in the lower mass range. Characteristic local maxima from S-containing fragments, CnH2n+lS (m/z 47, 61, 75, 89, ...). Molecular ion: Usually strong. Characteristic 34S isotope peak at [M+2]+' and [Frag+2]+ for S-containing fragments (per S atom 4.4% relative to M+').
S
7.1 0.4 Alkyl Vinyl Sulfides
Fragmentation: Loss of alkyl radicals (Am 15, 29, 43, ...). Elimination of thioethanol (Am 62) after triple H rearrangement. Dominant m/z 60 (CH&H=S+') accompanied by m/z 61 (CH3CH2S+). Zon series: Sulfur-containing unsaturated aliphatic fragments, CnH2n-1S (m/z 45, 59, 73 ,...). Unsaturated hydrocarbon ions, CnH2, (m/z 42, 56, 70,...) and CnH2n-2 (m/z 40, 54, 68,...) Intensities: Intensive peaks evenly distributed over the whole mass range. Molecular ion: Of medium intensity. Characteristic 34S isotope peak at [M+2]+' and [Frag+2]+ for S-containing fragments (per S atom 4.4% relative to M+').
7.10 Sulfur-Containing Functional Groups
35 1
7.1 0 . 5 Cyclic Sulfides [3] Fragmentation: Primary cleavage of the C-C bond next to S, followed by rearrangements and elimination of CH3' (base peak for tetrahydrothiapyrane) and C2H.s'. In tetrahydrothiophene, [M-l]+ is also significant. HS', H2S, and C2H4 elimination from M+'. Zon series: Sulfur-containing aliphatic fragments with one degree of unsaturation, CnH2n-1S ( d z 45, 59, 73, 87, 101,...), d z 87 being of special dominance. Intensities: Overall distribution of peaks maximizing in the low mass range due to S-containing fragments, CnH2n-1S ( d z 45, 59, 73, 87,. ..). Molecular ion: Very strong. Characteristic 34S isotope peak at [M+2]+' and [Frag+2]+ for S-containing fragments (per S atom 4.4% relative to M+').
7.1 0 . 6 Aromatic Sulfides [2] Fragmentation: Loss of CS (Am 44) and of HS (Am 33) from M+'.
Zon series: HCS+ ( d z 45) is characteristic besides the aromatic fragments, CnHn and CnHnkl ( d z 39,51-53, 63-65,75-77 ,...). Intensities: Intensive peaks mainly in the higher mass range. Molecular ion: Strong. Characteristic 34S isotope peak at [M+2]+' and [Frag+2It for S-containing fragments (per S atom 4.4% relative to M+'). 7.10.7 Disulfides Fragmentation: Loss of RSS' leading to alkyl cations and alkene elimination to give RSSH+'. Cleavage of the S-S bond with or without H rearrangements, leading to RS+, [RS-H]+', and [RS-2H]+. Loss of one or two S with or without H
atoms is a common process in cyclic, unsaturated, and aromatic disulfides. Zon series: In saturated aliphatic disulfides, H2S2 and its alkyl homologues are characteristic ( d z 66, 80, 94,...). Intensities: Variable. Molecular ion: Usually strong. Characteristic 34S isotope peak at [M+2]+' and [Frag+2]+ for S-containing fragments (per S atom 4.4% relative to M+').
S
7 Mass Spectrometry
352
7.1 0.8 Aliphatic Sulfoxides [4,5] Fragmentation: Most fragments are produced after rearrangement with non-specific H transfer to the 0 atom and subsequent OH' elimination to yield [M-17]+ or alkene elimination to [M-alkene]+', followed by OH', SOH' (giving alk+ ions), or alk' elimination (yielding CH2=S-OH+, m/z 63).
1+.
R'-y&
-
- CH2=CHR2
OH I R2
1
-
1 +.
R'-S
YH
J+
-OH'
+
R
L
+
R-CH2 /SOH' m/z 29,43,57
CH&-OH m/z 63
Zon series: Characteristic ion at m/z 63 (CH2=S-OH+) as well as alkyl and alkenyl fragments, CnH2n+l (29, 43, 57, 71,...) and C,H2n-1(27, 41, 5 5 , 69,...). Intensities: Intensive peaks evenly distributed over the whole mass range. Molecular ion: Of medium intensity. Characteristic 34S isotope peak at [M+2]+' and [Frag+2]+for S-containing fragments (per S atom 4.4% relative to M+').
7.1 0 . 9 Alkyl Aryl and Diary1 Sulfoxides [4,5]
s
Fragmentation: Most fragments of methyl aryl sulfoxides are produced, after rearrangement to CH3S-O-ar+', by elimination of CH2S (yielding [M-46]+', a phenol), of CO (to [M-28]+'), and of CH3'. (to [M-15]+). The latter ion loses CO to give the thiapyranyl cation (m/z 97 if ar is phenyl).
of+'= eo-
- CH3'
S-+-
\
/CO [M-28]+'
m/z 112
I-CH2S
[M-15]+ m/z125
p o
7.10 Sulfur-Containing Functional Groups
353
The skeletal rearrangement is not relevant for the fragmentation of higher alkyl aryl sulfoxides. Here, direct cleavage of the C-S bonds and McLafferty rearrangements dominate. For diary1 sulfoxides, elimination of SO (to give [M-48]+’)as well as of 0, OH’, and COH’ (yielding [M-16]+‘, [M-17]+, and [M-29]+). After rearrangement to sulfenates, fragmentation of the S-0 bond to produce ar-S+ and ar-O+ ions, which further lose CS and CO, respectively, to give C5H5+ ( d z 65).
[M-16]+’
[M-48]+‘
Ion series: Besides the ions described under Fragmentation, mainly fragments of the aromatic type, Le., CnHn and CnH,*l ( d z 39, 51-53, 63-65, 75-77,...), as well as 0- and S-containing ions. Intensities: Intensive peaks mainly in the high mass range. Molecular ion: Very strong. Characteristic 34S isotope peak at [M+2]+’ and [Frag+2]+ for S-containing fragments (per S atom 4.4% relative to M+’). 7.1 0 . 1 0 Aliphatic Sulfones [4,51 Fragmentation: Fragmentation of the S-C bond with the charge remaining on either side. Single and double H rearrangements to give RS(O)OH+’ and RS(OH)2+. The probability of the double H rearrangement increases with increasing chain length. If one of the substituents is unsaturated, rearrangement to RS(0)O-alkene and fragmentation of the S-0 bond yields the ion RSO+’. Ion series: Dominating aliphatic fragments, CnH2,-,+1 ( d z 29, 43, 57,,..) and CnH2n-1 ( d z 27, 41, 5 5 , ...). Usually one significant fragment corresponding to alk-S(O)OH+’ (from the series of d z 80, 94, 108,...) or alk-S(OH)2+ (from the series of d z 81,95, 109,...) can be observed. Intensities: Intensive peaks mainly aliphatic fragments in the lower mass range.
S
7 Mass Spectrometry
354
Molecular ion: Weak. Characteristic 34S isotope peak at [M+2]+' and [Frag+2]+ for S-containing fragments (per S atom 4.4% relative to M+').
-k
OH // I49c4-q OH m/z 123 (70%)
+.
- C4H7'
- C2H5'
4
m/z 178
-
c4H9s0;/
1 \-C4H9'
+
m/z 149
C4H9+ m/z 57 (100%) 7.1 0 . 1 1 Cyclic Sulfones [4]
Fragmentation: Dominant eliminations of SO2 (Am 64, followed by loss of CH3'), HS02' (Am 65, followed by loss of C2H4), or CH2SO2 (Am 78). Weak fragment at [M-17]+ due to OH' elimination. Zon series: Mainly unsaturated hydrocarbon fragments, C,H2,-1 (m/z 27, 41, 55, ...). Intensities: Intensive peaks in the lower mass range. Molecular ion: Moderate. Characteristic 34S isotope peak at [M+2]+' and [Frag+2]+ for S-containing fragments (per S atom 4.4% relative to M+').
s
7.10.12 Alkyl Aryl Sulfones [4] Fragmentation: Isomerization of M+' to ar-OS(=O)alk and formation of the phenoxy ion or the phenol radical cation with H rearrangement. The migration of the aryl group depends on the type of substituents. It is facilitated by electron donators and hindered by acceptors. Mainly in substituted or unsaturated alkyl derivatives also isomerization to ar-S(=O)O-alk(ene) and formation of ar-S=O+ (m/z 125 if ar is phenyl). Single and double H rearrangements to give ar-S(O)OH+' and ar-S(OH)2+. The probability of the double H rearrangement increases with increasing chain length. In some derivatives, SO2 elimination from M+' dominates. Substituents X of the alkyl group may migrate to the aryl group to yield X-ar-S=O+ ions. Zon series: Aromatic fragments, C,H, and C,H,+l ( d z 39, 51-53, 63-65, 7577,. ..), as well as S - and O-containing aromatic fragments at higher masses.
