Metal complexes play important roles as catalysts or other participants in synthetic and biological reactions. Substrates and sometimes attacking reagents also are activated through coordination with metal atoms or ions. In these events the natures not only of the central metals but also of ancillary ligands exert important influences on the stability and reactivity of the coordinated substrates. A ligand in general can adopt various coordination modes depending on its chemical environment, thus functioning as a probe. The number of coordination modes increases with increasing complexity of the ligand. In this book it is shown that even the simplest mono- and diatomic ligands such as H, CO, and N2 exhibit a variety of coordination modes, which are related to their reactions. The thiocyanate anion is taken up as a representative of the triatomic ambidentate ligands, and factors influencing the preferences for N- und S-bonding are summarized. Coordination chemistry of ss-dicarbonyl compounds is a highlight of this book. Acetylacetone, one of the most familiar Werner ligands, is shown to favor -carbon and n-allylic bonding in many instances. Its versatile behaviour in changing coordination modes is revealed."

Phthalocyanines exhibit intriguing physic-chemical properties that render them important as a class of molecular functional materials. In addition to their tra- tional industrial applications as dyes and pigments, more recently their use as the organic semiconductors,photodynamictherapy medicines, non-linear optical ma- rials, catalysts for the photo oxidation, optical recording materials, and gas sensors attracts great research interests in these tetrapyrrole species. As manifested by the rapidly increasing number of related scienti?c publications in recent years, great progress has been made in the ?eld of advanced phthalocyaninematerials. Tremendous efforts have been paid toward the development of new phtha- cyanine molecular materials as well as toward their applications. Recent emphasis in both academic researches and technical ?eld has been put on the design and synthesis of novel phthalocyanine species, the structure-propertyrelationship, se- assembly properties, molecular electronics and opto-electronics, and dye-sensitized solarcells.Althoughexcellentreviewsandmonographsaboutphthalocyanineswere publishedseveralyearsago,it is time to providea surveyof a numberof newimp- tant developments in this fascinating area of phthalocyanine chemistry. The aim of this book is to bring both the academic and industrial researchers an easy way to the new progress of phthalocyanines made lately in related ?eld.

This book is devoted to nonmetal-to-metal transitions. The original ideas of Mott for such a transition in solids have been adapted to describe a broad variety of phenomena in condensed matter physics (solids, liquids, and fluids), in plasma and cluster physics, as well as in nuclear physics (nuclear matter and quark-gluon systems). The book gives a comprehensive overview of theoretical methods and experimental results of the current research on the Mott effect for this wide spectrum of topics. The fundamental problem is the transition from localized to delocalized states which describes the nonmetal-to-metal transition in these diverse systems. Based on the ideas of Mott, Hubbard, Anderson as well as Landau and Zeldovich, internationally respected scientists present the scientific challenges and highlight the enormous progress which has been achieved over the last years. The level of description is aimed to specialists in these fields as well as to young scientists who will get an overview for their own work. A common feature of all contribution is the extensive discussion of bound states," i.e. their formation and dissolution due to medium effects. This applies to atoms and molecules in plasmas, fluids, and small clusters, excitons in semiconductors, or nucleons, deuterons, and alpha-particles in nuclear matter. In this way, the transition from delocalized to localized states and vice versa can be described on a common level."

This series of books, which is published at the rate of about one per year, addresses fundamental problems in materials science. The contents cover a broad range of topics from small clusters of atoms to engineering materials and involve chemistry, physics, materials science, and engineering, with length scales ranging from Angstroms up to millimeters. The emphasis is on basic science rather than on applications. Each book focuses on a single area of current interest and brings together leading experts to give an up-to-date discussion of their work and the work of others. Each article contains enough references that the interested reader can access the relevant literature. Thanks are given to the Center for Fundamental Materials Research at Michigan State University for supporting this series. M.F. Thorpe, Series Editor E-mail: [email protected] East Lansing, Michigan, November 200 I v PREFACE The study of the atomic structure of crystalline materials began at the beginning of the twentieth century with the discovery by Max von Laue and by W.H. and W.L. Bragg that crystals diffract x-rays. At that time, even the existence of atoms was controversial.

