Gerard van Koten: The Mono-anionic ECE-Pincer Ligand - a Versatile Privileged Ligand Platform: General Considerations.- Elena Poverenov, David Milstein: Non-Innocent Behavior of PCP and PCN Pincer Ligands of Late Metal Complexes.- Dean M. Roddick: Tuning of PCP Pincer Ligand Electronic and Steric Properties.- Gemma R. Freeman, J. A. Gareth Williams: Metal Complexes of Pincer Ligands: Excited States, Photochemistry, and Luminescence.- Davit Zargarian, Annie Castonguay, Denis M. Spasyuk: ECE-Type Pincer Complexes of Nickel.- Roman Jambor and Libor Dostal: The Chemistry of Pincer Complexes of 13 - 15 Main Group Elements.- Kalman J. Szabo: Pincer Complexes as Catalysts in Organic Chemistry.- Jun-ichi Ito and Hisao Nishiyama: Optically Active Bis(oxazolinyl)phenyl Metal Complexes as Multi-potent Catalysts.- Anthony St. John, Karen I. Goldberg, and D. Michael Heinekey: Pincer Complexes as Catalysts for Amine Borane Dehydrogenation.- Dmitri Gelman and Ronit Romm: PC(sp3)P Transition Metal Pincer Complexes: Properties and Catalytic Applications.- Jennifer Hawk and Steve Craig: Physical Applications of Pincer Complexes.

Computational methods have become an indispensible tool for elucidating the mechanism of organometallic reactions. This snapshot of state-of-the-art computational studies provides an overview of the vast field of computational organometallic chemistry. Authors from Asia, Europe and the US have been selected to contribute a chapter on their specialist areas. Topics addressed include: DFT studies on zirconium-mediated reactions, force field methods in organometallic chemistry, hydrogenation of -systems, oxidative functionalization of unactivated C-H bonds and olefins, the osmylation reaction, and cobalt carbonyl clusters. The breadth and depth of the contributions demonstrate not only the crucial role that computational methods play in the study of a wide range of organometallic reactions, but also attest the robust health of the field, which continues to benefit from, as well as inspire novel experimental studies.

Bismuth Catalysts in Aqueous Media, by Shu Kobayashi, Masaharu Ueno and Taku Kitanosono.- Pentavalent Organobismuth Reagents in Organic Synthesis: Alkylation, Alcohol Oxidation and Cationic Photopolymerization , by Yoshihiro Matano.- Environmentally Friendly Organic Synthesis Using Bismuth(III) Compounds, by Scott W. Krabbe and Ram S. Mohan.- Bismuth-Catalyzed Addition of Silyl Nucleophiles to Carbonyl Compounds and Imines, by Thierry Ollevier.- Bismuth Salts in Catalytic Alkylation Reactions, by Magnus Rueping and Boris J. Nachtsheim.- New Applications for Bismuth(III) Salts in Organic Synthesis: From Bulk Chemicals to Steroid and Terpene Chemistry, by J. A. R. Salvador, S. M. Silvestre, R. M. A. Pinto, R. C. Santos and C. Le Roux.- Cationic Bismuth-Catalyzed Hydroamination and Direct Substitution of the Hydroxy Group in Alcohols with Amides, by Shigeki Matsunaga and Masakatsu Shibasaki.- Transition-Metal Catalyzed C-C Bond Formation Using Organobismuth Compounds, by Shigeru Shimada and Maddali L. N. Rao.- Bismuth(III) Salts as Synthetic Tools in Organic Transformations, by J. S. Yadav, Aneesh Antony and Basi V. Subba Reddy.