7.1 0 Sulfur-Containing Functional Groups
355
Intensities: Intensive peaks mainly in the higher mass range. Molecular ion: Strong. Characteristic 34S isotope peak at [M+2]+' and [Frag+2]+ for S-containing fragments (per S atom 4.4% relative to M+'). 7.10.13 Diary1 Sulfones [4,5]
Fragmentation: Predominant aromatic fragments of the type ar-O+ and ar-SO+ ( d z 125 if ar is phenyl), formed after migration of one of the aryl groups. The ar-S02+ ion is unimportant; ar+ is intense. Small fragments due to SO,, S02H', and S 0 2 H 2 eliminations (Am 64, 65, and 66, respectively). With alkyl substituents in ortho position, [M-OH]+ and [M-H20]+' are formed, upon which SO elimination follows. Zon series: Aromatic fragments, CnH, and C,Hnkl ( d z 39, 51-53, 63-65, 7577,. . .) and the S- and 0-containing aromatic fragments at higher masses. Usually, ar-SO+ ( d z 125 if ar is phenyl) is very strong. Intensities: Intensive peaks mainly in the higher mass range. Molecular ion: Strong. Characteristic 34S isotope peak at [M+2]+' and [Frag+2]+ for S-containing fragments (per S atom 4.4% relative to M+'). 7 . 1 0.1 4 Aromatic Sulfonic Acids [6]
Fragmentation: The most prominent fragment, [M-HS03]+ (Am Sl), is formed in a two-step process. In the first step, OH' elimination leads to a weak fragment ion [M-OH]+ (Am 17). If an alkyl group is present in ortho position, [M-H2S03]+' (Am 82) is formed instead of [M-81]+. Other important fragments are [M-S02]+' (Am 64), [M-HS02]+ (Am 65), and [M-S03]+' (Am 80). Ion series: Aromatic fragments, CnHn and CnHnkl ( d z 39, 51-53, 63-65, 7577,. . .), and 0-containing aromatic fragments at higher masses. Intensities: Intensive peaks mainly in the higher mass range. Molecular ion: Very strong. Characteristic 34S isotope peak at [M+2]+' and [Frag+2]+ for S-containing fragments (per S atom 4.4% relative to M+'). 7.10.1 5 Alkylsulfonic Acid Esters [6]
Fragmentation: Loss of alkyl by fragmentation of the C-0 bond with concomitant double H rearrangement to form the protonated sulfonic acid ion ( d z 97 for methanesulfonates), which then loses water. Loss of the alkoxy1 residue (fragmentation of the S-0 bond). Formation of an alkene ion from the sulfonate alkyl by a McLafferty-type rearrangement. In aryl esters, the phenoxy ion and the phenol radical cations dominate the spectrum. Ion series: Besides RS03H2+ and RS02+ ( d z97 and 79 for methanesulfonates), for aliphatic esters mainly alkene fragments. In aryl esters, aromatic fragments,
S
7 Mass Spectrometry
356
C,H, and C,H,*1 ( d z 39, 51-53, 63-65, 75-77,...), as well as 0-containing aromatic fragments at higher masses. Intensities: Intensive peaks in the lower mass range. Molecular ion: Small or negligible in alkyl esters; strong in aryl esters. Characteristic 34S isotope peak at [M+2]+' and [Frag+2]+ for S-containing fragments (per S atom 4.4% relative to M+'). 7.10.16 Arylsulfonic Acid Esters [6] Fragmentation: Dominating fragments resulting from cleavage of the S-0 bond (leading to the ar-S02+ ion), which loses SO2 ( d z 155 and 91 for p-toluenesulfonates). In alkylsulfonates with longer chains, double H rearrangement to give the protonated acid ( m / z 173 for p-toluenesulfonates). Zon series: Aromatic fragments, CnHn and C,Hn*l ( d z 39, 51-53, 63-65, 7577, ...). Intensities: Intensive peaks mainly in higher mass range. Molecular ion: Medium or weak. Characteristic 34S isotope peak at [M+2]+' and [Frag+2]+ for S-containing fragments (per S atom 4.4% relative to M+').
7.10.17 Aromatic Sulfonamides [61 Fragmentation: In N-alkylamides, the C-C bond next to N is split preferably. In N-arylamides, besides [M-S02]+' and [M-HSOz]+, the ions ar-S02+ and ar'-NH+ are formed.
+
\02
1-
so2 +.
j
-
so2
-
- HCN
C,jHs+ (100%) Zon series: Ions typical of the tosyl group: d z 155, 91, and 65. Molecular ion: In arylamides, M+' is dominant.
7.1 0 Sulfur-Containing Functional Groups
357
7 . 1 0.1 8 Thiocarboxylic Acid S-Esters [7] In contrast to esters, elimination of the alkyl radical from the thiol site is the major fragmentation process. Ethylene sulfide is eliminated from thioesters with longer alkyl chains. Aromatic dithiocarboxylic acid esters usually fragment in two steps to the aryl cation.
[M-601"
d z 121
7.1 0 . 1 9 References
[l] C.C. van de Sande, The mass spectra of ethers and sulphides. In: The Chemistry of Ethers, Crown Ethers, Hydroxyl Groups and Their Sulfur Analogues, Suppl. E; S . Patai, Ed.; Wiley: Chichester, 1980; p 299. 123 C. Lifshitz, Z.V. Zaretskii, The mass spectra of thiols. In: The Chemistry of the Thiol Group, Part 1; S. Patai, Ed.; Wiley: London, 1974; p 325. [3] Q.N. Porter, Mass Spectrometry of Heterocyclic Compounds, 2nd ed.; Wiley: New York, 1985. [4] K. Pihlaja, Mass spectra of sulfoxides and sulfones. In: The Chemistry of Sulphones and Sulphoxides; S. Patai, Z. Rappoport, C.G. Stirling, Eds.; Wiley: Chichester, 1988; p 125. [5] R.A. Khmel'nitskii, Y.A. Efremov, Rearrangements in sulphoxides and sulphones induced by electron impact, Russ. Chem. Rev. 1977,46, 46. [6] S. Fornarini, Mass spectrometry of sulfonic acids and their derivatives. In: The Chemistry of Sulphonic Acid Esters and their Derivatives, S. Patai, Z . Rappoport, Eds.; Wiley: Chichester, 1991; p. 73. [7] K.B. Tomer, C. Djerassi, Mass spectrometry in structural and stereochemical problems. CCXXV. Sulfur migration in [M-C2H A]+' of S-ethyl thiobenzoate, Org. Mass. Spectrom. 1973, 7 , 77 1.
s
358
7 Mass Spectrometry
7.1 1 Carbonyl Compounds [I-41 7.1 1.1 Aliphatic Aldehydes [5]
Fragmentation: Cleavage of the bond next to CO. The fragmentation of the hydrocarbon chain is similar to that in corresponding alkanes. McLafferty rearrangement with localization of the charge on either side, giving rise to CnH2n+' ( d z 28, 42, 56, ...) and, often less important, to CnH2nO+' ions ( d z 44, 58, 72, ...). At least one product (often both) is significant. Elimination of water from the molecular ion to give [M-18]+', occasionally very pronounced. Zon series: Dominating consecutive fragments of the series of CnH2n+l and CnH2n-10 (in both cases: d z 29, 43, 57, ...). Weaker fragments of the senes CnH2n-I ( d z 41, 5 5 , 69, ...) and rearrangement products, CnH2,, ( d z 28, 42, 56, ...). Intensities: Intensive peaks concentrated in the lower mass range. Local even-mass maxima from McLafferty-type reactions ([M-44]+' when aldehyde not substituted in a-position). Molecular ion: Only strong for molecules of low molecular weight; very weak for Cn,g. [M-l]+ may be more relevant than M+'. 7.1 1.2 Unsaturated Aliphatic Aldehydes
Fragmentation: Cleavage of the bond next to CO, leading to [M-l]+ (more significant than in saturated aldehydes), [M-29]+, and m/z 29. No McLafferty rearrangement occurs if the y-hydrogen atom is attached to a double bond or if there is a double bond in a$-position. Zon series: Fragments of the series of CnH2n-1 and CnH2n-30 (in both cases d z 41, 55, 69,...). MoZecuZar ion: Stronger than in saturated aldehydes. Usually, m-1]+ is relevant.
