《有机化学》课程教学资源（参考书籍）Solvents and Solvent Effects in Organic Chemistry, Third, Updated and Enlarged Edition, 2003, Christian Reichardt

Copyrighted Material WILEY-VCH Christian Reichardt Solvents and Solvent Effects in Organic Chemistry Third, Updated and Enlarged Edition 0Z Copyrighted Material

er Phil pps- n-Marburg cichardt-Marbur This book ments,data,illustrations,procedural details or other items may inadvertently be inaccurate. First Reprint 2004 Library of Congress Card No.:applied for A catalogue record for this book is available from the British Library. hBibotek lists this publication in the DeutscheNa n in u he Nationalbibliografie:detailed biblio- temet at http://dnb ddb.de ISBN3-527-30618-8 2003 WILEY-VCH Verlag GmbH Co.KGaA,Weinheim d on acid-t those of translation b uced in any form part of this book photo y other m ans r trans s.Reg considered unprotectedby law. s book even ch are not to g K Printing:Strauss Offsetdruck GmbH,Morlenbach Printed in the Federal Republic of Germany

Prof. Dr. Christian Reichardt Fachbereich Chemie der Philipps-Universita¨t Marburg Hans-Meerwein-Straße 35032 Marburg Germany e-mail: Reichardt-Marburg@t-online.de This book was carefully produced. Nevertheless, author and publisher do not warrant the infor￾mation contained therein to be free of errors. Readers are advised to keep in mind that state￾ments, data, illustrations, procedural details or other items may inadvertently be inaccurate. First Reprint 2004 Library of Congress Card No.: applied for A catalogue record for this book is available from the British Library. Bibliographic information published by Die Deutsche Bibliothek Die Deutsche Bibliothek lists this publication in the Deutsche Nationalbibliografie; detailed biblio￾graphic data is available in the Internet at http://dnb.ddb.de. ISBN 3-527-30618-8 6 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Printed on acid-free paper. All rights reserved (including those of translation in other languages). No part of this book may be reproduced in any form – by photoprinting, microfilm, or any other means – nor transmitted or translated into machine language without written permission from the publishers. Registered names, trademarks, etc. used in this book, even when not specifically marked as such, are not to be considered unprotected by law. Composition: Asco Typesetters, Hong Kong. Printing: Strauss O¤setdruck GmbH, Mo¨rlenbach Bookbinding: J. Scha¨¤er GmbH & Co. KG, Gru¨nstadt Printed in the Federal Republic of Germany

Preface to the Third Edition Meeting the demand for the second edition of this book,which is-despite a reprint in 1990-no longer available,and considering the progress that has been made during the last decade in the study of solvent effects in expe ntal and theoretical organic chem istry,this im ved third edit n is n esented to the interested re der Following the same layout as in the sec ond edition all to ics retained have beer brought up to date. with smaller and larger chang and additio ns(4.4.7and5.5.13)are ith soly pag dealing host/guest co equilibria and i s in biphasic olvent syste ms and ne olvents ely more than 900 ney added.giving S P and n older olde dded he The list of ea ch chapter he lite th f200i the st nur f pu papers deali ng with solve efects in all ar f orga che didacti oint of uld on selected.Th examples from the this field not a mo The resp apo 0 review d in a certain field reade ffects Great progress has been made during the last decade in theoretical treatments solvent effects by various quantum-chemical meth ods and computational strategie When indicate d,relevant references are given to solution reactions o absorptions. However,a critical evaluation o all the the l models and method used to calculate the differential solvation of educts,activated complexes,products. ground and excited states,is outside the expertise of the present author.Thus,a book on all kinds of theoretical calculations of solvent influences on chemical reactions and physical absorptions has still to be written by someone else. Consistent use of the nomenclature.symbols.terms.and SI units recom mended by the IUPAC commissions has also been made in this third edition. For comments and valuable suggestions I have to thank many colleagues,in par ticular Prof.E.M.Kosower,Tel Aviv/Israel,Prof.R.G.Makitra,Lviv/Ukraine,Prof N.O.Mchedlov-Petrossyan,Kharkiv/Ukraine,and Prof.K.Mockel,Muhlhausen/ Germany.For their assistance in drawing formulae,preparing the indices,and provid ing me with difficult to obtain literature,I thank Mr.G.Schafer(technician),Mrs.S. Schellenberg (secretary),and Mrs.B.Becht-Schroder (librarian),all at the Department G.J.Leigh. and W V.Met ski- ePublications,London,1998 menclature-A U AC Recom es Units and Symbols in in Physical Organic Chemistry-IUPAC Recommendations Tristan:SI Chemical Data,4th ed.,Wiley,Chichester,1999: Datensammlung Chemie in SI-Einheiten,3d ed.,Wiley-VCH,Weinheim/Germany,1999