Fundamental QSARs for Metal Ions describes the basic and essential applications of quantitative structure-activity relationships (QSARs) for regulatory or industrial scientists who need to predict metal ion bioactivity. It includes 194 QSARs that have been used to predict metal ion toxicity and 86 QSARs that have been used to predict metal ion bioconcentration, biosorption, and binding. It is an excellent sourcebook for academic, industrial, and government scientists and policy makers, and provides a wealth of information on the biological and chemical activities of metal ions as they impact health and the environment. Fundamental QSARs for Metal Ions was designed for regulatory and regulated organizations that need to use QSARs to predict metal ion bioactivity, as they now do for organic chemicals. It has the potential to eliminate resources to test the toxicity of metal ions or to promulgate regulations that require toxicity testing of metal ions because the book illustrates how to construct QSARs to predict metal ion toxicity. In addition, the book: Provides a historical perspective and introduction to developing QSARs for metal ions Explains the electronic structures and atomic parameters of metals essential to understanding differences in chemical properties that influence cation toxicity, bioconcentration, biosorption, and binding Describes the chemical properties of metals that are used to develop QSARs for metal ions Illustrates the descriptors needed to develop metal ion-ligand binding QSARs Discusses 280 QSARs for metal ions Explains the differences between QSARs for metal ions and Biotic Ligand Models Lists the regulatory limits of metals and provides examples of regulatory applications Illustrates how to construct QSARs for metal ions Dr. John D. Walker is the winner of the 2013 SETAC Government Service Award.

As natural minerals, silica and silicates constitute by far the largest part of the earth's crust and mantle. They are equally important as raw materials and as mass produced items. For this reason they have been the subject of scientific research by geoscientists as well as by applied scientists in cement, ceramic, glass, and other industries. Moreover, intensive fun damental research on silicates has been carried out for many years because silicates are, due to their enormous variability, ideally suited for the study of general chemical and crystallographic principles. Several excellent books on mineralogy and cement, ceramics, glass, etc. give brief, usually descriptive synopses of the structure of silicates, but do not contain detailed discussions of their structural chemistry. A number of monographs on special groups of silicates, such as the micas and clay min erals, amphiboles, feldspars, and zeolites have been published which con tain more crystal chemical information. However, no modern text has been published which is devoted to the structural chemistry of silicates as a whole. Within the last 2 decades experimental and theoretical methods have been so much improved to the extent that not only have a large number of silicate structures been accurately determined, but also a better under standing has been obtained of the correlation between the chemical composition of a silicate and its structure. Therefore, the time has been reached when a modern review of the structural chemistry of silicates has become necessary."

Since the early 1930's, Soviet chemists have played a lead ing role in the study of unfamiliar oxidation state compounds of the peroxide, superoxide, and ozonide types. Interest in the alkali and alkaline earth metal derivatives is now widespread and diverse, and numerous practical applications of these com pounds have evolved, ranging from their use as air revitaliza tion materials in space cabins to their use in compounding semiconductor materials. Professor Vol'nov is eminently qualified to write this monograph since for many years he has been a leading investi gator and prolific writer in the field of peroxide, superoxide, and ozonide chemistry. He has succeeded in presenting a lucid and detailed discussion of past work, the present state, and the future potential of this area of unfamiliar oxidation state chemistry. Of particular interest is Professor Vol 'nov's extensive compilation of available thermodynamic, kinetic, and structural data for the alkali and alkaline earth peroxides, superoxides, and ozonides. In addition, he has reviewed the known methods of synthesis, as well as the practical applications for which these compounds are suited. This monograph will be of interest and value to chemists, not only for the information it imparts, but equally for the information it does not impart, thereby illuminating the re search paths and investigation which must be undertaken in order to increase our knowledge concerning the chemistry of this important class of chemical compounds."