C=X 7.1 1.3 Aromatic Aldehydes
Fragmentation: Characteristic H' loss to yield the corresponding benzoyl ion, [M1]+, followed by decarbonylation to a phenyl ion, [M-1-28]+, of lower intensity. To a small extent also decarbonylation of the molecular ion, leading to [M-28]+'. Weak signal at d z 29 (CHO+). Zon series: Aromatic hydrocarbon fragments corresponding to CnHn and CnHn+l ( d39,~5 1-53, 63-65, 75-77,. ..). Intensities: Intensive peaks predominantly in the molecular ion region. Molecular ion: Usually prominent. [M-1]+ is strong.
7.1 1 Carbonyl Compounds
359
7.1 1 . 4 Aliphatic Ketones
Fragmentation: Cleavage of the bond next to CO is the most important primary fragmentation. The charge can remain on either side. The acyl ions then lose CO. McLafferty rearrangement giving rise to CnH2nO+' ions (m/z 58, 72, 86,. ..). Consecutive rearrangements occur if both alkyl chains contain a y-H atom. Ketoenol tautomerism of the first rearrangement product is not a prerequisite for the second rearrangement to occur. Oxygen is sometimes indicated by weak signals at [M-18]+' and m/z 31, 45, 59. Fragmentation of the hydrocarbon chain similar to that in the corresponding alkanes. Zon series: Dominating consecutive fragments of the series C , H Z ~ +and ~ CnH2n-10(in both cases: m/z 29, 43, 57, ...), with maxima due to cleavage at the CO group to give acyl ions and their decarbonylation products. Weaker fragments in the series CnH2n-l (m/z 41, 55, 69, ...). Even-mass maxima, CnH2n0 (m/z 58, 72, 86,. . .), due to alkene elimination (McLafferty rearrangement). Usually, m/z 43 (CH$O+) is strong if an unsubstituted a-CH2 group is present. Intensities: Intensive peaks mainly in the lower mass range. Molecular ion: Relatively abundant, weak in long-chain and branched aliphatic ketones. 7.1 1 . 5 Unsaturated Ketones
Fragmentation: Cleavage of the bond next to CO, more favorably on the saturated side, is the most important primary fragmentation. The acyl ion then loses CO. The McLafferty rearrangement occurs neither when the unsaturated substituents are in a,P position nor when the only available y-hydrogen atom is attached to a double-bonded carbon. Molecular ion: Relatively abundant. 7.1 1.6 Alicyclic Ketones
Fragmentation: Major primary fragmentation by bond cleavage next to carbonyl, followed by loss of alkyl residue.
(for R' = H)
c=x
360
7 Mass Spectrometry
Prominent McLafferty-type elimination of larger alkyl groups in position 2 or 6 as alkenes. This rearrangement is very favorable; even aromatically bonded H atoms can rearrange. For cyclohexanones, a consecutive retro-Diels-Alder reaction can occur:
m/z 98
m/z 70
Oxygen is sometimes indicated by a weak signal at [M-18]+'. Zon series: Consecutive alkene fragments of the type of CnH2n-1 0: CnH2n-30 (for both: m/z 41, 5 5 , 69, ...) with maxima due to alkyl loss after nng opening next to the carbonyl group and H transfer. Prominent even-mass maxima by elimination of substituents at position 2 or 6 as alkenes via sterically favored McLafferty rearrangements. Intensities: Overall more intensive peaks in the lower mass range or even distribution of major peaks over the whole mass range. Local maxima from major fragmentation pathway. Molecular ion: Abundant.
7.11.7 Aromatic Ketones
c =x
Fragmentation: Dominant a-cleavage to give the benzoyl ion, followed by decarbonylation to a phenyl ion of lower intensity. a-Cleavage in acetophenone also produces the acetyl cation ( d z 43). Even-mass maxima due to alkene elimination via McLafferty rearrangement. CO elimination from diary1 ketones through skeletal rearrangements. Zon series: Aromatic hydrocarbon fragments corresponding to CnH, and CnHn,l ( m / z 39, 51-53, 63-65, 75-77 ,...). Intensities: Intensive peaks predominantly in the molecular ion region. Molecular ion: Strong.
7.1 1.8 Aliphatic Carboxylic Acids Fragmentation: Fragmentation of the C-CO bond leading to m/z 45 and to [M-45]+. Loss of OH' leading to [M-17]+; may be followed by decarbonylation. Cleavage of the y bond (relative to CO) leading to +CH2CH2COOH (m/z 73) if there is no branching on the a- and p-C atoms. Loss of H' (not the carboxylic one) leading to [M-1]+. Water elimination to give [M-18]+' if the alkyl group
7.1 1 Carbonyl Compounds
36 1
consists of at least 4 C atoms; may be followed by decarbonylation. McLafferty rearrangement to m/z 60 (acetic acid) if there is no a-substituent. Zon series: Saturated and unsaturated alkyl ions mainly in the lower mass range (CnHzn+1 and CnH2,-l, m/z 29, 43, 57 ,... and 27, 41, 55,...). With long-chain aliphatic acids, CnH2,-102 series (m/z 59, 73, 87,. ..), exhibiting maxima for n = 3, 7, 11, 15,... (m/z 73, 129, 185, 241,... ). Even-mass maxima, CnH2n02 (m/z 60,74, 88,. ..), due to McLafferty rearrangements. Intensities: Intensive peaks due to the above mentioned ions. MoZecular ion: Generally detectable. Easily protonated to [M+H]+. 7.1 1.9 Aromatic Carboxylic Acids
Fragmentation: Pronounced loss of OH', leading to [M-17]+ and followed by decarbonylation (Am 28) to a phenyl ion of lower intensity. Water elimination to [M- 18]+' if a H-bearing ortho-substituent is present. Some acids decarboxylate (Am 44). Loss of CO (Am 28) from M+'. 0 m/z 118forX=CH2 m/z 1 1 9 f o r X = N H m/z 120 for X = 0
Zon series: Aromatic hydrocarbon fragments, C,H, and C,H,,1 (m/z 39, 51-53, 63-65, 75-77,...). Intensifies: Intensive peaks predominantly in the molecular ion region. Molecular ion: Strong. 7.11.10 Carboxylic Acid Anhydrides
Fragmentation: In the case of linear anhydrides abundant acyl ions due to cleavage next to carbonyl group. For cyclic anhydrides maxima due to decarboxylation (Am C = 44), followed by decarbonylation. Molecular ion: Weak or absent (especially in linear aliphatic anhydrides), easily protonated to [M+H]+. Relatively strong for phthalic anhydrides. 7.1 1.1 1 Saturated Aliphatic Esters
Fragmentation: Dominant fragmentation of the bonds next to the carbonyl C, leading to alk-CO+ (m/z 43, 57, 71,. . .; decreasing intensity with increasing length of the alkyl chain) and followed by decarbonylation, as well as fragmentation to COOR+ (m/z 59, 73, 87,...) and to alk+ (m/z 15, 29, 43,...).
x
362
7 Mass Spectrometry
Alcohol elimination to C,H 2,-?0 (m/z 42, 56, 70, ...), followed by decarbonylation (Am 28) or ketene elimination (Am 42). Alkene elimination from the acid side via McLafferty rearrangements, leading to C,H2nO? ( d z 60, 74, 88, ...). The larger alkyl group participates in the rearrangement if several y-H atoms are available. In the following example, the alternative process leading to [M-C2H4]+' is negligible.