Giovanni Poli, Guillaume Prestat, Frederic Liron, Claire Kammerer-Pentier: Selectivity in Palladium Catalyzed Allylic Substitution.- Jonatan Kleimark and Per-Ola Norrby: Computational Insights into Palladium-mediated Allylic Substitution Reactions.- Ludovic Milhau, Patrick J. Guiry: Palladium-catalyzed enantioselective allylic substitution.- Wen-Bo Liu, Ji-Bao Xia, Shu-Li You: Iridium-Catalyzed Asymmetric Allylic Substitutions.- Christina Moberg: Molybdenum- and Tungsten-Catalyzed Enantioselective Allylic Substitutions.- Jean-Baptiste Langlois, Alexandre Alexakis: Copper-catalyzed enantioselective allylic substitution.- Jeanne-Marie Begouin, Johannes E. M. N. Klein, Daniel Weickmann, B. Plietker: Allylic Substitutions Catalyzed by Miscellaneous Metals.- Barry M. Trost, Matthew L. Crawley: Enantioselective Allylic Substitutions in Natural Product Synthesis.

The fields of hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) continue to attract the attention of researchers in the various disciplines connected to these fascinating problems that represent two of the key outstanding chemical challenges for the petroleum refining industry in view of their very strong environmental and commercial implications. One area that has flourished impressively over the last 15 years is the organometallic chemistry of thiophenes and other related sulfur-containing molecules. This has become a powerful method for modeling numerous surface species and reactions implicated in HDS schemes, and nowadays it represents an attractive complement to the standard procedures of surface chemistry and heterogeneous catalysis, for understanding the complex reaction mechanisms involved in this process. Similar developments have begun to appear in connection with HDN mechanisms, although in a much more modest scale and depth. Some years ago when, encouraged by Prof. B. R. James, this book was planned, several excellent reviews and monographs treating different aspects of HDS were already available including some on the subject of organometallic models. However, it seemed appropriate to try to summarize the most striking features of this chemistry in an updated and systematic way, and inasmuch as possible in connection with the common knowledge and beliefs of the mechanisms of heterogeneous HDS catalysis. Hopefully, this attempt to build some conceptual bridges between these two traditionally separated areas of chemistry has met with some success.

Organolithium chemistry occupies a central position in the selective construction of C-C bonds in both simple and complex molecules. Paralleling the surge of interest in methods for asymmetric synthesis, the use of organolithiums in enantioselective synthesis has witnessed spectacular advances in a little over a decade. This volume is the first dedicated to a comprehensive coverage of this important area. It is designed to provide graduate students and researchers with a rich source of essential information on synthesising molecules in an enantioselective manner using organolithiums, and be an inspiration for future developments. Following an overview chapter summarising the key milestones, successive chapters, each written by leading experts in their field, critically survey all the major areas of progress.

to thank Messrs J. R. Sanders, W. E. Lindsell and M. G. Swanwick for helping to check the text and references and prepare indexes. Finally, I should like to thank my wife for the very considerable assis tance she has given me in the writing and production of this book. M. L. H. G. Contents Preface to the Third Edition, Volume Two Page v INTRODUCTION TO VOLUME TWO I Oassification I The IS-electron rule 2 (i) The basis of the I8-electron rule p. 4, (ii) Exceptions to the I8-electron rule p. 5 1. TWO-ELECTRON LIGANDS 7 A. Classification 7 B. The preparation of olefin-transition metal complexes 7 (a) Displacement of solvent ligands p. 9, (b) Preparations from metal carbonyls p. 9, (c) Less common preparative routes p. 11, Reductive olefination method p. 12 C. A molecular orbital description of the bonding in orga- metallic complexes 13 (a) General comments p. 13, (b) Symmetry considerations p. 13, (c) Energies of the molecular orbitals p. 14 D. A description of the bonding of 2-electron ligands to transition metals 14 E. General comments of 2-electron ligands 19 (a) Infrared studies p. 20, (b) Effect of olefin substituents p. 21, (c) The rotation of ethylene about the ligand-metal bond p. 22, (d) Chemical properties p. 23 F. Particular complexes of metals with 2-electron ligands 25 (a) Copper, silver and gold p. 25, Complexes with benzene p. 28, (b) Nickel, palladium and platinum p."