In recent years many research workers have turned their attention to the quantitative characterization of complex compounds and reactions of complex-formation in solution. Instability constants characterize quantitatively the equili bria in solutions of complex compounds and are extensively used by chemists of widely-varying specialities, in analytical chemistry, electrochemistry, the technology of non-ferrous and rare metals, etc., for calculations of various kinds. Despite the wealth of numerical data, no reasonably full coliection of instability constants of complex compounds has been made until now. The various individual collections of data are far from complete and in most cases omit references to the source materials. Moreover, the present state of the chemistry of complex compounds most urgently demands the complete systematization of data on instability constants and an extension of work in this field which would take advantage of the latest physico-chemical methods. The present work contains instability constants for 1,381 complex compounds. We have considered it convenient to preface the summary of the instability constants with an introductory section of a general theoretical character. This section deals with methods for the calculation of instability constants from experimental data, the influence of external conditions, such as temperature and ionic strength, on the stability of com plexes, and the principal factors determining the stability of complex compounds in aqueous solution. (vii) PREFACE In compiling the summary we have used the original litera ture and abstracts for the most part up to 1954, and some work published in 1955-1956."

The upsurge in development of homogeneous catalysis in both aca- demic and industrial areas has prompted us to organize the Second Interna- tional Workshop at Shiga, Japan, 1977. The objective of this workshop was similar to that of the first: to identify opportunities for the solution of energy problems and industrial production problems by homogeneous catalysis. This workshop on homogeneous catalysis was sponsored by the Toray Science Foundation, the Yoshida Foundation for Science and Technology, the Yamada Science Foundation, and the National Science Foundation. The Robert A. Welch Foundation Grant A-420 partially supported the time spent by M. Tsutsui for the organization of the workshop and the edi- torial work of these proceedings. Organizing Committee, April, 1978 Jack Halpern (U.S.A.) Yoshio Ishii Oapan) Jiro Tsuji Oapan) Minoru Tsutsui (U.S.A.) Akio Yamamoto Oapan) v Contents Metal Clusters in Catalysis XVII: Catalytic Hydrocarbon Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 E.L. Muetterties Cluster Catalysis: Homogeneous Catalytic Oxidation of Carbon Monoxide and of Ketones with Molecular Oxygen Using Complexes of Rhodium(O), Iridium(I), and Platinum(O). . . . . . 11 D.M. Roundhill Metal Carbonyl Catalysis of Carbon Monoxide Reactions. . . . . . . . . . 25 . R.B. King, A.D. King, Jr., M.Z. Iqbal, C.C. Frazer and R.M. Hanes Activation of Saturated Hydrocarbons by Ruthenium(I) Complexes? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 . . . . . . . . . . Brian R. James and Daniel K.W. Wang Oxidative Addition to Metal Atoms: Mechanism, Use of Resultant Reactive RMX and R2M Species in Homogeneous Catalysis Processes and Metal Atom-Alkane Interactions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 . . . . . . . . . .

In recent years several improvements have been made in the manufacturing of resistive, superconducting and hybrid mag nets. Condensed matter physicists are nowadays doing ex periments in steady magnetic fields of up to 30 Tesla. But the field homogenity {/B}, required in a volume of the order of a 3 few cm is usually several orders of magnitude less severe than the one which is needed for high resolution NMR. Over the last 30 years, with each generation of new high resolution NMR spectrometers, from 100 MHz up to 600 MHz, taking advan tage of the increase in sensitivity and resolution, new areas of research have been opened in chemistry, physical chemistry and biochemistry. The generation of the 20 Tesla supercon ducting magnets is coming. Thus one may seriously start to consider high resolution NMR at 1 GHz. The purpose of this volume is to examine some of the advantages which can be obtained at such high frequencies and some of the problems we shall be facing. An important aspect of NMR at high field which is not presented in this volume concerns the design of the magnet. The building of a superconducting magnet, producing a field 10 3 higher than 20 T, with a field homogeneity IlB/B 10-, in a cm volume still remains today in 1990 a major challenge. Grenoble, France J. B. Robert Guest-Editor Professor J. B. Robert Service National des Champs Intenses B. P."