Non-specific H rearrangements at the alcohol side (from M+' or the McLafferty product) lead to C,H2,02 and to the corresponding alkene, CnH2n ( d z 28,42, 56,. . .). In methyl esters of long chain acids, the ions [(CH&+4,COOCH3]+ ( d z 87, 143, 199,...) correspond to maxima. For esters of higher alcohols (at least C3), double H rearrangement to the protonated acid, C,H2,+102 ( d z 61, 75, 89, ...). a-Substituted esters may lose the substituent and then CO (Am 28) via alkoxy1 rearrangement. In an analogous reaction, P-substituted esters may eliminate ketene (Am 42). Besides usual ester reactions, specific rearrangements can be observed in formates.
- CO, - R2
+ ( d z 31 for R' = H)
C =X
Zon series: CnH2,+l ( d z 29, 43, 57,. ..) for the alkyl groups at the ester oxygen (except for methyl esters). CnH2n-l ( d z 27, 41, 55, ...). C,H2n-102 ( d z 59, 73, 87 ,...), exhibiting maxima for n = 4, 8, 12,... ( d z 87, 143, 199,...) in case of the methyl esters of long-chain acids. Even-mass maxima for CnH2,02 ( d z 60, 74, 88, ...) due to alkene elimination via McLafferty rearrangements on both sides of the carboxyl group. CnH2, ( d z 28, 42, 56, ...) as H rearrangement product from the alcohol side. Intensities: Intensive peaks due to above mentioned ions from the lower mass range. Molecular ion: Often of low abundance. Easily protonated to [M+H]+.
7.11.12 Unsaturated Esters a,p-Unsaturated esters: Loss of alk-0' followed by C=O elimination is the dominant fragmentation path. Also, loss of the &substituent yields a 6-membered oxonium ring:
U
Tr O C H 3 LR
'
7.1 1 Carbonyl Compounds
+ - R'
363
0 + O C H 3 m/z 113
Significant difference between Z and E isomers of long-chain a,P-unsaturated esters: Single H rearrangement occurs with Z esters and double H rearrangements (leading to protonated acids) have been found for E esters. p,y- Unsaturated esters: Only slight qualitative, but significant quantitative differences have been observed as compared to a$-unsaturated esters. y,6-Unsaturated esters: Loss of the alcohol chain as a radical, R', followed by ketene elimination. Aliphatic enol esters and aryl esters: Formation of alk-CO+ (m/z 43, 57, 71,...). Elimination of a ketene to give the enol/phenol radical cation. The rearrangement occurs prodominantly, but not exclusively, through a 4-membered transition state.
R40aJ +'
-RCH=C=Z
HO
G
l
+
*
[M-42]+' for R = H
7.11.13 Esters of Aromatic Acids Fragmentation: Dominant loss of RO' to form the benzoyl ion, followed by decarbonylation (Am 28) and further loss of acetylene (Am 26). Ethyl esters also eliminate C2Hq (Am 28) to give the acid radical cation, which then loses OH' to yield the benzoyl ion. In higher alkyl esters, besides the acid, the protonated acid is formed (double H rearrangement). In ortho-substituted aryl esters with an a-hydrogen atom on the substituent, an alcohol is eliminated from M+'. In the case of alkyl phthalates (other than dimethyl phthalate), alkenyl elimination to give the protonated ester acid, followed by alkene elimination from the other ester group, and subsequently water elimination to the protonated anhydride ion, which forms the base peak at m/z 149. Zon series: Aromatic hydrocarbon fragments, CnHn and C,Hnel (m/z 39, 51-53, 63-65, 75-77,. . .). Intensities: Prominent maximum at the mass of the related benzoyl ion and its decarbonylation product. Molecular ion: Usually strong.
c=x
364
7 Mass Spectrometry
7.11.14 Lactones Fragmentation: The most prominent reaction is the loss of substituents (or H') at the 0-bearing C atom, followed by decarbonylation (Am 28), decarboxylation (Am 44, mainly in smaller molecules), and ketene elimination (Am 42). Decarboxylation of M+' is rarely significant. Competing reactions are several kinds of primary ring cleavages. Aromatic lactones show maxima due to two consecutive decarbonylations. Zon series: No specific ion series. The acetyl ion ( d z 43) is often an important fragment. Intensities: Maxima at the mass resulting from loss of substituents at the C atom next to oxygen. Otherwise, intensive peaks evenly distributed over whole mass range. Molecular ion: Usually of low intensity and easily protonated to [M+H]+ in aliphatic lactones; abundant in the case of aromatic lactones.
7.11.15 AI iphatic Am ides Fragmentation: Alkene elimination on the acid side via McLafferty reaction to yield the corresponding acetamide radical cation. Loss of alkenes on the amine side to give the ion of the desalkyl amide, often via double H rearrangement to the protonated desalkyl amide ion. Cleavage on both sides of the carbonyl group. Cleavage of the C-C bond attached to N, and the p,y-C-C bond (relative to N; see scheme).
IIUZ 44
Cleavage of the bonds to the p-C (see scheme) and y-C on the acid side.
c=x
Zon series: Even-mass fragments corresponding to CnH2,N0 ( d z 44, 58, 72,. ..) produced by cleavage of the bond next to CO on the acidic side. Odd-mass fragments (in secondary and tertiary amides), CnH2n-10 ( d z 43, 57, 71, ...), produced by cleavage of the bond next to CO on the amme side. Intensities: Overall peak distribution maximizing in the low mass range. Local maxima from McLafferty and from y-cleavage products. Molecular ion: Significant. Strong tendency to protonate to [M+H]+.
7.11 Carbonyl Compounds
365
7.11.16 Amides of Aromatic Carboxylic Acids
Fragmentation: Amides of aromatic acids exhibit maxima due to amide bond cleavage yielding the benzoyl ion, followed by decarbonylation (Am 28). Zon series: Aromatic hydrocarbon fragments corresponding to CnHn and CnHn+1 ( m / ~39, 51-53, 63-65, 75-77 ,...). Intensities: Intensive peaks predominantly in the molecular ion region. Molecular ion: Abundant. [M-H]+ is significant in N,N-disubstituted anilides, weaker in monosubstituted derivatives, and absent from the spectrum of benzamide. It is formed exclusively by loss of ortho-hydrogens of the aromatic ring. 7.11.17 Anilides
Formanilides: Loss of CO (Am 28) to give the aniline radical cation and consecutive HCN elimination (Am 27). Acetanilides: Ketene elimination to yield the aniline radical cation (often base peak), which consecutively eliminates HCN (Am 27), and formation of the acetyl cation (m/z 43). Trichloroacefunilides: Dominant loss of CC1,' (Am 117). Pivalanilides: Besides reactions analogous to those of acetanilides (formation of the aniline radical cation, Am 84), also formation of the tert-butylbenzene radical cation through elimination of HNCO (Am 43). 7.11.18 Lactams
Fragmentation: Cleavage of the C-C bond at the N-bearing C atom. Cleavage of the CO-N bond, followed by loss of CO (Am 28) or by further cleavage of the C-C bond next to N, giving an iminium ion. In 2-pyrrolidone and 2-piperidone, the signal at m/z 30 ([CH2=NH2]+) is strong. The base peak of 2-pyridone is formed by CO elimination (Am 28).
c=x
7 Mass Spectrometry
366
2-Pyrrolidone:
- C2H5'
+ CH2=NH;! m/z 30
CH2=N=C=O
+
H m/z 56
2-Pipendone:
*$+ H2*c% J
0
0 1 ' + H
m/z 99
CCH*'+
N,c=o H m/z 99
d z 99
+ CH2=NH2 m/z 30
H m/z 99
N H
J
d z 71
d z 70 d z 55
c =x
Molecular ion: Often observable; more abundant than for the corresponding lactones.