Preface to the Third Edition Meeting the demand for the second edition of this book, which is – despite a reprint in 1990 – no longer available, and considering the progress that has been made during the last decade in the study of solvent e¤ects in experimental and theoretical organic chem￾istry, this improved third edition is presented to the interested reader. Following the same layout as in the second edition, all topics retained have been brought up to date, with smaller and larger changes and additions on nearly every page. Two Sections (4.4.7 and 5.5.13) are completely new, dealing with solvent e¤ects on host/guest complexation equilibria and reactions in biphasic solvent systems and neo￾teric solvents, respectively. More than 900 new references have been added, giving pre￾ference to review articles, and many older ones have been deleted. New references either replace older ones or are added to the end of the respective reference list of each chapter. The references cover the literature up to the end of 2001. From the vast number of published papers dealing with solvent e¤ects in all areas of organic chemistry, only some illustrative examples from the didactic and systematic point of view could be selected. This book is not a monograph covering all relevant literature in this field of research. The author, responsible for this subjective selec￾tion, apologizes in advance to all chemists whose valuable work on solvent e¤ects is not mentioned in this book. However, using the reviews cited, the reader will find easy access to the full range of papers published in a certain field of research on solvent e¤ects. Great progress has been made during the last decade in theoretical treatments of solvent e¤ects by various quantum-chemical methods and computational strategies. When indicated, relevant references are given to the respective solution reactions or absorptions. However, a critical evaluation of all the theoretical models and methods used to calculate the di¤erential solvation of educts, activated complexes, products, ground and excited states, is outside the expertise of the present author. Thus, a book on all kinds of theoretical calculations of solvent influences on chemical reactions and physical absorptions has still to be written by someone else. Consistent use of the nomenclature,a) symbols,b) terms,c) and SI unitsd) recom￾mended by the IUPAC commissions has also been made in this third edition. For comments and valuable suggestions I have to thank many colleagues, in par￾ticular Prof. E. M. Kosower, Tel Aviv/Israel, Prof. R. G. Makitra, Lviv/Ukraine, Prof. N. O. Mchedlov-Petrossyan, Kharkiv/Ukraine, and Prof. K. Mo¨ckel, Mu¨hlhausen/ Germany. For their assistance in drawing formulae, preparing the indices, and provid￾ing me with di‰cult to obtain literature, I thank Mr. G. Scha¨fer (technician), Mrs. S. Schellenberg (secretary), and Mrs. B. Becht-Schro¨der (librarian), all at the Department a) G. J. Leigh, H. A. Favre, and W. V. Metanomski: Principles of Chemical Nomenclature – A Guide to IUPAC Recommendations, Blackwell Science Publications, London, 1998. b) I. Mills, T. Cvitas, K. Homann, N. Kallay, and K. Kuchitsu: Quantities, Units and Symbols in Physical Chemistry, 2nd ed., Blackwell Science Publications, London, 1993. c) P. Mu¨ller: Glossary of Terms used in Physical Organic Chemistry – IUPAC Recommendations 1994, Pure Appl. Chem. 66, 1077 (1994). d) G. H. Aylward and T. J. V. Tristan: SI Chemical Data, 4th ed., Wiley, Chichester, 1999; Datensammlung Chemie in SI-Einheiten, 3rd ed., Wiley-VCH, Weinheim/Germany, 1999

VIII Preface to the Third Edition of Chemistry,Philipps University,Marburg/Germany.Special thanks are due to the staff of Wiley-VCH Verlag GmbH,Weinheim/Germany,particularly to Dr.Elke Westermann,for their fine work in turning the manuscript into the final book.Lastly. my biggest debt is to my wife Maria,not only for her assistance in the preparation of the manu cript,but also for her constant encouragement and support during the writing of this book Marburg (Lahn),Spring 2002 Christian Reichardt

of Chemistry, Philipps University, Marburg/Germany. Special thanks are due to the sta¤ of Wiley-VCH Verlag GmbH, Weinheim/Germany, particularly to Dr. Elke Westermann, for their fine work in turning the manuscript into the final book. Lastly, my biggest debt is to my wife Maria, not only for her assistance in the preparation of the manuscript, but also for her constant encouragement and support during the writing of this book. Marburg (Lahn), Spring 2002 Christian Reichardt VIII Preface to the Third Edition

