Reactive Intermediates J6/ume 1 Metal Atoms as Reactive Intermediates 89 In the case of Ge atoms, oxidative addition of CCl occurs, but the resulting 4 Cl CGeCI abstracts CI atoms from excess CCI resulting in a respectable yield 3 4, of CI3CGeCI3• Chloroform and silicon tetrachloride reacted similarly as shown below 110: r ClaCGeCIa 20% ~(....:.C..:..;H,-C...:Ia,- Ge ~ ClaSiGeCla 10% B. Acyl Halides with Metal Atoms (Macroscale Co condensation) Acyl chlorides oxidatively add to palladium atoms and nickel atoms.27i.95 In all the examples studied, the resultant RCOMCI species liberated CO very o o II 1/ RCCI + M atom --+ RC-M-CI M = Ni, Pd R = CHa, CFa, C.Hs, C.Fs, n-CaF7 readily. By carrying out low-temperature trapping experiments with Et P we 3 were ahle to reach some conclusions about thermal stabilities and decomposition pathways. Table 10 summarizes our findings,27i.95 and Figure 20 illustrates the TABLE /0. Acyl Chloride-Metal-Atom Reactions, Products, and Comments271.95 Reactants Comments Pd, CF COCI CFaCOPdCl eliminates CO at -80T, at which point Et P addi 3 3 tion yielded almost equal quantities of (Et3PhPdCI(CF3), (Et3P),PdCI(COCF3) and (Et3P),PdCI2 Pd, CFaCF2CF2COCI CF3CF2CF2COPdCI stable above -80vC (but <O'T), where it was efficiently trapped to yield (Et3P),PdCI(CO-n-C3F7) Pd, C6 FsCOCl C.FsCOPdCllost CO at - -50°C to yield C6FsPdCI efficiently, which could be trapped with PEt at· 40°C 3 Pd, C6HsCOCI C6HsC6HS, C6HsCI, and (Et3P),PdCI2 found with Et3P trapping at 40°C Pd, CH3COCI CO loss at < -100°C, only (Et3P),PdCI2 found after trapping at o or -78T Ni, CF COCI Et P trapping at - 80T yielded small amount of(Et P),NiCI(CF > 3 3 3 3 and mostly (Et3P)2NiCl2, but no (EtaP),NiCl(COCF3) CO loss at < -lOOT, and Et P trapping at - 80°C yielded only 3 (Et P),NiCI 3 2 Library of Congress Cataloging in Publication Data Main entry under title: Reactive intermediates. Includes bibliographies and index. I. Chemical reaction, Conditions and laws of-Addresses, essays, lectures. I. Abramovitch, R. A., 1930- QD50l.R345 541'.39 79-344 ISBN-13: 978-1-4613-2975-6 e-ISBN-13: 978-1-4613-2973-2 001: 10.1007/978-1-4613-2973-2 © 1980 Plenum Press. New York Softcover reprint of the hardcover 15t edition 1980 A Division of Plenum Publishing Corporation 227 West 17th Street, New York, N.Y. 10011 All righ ts reserved No part of this book may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, without written permission from the Publisher Contributors Yuan L. Chow, Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A I S6 Kenneth). Klabunde, Department of Chemistry, The University of North Dakota, Grand Forks, North Dakota 58201 B. Poling, Department of Chemical Engineering, University of Missouri-Rolla, Rolla, Missouri 65401 Philip B. Shevlin, Department of Chemistry, Auburn University, Auburn, Alabama 36830 Curt Wentrup, Fachbereich Chemie, University of Marburg, Lahnberge, 0-3550 Marburg, West Germany David S. Wulfman, Department of Chemistry, University of Missouri-Rolla, Rolla, Missouri 65401 Preface The field of reactive intermediates has been blossoming at a rapid rate in recent years and its impact on chemistry, both "pure" and "applied," as weIl as on biology, astronomy, and other areas of science, is enormous. At least two books have been published which cover