7.1 1 Carbonyl Compounds
367
7.11.19 Imides
Saturuted acyclic imides: Consecutive CO (Am 28) and alkoxy elimination:
J)NL.&,?
+. -c,o
A
1+- - CH30’
0 ’
N
+
m h 56
I
I Ketene elimination:
+*
- CH2CO
I
-C=N-
- CH3’
H0-c~;m/z 58
I
If the N-substituent chain is sufficiently long, cleavages of the C-C bond next to N with or without H rearrangement. Cyclic imides: The spectra of saturated cyclic imides are almost identical to those of the corresponding diketones. Loss of HNCO (Am 43) from succinimide, followed by CO elimination (Am 28). Aroyl migration and loss of CO2 from aromatic cyclic imides.
Dibenzoylamine: Loss of CO to N-phenylbenzamide:
368
7 Mass Spectrometry
7.1 1 . 2 0 References
[l] J.H. Bowie, Mass spectrometry of carbonyl compounds. In: The Chemistry of the Carbonyl Group, vol. 2; J. Zabicky, Ed.; Wiley-Interscience: London, 1970; p 277. [2] S.W. Tam, Mass spectra of acid derivatives. In: The Chemistry of Acid Derivatives, Part 1 ; S . Patai, Ed.; Wiley: Chichester, 1979. [3] D.G.I. Kingston, J.T. Bursey, M.M. Bursey, Intramolecular hydrogen transfer in mass spectra. II. The McLafferty rearrangement and related reactions, Chem. Rev. 1974, 7 4 , 215. [4] D.G.I. Kingston, B.W. Hobrock, M.M.Bursey, J.T. Bursey, Intramolecular hydrogen transfer in mass spectra. 111. Rearrangements involving the loss of small neutral molecules, Chem. Rev. 1975, 75, 693. [5] A.G. Harrison, High-resolution smass spectra of aliphatic aldehydes, Org. Mass. Spectrom. 1970,3, 549.
c=x
7.12 Miscellaneous Compounds
369
7.1 2 Miscellaneous Compounds 7.12.1 Trialkylsilyl Ethers [ 1,2]
Fragmentation: Loss of alkyl attached to Si (preferential loss of larger groups). Cleavage of the C-C bond adjacent to 0, followed by alkene elimination. Loss of alkoxyl, followed by alkene eliminations. Elimination of trialkylsilanol. The R2Si-OR' cation has the tendency to attack, in an electrophilic manner and even over long distances, free electron pairs and n-electron centers, causing the expulsion of neutral fragments from the interior of the molecule via a rearrangement: Br-(CH2)lo-O-Si
-- C(CH3)3'
- (CH2)100
Am 57
Am 156
/ Br-Si+ \
Zon series: [CnH2,.,+30Si]+ ( d z 75, 89, 103, 117,...). [CnH2,.,+3Si]: ( d z 45, 59, 73, 87, ...). Occasionally, maxima at even mass due to elimination of trialkylsilanol. Molecular ion: M+' often of low abundance or absent, easily protonated to [M+H]+. Typical isotope patterns owing to 28Si, 29Si, and 30Si (see Chapter 2.5.5).
7.12.2 Alkyl Phosphates [3]
Fragmentation: Maxima due to alkenyl loss from M+' via double H rearrangement, followed by successive alkene eliminations down to protonated phosphoric acid ( d z 99). Zon series: PO+ (m/z 47), H2P02+ ( d z 65), H2PO3+ ( d z S l ) , often as nonspecific P indicators. Molecular ion: M+' observable. 7.1 2.3 Aliphatic Phosphines and Phosphine Oxides
Zon series: Maxima of the ion series of [CnH2,.,+3P]+( d z 48, 62, 76, 90,. ..) due to alkene eliminations. Molecular ion: M+' observable.
Misc
370
7 Mass Spectrometry
7.1 2.4 Aromatic Phosphines and Phosphine Oxides Fragmentation: Maxima due to loss of an aryl group, followed by H2 elimination to yield the 9-phosphafluorenyl ion ( d z 183). Molecular ion: M+' abundant, easily losing H' to give [M-l]+.
m/z 183
7.12.5 References [ 11 D.G.I. Kingston, B.W. Hobrock, M.M. Bursey, J.T. Bursey, Intramolecular
hydrogen transfer in mass spectra. 111. Rearrangements involving the loss of small neutral molecules, Chem. Rev. 1975, 75, 693. [2] H. Schwarz, Positive and negative ion chemistry of silicon-containing molecules in the gas phase. In: The Chemistry of Organic Silicon Compounds;.S. Patai,, Z. Rappoport, Eds.; Wiley: Chichester, 1989; p 445. [3] D.G.I. Kingston, J.T. Bursey, M.M. Bursey, Intramolecular hydrogen transfer in mass spectra. 11. The McLafferty rearrangement and related reactions, Chem. Rev. 1974, 74, 215.
Misc.
7.13 Spectra
371
7.13 Mass Spectra of Common Solvents and Matrix Compounds 7.13.1
Electron Impact Ionization Mass Spectra of Common Solvents The label (50) indicates that the intensity scale ends at 50% relative intensity and is subdivided in 10% steps. In these cases, the height of the base peak has to be doubled to bring it to 100%.All spectra represent positive ions only. Water { 50}
Methanol
Acetonitri1e
Ethanol { 50)
Dimethyl ether
Acetone ( 5 0 )
Acetic acid
Ethylene glycol { 50)
,)[, ,,3:
6[ , , , ,
,1,5,
29 Tetrahydrofuran (50)
II
62 Pentane
, , ,
,I
Furan
;,
14
, 9J
,6[ , ,
,
29
N,N-Dimethylformamide
Solvents
7 Mass Spectrometry
372
Methyl acetate { 50)
4
Diethyl ether
Carbon disulfide { 50)
Pyridine
Benzene-dg { 50)
143
Benzene {SO)
I
78
Cyclohexane
1
52
I 79
1-Hexene
Methylene chloride
1
1,CDioxane ( 50}
Ethyl acetate { 50}
Hexane
I 57
1
Tetramethylsilane { 50)
Dimethyl glycol { 50)
Toluene
I
i
I 91
Diisopropyl ether { 50)
Butyl acetate { 50)
1
I
I
I 27
45
87 59 69
102
4 3 ~
js6
7.13 Spectra
373
j 1 ,7;l,i;,,I, Chloroform
Chloroform-d
118
I
Trichloroethylene
, 119 , ,
I
,(
,
Carbon tetrachloride
129
35 7759 ,
I
I
I
I
;" 4' 1
1
1
1
I
82 ,
I
94 I
,
l r ,;.{,
I
I
l
l
1
I
1
1
I
II 1
1
,ah l
I
203 223
i765 76 93 105 121 I
, , , , , , , , , , ,
I
I
1
168 182
l I
I
I
I
I
278 I
I
I
I
I
I
I
I
I
I
Dioctyl phthalate (frequent impurity due to its use as polymer plasticizer)
1
57 28 43 I
71
83g29:04113 132 I,.I1 ,.l,.j.&,l, ,. , I , , U ; ,*
~
167 .
,
1,
279
, , , , , , , , , , li ,
,
Heptacosafluorotributylamine(calibration reagent)
Solvents
7 Mass Spectrometry
374
7.1 3.2 Spectra of Common FAB MS Matrix and Calibration Compounds Fast atom bombardment (FAB) mass spectra (MS) usually exhibit protonated or deprotonated molecular ions, [M*H]*, and protonated clusters, [M,+X,kH]' (n,m = 0,1,2,...), of the sample and matrix molecules, X. If there are even traces of metal salts in the sample, clusters of the type [M,+X,+metal cation]+ occur in positive ionization mass spectra. Sodium (23 u) and potassium (39 u) ion adducts are most commonly encountered. The nature of the clusters is often revealed by the regular intervals at which they occur in the spectra.