Preface to the Second Edition The response to the first English edition of this book,published in 1979,has been both gratifying and encouraging.Its mixed character,lying between that of a monograph and a textbook.has obviously made it attractive to both the industrial and academic chemist as well as the advanced student of chemistrv During the last eight vears the study of solvent effects on both chemical reac tions and absc ectra has made much r ss,and nume as interesting and nles have heen dese ibed in In cular the st idy of ionic reactions in the ga s phase ow po ssible due to r mental techniau has allowed direct co ons be s-p actions.This has led to a gre ter arged to ng of solut equent apters 4 and 5 hav nclude a description o of ioni c gas-phase reactions compare ed to t the The of well-studied solvent-de nden ses abso on,has increase 1979.0n ,Le.reaction and y a re more instructive,recently studi d examples could be included in this secon d The search for empirical ters of solvent ity and their application in mul s recently been intensified,thus making it necessary to arge parts e Spe tention n give the chemical phys solvents common in daily labora ry wort and refore,al Appendi mproved:sor e have been completely replaced by new A new well-refere nced table on solvent-drying has be en added(Table A-3).Chapte 3 has been enlarged,in parti ular by the inclusion of sol vent classi ations using multivariate s tistical methods (Section 3.5).All these amendments justify the change in the title of the book to Soltents and Solvent Effects in Organic Chemistry The references have been up-dated to cover literature appearing up to the first part of 1987.New references were added to the end of the respective reference list of each chapter from the first edition. Consistent use of the nomenclature,symbols,terms,and SI units recommended by the IUPAC commissions has also been made in the second edition.* I am very indebted to many colleagues for corrections.comment and valuable suggestions.Especially helpful suggestions came from Professors H-D.Forsterling. Marburg,J.Shorter,Hull/England,and R.I.Zalewski,Poznani/Poland,to whom I am very grateful.For critical reading of the whole manuscript and the improvement of my English I again thank Dr.Edeline Wentrup-Byrne,now living in Brisbane/Australia Dr.P.-V.Rinze,Marburg,and his son Lars helped me with the author index.Finally, I would like to thank my wife Maria for her sympathetic assistance during the prepara- tion of this edition and for her help with the indices. Marburg(Lahn),Spring 1988 Christian reichardt ◆Cf.Pure Appl..Chem.5,1(1979：外ibid.53,753(1981:ibid.55,1281(1983 )ibid.57,105 (1985)

Preface to the Second Edition The response to the first English edition of this book, published in 1979, has been both gratifying and encouraging. Its mixed character, lying between that of a monograph and a textbook, has obviously made it attractive to both the industrial and academic chemist as well as the advanced student of chemistry. During the last eight years the study of solvent e¤ects on both chemical reac￾tions and absorption spectra has made much progress, and numerous interesting and fascinating examples have been described in the literature. In particular, the study of ionic reactions in the gas phase – now possible due to new experimental techniques – has allowed direct comparisons between gas-phase and solution reactions. This has led to a greater understanding of solution reactions. Consequently, Chapters 4 and 5 have been enlarged to include a description of ionic gas-phase reactions compared to their solution counterparts. The number of well-studied solvent-dependent processes, i.e. reactions and absorptions in solution, has increased greatly since 1979. Only a representative selection of the more instructive, recently studied examples could be included in this second edition. The search for empirical parameters of solvent polarity and their applications in multiparameter equations has recently been intensified, thus making it necessary to rewrite large parts of Chapter 7. Special attention has been given to the chemical and physical properties of organic solvents commonly used in daily laboratory work. Therefore, all Appendix Tables have been improved; some have been completely replaced by new ones. A new well-referenced table on solvent-drying has been added (Table A-3). Chapter 3 has been enlarged, in particular by the inclusion of solvent classifications using multivariate sta￾tistical methods (Section 3.5). All these amendments justify the change in the title of the book to Solvents and Solvent E¤ects in Organic Chemistry. The references have been up-dated to cover literature appearing up to the first part of 1987. New references were added to the end of the respective reference list of each chapter from the first edition. Consistent use of the nomenclature, symbols, terms, and SI units recommended by the IUPAC commissions has also been made in the second edition.*) I am very indebted to many colleagues for corrections, comments, and valuable suggestions. Especially helpful suggestions came from Professors H.-D. Fo¨rsterling, Marburg, J. Shorter, Hull/England, and R. I. Zalewski, Poznan´/Poland, to whom I am very grateful. For critical reading of the whole manuscript and the improvement of my English I again thank Dr. Edeline Wentrup-Byrne, now living in Brisbane/Australia. Dr. P.-V. Rinze, Marburg, and his son Lars helped me with the author index. Finally, I would like to thank my wife Maria for her sympathetic assistance during the prepara￾tion of this edition and for her help with the indices. Marburg (Lahn), Spring 1988 Christian Reichardt * Cf. Pure Appl. Chem. 51, 1 (1979); ibid. 53, 753 (1981); ibid. 55, 1281 (1983); ibid. 57, 105 (1985)