Masakatsu Shibasaki, Motomu Kanai, Shigeki Matsunaga, and Naoya Kumagai: Multimetallic Multifunctional Catalysts for Asymmetric Reactions.- Takao Ikariya: Bifunctional transition metal-based molecular catalysts for asymmetric syntheses.- Chidambaram Gunanathan and David Milstein: Bond Activation by Metal-Ligand Cooperation: Design of Green Catalytic Reactions Based on Aromatization-Dearomatization of Pincer Complexes.- Madeleine C. Warner, Charles P. Casey, and Jan-E. Backvall: Shvo s Catalyst in Hydrogen Transfer Reactions.- Noritaka Mizuno, Keigo Kamata, and Kazuya Yamaguchi: Liquid-Phase Selective Oxidation by Multimetallic Active Sites of Polyoxometalate-Based Molecular Catalysts.- Pingfan Li and Hisashi Yamamoto: Bifunctional Acid Catalysts for Organic Synthesis.- Jun-ichi Ito, Hisao Nishiyama: Bifunctional Phebox Complexes for Asymmetric Catalysis."

While the organometallic chemistry of the d-block transition elements has been a flourishing field for the past 25 years, it has only been in the last several years that dramatic activity and progJ'ess has occurred in the area of lanthanide and actinide organometallic chemistry. The f. -element organometallic research effort has been truly multinational and multidisciplinary. In a large number of countries, sCientists have become increasingly interested in the synthesis, reactivity, spectroscopy, and the molecular and electronic structures of f-element organometallic compounds. The backgrounds of these scientists range from organic, inorganic, nuclear, and catalytic chemistry to chemical and nuclear physics. The motivations for the study of f-element organometallics have been equally varied. In the area of basic research, there has been a growing realization that the lanthanides and actinides represent two unique and, to a great extent, neglected families of elements in which many fascinating aspects of chemistry and bonding remain to be explored. On a more practical level, an increasing number of these elements play important roles in nuclear energy production and in industrial catalytic processes. It has become apparent that efficiency and safety in both areas could greatly benefit from increased knowledge. In the past there has been no suitable international forum available for bringing together researchers in the diverse areas of f-element organometallic science mentioned above.

Structure, Bonding, and Reactivity of Reactant Complexes and Key Intermediates, by Elena Soriano and Jose Marco-Contelles.-

Cycloisomerization of 1, "n"-Enynes Via Carbophilic Activation, by Patrick Yves Toullec and Veronique Michelet.-

DFT-Based Mechanistic Insights into Noble Metal-Catalyzed Rearrangement of Propargylic Derivatives: Chirality Transfer Processes, by Olalla Nieto Faza and Angel R. de Lera.-

"N"-Heterocyclic Carbene Complexes of Au, Pd, and Pt as Effective Catalysts in Organic Synthesis, by Andrea Correa, Steven P. Nolan and Luigi Cavallo.-

Activation of Allenes by Gold Complexes: A Theoretical Standpoint, by Max Malacria, Louis Fensterbank and Vincent Gandon.-

Heterocyclization of Allenes Catalyzed by Late Transition Metals: Mechanisms and Regioselectivity, by Benito Alcaide, Pedro Almendros, Teresa Martinez del Campo, Elena Soriano and Jose Marco-Contelles.-

Gold-Catalyzed Cycloadditions Involving Allenes: Mechanistic Insights from Theoretical Studies, by Sergi Montserrat, Gregori Ujaque, Fernando Lopez, Jose L. Mascarenas and Agusti Lledos.-

"