Calibration Compounds in Positive Ionization FAB Mass Spectra Ultramark 1621 (erroneously also referred to as "perfluoroalkyl phosphazine")
:654
766
866 878
Polyethylene glycol 400 (often used as an internal reference for high resolution m/z determinations) 547
591
il
6?5
679
' ' ' ' I ' '
I . ,
500 1007
550 45
50
650
73 0
Solvents
600
50
! '
723 I '
700
I . 8
' I ' ' ' ' I '
750
283
177 . 100
150
200
250
"
' I ' ' ' ' I ' ' ' ' I ' ' ' '
800
300
850
327
371
350
900 415
400
950
I
1000
459 450
500
7.13 Spectra
375
Polyethylene glycol 600 (often used as an internal reference for high resolution m/z determinations)
50 1 0'
73 ' ' ;
100:
.y,'*
:'A.
I
0.8 177
113
89 "
"
I '
283
50
0
100
371
459
415
*
. ' I
57.0 93.1 132.9 185.1 45.0 75.0
50;
327
150
225.0 392.7 448.9 277.1 317.0 356.8 409.0 484.8
200
250
300
350
400
500
450
Matrix Compounds in Positive Ionization FAB Mass Spectra
136 154 5:
289 307 1
50 1 0'
~
~
"
', :'
"11.
'1.
"
~
'
I '
"
' I
"
8 ' .
I
"
'
I
-
~
~
~
460 '
" 1" I ~
"
k,, ~
, 1
277
101
45 57 75 3
1
L' I 1
'
I . ,
' I
369
"
"
I '
!
' ' I
46 1
"
"
I ; '
"1
~
~
~
'
7 Mass Spectrometry
376
541
3.0;
1'5j 525 0.0-
8
rl-
569 I
3
/!
*-',
613 I
657
,',
.,
1 1 ,
7
1'
r
I-1
'
' 1
'
r
'
i
'
--
7
1
7
7
8
' '
i
I
7
309 l 0 i 259 , , ,391 ; I , , , , I46 , 1 ' " ,
, I , , , , :4,J.:;al
789 ~
500
~
550
~
~
600
~
~
650
'p3
~
~
~
"
I
~
"
700 750 800 219 265 177 221
~
I
"
850
~
I
~
950
'
I
'
1000
i
i " ! ' l ' " ' ~ ' i ' ~ " l~ ' ~ " ' I " i " ' *
0 50 100 150 200 2-Nitrophenyl octyl ether (M, 25 1)
600
"
900
650 140
700
I
"
9
'
I
250
300
350
400
450
500
2r
800
850
900
950
lo00
250
300
750
221 235
lo{
333 364 Y
l
47 1486
'.
I " ' " " ' " ' ' " 1 ' ' " I ' ' ~ ' 1 ' " ' I ~ '
Solvents
0
50
100
150
200
350
400
450
500
~
~
~
I
Spectra
7.13
0.5:
377
597
0 . 0 " " ' " " . ~ " " ' " ' ' ' ~ " " ~ ' ' " ~ " ' ~ " ' ' I ' ' ' ' ~ " ' ' r
118
50 {
o
150
304%6 74
:
5'
194
132
: I . ' . i'
+I".
8
'
4: 267 : 281
J '
'
'
I
'
448
?
.'.;.,
~
~
,'',
' '
307 '
'
7
8
'
I *
8
7
..'-
-
8
8
I
1
60 1
~
-
~
.
~
~
105 87
~
,
.
~
'
~
.
:
,
~
~
~
~
24 1
12'
1
;
151 ;66
2251
286
48 1
690
5'
o-....
7
"
'
608 +'"
...?
"
"
80 120 148 176 204 1
'
50 1 501 545
589
1
L
1
L
L
,
,
"
'
"
'
"
1
"
"
"
"
' . "
304
,I
633 679
721
Solvents
,
7 Mass Spectrometry
378
Polyethylene glycol 600 (often used as internal reference for high resolution MS)
0
50
100
150
200
250
300
350
400
450
Ultramark 1621 (erroneously also referred to as "peffluoroalkyl phosphazine")
50
Solvents
59.0 91.0
19.0
392.8 422.8
1
500
7.13 Spectra
379
Matrix Compounds in Negative Ionization FAB Mass Spectra 3-Nitrobenzyl alcohol (M, 153) 1007
306 50i
459
352
0'
1 -
I " " I
A,,
,
25 ! 55 1 O
'
.
-
~
,
643 i
~
91
~
-
~
735 I
~
~
-
-
I
.
.
-
183
59 71
64 89
367
139 179
197
287
377
459
467
Solvents
7 Mass Spectrometry
380
2-Nitrophenyl octyl ether (M, 25 1)
~
500
~
~
550
~
600
"
~
"
650
"
~
700
.
'
"
'
~
'
'
750 800 25 1
~
'
850
'
'
'
900
~
'
~
950
~
~
1
'
~
'
'
lo00
470 "
50
0
100
150
200
250
300
'
I
350
~
*
"
400
I
~
'
450
'
~
I
~
~
~
*
500
2-Nitrobenzyl alcohol solution of hexadecylpyridiniumbromide (M, 385; hexadecylpyridinium = 304; enhances detectability and reduces metal ion adducts of sample [3].) 100 50 0 500
0
845
L
.
550 600 79
650
700
750
800
850
900
950 462
1000
50
150
200
250
300
350
400
450
500
100
7.1 3.3 Spectra of Common MALDI MS Matrix Compounds
Matrix-assisted laser desorption ionization (MALDI) mass spectra (MS) usually exhibit protonated or deprotonated molecular ions, [MkH]', and protonated clusters, [M,+X,kH]* (n,m = 0, 1, 2, ...), of the sample and matrix molecules, X. If there are even traces of metal salts in the sample, clusters of the type [M,+X,+metal cation]+ occur in positive ionization mass spectra. Sodium (23 u) and potassium (39 u) ion adducts are most commonly encountered. The nature of the clusters is often revealed by the regular intervals at which they occur in the spectra [4].
Matrix Compounds in Positive Ionization MALDI Mass Spectra 3-Aminoquinoline (M, 144)
I So'vents
289
A
L
6. ;o* 'lob' ''
WNH2
145
'26b' '2;o
433
'3k' 3 S O '4b'4;b:'Sob' z '6& '6;o '7k ,;io '8bo
l
7.13 Spectra
381
a-Cyano-4-hydroxycinnamic acid (M, 189; m/z 212, [M+Na]+) I102 I
I
H
190
I,;,, .;,I.!,;,
myH
212
&
1"'~l"''l
0
I'
379
I ' " ' I ' " " ' " " ' " I " ' " ~ ' " I ' " ' ~ ' ~ " I ~ ~ ~ ~ I ' ~ " I ' ' ~ ' I
I
50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800
2,5-Dihydroxybenzoic acid (M, 154; m/z 177, [M+Na]+; m/z 193, [M+K]+)
I ' ~ ~ ' I ' ~ " I ' ' ' ' I ' ' ~ ' I
0
50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800
2,6-Dihydroxyacetophenone(M, 152; m/z 175, [M+Na]+; m/z 191, [M+K]+; m/z 365, [2M+Na+K-H]+ ?)
e.
153
H
23 39 175 191 i
b
L
,
I 0
, , ,
,,,,
,,,,
211 195 177
1
365 L L
L
- A
227
,,:;A
,,,, ),,,
H
,,,,
.
, , , , ,,.,
H
H
,,,, ,,,, ,,,,
,,,, ,,,, , , , ~
50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800
Ferulic acid (4-hydroxy-3-methoxycinnamicacid; M, 194)
H
37 I 389
7 Mass Spectrometry
382
Sinapinic acid (3,5-dimethoxy-4-hydroxycinnamicacid; M, 224; m/z 471, [2M+Na]+ )
'oTco
HO
/o
640 L I""I""I""I""I""I""I""I""I""I""I'~~"I""I""I""l''"l
0
50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800
Matrix Compounds in Negative Ionization MALDI Mass Spectra 3-Aminoquinoline (M, 144)
mNHz
285 I 295
N
437 1
. A .