For almost a quarter of a century the words "nuclear magnetic reso nance" were synonymous with proton I, leasurements. During this period the literature abounded with a seemingly infinite variety of 1H NHR studies concerned primarily with carbon chemistry. Occasionally a "novel" nucleus was studied and, even in those early days, the poten- 13 14 31 19 tial offered by C, N, P and F was clearly recognized. Despite the allure, the technical difficulties involved in measuring some of these nuclei were far from trivial. Small magnetic moments and low natural abundance in combination with spin-spin coupling from other nuclei, mostly protons, resulted in a signal-to-noise problem whose severity effectively excluded the study of metal complexes with unfa vorable solubility characteristics. The first important breakthrough came with the advent of broad band 1H-decoupling. For example, the featureless broad 31p resonance associated with the commonly used ligand triphenyl phosphine is converted to a sharp, more readily ob served singlet when wide-band decoupling is employed (see Fig. 1). Despite this improvement investigation of more interesting molecules, such as catalytically active complexes was forced to await the devel opment of Fourier Transform methods since only with relatively rapid signal averaging methods could sufficient signal-to-noise ratios be achieved."

Low dimensionality is a multifarious concept which applies to very diversified materials. Thus, examples of low-dimensional systems are structures with one or several layers, single lines or patterns of lines, and small clusters isolated or dispersed in solid systems. Such low dimensional features can be produced in a wide variety of materials systems with a broad spectrum of scientific and practical interests. These features, in turn, induce specific properties and, particularly, specific transport properties. In the case of zeolites, low dimensionality appears in the network of small-diameter pores of molecular size, extending in one, two or three di mensions, that these solids exhibit as a characteristic feature and which explains the term of "molecular sieves" currently used to name these ma terials. Indeed, a large number of industrial processes for separation of gases and liquids, and for catalysis are based upon the use of this low dimensional feature in zeolites. For instance, zeolites constitute the first class of catalysts employed allover the world. Because of the peculiarity and flexibility of their structure (and composition), zeolites can be adapted to suit many specific and diversified applications. For this reason, zeolites are presently the object of a large and fast-growing interest among chemists and chemical engineers.

There are both a remote and a proximate history in the development of this book. We would like to acknowledge first the perceptiveness of the technical administrators at RCA Laboratories, Inc. during the 1970s, and in particular Dr. P. N. Yocom. Buoyed up by the financial importance of yttrium oxysulfide: europium as the red phosphor of color television tubes, they allowed us almost a decade of close cooperation aimed at understanding the performance of this phosphor. It is significant that we shared an approach to research in an industrial laboratory which allowed us to avoid the lure of "first-principles" approaches (which would have been severely premature) and freed us to formulate and to study the important issues directly. We searched for a semiquantitative understanding of the properties observed in luminescence, i. e., where energy absorption occurs, where emission occurs, and with what efficiency this conversion process takes place. We were aware that the nonradi ative transition rates found in practice vary enormously with temperature and, for a given activator, with small changes in its environment. We traced the source of this enormous variation to the magnitude of the vibrational overlap integrals, which have strong dependences on the rearrangements occurring during optical transitions and on the vibrational number of the initial electronic state. We were willing to excise from the problem the electronic aspects - the electronic wavefunctions' and their transition integrals -by treating them as parameters to be obtained from the experimental data."