the area; the latest one, edited by McManus, * surveys the subject in general at the senior undergraduate or beginning graduate level. In addition, a number of monographs have appeared which deal with individual topics such as carbenes, nitrenes, free radicals, carbanions, carbenium ions, and so on, in great depth. Our objective is somewhat different. We hope that these Advances in ... type of volumes wiIl appear at irregular intervals of a year to 18 months each. We intend to publish up-to-date reviews in relatively new areas of the chemistry of reactive intermediates. These wiIl be written by world authorities in the field, each one of whom wiIl give the reader a current in-depth review of all aspects of the chemistry of each of these species. It is our plan that the subjects to be reviewed wiIl cover not only organic chemistry but also inorganic, physical, bio-, industrial, and atmospheric chemistry. The volumes themselves, we hope, wiIl end up being reasonably interdisciplinary, though this need not and probably wiIl not be the case for the individual reviews. It is our intention to give readers ideas about the importance of reactive intermediates in fields other than their own, as well as to bring them up to date in their own individual areas. In most cases in the present volume, the literature has been covered to the end of 1977, and in some instances references or unpublished results from 1978 have also been included. I welcome suggestions of topics (and authors) that should be discussed in future volumes. Finally, I would like to express my thanks to the authors who submitted their chapters so promptly. My wife, Dorota, is due special thanks for her patience and understanding on those occasions when my patience wore rather thin-too often, she will say. Clemson, S.c. R. A. Abramovitch * Samuel P. McManus, Ed., Organic Reactil'e Intermediate:" Vol. 26 in Organic Chemi:,try, Academic Press, New York (1973). vii Contents I. The Preparation and Reactions of Atomic Carbon Philip B. Shevlin I. Introduction II. Methods of Producing Carbon Atoms 2 1. Nuclear Recoil Methods . 2 2. Graphite Vaporization Techniques 3 A. The Carbon Arc 3 B. Heating of Graphite 4 3. Photolytic Production of Carbon Atoms 5 A. Photolysis of Carbon Suboxide 5 B. Photochemical Generation of Carbon Atoms in Low-Temperature Matrices. 6 4. Carbon Atoms as Products of Chemical Reactions 7 5. Miscellaneous Methods of Producing Carbon Atoms 8 III. Reactions of Atomic Carbon 9 1. Reaction with Hydrogen . 9 2. Reaction with Saturated Hydrocarbons 11 3. Reaction of Atomic Carbon with Compounds Containing Carbon-Carbon Double Bonds 17 4. Reaction with Oxygen- and Sulfur-Containing Compounds 21 5. Reaction of Carbon with Organic Halogen and Nitrogen Compounds 27 6. Reaction of Atomic Carbon with Inorganic Molecules 28 7. The Use of Carbon-II in Nuclear Medicine 32 IV. Summary and Future Prospects 33 V. References . 33 2. Metal Atoms as Reactive Intermediates Kenneth J. Klabunde I. Introduction 37 II. Energetics of Atoms 38 III. Techniques for Producing and Studying Metal Atoms 40 1. Diffusion Flame Method and Life-Period Method. 40 2. Gas Phase Flow System Method . 41 3. Cocondensation Methods (Macroscale for Synthetic Purposes) 41 A. Static Cocondensation Reactor 41 B. Rotating Reactors . 