Kyle A. Grice, Margaret L. Scheuermann and Karen I. Goldberg: Five-Coordinate Platinum(IV) Complexes.- Jay A. Labinger and John E. Bercaw: The Role of Higher Oxidation State Species in Platinum-Mediated C-H Bond Activation and Functionalization.- Joy M. Racowski and Melanie S. Sanford: Carbon-Heteroatom Bond-Forming Reductive Elimination from Palladium(IV) Complexes.- Helena C. Malinakova: Palladium(IV) Complexes as Intermediates in Catalytic and Stoichiometric Cascade Sequences Providing Complex Carbocycles and Heterocycles.- Allan J. Canty and Manab Sharma: h1-Alkynyl Chemistry for the Higher Oxidation States of Palladium and Platinum.- David C. Powers and Tobias Ritter: Palladium(III) in Synthesis and Catalysis.- Marc-Etienne Moret: Organometallic Platinum(II) and Palladium(II) Complexes as Donor Ligands for Lewis-Acidic d10 and s2 Centers.

This book serves as a concise guide to essential topics in Transition Metal Organometallic Chemistry for senior undergraduate and graduate students; it blends qualitative theoretical approach with experimental description of the facts. Its content emphasizes on the orbital description of M-L bonds; the electronic structures of the main types of organometallic complexes (ML2 to ML6); main types of organometallic reactions; organometallic compound synthesis, analytical characterization and the reactivity and lastly the applications of transition metals in homogeneous catalysis.

According to R.H. Crabtree, Metal Dihydrogen and sigma-Bond Complexes is described as 'the definitive account of twentieth-century work in the area of sigma complexation'. It covers not only Kubas' discovery of dihydrogen coordination and the study of its structure and general properties but also discusses both the theoretical beliefs and experimental results of bonding and activation of dihydrogen on metal centers and the coordination and activation of C-H, B-H, X-H, and X-Y bonds, giving an overview of 'one of the hottest areas in chemistry'.

Juan I. Padron and Victor S. Martin: Catalysis by means of Fe-based Lewis acids; Hiroshi Nakazawa*, Masumi Itazaki: Fe-H Complexes in Catalysis; Kristin Schroder, Kathrin Junge, Bianca Bitterlich, and Matthias Beller: Fe-catalyzed Oxidation Reactions of Olefins, Alkanes and Alcohols: Involvement of Oxo- and Peroxo Complexes; Chi-Ming Che, Cong-Ying Zhou, Ella Lai-Ming Wong: Catalysis by Fe=X Complexes (X=NR, CR2); Rene Peters, Daniel F. Fischer and Sascha Jautze: Ferrocene and Half Sandwich Complexes as Catalysts with Iron Participation; Markus Jegelka, Bernd Plietker: Catalysis by Means of Complex Ferrates."

The present book is based on the work of M.N.Bochkarev, G.S.Kalinina, L.N. zakharov and S.Ya.Khorshev. The Russian edition of that book appeared under the same title in 1989 and covered literature data up to the middle of 1986. Since that time the number of publications on this subject increased significantly. In this volume we include all the data published up to the end of 1990, as well as some of the most important relevant articles of 1991. Therefore, this book should be considered as a new book, devoted to the same problems, rather than as just a translation of the mentioned issue. This book deals with compounds of scandium, yttrium, lanthanum and lanthanoids containing direct metal-carbon bond, Le. with the real organometallic complexes of these metals. Besides, the volume includes the rare earth complexes, in which organic ligand is bonded to the metal atom via the atom of another element of the Periodic Table. In other words, the book includes all classes of rare earth organoderivatives. Carboxilates, fl-diketonates and related chelates are the exceptions, because their properties are closer to inorganic compounds and they were fully described elsewhere. It should be noted, that "rare earth elements," "rare earth metals," "lanthanoids" and related terms are used in this book for indicating scandium, yttrium, lanthanum and the following 14 elements of the Periodic Table.