This is a textbook of what is often called magnetochemistry. We take the point of view that magnetic phenomena are interesting because of what they tell us about chemical systems. Yet, we believe it is no longer tenable to write only about such subjects as distinguishing stereochemistry from the measurement of a magnetic susceptibility over a restricted temper ature region; that is, paramagnetism is so well-understood that little remains to explore which is of fundamental interest. The major purpose of this book is to direct chemists to some of the recent work of physicists, and in particular to a lengthy exposition of magnetic ordering phenomena. Chemists have long been interested in magnetic interactions in clusters, but many have shied away from long-range ordering phenomena. Now however more people are investigating magnetic behavior at temperatures in the liquid helium region, where ordering phenomena can scarcely be avoided. The emphasis is on complexes of the iron-series ions, for this is where most of the recent work, both experimental and theoretical, has been done. The discussion therefore is limited to insulating crystals; the nature of magnetism in metals and such materials as semiconductors is sufficiently different that a discussion of these substances is beyond our purposes. The book is directed more at the practical experimentalist than at the theoretician."

Although the chemistry of boron is still relatively young, it is developing at a pace where even specific areas of research are difficult to compile into a monograph. Besides the boron hydrides, boron-nitrogen compounds are among the most fascinating derivatives of boron. Nitrogen compounds exist in a wide variety of molecular structures and display many interesting properties. The combination of nitrogen and boron, however, has some unusual features that are hard to match in any other combination of elements. This situation was first recognized by ALFRED STOCK and it seems proper to pay tribute to his outstanding work in the area of boron chemistry. One should realize that about forty years ago, STOCK and his coworkers had to develop completely new experimental techniq'\les and that no guidance for the interpreta tion of their rather unusual data had been advanced by theoretical chemists. In this monograph an attempt has been made to explore the general characteristics of structure and the principles involved in the preparation and reactions of boron-nitroge compounds. It was a somewhat difficult task to select that information which appears to be of the most interest to "inorganic and general chemistry" since the electronic relationship between a boron-nitrogen and a carbon-carbon grouping is reflected in the "organic" character of many of the reactions and compounds."

The present volume of this series, following the tradition of the previous volumes, covers three major lines of research on crystallization: growth from vapor and epitaxy, growth from solution, and growth from melt. As in the previous volumes, preference is given to papers that provide original results and reviews of results obtained by the authors and those from published sources, although some of the papers are either purely original or purely of review character. The first section deals with crystal growth from vapor and epitaxy and contains three papers. One of them, on artificial epitaxy, discusses and reviews published results from the last three years in this rapidly developing area. The results are used in outlining mechanisms for oriented film growth on amorphous substrates. Another paper in this section deals with classical epitaxy, namely oriented growth on single-crystal substrates, where some important conclusions are drawn from the growth of gallium nitride films on sapphire, which concern the orientation relationships in that pair of substances. The last paper in the section deals with film growth under ion bombardment (the corresponding techniques in film crystallization have already advanced from theory to practical applications).

John Berry: Metal-Metal Bonds in Chains of Three or More Metal Atoms: From Homometallic to Heterometallic Chains.- Malcolm Chisholm: Electronically Coupled MM Quadruple Bonded Complexes of Molybdenum and Tungsten.- Philip Power: Transition Metal Complexes Stabilized by Bulky Terphenyl Ligands: Applications to Metal-Metal Bonded Compounds.- Gerard Parkin: Metal-Metal Bonding in Bridging Hydride and Alkyl Compounds.- Roland Fischer and Gernot Frenking: Structure and Bonding of Metal Rich Coordination Compounds Containing Low Valent Ga(I) and Zn(I) Ligands.- Mike Hill: Homocatenation of Metal and Metalloid Main Group Elements.- Constandinos A. Tsipis: Aromaticity/Antiaromaticity in "Bare" and ''Ligand-Stabilized'' Rings of Metal Atoms.- Alexander Boldyrev: All-Transition Metal Aromaticity and Antiaromaticity.

Even brilliant colors are all bound to scatter, Who in our changing world can stay forever? From Iroha-uta, ancient Buddhistic poem of Japan For many years we have been engaged in the preparation and characterization of new metal complexes and chelates, and especially the interpretation of their electronic spectra in solutions. In the course of these studies, we have encountered a number of strange changes in color which occur upon heating, cooling or compressing the solutions, or changing the nature of the solvent. Similar effects of temperature and pressure on the color were often also observed in the solid state. Records of visual observations, spectral measurements, and their interpretations and analyses accumulated each year, until we found ourselves, quite suddenly, in the middle of a fantastic world of color changes - the world of inorganic thermochromism and related chromo tropic phenomena. This book is a result of the reviews by Sone and Prof. S. Utsuno (Kagaku no Ryoiki, 22, 222 (1968); Bunko Kenkyu, 25,123 (1976)), and a series of papers by Fukuda, Sone et al. published in the 1. Inorg. Nucl. Chern., Bull. Chern. Soc. Japan, and various other journals after 1970.

