LECTURE NOTES SOLUTION CHEMISTRY

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1 LECTURE NOTES ON SOLUTION CHEMISTRY

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3 LECTURE NOTES ON SOLUTION CHEMISTRY Viktor Gutmann Gerhard Resch Wien, Technical University, Austria World Scientific Singapore»New Jersey London Hong Kong

4 Published by World Scientific Publishing Co. Pte. Ltd. P O Box 128, Farrer Road, Singapore 9128 USA office: Suite IB, 1060 Main Street, River Edge, NJ UK office: 57 Shelton Street, Covent Garden, London WC2H 9HE Library of Congress Cataloging-in-Publication Data Gutmann, Viktor Lecture notes on solution chemistry / by Viktor Gutmann and Gerhard Resch. p. cm. Includes index. ISBN Solution (Chemistry) I Resch, Gerhard, II. Tide QD541.G '4--dc CIP British Library Cataloguing-in-Publication Data A catalogue record of this book is available from the British Library. Copyright 1995 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. This book or parts thereof, may not be reproduced in any form or by any means, electronic or mechanical, including photocopying, recording or any information storage and retrieval system now known or to be invented, without written permission from the Publisher For photocopying of material in this volume, please pay a copying fee through the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA USA. Printed in Singapore.

5 V PREFACE One of the authors of this book has been active in research concerning liquid solutions for nearly half a century ' and both of them have been in close cooperation for more than 20 years on this subject as well as on the philosophical foundations of the acquisition of knowledge of "things as they are" These activities have been linked with extensive lecturing The arrangement of the 21 lectures in this book should help to provide a better understanding of the liquid state, particularly of water and its solutions It is not a new theory, derived from imagination that is presented, but rather a new approach to the understanding of the qualities of solutions In the first Chapter a brief historical account about the development of solution chemistry is presented, together with its present emphasis on quantitative aspects. The second Chapter deals with the fact that atoms and molecules are real only within the continuous relationships found in nature, from which they actually cannot be removed as "isolated entities" Molecular changes are described by the extended donor-acceptor approach, which is independent of model assumptions. Its limitations for an understanding of the properties of a liquid lead us to turn our attention to water, the most abundant and versatile liquid on earth and a "conditio sine qua non" for all life processes. In order to learn about the "potentialities" i.e. the abilities of water and its molecules which are developing under appropriate complex conditions, it is necessary to study water under complex conditions, not only under selected and simplified experimental conditions. It is pointed out that a solution always acts as a unity and this requires a high differentiation in itself. Chapters 6 to 12 are devoted to a description of various observations on water and its solutions, both under natural and under experimental conditions, and to the elucidation of their molecular differentiation In Chapters 13 to 15 we present the current state of knowledge of chemistry in non-aqueous solutions and their differentiations After consideration of all of these facts, Chapter 16 is devoted to the methodology of ordering the observed facts according to natural requirements rather than according to our model assumptions. The differences and the connections between quality and quantity are outlined and the hierarchical differences between different molecules established These observable differences lead to the conclusion that each observable thing must be subject to a "system organization", which is a ' H Gamsjager, Coord Chem. Rev 135 (1994) 1

6 VI requirement for its characteristic quality. Their study requires similarity considerations rather than the exclusive consideration of quantitative aspects that is applied in system theory In the following Chapters the approach is presented as a means of gaining knowledge of the system organization of liquid water and its solutions. It is shown that supercooled water is highly organized and that water provides for both the unity of the human body as well as its differentiation. Chapter 20 deals with the organization of non-aqueous solutions with emphasis on the role of traces of water. In the last Chapters guidelines are presented for intramolecular system organizations. In these ways a new outlook appears to be forged, not only for chemistry, but also for biochemistry, biology, medicine and other branches of science It is hoped that extended research in all fields of science may be stimulated for scientists who are prepared to overcome their specialist attitude and to reorganize their knowledge in order to learn more about the natural requirements for the existence of things, their qualities, and their system organizations. The authors wish to express their special gratitude to Prof. Reginald F Jameson, University of Dundee/Scotland for reading the manuscript and for providing useful suggestions, to Dr. Christiana Kuttenberg for the preparation of the tables and to Mr. Harald Schauer for the production of all of the figures. Special thanks are due to the daughter of the first author, Elisabeth Bruckner, for the preparation of the "camera ready" layout and last, but not least, to Dr. Rumen Duhlev of World Scientific Publishing Co for having encouraged us to make this contribution and for its publication Vienna, May 1995 Viktor Gutmann and Gerhard Resch

7 VII CONTENTS Preface v Chapter 1 Development and Present State 1 1. The Qualitative Approach 1 2. Advancement of Quantitative Considerations 2 3. Reversible Thermodynamics 4 4. The Ionic Theory 5 5. Chemical Kinetics 6 6. Non-Aqueous Solutions 7 7. Solute Structures 7 8. Irreversible Thermodynamics 8 9. Modern Calculation Techniques Conclusions 9 Chapter 2 Atoms and Molecules Early Views Ether Concept and Atomism The Field Concept and the Ether Concept Quantum Mechanics The Concept of the Vacuum Field Observability and Measurability of Atoms and Molecules 16 Chapter 3 Chemical Bonding Introduction Stoichiometry The Electrostatic Approach Covalency Advances and Limitations of Quantum Chemistry 22 Chapter 4 Interactions between Molecules General Chemical Functionality Variations in Bond Lengths 27 Introduction 27 The First Bond Length Variation Rule and the Pileup and The Spillover Effects 27 The Second Bond Length Variation Rule 31