The chemistry of transition metal carbyne complexes has become a highly attractive field during the past twenty years. In recent years its application to aspects of catalysis and metathesis has gained considerable interest from inorganic as well as organic chemists. In addition, organic synthesis by means of metal carbon multiple bond reagents offers the most sophisticated technology currently available. In consideration of these developments some of Professor E. O. Fischer's former coworkers and colleagues felt obliged to orga nize this NATO Advanced Research Workshop on Transition Metal Carbyne Complexes in the Bavarian Alps. They have been encouraged by the fact that most of the distinguished scientists in the field of metal-carbon multiple bond chemistry had finally agreed to participate and to present stimulating lectures. The organizers of the workshop are deeply grateful to the Scientific Affairs Division of the NATO for the generous financial support of the meeting in Wildbad Kreuth and for the preparation of this book. They also feel indebted to acknowledge the generous support from Wacker-Chemie, BASF, Peroxid-Chemie, Hoechst and Bayer. Finally they thank the staff of the Hanns-Seidel-Stiftung in Wildbad Kreuth for providing a pleasant and stimu lating atmosphere during the meeting."

Contents: Gerard Jaouen, Nils Metzler-Nolte : Introduction ; Stephane GIBAUD and Gerard JAOUEN: Arsenic - based drugs: from Fowler's solution to modern anticancer chemotherapy; Ana M. Pizarro, Abraha Habtemariam and Peter J. Sadler : Activation Mechanisms for Organometallic Anticancer Complexes; Angela Casini, Christian G. Hartinger, Alexey A. Nazarov, Paul J. Dyson : Organometallic antitumour agents with alternative modes of action; Elizabeth A. Hillard, Anne Vessieres, Gerard Jaouen : Ferrocene functionalized endocrine modulators for the treatment of cancer; Megan Hogan and Matthias Tacke : Titanocenes - Cytotoxic and Anti-Angiogenic Chemotherapy Against Advanced Renal-Cell Cancer; Seann P. Mulcahy and Eric Meggers : Organometallics as Structural Scaffolds for Enzyme Inhibitor Design; Christophe Biot and Daniel Dive : Bioorganometallic Chemistry and Malaria; Nils Metzler-Nolte : Biomedical applications of organometal-peptide conjugates; Roger Alberto : Organometallic Radiopharmaceuticals; Brian E. Mann : Carbon Monoxide - an essential signaling molecule.

An overview of modern organometallic thermochemistry, made by some of the most active scientists in the area, is offered in this book. The contents correspond to the seventeen lectures delivered at the NATO ASI Energetics of Organometallic Species (Curia, Portugal, September 1991), plus three other invited contributions from participants of that summer school. These papers reflect a variety of research interests, and discuss results obtained with several techniques. It is therefore considered appropriate to add a few preliminary words, attempting to bring some unity out of that diversity. In the first three chapters, results obtained by classical calorimetric methods are described. Modern organometallic thermochemistry started in Manchester, with Henry Skinner, and his pioneering work is briefly surveyed in the first chapter. The historical perspective is followed by a discussion of a very actual issue: the trends of stepwise bond dissociation enthalpies. Geoff Pilcher, another Manchester thermochemist, makes, in chapter 2, a comprehensive and authoritative survey of problems found in the most classical of thermochemical techniques - combustion calorimetr- applied to organometallic compounds. Finally, results from another classical technique, reaction-solution calorimetry, are reviewed in the third chapter, by Tobin Marks and coworkers. More than anybody else, Tobin Marks has used thermochemical values to define synthetic strategies for organometallic compounds, thus indicating an application of thermochemical data of which too little use has been made so far.

The scope of this paper is to recall fundamental notions of the molecular spectroscopy and dynamics, necessary for discussion of photophysical and photochemical processes in condensed phases. We will thus treat in a more detailed way the specific features which are important for molecular systems strongly interacting with their environment. Other aspects such as the time evolution of isolated molecules, single-level excitation and state-to-state chemistry, important for the gas-phase photophysics are omitted. We start (Sec.2) with a brief description of radiative processes (light absorption and emission) in molecules. In the quantum-mechanical treatment of this problem, the appropriate basis is that of so-called zero-order states, corresponding to the traditional scheme of electronic states (singlets, doublets, triplets etc.) and vibrational levels belonging to each state. The important point will be deduction of selection rules for most radiative transitions. At this stage all molecular states are considered as stationary states. In order to treat the breakdown of simple selection rules and non-radiative transitions between individual molecular states, it is necessary to take into account the mechanisms coupling the zero-order states (Sec.3). We will first focus on intramolecular coupling effects and then discuss the solvent effects on intramolecular relaxation processes. The problem of the non-radiative transfer of the electronic energy between different molecules - closely related to that of the energy dissipation within a single molecule will be treated in Sec.4.