The present book covers different aspects of proton conduction: the first part describes chemical and physical parameters necessary for fast proton conduction and proposes a classification of different kinds of proton conductors. Comparison is made with other hydrogen containing materials (metals, graphites). The importance of partial water pressure, the role of defects and surface phenomena are discussed. The second part treats the chemistry, structures and electrical properties of typical materials from hydrogen bronzes to polymers via ice, hydroxides, acid sulphates, layer hydrates, clays, gels and porous or fractal media. The third part discusses the methods concerning the proton dynamics from local to macroscopic scale. The fourth part deals with conductivity mechanisms and the last one presents typical applications: electrochemical systems for production or energy storage and microionic devices.

The two-word title of this book can only give an indication about its content and approach to the subject it deals with. In the course of time, the term has gradually become somewhat blurred. The reason is easy to see: similar problems are now more and more frequently studied by different branches of natural science. The term "mixed crystals" has acquired specific connotations in physics, chemistry, biology, and geology. One and the same term can now serve as a name for things which are either not quite the same or sometimes quite different. And this is precisely what happened to the two words in the title of the book. One of them, the term "crystal," for which crystallography had an un ambiguous definition, is now employed by biologists to describe the structure of cell membranes and by chemists who use it to denote degrees of polymer crystallinity. "Crystal" has thus become a broad term that can help describe any solid, or just a condensed state of a substance, if the solid has a suf ficient degree of order in the arrangement of its components. But the book is called " lixed Crystals." The other word in its title, the adjective "mixed," has also developed several meanings. It is now thought ap plicable to both homogeneous and heterogeneous systems, that is, to crystals composed of different molecules and also to solids that are a mixture of crys tals with different structures."

This book is about compounds such as the boron hydrides and associated metal hydrides and alkyls which acquired the label 'electron deficient' when they were thought to contain too few valence electrons to hold together. Though they are now recognized as containing the numbers of bonding electrons appropriate for their structures, the term 'electron deficient' is still commonly applied to many substances that contain too few valence electrons to provide a pair for every pair of atoms close enough to be regarded as covalently bonded. The study of such substances has contributed much to chemistry. Techniques for the vacuum manipulation of volatile substances were devised specifically for their study; developments in valence theory resulted from considerations of their bonding; and the reactivity of several (for example, diborane and complex metal hydrides, lithium and aluminium alkyls) has made them valuable reagents. The purpose of this book is to provide an introduction to the chemistry of these fascinating compounds. The experimental and spectroscopic methods by which they can be studied are outlined, the various types of structure they adopt are described and profusely illustrated, and the relative merits of extended valence bond and simple molecular orbital treatments of their bonding are discussed, with as liberal use of diagrams and as limited recourse to the Greek alphabet as possible. A recurring theme is the importance attached to considerations of molecular sym metry. Their reactions are treated in sufficient detail to show whether these reflect any deficiency of electrons."