Preface to the First Edition The organic chemist usually works with compounds which possess labile covalent bonds and are relatively involatile,thereby often rendering the gas-phase unsuitable as a reaction medium.Of the thousands of reactions known to occur in solution only few have been studied in the gas-phase,even though a description of reaction mechanisms is much simpler for the gas-phase.The frequent necessity of carrying out reactions in the presence of a more or less inert solvent results in two main obstacles:The reaction depends on a larger number of parameters than in the gas-phase.Consequently,the experimental results can often be only qualitatively interpreted because the state of aggregation in the liquid phase has so far been insufficiently studied.On the other hand, the fact that the interaction forces in solution are much stronger and more varied than in the gas-phase,permits to affect the properties and reactivities of the solute in manifold modes. Thus.whenever a chemist wishes to carry out a chemical reaction he not only has to take into consideration the right reaction partners.the proper reaction vessels.and ooetst o chemical reactivity have been known for more than a century.most chemists are now familiar with the fact that solvents may have a strong influence on reaction rates and quilibria Today there are about three hundred cor his intuition.some g neral rules and guiding-principles for this often difficult choice The present book is b sed on an earlier erback"Losungsmitteleftekte in der Che which though follo t has hee ded and bro ught up to date.The boc k is dire ted hoth oward the industrial and ad ade ic chemist and ticularly the ced student of chemist yho on the ne hand ne for the solvent but on th hes to dra eac the olvent eftects ve wledge of the pny ical principles of solve cts is requ ired for prope ork Th ent is pre a clas ical equ cription solven vent polarity are giver y,empi n an ines to t e everyday are g nt effects examined is piete des would 85 (1976),approximately e rticl spe in which the words 'Solvent effects on appeared in the title. he pres only a lew mportant and relatively well-define d areas of genera mportance have been selected.The book has been written from the point of view of practical use for the organic chemist rather than from a completely theoretical one In the selection of the literature more recent reviews were taken into account mainly.Original papers were cited in particular from the didactic point of view rather

Preface to the First Edition The organic chemist usually works with compounds which possess labile covalent bonds and are relatively involatile, thereby often rendering the gas-phase unsuitable as a reaction medium. Of the thousands of reactions known to occur in solution only few have been studied in the gas-phase, even though a description of reaction mechanisms is much simpler for the gas-phase. The frequent necessity of carrying out reactions in the presence of a more or less inert solvent results in two main obstacles: The reaction depends on a larger number of parameters than in the gas-phase. Consequently, the experimental results can often be only qualitatively interpreted because the state of aggregation in the liquid phase has so far been insu‰ciently studied. On the other hand, the fact that the interaction forces in solution are much stronger and more varied than in the gas-phase, permits to a¤ect the properties and reactivities of the solute in manifold modes. Thus, whenever a chemist wishes to carry out a chemical reaction he not only has to take into consideration the right reaction partners, the proper reaction vessels, and the appropriate reaction temperature. One of the most important features for the success of the planned reaction is the selection of a suitable solvent. Since solvent e¤ects on chemical reactivity have been known for more than a century, most chemists are now familiar with the fact that solvents may have a strong influence on reaction rates and equilibria. Today, there are about three hundred common solvents available, nothing to say of the infinite number of solvent mixtures. Hence the chemist needs, in addition to his intuition, some general rules and guiding-principles for this often di‰cult choice. The present book is based on an earlier paperback ‘‘Lo¨sungsmittele¤ekte in der organischen Chemie’’ [1], which, though following the same layout, has been completely rewritten, greatly expanded, and brought up to date. The book is directed both toward the industrial and academic chemist and particularly the advanced student of chemistry, who on the one hand needs objective criteria for the proper choice of solvent but on the other hand wishes to draw conclusions about reaction mechanisms from the observed solvent e¤ects. A knowledge of the physico-chemical principles of solvent e¤ects is required for proper bench-work. Therefore, a description of the intermolecular interactions between dissolved molecules and solvent is presented first, followed by a classification of solvents derived therefrom. Then follows a detailed description of the influence of solvents on chemical equilibria, reaction rates, and spectral properties of solutes. Finally, empirical parameters of solvent polarity are given, and in an appendix guidelines to the everyday choice of solvents are given in a series of Tables and Figures. The number of solvent systems and their associated solvent e¤ects examined is so enormous that a complete description of all aspects would fill several volumes. For example, in Chemical Abstracts, volume 85 (1976), approximately eleven articles per week were quoted in which the words ‘‘Solvent e¤ects on . . .’’ appeared in the title. In the present book only a few important and relatively well-defined areas of general importance have been selected. The book has been written from the point of view of practical use for the organic chemist rather than from a completely theoretical one. In the selection of the literature more recent reviews were taken into account mainly. Original papers were cited in particular from the didactic point of view rather