The analogy between the chemistry of molecular transition metal clusters and the processes of chemisorption and catalysis at metal surfaces (the Cluster Surface analogy) has for a number of years provided an interplay between experimental and theoretical inorganic and physical chemists. This collaborative approach has born fruit in the use of well defined modes of metal-ligand bonding in discrete molecular clusters, models for metal-ligand binding on surfaces. Some of the key topics discussed in The Synergy between Dynamics and Reactivity at Clusters and Surfaces are: (1) Mechanisms of the fluxional behaviour in clusters in the liquid phase and the connections with diffusion processes on extended surfaces. The role of metal-metal bond breaking in diffusion. (2) Analogies in the structure of chemisorbed species and related ligands on metallic clusters. (3) Analogies between benzene surface chemistry on extended metal surfaces and on metal surfaces in molecular cluster compounds with particular reference to structural distortions. (4) The role of mobile precursors for dissociation of chemisorption on extended metals and on clusters. Are there analogies in the ligand attachment during cluster compound synthesis? (5) The role of defect sites on metal surfaces in catalyzing chemical reactions and the connection to the special bonding properties of sites on metal clusters having lowest metal-metal coordination. (6) The size of metal clusters needed to mimic surface phenomena on bulk metal surfaces. Different sites needed for different phenomena.

217 2. COPOLYMERIZATION OF PROPENE OR HIGHER I-ALKENES WITH 218 CARBON MONOXIDE 2. 1. Ligands and polymerization conditions 218 2. 2. Spiroketal formation 221 2. 3. Enantioselectivity 222 2. 4. Higher I-Alkenes 226 3. COPOLYMERIZATION OF STYRENE OR ITS DERIVATIVES WITH 226 CARBON MONOXIDE 4. COPOLYMERIZATION OF OTHER OLEANS WITH CARBON MONOXIDE 230 5. ASYMMETRIC TERPOLYMERIZATION OF MORE THAN Two KINDS OF 232 OLEFINS WITH CARBON MONOXIDE 6. POLYKETONE CONFORMATION 233 7. CONCLUSION 234 Chapter 8. Chain Propagation Mechanisms 237 Ayusman Sen 1. INTRODUCTION 237 2. PALLADIUM (II) BASED SYSTEMS 238 3. NICKEL (II) BASED SYSTEMS 256 4. RHODIUM (I) BASED SYSTEMS 257 5. CONCLUSION 261 Chapter 9. Theoretical Studies on Copolymerization of Polar Monomers 265 Peter Margl, Artur Michalak, and Tom Ziegler 1. INTRODUCTION 265 2. COPOLYMERIZATION OF CARBON MONOXIDE WITH ETHYLENE 267 2. 1. Experimental and calculated rates for the insertion processes for 267 copolymerization catalysed by Pd(II) systems. 2. 2. A more detailed look at the productive and unproductive cycles 270 in copolymerization catalysed by Pd(II) complexes. 2. 2. 1. The productive cycle 270 2. 2. 2. C2H4 misinsertion into an ethylene terminated polyketone 275 chain 2. 3. Experimental and calculated rates for the insertion processes for 277 alternating copolymerization catalyzed by Ni(II) systems 3. COPOLYMERIZATION OF OLEFINS WITH POLAR MONOMERS OTHER 280 THAN CO 3. 1. Preferred binding mode of oxygen containing monomers 282 3. 2. Preferred binding mode of nitrogen containing monomers 285 3. 3.