I " " I " " I " ~ ' I " " I " " I " ~ ' I " " I ~ ~ ~ ~ ~ " ~ ~ ~ ~ ' " I ~ ~ " ~ ~ ~ " ~ ~
0
50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800
a-Cyano-4-hydroxycinnamic acid (M, 189; m/z 399, [2M+Na-2H]-)
99 110 ""I""1""I"'~l""I""1""1""I~"'I""I""~""I~"'~
t""I""I'"'
2,6-Dihydroxyacetophenone(M, 152; m/z 325, [2M+Na-2H]-)
I
HO 151
0
AA
Spectra
7.13
383
Dithranol (M, 226) 225 240
193
0
465
387
L.
688
100 150 200 250 300 350 400 450 500 550 600 650 700 750 800
50
Ferulic acid (4-hydroxy-3-methoxycinnamicacid; M, 194)
I
0
'
~
50
~
~
I
~
~
~
'
I
'
~
~
'
I
~
'
~
'
I
'
~
~
~
I
~
~
~
'
I
"
'
~
I
~
~
"
I
~
~
100 150 200 250 300 350 400 450 500 550 600 650 700 750 800
Sinapinic acid (3,5-dimethoxy-4-hydroxycinnamic acid; M, 224)
188
1223
447 HO ' T
O
o
H
/o
l""l~"'l""l""l""l""l~"'l""l""l'"'l''''l""l""l""l"'l
0
50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800
7.1 3.4 References R. Orlando, Analysis of peptides contaminated with alkali-metal salts by fast atom bombardment mass spectrometry using crown ethers, Anal. Chem. 1992, 64, 332. P.K. Singh, L. Field, B. Sweetman, Organic disulfides and related substances, J. Org. Chem. 1988, 53, 2608. Z.-H. Huang, B.-J. Shyong, D.A. Gage, K. R. Noon, J. Allison, N-Alkylnicotinium halides: a class of cationic matrix additives for enhancing the sensitivity in negative ion fast-atom bombardment mass spectrometry of polyanionic analytes, J. Am. SOC.Mass Spectrom. 1994, 5, 928. A.E. Ashcroft, Ionization in Organic Mass Spectrometry, RSC Analytical Spectroscopy Monographs, The Royal Society of Chemistry: Cambridge, 1997.
Solvents
~
8.1 Absorbed Radiation and Color
385
8 UVNis Spectroscopy
8.1 Correlation between Wavelength of Absorbed Radiation and Observed Color Absorbed light Wavelength [nm] 400 425 450 490 5 10 530 550 590 640 730
Observed (transmitted) color
Corresponding color violet indigo blue blue blue-green green yellow-green yellow orange red
purple
yellow-green yellow orange red purple violet indigo blue blue blue-green peen
8.2
UVNis Absorption of Simple Chromophores Chromophore Compound C-H CHA c-c CHi-CH3 c=c CH,=CH2 (CH3)2C=C(CH3)2 c=c=c CH2=C=CH2
c-c1 C-Br c-I
CH3C1 n-C3H7Br CH31
Transition
o+o* o+o* n+n* Z+X*
n+o* n+o* n+o*
h,, 122 135 162 196 170 227 173 178 196 222 173 208 259
E,,,
strong strong 15000 11500 4000 630 6000 10000 2000 160 200 300 400
Solvent gas gas heptane heptane
gas hexane hexane hexane hexane
386
8 UVNls
Chromophore Compound
Transition
c-0 C-N C=N
N=N N=O
C-N X=Y=Z J
c-s
n+o*
n+o* n+o* n+o* n+o* n+o*
c=s
h,
,E ,,
177 184 193 199
200 2500 2500 4000
265
15
193 265 340 300 665 276 218 313-384 260 490 250 230 270 195 235 194 225 194 250 460
2000 200 16
495
c=o
n+o* n+n* CH3COOH CH3COONa CH3COOC2H5 CH3CONH2
c=c=o
Q.
(C2H&C=C=O
n+n* n+n*
n+n* n+n* n+n*
Solvent hexane gas hexane hexane water
ethanol ethanol ethanol 100 ether 20 27
ethanol 1050 ethanol 20-40 ethanol 15 ethanol 1200 hexane 4000 25 1800 gas 180 4500 gas 1800 5500 hexane 380
Weak weak
ethanol
166 189 279 200 210 210 220
16000 gas
191
15200 CH3CN
227
900 15 50 150 50 63
360
hexane hexane gas water gas water
8.3 Conjugated Alkenes
387
8.3 UVNis Absorption of Conjugated Alkenes 8.3.1 UV Absorption of Dienes and Polyenes The n-n* transition of conjugated double bonds is above =200 nm with typical intensities of the order of log E = 4. Its position can be estimated with the Woodward-Fieser rule. For cross-conjugated systems, the value for the chromophore absorbing at the longest wavelength must be calculated.
Woodward-Fieser rule f o r estimating the position of the x-x* transition (Amax in nm) Parent system m
-
5
,' I
I. ,A. V
Increments
"
acyclic
217
heteroannular
214
homoannular
253
for each additional conjugated double bond
for each exocyclic double bond for each substituent
Solvent correction
c-
+30
+5
C-substituent
+5
c1
+5
Br
+5
0-alkyl
+6
OCOCH,
0
WlkYU2
+60
S - alkyl
+30
=o
388
8 UVNls
Example: Estimation of the absorption maximum for
n
base value (homoannular) 1 additional conjugated double bond 1 exocyclic double bond 3 C-substituents 1 OCOCHq estimated eXP
253 30 5 15 0 303
306
8.3.2
UV Absorption of a,P-Unsaturated Carbonyl Compounds The z-z* transition of a$-unsaturated carbonyl compounds is above =200 nm with typical intensities of the order of log E = 4. Its position can be estimated with the extended Woodward rule. For cross-conjugated systems, the value for the chromophore absorbing at the longest wavelength should be calculated.
Extended Woodward rule for estimating the position of the n-n* transition (Amax in nm)
S Parent system
@ fXo
P
X X: alkyl X: H X: OH X: 0-alkyl
215 207 193 193 215 202
8.3 Conjugated Alkenes
Increments
for each additional conjugated double bond
for each exocyclic double bond
Solvent corrections
+30
cK
+5
n 0
+39
for each homoannular diene system For each substituent on double bond system C-substituent c1 Br OH 0-alkyl 0-COCH3 S-alkyl NWYl)2
389
Increment
a
P
Y
6 and beyond
+IO +15 +25 +35 +35 +6
+12 +12 +30 +30 +30 +6 +85 +95
+18
+18
+17 +6
+50 +3 1 +6
Solvent water hexane cyclohexane chloroform methanol ethanol diethyl ether dioxane
Correction term -8 +11 +11 +1 0 0 +7 +5
Example: Estimation of the absorption maximum in ethanol for
base value 2 additional conjugated double bonds exocyclic double bond homoannular diene system 1 P-C-substituent 3 additional C-substituents solvent correction estimated exP
215 60
5 39 12 54 0 385 388
390
8 UVNis
8.4 UVNis Absorption of Aromatic Compounds 8.4.1 UV Absorption of Monosubstituted Benzenes