8 VIII 4. Variations in Bond Angles Effects at Terminal Positions "Intelligent Behaviour'' 37 Chapter 5 The Liquid State Macroscopic Properties Molecular and Structural Properties Theoretical Approaches Suggestions of Ways by which Liquids may be Classified The Molecular Approach to Liquid Water Structural Models for Liquid Water Unsolved Problems 47 Chapter 6 Anomalous Physical Properties of Liquid Water General Anomalies in the Normal Liquid Range 53 Melting Point and Boiling Point 53 Heat of Vaporization and Surface Tension 54 Density 55 Heat Capacity 55 Thermal Conductivity 57 Compressibility 57 Viscosity 57 Dielectric Constant 58 Other Effects Anomalies in the Supercooled State 58 Temperature Range of Supercooled Water 58 Molar Heat Capacity 60 Density 61 Compressibility 61 Gas Solubilities 63 Free Energy and Entropy Liquid Water at High Temperatures and Pressures 65 Chapter 7 Some Trivia about Water General Water as a Solvent 69 Complete Miscibilities 69 Hydrophilic Solutes 70 Hydrophobic Solutes 71

9 IX Amphipathic Solutes Reactivity of Water 72 Self-Ionization 72 Hydrolysis Reactions 73 Redox Reactions The Hydrologic Cycle 74 Chapter 8 The Phase Boundary of Liquid Water Introduction Surface Tension Characterization of a Phase Boundary The Electrical Double Layer Bond Length Considerations Water in Thin Layers Water Effects in Extremely Thin Layers Water at Interfaces in Biological Systems 85 Chapter 9 Water in Biological Systems Amphipathic Solutes Surfactants Micelles Phospholipid - Bilayers The Role of Membranes in the Organism 94 Chapter 10 Hydrophobic Solutes in Water Solubility Considerations Structural Aspects Structures and Properties of Solutions Dynamic Features 105 Chapter 11 Hydrophilic Solutes in Water Hydrated Ions in Pure Water Structure of Hydrated Hydrogen Ions The Donor - Acceptor Approach to the Hydration of Ions Solution Structures 115 Chapter 12 Water and Alcohols Liquid Alcohols Physical Properties of Water - Alcohol Mixtures 119 Freezing and Boiling Points 119

10 X Vapour Pressure 120 Surface Tension 120 Density and Volume of Mixing 120 Molar Heat Capacity 122 Gas Solubilities 122 Adiabatic Compressibility 123 Viscosity Physical and Molecular Properties 125 Chapter 13 Characterization of Non-Aqueous Solvents Historical Solvent Properties The Donor - Acceptor Approach Colour Indicators for the Estimation of Donor- and Acceptor Properties 137 Estimation of Donor Properties 138 Estimation of Acceptor Properties 140 Chapter 14 Solvation in Non-Aqueous Solvents Cation Solvation Anion Solvation Solvation in Solvent Mixtures 152 Preferential Solvation 152 Homoselective and Heteroselective Solvation 154 Chapter 15 lonization and Association in Non-Aqueous Solutions lonization Formation of Reactive Anions Formation of Reactive Cations Ion Association 160 Solvent - Separated Ion Pairs 160 Contact Ion Pairs 161 Other Hydrogen Bonded Features Less Common Aspects of Non-Aqueous Solvents 164 Non-Aqueous Micelles 164 Hardly Removable Solutes 165 Chapter 16 Qualitative Aspects of the Molecular Concept Impact and Limitations of the Present Molecular Concept Quality and Quantity 169

11 xi 3. Starting Points for Qualitative Investigations Dynamically Ordered Relations System Considerations Order and Finality System Organization Introduction of Hierarchic Levels 181 Chapter 17 System Organization of Liquid Water General Considerations The Boundary Areas as Highest Hierarchic Level The Decisive Role of Voids and of Dissolved Gases The Role of Hydrophilic Solutes The Role of all other Solvent Molecules Illustration of the System Organization 191 Chapter 18 Changes in Organization of Liquid Water Changes in the Temperature Range between 0 C and 100 C Supercooled Water Water in Thin Layers Actions of Hydrophilic Solutes Electrode - Electrolyte Interfaces Static Aspects of the System Organization 203 Chapter 19 Water within the Human Body The Human Organism Water and the Unity of the Body Water and Information Water and the Differentiation of the Human Body 209 Cell Membranes as Parts of the Water System 209 Boundaries Within the Cell 212 Genetic Information 212 Boundaries Outside the Cell 213 Chapter 20 Organization in Non-Aqueous Solutions Protic Solvents and their Solutions Aprotic Solvents and their Solutions 217 "Structured" Solvents 217 Other Aprotic Solvents Changes in Organization 219 Influence of Solutes 219

12 XII Remarks on Homogeneous Catalysis 222 Chapter 21 Intramolecular System Organizations Tris(phenantroline)-iron Complexes Solvatochromic Complexes 227 Bis(phenantroline) iron(h)cyanide 227 Copper(II)-Complexes with Tetramethylethylenediamine and a p-diketone Haemoglobin Water Molecules 230 Epilogue 233 Index 235