In the last 15 years aqueous organometallic chemistry and catalysis has emerged from being a laboratory curiosity to become an established field of research. Topics reviewed here include mechanistic studies on the effect of water on catalyzed reactions, the preparation of water soluble phosphines as ligands for catalysis, metal catalyzed organic reactions in water (hydrogenation, hydroformylation, carbonylation, olefin metathesis, hydrophosphination, etc.), chiral ligands and enantioselective catalysis, organometallic radical photochemistry in aqueous solutions, bioorganometallic chemistry, organometallic reactions of biopolymers, and catalytic modification of biomembranes. The summary of recent results is supplemented by an assessment of probable future research trends. Audience: Researchers in both academia and industry, as well as graduate students of homogeneous catalysis.

The activation of dioxygen by metal ions has both synthetic potential and biological relevance. Dioxygen is the cleanest oxidant for use in emission-free technologies to minimize pollution of the environment. The book gives a survey of those catalyst systems based on metal complexes which have been discovered and studied in the last decade. They activate molecular oxygen and effect the oxidation of various organic compounds under mild conditions. Much of the recent progress is due to a search for biomimetic catalysts that would duplicate the action of metalloenzymes. Mechanistic aspects are emphasized throughout the book. An introductonary chapter reviews the chemistry of transition metal dioxygen complexes, which are usually the active intermediates in the catalytic reactions discussed. Separate chapters are devoted to oxidation of saturated, unsaturated and aromatic hydrocarbons, phenols, catechols, oxo-compounds, phosphorus, sulfur and nitrogen compounds.

The serious study of the reaction mechanisms of transition metal com plexes began some five decades ago. Work was initiated in the United States and Great Britain; the pioneers ofthat era were, inalphabetical order, F. Basolo, R. E. Connick, 1. O. Edwards, C. S. Garner, G. P.Haight, W. C. E. Higgision, E.1. King, R. G. Pearson, H. Taube, M.1. Tobe, and R. G. Wilkins.A larger community of research scientists then entered the field, many of them stu dents ofthose just mentioned. Interest spread elsewhere as well, principally to Asia, Canada, and Europe. Before long, the results ofindividual studies were being consolidated into models, many of which traced their origins to the better-established field of mechanistic organic chemistry. For a time this sufficed, but major revisions and new assignments of mechanism became necessary for both ligand sub stitution and oxidation-reduction reactions. Mechanistic inorganic chemistry thus took on a shape of its own. This process has brought us to the present time. Interests have expanded both to include new and more complex species (e.g., metalloproteins) and a wealth of new experimental techniques that have developed mechanisms in ever-finer detail. This is the story the author tells, and in so doing he weaves in the identities of the investigators with the story he has to tell. This makes an enjoyable as well as informative reading."

Zeolites, with their crystalline microporous structures, are cordial hosts to a wide variety of guests. However, it was the abrupt and unexpected departure of one of these guests (water) from a host (stilbite) on heating which led Cronstedt, in 1756, to coin the term "zeolite" (from the Greek meaning "boiling stone") to describe this material. Since that time, approximately 40 different naturally-occurring zeolites have been discovered on earth. Recent studies of meteorite compositions have shown that these guest-host materials (e. g. , sodalite) occur in other parts of the universe as well. However, it wasn't until the twentieth century that synthetic routes to zeolites and other non-aluminosilicate molecular sieves were discovered. In addition, with the development of X-ray diffraction and the various spectroscopies, better understanding of the nature of the cavities, cages, and channels of these materials has led to the industrial exploitation of their guest-host properties. The world of zeolites has now expanded into a greater than 2 billion pound per year business, with major applications in detergent formulations, catalysis, and as adsorbents and desiccants. Their economic impact is difficult to determine; however, the improvement in gasoline yields alone (from catalytic cracking) must account for hundreds ofbillions ofdollars in increased GDP. In this volume, we have brought together a sampling of recent developments in various areas of guest-host or inclusion chemistry in zeolites.