Primarily, the aim of this book is to provide a reference work for senior students and research workers engaged in the synthetic aspects of chemistry. The various classes of compounds under discussion provide useful interme diates for the synthesis of numerous nitrogen-containing derivatives. Imidoyl halides are also intermediates in several classical name reactions, such as the Gattermann, Houben-Hoesch, and Vilsmeier-Haack syntheses of aldehydes and ketones, the Beckmann rearrangement, and the v. Braun degradation. Some imidoyl halides have shown interesting agricultural activities, and the generation of highly reactive species (ketenimines, nitrile oxides, nitrile imides, carbodiimides, etc.) from imidoyl halides has contributed to the study of polar cycloaddition reactions. To enable researchers to utilize this chemistry without consulting the original references, I have included a number of selected working examples. This procedure will facilitate the transformation of written information into well designed experiments, especially since part of the cited literature is not readily available. The book is organized around classes of imidoyl halides, with synthesis and chemistry discussed in an orderly fashion. The physical properties of the known imidoyl halides are listed in tables, and I have attempted to draw attention to the more recent literature. The one or two references provided for each compound represent those which best describe its physical constants and synthesis.

The correlation of spectroscopic and chemical investigations in recent years has been highly beneficial of many reasons. Around 1950, no valid explanation was available of the colours of compounds of the five tran sition groups. Later, it was possible to identify the excited levels with those expected for an electron configuration with adefinite number of electrons in the partly filled shell. I t is not generally recognized that this is equivalent to determining spectroscopic oxidation states related to the preponderant electron configuration and not to estimates of the fractional atomic charges. This brings in an entirely different type of description than the formal oxidation numbers used for characterizing compounds and reaction schemes. However, it must be realized that collectively oxidized ligands, formation of cluster-complexes and catenation may prevent the oxidation state from being well-defined. The writer would like to express his gratitude to many, but first of all to DR. CLAUS SCHAFFER, University of Copenhagen, who is the most efficient group-theoretical engineer known to the writer; his comments and discussions have been highly valuable. The writer's colleague, Pro fessor FAUSTO CALDERAZZO (now going to the University of Pisa) has been most helpful in metallo-organic questions. Thanks are also due to Professors E. RANcKE-MADsEN and K. A. JENSEN for correspondence and conversations about formal oxidation numbers."

In May of 1978, several hundred of the friends, colleagues and former students of Professor Herbert C. Brown gathered on the campus of Purdue University to note his formal retirement, to honor him for his past contributions to chemistry and to wish him continued success in research. It was a time of reunion and recollection, a time for looking back and giving recognition to a lifetime of accomplishment. There was the ceremony of a banquet, presided over with inimitable wit by Professor Derek Davenport, and the dedication of the Herbert C. Brown Archives, with addresses by Dr. Alfred Bader, of Aldrich Chemicals, and Dr. Alan Schriesheim, of Exxon. There was the publi cation of a book of the personal reminiscences of students and post doctoral colleagues - "Remembering HCB." But it was also a time for looking at the present and into the future with a set of scien tific lectures, mainly by former students or associates, who des cribed their current or projected research activities. That is what this book is about. The papers, some of which are expanded versions of the lectures, fall into two broad groups - some deal with the interplay of struc ture and mechanism, the others deal with the use of organometallics in synthesis. It is, perhaps, no accident that these are the two main areas of H. C. Brown's research interest."

The first concern of scientists who are interested in synthetic polymers has always been, and still is: How are they synthesized? But right after this comes the question: What have I made, and for what is it good? This leads to the important topic of the structure-property relations to which this book is devoted. Polymers are very large and very complicated systems; their character ization has to begin with the chemical composition, configuration, and con formation of the individual molecule. The first chapter is devoted to this broad objective. The immediate physical consequences, discussed in the second chapter, form the basis for the physical nature of polymers: the supermolecular interactions and arrangements of the individual macromolecules. The third chapter deals with the important question: How are these chemical and physical structures experimentally determined? The existing methods for polymer characterization are enumerated and discussed in this chapter. The following chapters go into more detail. For most applications-textiles, films, molded or extruded objects of all kinds-the mechanical and the thermal behaviors of polymers are of pre ponderant importance, followed by optical and electric properties. Chapters 4 through 9 describe how such properties are rooted in and dependent on the chemical structure. More-detailed considerations are given to certain particularly important and critical properties such as the solubility and permeability of polymeric systems. Macromolecules are not always the final goal of the chemist-they may act as intermediates, reactants, or catalysts. This topic is presented in Chapters 10 and 11."