XII Preface to the First Edition than priority importanc e the th 正a reade are given. The ture up un til De 1977 es of the the recommendations of the Symbol Com 19712 am very gra teful to Pr Karl Dimroth th,Marburg who first sti nterest in sol effects in organ emistry.I am indebted to Urbana/Illinc is,D.Seebach,Zirich/Switzerland,J.Shorter,Hull/England,and nume for helpfuladvice and so due to the authors and publishers of copyrighted materials reproduced with their permission (cf.Figure and Table credits on page 495).For the careful translation and improvement of the English manuscript I thank Dr.Edeline Wentrup-Byrne,Marburg.Without the assistance and patience of my wife Maria.this book would not have been written. Marburg (Lahn),Summer 1978 Christian Reichardt References meder orghe Chemie.dto Verlag Chemie. en chimie organique (translation of the first-mentioned title into French,by I.Tkatchenko),Flamma 191 aslation of the first-mentioned title into Russian,by E.R Zakhsa).Izdatel'stvo Khimiya,Leningrad 1973. nm isud by The ymbols Commitee of the Royal Society Lo

than priority, importance or completeness. This book, therefore, does not only have the character of a monograph but also to some extent that of a textbook. In order to help the reader in his use of the literature cited, complete titles of the review articles quoted are given. The literature up until December 1977 has been considered together with a few papers from 1978. The use of symbols follows the recommendations of the Symbols Committee of the Royal Society, London, 1971 [2]. I am very grateful to Professor Karl Dimroth, Marburg, who first stimulated my interest in solvent e¤ects in organic chemistry. I am indebted to Professors W. H. Pirkle, Urbana/Illinois, D. Seebach, Zu¨rich/Switzerland, J. Shorter, Hull/England, and numer￾ous other colleagues for helpful advice and information. Thanks are also due to the authors and publishers of copyrighted materials reproduced with their permission (cf. Figure and Table credits on page 495). For the careful translation and improvement of the English manuscript I thank Dr. Edeline Wentrup-Byrne, Marburg. Without the assistance and patience of my wife Maria, this book would not have been written. Marburg (Lahn), Summer 1978 Christian Reichardt References [1] C. Reichardt: Lo¨sungsmittele¤ekte in der organischen Chemie. 2nd edition. Verlag Chemie, Weinheim 1973; E¤ets de solvant en chimie organique (translation of the first-mentioned title into French, by I. Tkatchenko), Flammarion, Paris 1971; Rastvoriteli v organicheskoi khimii (translation of the first-mentioned title into Russian, by E. R. Zakhsa), Izdatel’stvo Khimiya, Leningrad 1973. [2] Quantities, Units, and Symbols, issued by The Symbols Committee of the Royal Society, Lon￾don, in 1971. XII Preface to the First Edition

