MOLECULES IN PHYSICS, CHEMISTRY, AND BIOLOGY TOPICS IN MOLECULAR ORGANIZATION AND ENGINEERING Honorary Chief Editor: W. N. LIPSCOMB (Harvard, U.S.A.) Executive Editor: Jean MARUANI (Paris, France) Editorial Board: Henri AT LAN (Jerusalem, Israel) Alexandre LAFORGUE (Reims, France) Sir Derek BAR TON (Texas, U.S.A.) J-M. LEHN (Strasbourg, France) Christiane BONNELLE (Paris, France) P-O. LODWIN (Uppsala, Sweden) Paul CAR 0 (Meudon, France) Patrick MacLEOD (Massy, France) Stefan CHRISTOV (Sofia, Bulgaria) H. M. McCONNELL (Stanford, U.S.A.) I. G. CSIZMADIA (Toronto, Canada) C. A. McDOWELL (Vancouver, Canada) P-G. DE GENNES (Paris, France) Roy McWEENY (pisa, Italy) J-E. DUBOIS (Paris, France) Ilya PRIGOGINE (Brussels, Belgium) Manfred EIGEN (Gottingen, Germany) Paul RIGNY (Saclay, France) Kenishi FUKUI (Kyoto, Japan) Ernest SCHOFFENIELS (Liege, Belgium) Gerhard HERZBERG (Ottawa, Canada) R. G. WO OLLEY (Nottingham, U.K.) Molecules in Physics, Chemistry, and Biology Volume 3 Electronic Structure and Chemical Reactivity Edited by JEAN MARUANI Centre de Mecanique Ondulatoire Appliquee, Laboratoire de Chimie Physique, CNRS and University of Paris, France. Kluwer Academic Publishers Dordrecht / Boston / London Library of Congress Cataloging in Publication Data Molecules in physics, chemsitry, and biology. (Topics in molecular organization and engineering) Includes bibliographies and indexes. Contents: v. 1. General introduction to molecular sciences -- -- v. 3. Electronic structure and chemical reactivity. 1. Molecules. I. Maruani, Jean, 1937- II. Series. QC173.M645 1988 539' .6 88-6811 lSBN-13: 978-94-010-7783-5 e-lSBN-13: 978-94-009-2853-4 DOl: 10.1007/ 978-94-009-2853-4 Published by Kluwer Academic Publishers, P.O. Box 17, 3300 AA Dordrecht, The Netherlands. Sold and Distributed in the U.S.A. and Canada by Kluwer Academic Publishers, 101 Philip Drive, Norwell, MA 02061, U.S.A. In all other countries, sold and distributed by Kluwer Academic Publishers Group, P.O. Box 322, 3300 AH Dordrecht, The Netherlands. All Rights Reserved © 1989 by Kluwer Academic Publishers, Dordrecht, The Netherlands. Softcover reprint of the hardcover 1s t edition 1989 No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical including photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner Table of Contents Introduction to the Series / W. N. Lipscomb ix Preface to Molecules in Physics, Chemistry, and Biology / Jean Maruani xiii Preface to Volume 3 / Roy McWeeny xix DENSITY FUNCTIONS AND ELECTRONIC STRUCTURE The Molecule as a Many-Electron System: Electron Densities and Molecular Properties / R. McWeeny 3 1. Introduction 3 2. Electron Density Functions 4 3. Electronic Properties - Response 8 4. Static Response to Uniform Fields 13 5 . Spin-Dependent Properties 18 6. Dynamic Response and Related Properties 22 7. Conclusion 28 References 29 Analysis of the Electronic Density as a Support of the Concepts of Empirical Structural Chemistry / J. M. Garcia de la Vega, R. Lopez, J. R. Alvarez Collado, J. Fernandez Rico, and J.I. Fernandez Alonso 31 1. Introduction 31 2. Partitioning of the Electronic Density 32 3. Results and Discussion 37 4. Atoms and Functional Groups 41 Acknowledgements 47 References 47 Molecules as Ensembles of Modified Atoms / Z. B. Maksic 49 1. Introduction 49 2. Modified Atoms in Molecules 51 3. Conclusion 69 Acknowledgements 69 References 69 The Physical Basis of the Lewis Electron Pair Model / R. F. W. Bader 73 I. The Challenge and Lewis Model 73 vi T ABLE OF CONTENTS II. Properties of Density and Density Difference Functions 74 IIT. The Localization of Electrons 75 IV. The Laplacian of the Charge Density as a Basis for the Lewis Model 80 V. Summary and Conclusions 90 Dedication 91 References 91 The Chemical Bond and Model Exchange-Correlation Potentials / R. Gaspar and A Nagy 93 1. Introduction 93 2. The Hohenburg-Kohn Theorem and the Kohn-Sham Method 95 3. The Kinetic Energy Functional 97 4. The Exchange-Correlation Functional 98 5. Application to Chemical Systems 106 6. Problems and Prospects 107 References 108 Study of Chemical Bonding in Molecules: The Interest of Polarised Neutron Diffraction / B. Gillon and J. Schweizer 111 1. Introduction 111 2. Polarised Neutron Diffraction 112 3. 