Typical Ranges f o r Monosubstituted Benzenes Transition n+n* (allowed) n+n* (forbidden) n+m* (substituent delocalized by aryl; K Band) n+n* (substituent with lone pair, R band)
hmax 180-230 250-290 220-250 275-350
E
2000-1oooO 100-2000 10000-30000 10-100
Specific Examples of Monosubstituted Benzenes
Substituent R (solvent) -H (cyclohexane) -CH3 (hexane) -CH=CH2 (ethanol) -C&H (hexane) -C1 (ethanol) -OH (water) -0- (water) -NH2 (water) -NH3+ (water) -NO2 (hexane) -CN (water) -CHO (hexane) -COCH3 (ethanol) -COOH (water)
n+n*
n+n*
n+n*
(allowed)
(forbidden)
(K band)
I,,,
h,,
h,,
E
198 8000 208 7900
210 211 235 230 203 208 213
7500 6200 9400 8600 7500 9800 8100
202 8000
E
255 230 262 230 282 450 278 650 257 170 270 1450 287 2600 280 1430 254 160 270 800
251
271 1000 280 1400 278 1100 270 800
224 242 243 230
n+n* (R band) E
h,,
E
244 12000 236 12500
9000 322
150
13000 14000 ~ 3 3 0 4 0 13000 319 50 10000
8.4 Aromatic Compounds
8.4.2 UV Absorption of Substituted Benzenes Estimation of the position of the allowed n-n* transition in multiply substituted benzenes (Amax in nm, log E: 4 ) Base value: 203.5 Substituent -CH3
-c1
-Br -OH -0-OCH3 -NH2 -NHCOCH3 -NO2 -CN -CHO -COCH3 -COOH
Increment rnml 3.0 6.0 6.5 7.0 31.5 13.5 26.5 38.5 65.0 20.5 46.0 42.0 25.5
391
8 UVNis
392
8.4.3 UV Absorption of Aromatic Carbonyl Compounds
Scott rules for estimating the position of the K band (solvent: ethanol; Amm in nm, E 10000-30000) Parent system:
dH
doH doR
250
230
R
VIk /
Increments
246
230
Substituent
Ortho
meta
pmn
-alkyl
3
3
10
-cycloalkyl
3
3
10
-c1
0
0
10
-Br
2
2
15
-OH
7
7
25
-0-alkyl
7
7
25
-0-
11
20
78
-NH2
13
13
58
-N(CH3)2
20
20
85
-NHCOCH3
20
20
45
Example: Estimation of the absorption maximum (K band) for
‘0
base value ortho -cycloalkyl para -0-alkyl estimated exP
246 3 25 274 276
8.5 Reference Spectra
__
393
8.5 UV/Vis Reference Spectra 8.5.1 UV/Vis Spectra of Alkenes and Alkynes
5-1
I
0l 200
log&
log E
41r
200
1 400
hlnm
log E 54-
H
3-
0 200
? ,,
I
300
400
’
h/nm
400
,
,
, ,
h/nm
“i\L -To
1
1300
OH
\
2
2-
200
h / nL m
- - - -
HO
:I,, 34
300
400
- - - 4
3
0
300
200
300
400
hlnm
8 UV/Vis
394 log E
5-
-Yo OH
4-
5-
-Yo 0-
321-
200
hlnm
400
300
200
hlnm
400
300
8.5.2 UVNis Spectra of Aromatic Compounds log E 5-
log E 5-
4-
4-
3-
3-
2-
2-
1-
1-
0
1
1
1
,
~
1
1
1
1
~
,
1
log E
5-
6
I?.:
:; 21
1
hlnm
400
300
200
2l hlnm
400
300
200
5-
4-
32-
1-
0 200
I
I
I
I
I
300
I
I
I
I
,
400
I
I
I
I
hlnm
0
I
,
I
I
I
,
I
I
I
1
8
I
I
I
1
1
8.5 Reference Spectra
log E 5-
6
4-
32-
IogL 4
2
1
1-
0
395
1
1
1
1
,
,
1
1
1
,
9
8
8
1
200
300
log E 5Iog51
lol-h
400
hlnrn
I
2
1
200
h/nrn
400
300
200
300
400
hlnrn
!/y 21
0 l 200
L hlnrn
400
300
200
300
400
hlnrn
200
300
400
h/nm
log E 5
6
:!\ 2
1-
0
~
l
l
l
,
l
l
r
l
)
I
I
I
I
396
0 200
8 UV/Vis
1 300
400
hlnrn
200
300
400
hlnrn
200
300
400
hlnrn
Q"-o / /
log5E
4 1 v 3
0 l 200
400
hlnrni
300
log E
4:L e 5
23 -
-
0 200
1
300
400
htnm
300
400
k f nL rn
2
0 I 200
Iogh 2
1-
200
300
400
hlnrn
8.5 Reference Spectra
5-
5-
4-
4-
d
log E 5
::\
log E
2-
1-
1I
,
I
I
~
I
I
,
I
~
I
,
,
log E
0
,
I
I
I
~
I
I
I
,
~
,
,
,
,
5
::-L:
::\
o a , H
2
2-
1
1-
I
log E 5-
I
I
J
~
I
,
,
I
~
,
,
,
0
,
,
J
,
,
d o -
,
,
,
,
,
~
7 ;: \
21 I
I
I
I
~
I
I
I
,
~
,
,
,
,
,
,
log E 5-
&
4
0
J
log E
5-
0
OUO
53:\ 4-
2-
0
397
,
,
0
,
I
,
,
~
P ,
,
,
,
~
,
,
,
,
8 UVNls
398 109 E 54-
321-
0 200
I
I
I
I
,
I
I
I
,
~
400
300
I
I
I
hlnm
I
hlnm
400
300
200 log E
54-
32-
\
11
0 200
1-
1 300
400
0
,
I
I
I
~
I
I
I
I
~
I
I
I
I
hlnm
log54E-
3-
2l
2-
1
0 200
1-
1 300
400
hlnm
400
hlnm
7 8
0
\
I
I
J
I
~
I
I
I
/
I
~
I
I
:p 2
&
1
0 200
/
/
300
200
300
400
hlnm
I
I
8.5 Reference Spectra
200
300
400
h/nm
5hlL 4
200
, ,
200
300
400
hlnm
200
300
400
hlnm
0 200
,
hlnm
400
300
'i,,
399
, ,
"",
,
300
400
hlnm
300
400
1 hlnm
0 200
8.5.3
UVNis Spectra of Heteroaromatic Compounds
'"%
Q
"19
H
2
1-
0 200
300
400
hlnm
I
I
I
I
,
I
I
I
I
(
~
~
~
~
8 UVIVis
400
log E
5-1
Iogh Q
2
1
200
300
hlnm
400
200
300
5-
0
432-
0 200
SG,
2
11
1
1
,
1
,
300
1
1
,
1
,
400
,
,
,
hlnm
hlnm
400
1L
0200
hlnm
400
300
log E
5$ N-N
'ld
1 200
300
400
hlnm
or" '
0 200
5
0
300
, 400
, , , ,
hlnrn
rn "..! H
2
2
, ,
I 1 o g h '
0 200
300
400
hlnm
200
300
400
hlnm
8.5 Reference Spectra
'i..-;
40 1
2
1
200
300
14
400
hlnm
2l 1
200
200
300
400
hlnm
300
400
h/nm
21 $
300
400
h/nm
200
8.5.4 UVIVis Spectra of Miscellaneous Compounds
:I
log &
CHC13
CHBr3
'r\
3
1
200
lik
300
400
hlnm
200
300
400
hlnm
log E
yBr
21
200
300
400
h/nm
YI
IOg5] 4
200
300
400
hlnm
402
200
8 UV/Vis
300
400
hlnm
300
200 log e 5-
CH3-NOz
hlnm
400
KSCN
4321-
0
200
300
400
hlnm
1
1
1
1
,
1
1
1
1
,
1
1
1
,
".
log E
21
3 2 ol- 1
0 200
300
400
h/nm
0 200
300
400
hlnm
300
400
hlnm
200
300
400
hlnm
1
1
IOg5] 4
200
8.5 Reference Spectra
200
.k
hlnm
400
300
403
.i-\
300
400
hlnm
200
300
400
hlnm
200
log E
4
2
0H
21
1
o
h 300
200
h/nm
400
8.5.5 UVNis Spectra of Nucleotides
./ybo 2
1-
0
1 I
I
I
I
,
I
I
I
I
,
I
,
,
,
200
1-
0
H
300
400
hlnm
300
400
hlnm
1-I 1
1
1
,
,
1
,
,
,
,
,
,
,
,
200
404
8 UVlVis
8.6 UVNis Absorption of Common Solvents The end absorption, Lend, of several common solvents is given here as the wavelength at which the solvents absorb 80% of the irradiated light (Lend in nm; cell length, 1 cm; reference, water). Solvent acetone acetonitrile benzene carbon disulfide carbon tetrachloride chloroform cyclohexane dichloromethane diethyl ether 1,4-dioxane ethanol
%nd 335 190 285 380 265 245 210 230 210 215 205
Solvent ethyl acetate heptane hexane methanol pentane 2-propanol pyridine tetrahydrofuran toluene 2,2,4-trimethylpentane xylene
Lend 205 195 195 205 200 205 305 230 285 210
290