56 ix x Contents 4. Solution Metal Atom Reactors and Techniques (Macroscale for Synthetic Purposes) 56 A. Rotating Solution Reactors 56 B. Solution Methods Employing Classical Stationary Reactors 57 C. Solvated Metal Atom Solution Techniques 58 5. Product Removal (Macroscale for Synthetic Purposes) 59 6. Commercial Apparatus Available (Macroscale for Synthetic Purposes) 60 7. Microscale Cocondensation-Matrix Isolation Spectroscopy 62 IV. Chemical Reactions of Metal Atoms 64 I. Abstraction by Metal Atoms (Reaction Type I, Figure 15) 66 A. Sodium-Vapor-Organohalide Reactions in the Gas Phase 66 B. Alkali-Metal-Halide Reactions by Microscale Cocondensation 68 C. Synthetic Applications of Sodium-Potassium Organohalide Gas Phase Reactions 70 D. Abstractions by Excited State Mg Atoms 72 E. Cu, Ag, and Au with Halides; Formation of RM Compounds 73 F. Deoxygenation by Metal Atoms . 75 2. Oxidative Addition to Metal Atoms (Oxidative Insertion) (Reaction Type 2, Figure 15) . 77 A. Alkyl and Aryl Halides with Metal Atoms (Macroscale Cocondensation) 77 B. Acyl Halides with Metal Atoms (Macroscale Cocondensation) . 89 C. Acid Anhydrides with Metal Atom (Macroscale Cocondensation) 90 D. Future Work with Oxidative Addition to Metal Atoms 91 3. Electron Transfer from Metal Atoms (Reaction Type 3, Figure 15) 91 A. Alkali Metal and Alkaline Earth Metal Atoms (Microscale Cocondensation) 91 B. Synthetic Applications of Electron Transfer (Macroscale Cocondensation) 96 C. Further Studies and their Importance 96 4. Simple Orbital Mixing of Ligands with Metal Atoms (Reaction Type 4, Figure 15) (Macroscale and Microscale) . 97 A. Olefins with Metal Atoms. 97 B. Dienes with Metal Atoms (Sometimes with Other Added Ligands) 103 C. Nonaromatic Trienes with Metal Atoms 109 D. Acetylenes with Metal Atoms 110 E. Arenes with Metal Atoms. 111 F. Pyridines with Cr Atoms . 118 G. Phosphines with Metal Atoms 118 H. Isonitriles with Metal Atoms. 121 I. Metal Atoms with Nitric O~ide (NO) 121 J. Carbon Monoxide with Metal Atoms 121 K. Dinitrogen (N2) with Metal Atoms . 128 L. Dioxygen (02) with Metal Atoms 128 5. Cluster Formation from Metal Atom Aggregation (Reaction Type 5, Figure 15) 130 A. Background . 130 B. Small Discrete Clusters (Microscale Cocondensation) 133 C. Small Discrete Organometallic Clusters (Macroscale) 135 D. Large Clusters (Small Metal Particles or Crystallites, Metal Slurries) (Macroscale) 137 V. References . 141 Contents xi 3. Aminium Radicals Yuan L. Chow I. Introduction 151 II. General Methods of Aminium Radical Formation 153 III. Physicochemical Properties of Aminium Radicals 154 1. Esr Spectra 155 2. Electronic Absorption Spectra 156 3. Acid-Base Equilibria 161 4. Stability and Reactivity 165 IV. Anodic Oxidation of Amines 177 1. Redox Energetics 177 2. Reaction Patterns and Mechanisms 181 A. Primary and Secondary Amine Oxidations 182 B. Tertiary Amine Oxidations 186 V. Aminium Radical Intermediacy in Chemical Oxidations 190 1. Reaction Patterns and Mechanisms 190 A. Chlorine Dioxide and Potassium Ferricyanide 192 B. Metal Ions 194 C. Potassium Permanganate 194 D. Halogens and their Derivatives 195 E. Diacyl Peroxides 195 F. Molecular Oxygen 197 2. Applications 199 A. Aliphatic and Aromatic Amines 199 B. Vinylamines. 