3d Transition Metal Complexes 119 4. Organic Free Radicals 132 5. Conclusion 144 References 146 A Valence Concept for Molecular Structure and Reactions /Karl Jug 149 1. Historical Survey 149 2. Valence Index 150 3. Normal Valence versus Sub-and Hypervalence 159 4. Subvalence 161 5. Hypervalence 163 6. Geometry Changes 167 Acknowledgements 169 References 169 STRUCTURE AND REACTIVITY OF ORGANIC COMPOUNDS On the Role of the Orbital Interaction Concept in the Interpretation of Organic Free Radical Structures and Reactivities / Andrea Bottoni, Jacques Fossey, and Daniel Lefort 173 1. Introduction 173 2. Theoretical Aspects 174 TABLE OF CONTENTS vii 3. Interpretation of Free-Radical Reactivities 185 4. A Quantitative PMO Analysis 196 5. Conclusion 214 References 215 Theoretical Studies on the Reactions of Free Radicals / J. J. Dannenberg 221 1. Introduction 221 2. Thermolysis of Azoalkanes 221 3. Bimolecular Radical Combinations 225 4. Disproportionations 228 5. Conclusion 230 References 231 Thermochemistry and Kinetics of Ionic and Radical Reactions in the Gas Phase / G. Leroy, D. Peeters, M. Sana, and C. Wilante 233 1. Introduction 233 2. The Concept of Stabilization Energy 233 3. Thermochemistry and Kinetics of Elementary Processes 238 4. Rate Constant Calculations in Transition State Theory 252 5. Conclusions 255 Acknowledgement 256 References 256 Hydrocarbon Radical Cations in Condensed Phases / A. Lund, M. Lindgren, S. Lunell, and J. Maruani 259 1. Introduction 259 2. Generation and Stabilization of Radical Cations 260 3. Experimental Results 264 4. Theoretical Calculations 284 Acknowledgements 296 References 296 Recent Developments in Calixarenes and their Properties / D. Gamet, M. Bourakhouadar, Meublat, F. Leveiller, V. Bohmer, D. Jacquemain, J. Vincens, and R. Perrin 301 1. Introduction 301 2. Synthesis of Calixarenes 303 3. Chemical Transformations of Calixarenes 311 4. Conformational Properties 318 5. Inclusion Complexes 323 6. Other Types of Calixarenes and Parent Molecules 331 7. Miscellaneous 334 8. Conclusion 334 References 334 viii TABLE OF CONTENTS THEORETICAL APPROACHES TO CHEMICAL REACTIONS The Reaction-Rate Approach in Physics, Chemistry, and Biology / S. G. Christov 339 1. Introduction 339 2. General Theory 339 3. Applications to Gas-Phase Reactions 345 4. Applications to Dense-Phase Reactions 348 References 354 A Theoretical Study of the Unimolecular Dissociation of Diborane / John F. Stanton, Rodney J. Bartlett, and William N. Lipscomb 357 1. Introduction 357 2. Methods 358 3. Calculations 359 4. Summary of Results 359 Acknowledgements 361 References 362 Mode Selective Biomolecular Reactions / J. Manz 365 1. Introduction: Why Mode Selective Chemical Reactions? 365 2. Hydrogen Atom plus Diatomic Molecule Reactions 367 3. Elementary Hydrogen Transfer Reactions 381 4. Conclusions 396 Acknowledgements 398 References 398 An Overview of the Theory of Chemical Reactions and Reactivity in Enzymes and Solutions / O. Tapia 405 1. Introduction 405 2. Theory 406 3. Molecular Dynamics and Statistics of Reacting Systems 415 4. Conclusions and Perspectives 419 References 420 Index 423 Introduction to the Series The Series 'Topics in Molecular Organization and Engineering' was initiated by the Symposium 'Molecules in Physics, Chemistry, and Biology', which was held in Paris in 1986. Appropriately dedicated to Professor Raymond Daudel, the symposium was both broad in