Contents 1 Introduction......................................................... 1 2 Solute-Solvent Interactions.. Solutions 2.4 ntermolecular Forces.,..,..,,..,,,.,.,.,.,...,,...,.,...,,.,.,... 510 2.2.1 Ion-Dipole Forces....................................... 10 2.2. Dipole-Dipole Forces.. 2.3 Dipole-Induced Dipole Forces 2.2.4 Instantaneous Dipole-Induced Dipole Forces......................... 13 2.2.5 Hydrogen Bonding... 2.2.6 Electron-Pair Donor/Electron-Pair Acceptor Interactions(EPD/EPA nteractions)............................................... 。。。。。。 19 2.2.7 Solvophobic Interactions............................................ 7 2.3 Solvation 30 2.4 Selective Solvation. 38 2.5 Micellar Solvation(Solubilization)........ 42 2.6 Ionization and Dissociation..... 46 3 Classification of Solvents. 57 3.1 Classification of Solvents according to Chemical Constitution......... 3.2 Classification of Solvents using Physical Constants. 62 3.3 Classification of Solvents in Terms of Acid-Base Behaviour.... 3.3.1 Bronsted-Lowry Theory of Acids and Bases.......................... 13 3.3.2 Lewis Theory of Acids and Bases.. 9 3.4 Classification of Solvents in Terms of Specific Solute/Solvent Interactions.. 82 3.5 Classification of Solvents using Multivariate Statistical Methods....... 4 Solvent Effects on the Position of Homogeneous Chemical Equilibria.... 93 4.1 General Remarks. 93 4.2 Solvent Effects on Acid/Base Equilibria... 95 4.2.1 Bronsted Acids and Bases in Solution...... 95 42.2 Gas-Phase Acidities and Basicities. 99 4.3 Solvent Effects on Tautomeric Equilibria 106 43.1 Solvent Effects on Keto/Enol Equilibria. 106 432 Solvent Effects on other Tautomeric Equilibria 113 44 Solvent Effects on other Equilibria. 121 441 Solvent effects on Bronsted acid/Base equilibria 121 4.4.2 Solvent effects on lewis acid/Base equilibria 123 443 Solvent Effects on Conformational Equilibria 126 4.4.4 Solvent effects on cis/trans or e/z Isomerization eauilibria 132 A45 Solvent Effects on Valence Iso erization Equilibria 135 446 ent Effects on Electron-Transfer Equilibria 137 44.7 ent Effects on Host/Guest Complexation Equilibria. 139

Contents 1 Introduction ......................................................... 1 2 Solute-Solvent Interactions ........................................... 5 2.1 Solutions . .......................................................... 5 2.2 Intermolecular Forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.2.1 Ion-Dipole Forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.2.2 Dipole-Dipole Forces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.2.3 Dipole-Induced Dipole Forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.2.4 Instantaneous Dipole-Induced Dipole Forces . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.2.5 Hydrogen Bonding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.2.6 Electron-Pair Donor/Electron-Pair Acceptor Interactions (EPD/EPA Interactions) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2.2.7 Solvophobic Interactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 2.3 Solvation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 2.4 Selective Solvation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 2.5 Micellar Solvation (Solubilization) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 2.6 Ionization and Dissociation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 3 Classification of Solvents............................................. 57 3.1 Classification of Solvents according to Chemical Constitution . . . . . . . . . 57 3.2 Classification of Solvents using Physical Constants . . . . . . . . . . . . . . . . . . . . 62 3.3 Classification of Solvents in Terms of Acid-Base Behaviour. . . . . . . . . . . . 73 3.3.1 Brønsted-Lowry Theory of Acids and Bases . . . . . . . . . . . . . . . . . . . . . . . . . . 73 3.3.2 Lewis Theory of Acids and Bases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 3.4 Classification of Solvents in Terms of Specific Solute/Solvent Interactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 3.5 Classification of Solvents using Multivariate Statistical Methods . . . . . . . 84 4 Solvent E¤ects on the Position of Homogeneous Chemical Equilibria .... 93 4.1 General Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 4.2 Solvent E¤ects on Acid/Base Equilibria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 4.2.1 Brønsted Acids and Bases in Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 4.2.2 Gas-Phase Acidities and Basicities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 4.3 Solvent E¤ects on Tautomeric Equilibria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 4.3.1 Solvent E¤ects on Keto/Enol Equilibria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 4.3.2 Solvent E¤ects on other Tautomeric Equilibria . . . . . . . . . . . . . . . . . . . . . . . 113 4.4 Solvent E¤ects on other Equilibria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 4.4.1 Solvent E¤ects on Brønsted Acid/Base Equilibria . . . . . . . . . . . . . . . . . . . . . 121 4.4.2 Solvent E¤ects on Lewis Acid/Base Equilibria . . . . . . . . . . . . . . . . . . . . . . . . 123 4.4.3 Solvent E¤ects on Conformational Equilibria . . . . . . . . . . . . . . . . . . . . . . . . . 126 4.4.4 Solvent E¤ects on cis/trans or E/Z Isomerization Equilibria . . . . . . . . . . . 132 4.4.5 Solvent E¤ects on Valence Isomerization Equilibria . . . . . . . . . . . . . . . . . . . 135 4.4.6 Solvent E¤ects on Electron-Transfer Equilibria . . . . . . . . . . . . . . . . . . . . . . . 137 4.4.7 Solvent E¤ects on Host/Guest Complexation Equilibria . . . . . . . . . . . . . . . 139