202 VI. Photo-oxidation of Amines 205 1. Alkyl-and Arylalkylamines with Ketones 205 A. Kinetic Evidence for Charge Transfer 208 B. Linear Free-Energy Correlation 209 C. Spectroscopic Evidence 211 D. Product Patterns 211 2. Arylamines with Ketones 213 3. Amines with Aromatic Hydrocarbons 215 VII. Homolysis of N-X bonds in Acidic Solutions 220 1. Decomposition of N-Haloalkylamines 224 A. Hydrogen Abstraction. 225 B. Addition to Carbon-Carbon Multiple Bonds 231 C. Aromatic Substitution . 235 2. Decomposition of Hydroxylamines and Trialkylamine N-Oxides . 238 3. Photolysis of N-Nitrosamines . 241 4. Photolysis of N-Nitramines 250 5. Photolysis of 2-Tetrazenes 251 VIII. References 253 4. The Behavior of Arylcarbenes and Arylnitrenes in the Gas Phase Curt Wentrup I. Introduction 263 II. The C7H6 Energy Surface 263 xii Contents I. The Arylcarbene-Cycloheptatrienylidene Interconversion . 264 2. Miscellaneous Carbene-Carbene Rearrangements . 277 3. The Mechanism of Fulvenallene Formation 281 4. Automerization in Fulvenallene and its Consequences 290 5. Lack of Interconversion of Phenylmethylcarbene and Methylenecyclohexadienylidenes . 295 6. Bicyclo[3.2.01hepta-I,4,6-triene and its Isomers. 296 III. Carbene-Nitrene Rearrangements 297 I. Ring Contraction via IH-Benzazirine 299 2. Ring Contraction in Heterocyclic Nitrenes 304 A. Formation of C-Nitriles 306 B. Direct Contraction to N-Nitriles 308 C. The Carbodiimide Mechanism 310 3. Further Rearrangements of Heterocyclic Carbenes 312 IV. Concluding Remarks 316 V. References . 316 5. Metal-Salt-Catalyzed Carbenoids David S. Wulfman and B. Poling I. Introduction 321 I. What is a Carbene? 322 2. What is a Carbenoid? 328 3. How Does One Establish Their Presence? 343 4. The Theory of Methylene Transfer . 346 5. Types of Processes to be Expected 357 II. Reactions of Diazoalkanes with Metal Salts 360 1. Diazomethane and Alkyldiazomethane Reactions 361 2. Aryldiazomethane Reactions . 365 3. Reactions of Alkyldiazoketones and Diazoaldehydes 370 4. Aryldiazoketone Reactions 387 5. Reactions of Diazoacetic Esters and Diazoarylacetic Esters 389 A. Additions to Oletins 390 B. Additions to Acetylenes and Allenes 391 C. Aromatic Systems . 399 6. Diazomalonic Ester Reactions 404 A. Reactions with Oletins 404 B. Aromatic Substrates 415 7. Reactions of XYCN2 (X = H, C02R, COR, or pseudohalogen; Y = halogen or pseudohalogen) 417 8. Insertions into X-H Bonds (X of. C) Catalyzed by Lewis Acids 423 A. O-H Bonds 424 B. Insertions into S-H Bonds 427 C. Insertions into N-H Bonds 429 D. Insertions into M-H Bonds 431 9. Insertions into C-H Bonds . 431 10. Insertions into X-Y and X=Y Bonds Not Generating Three-Membered ~p ill A. C-C Bonds 434 B. C-B Bonds 434 Contents xiii C. C-Halogen Bonds 434 D. C-O'Bonds 437 E. C-S Bonds . 439 F, Reactions of M-X Bonds 441 G. Elimination Reactions. 448 II. Formation of Three-Membered Rings from C=X and X=Y 449 A. C=O 449 B. C=S. 449 C. C=N. 449 D. N=N 454 12. Cycloadditions 454 A. Keto Carbenoids 454 B. Carbonyl Ylids . 457 13. Dimers, Telomers, and Polymers. 461 14. Rearrangements 467 15. The Mechanisms of Metal-Salt-Catalyzed Cyclopropanations, C-H Insertions, and Dimerizations of Diazoalkanes . 468 A. The Mechanisms of Cyclopropanation and C-H Insertions. 469 B. Dimer Formation 470 III. Olefin Metathesis 471 IV. Addendum 474 V. References . 495 Index . 513