its scope and penetrating in its detail. The sections of the symposium were: 1. The Concept of a Molecule; 2. Statics and Dynamics of Isolated Molecules; 3. Molecular Interactions, Aggregates and Materials; 4. Molecules in the Biological Sciences, and 5. Molecules in Neurobiology and Sociobiology. There were invited lectures, poster sessions and, at the end, a wide-ranging general discussion, appropriate to Professor Daudel's long and distinguished career in science and his interests in philosophy and the arts. These proceedings have been arranged into eighteen chapters which make up the first four volumes of this series: Volume I, 'General Introduction to Molecular Sciences'; Volume II, 'Physical Aspects of Molecular Systems'; Volume ill, 'Electronic Structure and Chemical Reactivity'; and Volume IV, 'Molecular Phenomena in Biological Sciences'. The molecular concept includes the logical basis for geometrical and electronic structures, thermodynamic and kinetic properties, states of aggregation, physical and chemical transformations, specificity of biologically important interactions, and experimental and theoretical methods for studies of these properties. The scientific subjects range therefore through the fundamentals of physics, solid-state properties, all branches of chemistry, bio chemistry, and molecular biology. In some of the essays, the authors consider relationships to more philosophic or artistic matters. In Science, every concept, question, conclusion, experimental result, method, theory or relationship is always open to reexamination. Molecules do exist! Nevertheless, there are serious questions about precise definition. Some of these questions lie at the foundations of modem physics, and some involve states of aggregation or extreme conditions such as intense radiation fields or the region of the continuum. There are some molecular properties that are definable only within limits, for example, the geometrical structure of non-rigid molecules, properties consistent with the uncertainty principle, or those limited by the neglect of quantum-field, relativistic or other effects. And there are properties which depend specifically on a state of aggregation, such as superconductivity, ferroelectric (and anti), ferromagnetic (and anti), superfluidity, excitons, polarons, etc. Thus, any molecular definition may need to be extended in a more complex situation. Chemistry, more than any other science, creates most of its new materials. At least so far, synthesis of new molecules is not represented in this series, although the principles of chemical reactivity and the statistical mechanical aspects are Jean Maruani (ed.), Molecules in Physics, Chemistry, and Biology, Vol. III, ix-x. © 1989 by Kluwer Academic Publishers. x INTRODUCTION TO THE SERIES included. Similarly, it is the more physico-chemical aspects of biochemistry, molecular biology and biology itself that are addressed by the examination of questions related to molecular recognition, immunological specificity, molecular pathology, photochemical effects, and molecular communication within the living organism. Many of these questions, and others, are to be considered in the Series 'Topics in Molecular Organization and Engineering'. In the first four volumes a central core is presented, partly with some emphasis on Theoretical and Physical Chemistry. In later volumes, sets of related papers as well as single monographs are to be expected; these may arise from proceedings of symposia, invitations for papers on specific topics, initiatives from authors, or translations. Given the very rapid development of the scope of molecular sciences, both within disciplines and across disciplinary lines, it will be interesting to see how the topics of later volumes of this series expand our knowledge and ideas. WILLIAM N. LIPSCOMB