XIV Contents 5 Solvent Effects on the Rates of Homogeneous Chemical Reactions...... 147 1 General Remarks. 5.2 Gas-Phase Reactivities 155 5.3 Qualitative Theory of Solvent Effects on Reaction Rates.. 162 531 The Hughes-Ingold Rules 163 5.3.2 Solvent Effects on Dipolar Transition State Reactions. 533 Solvent Effeets on Is olar Transition State Reactions. 5.3.4 Solvent Effects on Free-Radical Transition State Reactions 199 535 Limitations of the Hughes-Ingold Rules 215 5.4 Quantitative Theories of Solvent Effects on Reaction Rates 218 541 General Remarks 218 54) Reactions between Neutral.Apolar Molecules 219 543 Reactions between ner ral Dinolar molecule 225 utral Molecules and Ion 233 545 234 5.5 ecific Solvation Effects on Reaction Rates 237 551 eof Specific Anion Solvation on the Rates of SN and other 238 552 and Dipolar Aprotic Solve 243 5.5.3 polar R of Solvent-Tran Aprotic Solvents ation or 556 Reactions. ven 5.5.7 on the Effects on Mechanisms and Stereochemistry of Organic 273 5.5.8 of Micelar n and Mechanisms. Reaction Rates 292 Liquid Crystals as Reaction Media..................... Solvent Ca age Effects. 5.5.11 External Pressure and Solvent Effects on Reaction Rates............. 5.5.12 00 Solvent Isotope Effects.................. 5.5.13 Reactions in Biphasic Solvent Systems and in Neoteric Solvents....... 317 6 Solvent Effects on the Absorption Spectra of Organic Compounds...... 329 61 62 on UV/Vis S nic Co pectra.. 8 mp 330 f Sol s on UV/Vis 340 vent ects on UV/Vi Ab sorption Spectra .............. 6.25 Efects on ORD and CD Spectra 6.3 Solvent cts on 6.4 frared Spectra fects on Electron Spin Resonance Spectra

5 Solvent E¤ects on the Rates of Homogeneous Chemical Reactions...... 147 5.1 General Remarks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147 5.2 Gas-Phase Reactivities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 5.3 Qualitative Theory of Solvent E¤ects on Reaction Rates. . . . . . . . . . . . . . 162 5.3.1 The Hughes–Ingold Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 5.3.2 Solvent E¤ects on Dipolar Transition State Reactions . . . . . . . . . . . . . . . . 173 5.3.3 Solvent E¤ects on Isopolar Transition State Reactions. . . . . . . . . . . . . . . . 187 5.3.4 Solvent E¤ects on Free-Radical Transition State Reactions . . . . . . . . . . . 199 5.3.5 Limitations of the Hughes–Ingold Rules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215 5.4 Quantitative Theories of Solvent E¤ects on Reaction Rates. . . . . . . . . . . 218 5.4.1 General Remarks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218 5.4.2 Reactions between Neutral, Apolar Molecules . . . . . . . . . . . . . . . . . . . . . . . 219 5.4.3 Reactions between Neutral, Dipolar Molecules. . . . . . . . . . . . . . . . . . . . . . . 225 5.4.4 Reactions between Neutral Molecules and Ions . . . . . . . . . . . . . . . . . . . . . . 233 5.4.5 Reactions between Ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234 5.5 Specific Solvation E¤ects on Reaction Rates . . . . . . . . . . . . . . . . . . . . . . . . . 237 5.5.1 Influence of Specific Anion Solvation on the Rates of SN and other Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238 5.5.2 Protic and Dipolar Aprotic Solvent E¤ects on the Rates of SN Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243 5.5.3 Quantitative Separation of Protic and Dipolar Aprotic Solvent E¤ects for Reaction Rates by Means of Solvent-Transfer Activity Coe‰cients 254 5.5.4 Acceleration of Base-Catalysed Reactions in Dipolar Aprotic Solvents 259 5.5.5 Influence of Specific Cation Solvation on Rates of SN Reactions . . . . . . 262 5.5.6 Solvent Influence on the Reactivity of Ambident Anions. . . . . . . . . . . . . . 269 5.5.7 Solvent E¤ects on Mechanisms and Stereochemistry of Organic Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273 5.5.8 Influence of Micellar and Solvophobic Interactions on Reaction Rates and Mechanisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292 5.5.9 Liquid Crystals as Reaction Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298 5.5.10 Solvent Cage E¤ects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303 5.5.11 External Pressure and Solvent E¤ects on Reaction Rates . . . . . . . . . . . . . 308 5.5.12 Solvent Isotope E¤ects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315 5.5.13 Reactions in Biphasic Solvent Systems and in Neoteric Solvents. . . . . . . 317 6 Solvent E¤ects on the Absorption Spectra of Organic Compounds ...... 329 6.1 General Remarks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329 6.2 Solvent E¤ects on UV/Vis Spectra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330 6.2.1 Solvatochromic Compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330 6.2.2 Theory of Solvent E¤ects on UV/Vis Absorption Spectra. . . . . . . . . . . . . 340 6.2.3 Specific Solvent E¤ects on UV/Vis Absorption Spectra . . . . . . . . . . . . . . . 348 6.2.4 Solvent E¤ects on Fluorescence Spectra. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352 6.2.5 Solvent E¤ects on ORD and CD Spectra . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359 6.3 Solvent E¤ects on Infrared Spectra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363 6.4 Solvent E¤ects on Electron Spin Resonance Spectra . . . . . . . . . . . . . . . . . . 369 XIV Contents

Contents XV 6.5 Solvent Effects on Nuclear Magnetic Resonance Spectra 1 6.5.1 Nonspecific Solvent Effects on NMR Chemical Shifts 6.5.2 Specific Solvent Effects on NMR Chemical Shifts 381 6.5.3 Solvent Effects on Spin-Spin Coupling Constants 387 7 Empirical Parameters of Solvent Polarity........... 389 7.1 Linear Gibbs Energy Relationships 389 7.2 solvent Polarity fr 86 pirical Parameters of Solvent Polarity from Spectroscopi ts pi ical Parameters of Soh relation and Applic 445 Multiparameter Approaches 452 Appendix 7 Properties,Purification,and Use of Organic Solvents.................. Physical Properties..... A.2 Purification of Organic Solvents..................................... 471 A.3 Spectroscopic Solvents 479 A.4 Solvents as Reaction Media......................................... 488 Solvents for Recrystallization... 488 A.6 Solvents for Extraction and Partitioning (Distribution)................ A.7 Solvents for Adsorption Chromatography. 492 A.8 Solvents for Acid/Base Titrations in Non-Aqueous Media............ 496 A.9 Solvents for Electrochemistry........ 496 A.10 Toxicity of Organic Solvents..................................... 500 References.......................................................... 509 Figure and Table Credits 。。 581 Subject Index 583 Author Index 599

6.5 Solvent E¤ects on Nuclear Magnetic Resonance Spectra . . . . . . . . . . . . . . 375 6.5.1 Nonspecific Solvent E¤ects on NMR Chemical Shifts . . . . . . . . . . . . . . . . . 375 6.5.2 Specific Solvent E¤ects on NMR Chemical Shifts . . . . . . . . . . . . . . . . . . . . . 381 6.5.3 Solvent E¤ects on Spin-Spin Coupling Constants . . . . . . . . . . . . . . . . . . . . . 387 7 Empirical Parameters of Solvent Polarity ............................. 389 7.1 Linear Gibbs Energy Relationships. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389 7.2 Empirical Parameters of Solvent Polarity from Equilibrium Measurements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396 7.3 Empirical Parameters of Solvent Polarity from Kinetic Measurements . 402 7.4 Empirical Parameters of Solvent Polarity from Spectroscopic Measurements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411 7.5 Empirical Parameters of Solvent Polarity from other Measurements . . . 443 7.6 Interrelation and Application of Solvent Polarity Parameters . . . . . . . . . . 445 7.7 Multiparameter Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 452 Appendix ................................................................... 471 A. Properties, Purification, and Use of Organic Solvents. . . . . . . . . . . . . . . . . . 471 A.1 Physical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 471 A.2 Purification of Organic Solvents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 471 A.3 Spectroscopic Solvents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 479 A.4 Solvents as Reaction Media. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 488 A.5 Solvents for Recrystallization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 488 A.6 Solvents for Extraction and Partitioning (Distribution) . . . . . . . . . . . . . . . . 490 A.7 Solvents for Adsorption Chromatography . . . . . . . . . . . . . . . . . . . . . . . . . . . . 492 A.8 Solvents for Acid/Base Titrations in Non-Aqueous Media . . . . . . . . . . . . . 496 A.9 Solvents for Electrochemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 496 A.10 Toxicity of Organic Solvents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500 References.................................................................. 509 Figure and Table Credits .................................................... 581 Subject Index ............................................................... 583 Author Index ............................................................... 599 Contents XV