The subject of acidity and basicity has enormous economic and technological value while it continues to present significant scientific challenges with prospects for further important technological developments. Historically, technological developments in acidity/basicity have often preceded the scientific understanding of the phenomena involved, certainly in the petroleum industry, a key beneficiarry and user of the concepts of acidity. This process, however, is very expensive and less efficient than developments based on a fundamental understanding of the scientific phenomena involved. This has been recognized over the years and it explains why university, government and industrial laboratories have in the last 50 years devoted large efforts to understanding acidity (and basicity to a lesser extent) so they can gain the technological advantage. The scientific and technological literature on the subject is truly enormous. There have been some very important articles and books on the subject that have attempted to critically review many individual contributions. During the last few years there have been three developments that led us to organize the Advanced Study Institute on which this volume is based: a) Significant developments in the theory of acids and bases; b) Developments in instrumentation that allow the detailed characterization of materials including in-situ conditions relevant to industrial processes; c) The realization that closer coupling of scientific and technological pursuits can lead to greater scientific understanding and better technology. The structure of the ASI reflected the coming-together of these three factors.

The first NATO Advanced Study Institute on Olefin Metathesis and Polymerization Catalysts was held on September 10-22, 1989 in Akcay, Turkey. Based on the fundamental research of RRSchrock, RGrubbs and K.B.Wagener in the field of ring opening metathesis polymerization (ROMP), acyclic diene metathesis (ADMET) and alkyne polymerization, these areas gained growing interest within the last years. Therefore the second NATO-ASI held on metathesis reactions was on Ring Opening Metathesis Po lymerization of Olefins and Polymerization of Alkynes on September 3-16, 1995 in Akcay, Turkey. The course joined inorganic, organic and polymer chemists to exchange their knowledge in this field. This volume contains the main and short lectures held in Akcay. To include ADMET reactions better into the title of this volume we changed it into: Metathesis Polymerization of Olefins and Alkyne Polymerization. This volume is addressed to research scientists, but also to those who start to work in the area of olefin metathesis and alkyne polymerization. The topics of the course were: mechanism of ROMP reactions/ new catalysts for ROMP/ new products by ROMP/ new catalysts for ADMET/ new products by ADMETI degradation of polymer by metathesis reactions/ alkyne polymerization and metathesis/ industrial application of metathesis reactions. The Advanced Study Institute was generously sponsored by the Scientific Affairs Division of NATO and the editor gratefully acknowledges this sponsorship. We also thank the Members of the Local Organizing Committee for their engagement on a successful NATO-AS ."

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 last two decades have seen a rapid growth in the synthetic processing of both simple and complex molecules, aimed at meeting the needs of society in all aspects of life. Many efforts have been devoted to the development of new biologically active compounds, new materials with innovative properties such as bio-compatibility, new catalysts that allow highly selective transformations, and technologies that facilitate the synthetic pro cesses. This book is a compendium of recent progress in all these aspects of synthetic chemistry. It collects the lectures of the XII International Conference on Organic Synthesis, held in Venice from June 28 to July 2, 1998, in which the present state of art of this discipline has been reported. The topics covered include: combinatorial chemistry, new synthetic methods, stereo selective synthesis, metal-mediated synthesis, and target oriented synthesis. The book collects the contributions, in the mentioned topics, of 43 scientists from 19 different countries. The contributions presented in the Conference as plenary lectures are reported in the first section of the book. Particular attention has been dedicated to combinatorial chemistry, a new and promising methodology for the synthesis of libraries of pharmaco logically interesting compounds in order to allow the automatic pharmacological screening of thousands of compounds. The Conference has dedicated to combinatorial chemistry a mini-symposium in which scientists from academy and companies have described the current trends of this very new technology.

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."

It was a great honor for us to organize ChiCat, a symposium devoted to Chiral Reactions in Heterogeneous Catalysis and to be the hostsofmore than 120 scientists coming from everywhere in the industrialized world, to celebrate together one century of existence ofInstitut Meurice. This school was established in 1892when an industrial chemist, named Albert Meurice, decided to educate practical chemists according to the perceived needs ofthe industry ofthat time. This is exactly what we are still trying to do. It is the reason why, thirty years ago, we started a research activity in catalysis, and why we progressively devote this research to the applications of catalysis in the field of fine chemicals. In this respect, we are very close to another initiative of Albert Meurice, who started the first production of synthetic pharmaceuticals in Belgium during World War I. This business later on became a part ofthe Belgian corporation DCB, still very active in pharmaceuticals today. The school created by Albert Meurice merged in the fifties with another school that had been created to meet the same needs in the field of the food industries, mainly distilleries and breweries. This merger was done in the frame of the establishment of CERIA. For people in catalysis, ceria stands for cerium oxide, but for those who engineered the concept, CERIA stood for Center of Education and Research for the Food and Chemical Industries.

Alexander L. Reznichenko and Kai C. Hultzsch: Catalytic -Bond Metathesis Zhichao Zhang, Dongmei Cui, Baoli Wang, Bo Liu, Yi Yang: Polymerization of 1,3-Conjugated Dienes with Lanthanide Precursors Frank T. Edelmann: Homogeneous Catalysis using Lanthanide Amidinates and Guanidinates Tianshu Li, Jelena Jenter, Peter W. Roesky: Rare Earth Metal Post-metallocene Catalysts with Chelating Amido Ligands

The demand for selective organic reactions is growing more acute everyday. Indeed, greater product selectivity has an important impact on energy and resource utilization, in terms of reduced process energy requirements for product separation and purification, in terms of low-value by-products, and in terms of environmental acceptance and compatibility. Moreover, more and more chemicals, especially pharmaceuticals, have to be sold in an optically active form. The search for selectivity constitutes a tremendous challenge for the chemists. In the last two decades, homogeneous transition metal based catalysis has emerged as one of the most promising tools for obtaining selectivity. In connection with developments in this area, this book contains updated and expanded versions of most of the lectures presented at a Cornett course held in Trieste (Italy) in 1989 and sponsored by the European Community. A primary aim is to cultivate a deeper understanding of the parameters that govern the selectivities and stimulate a wider utilization of transition metal based catalysis in organic synthesis. All aspects of selectivity, chemo-, regio-, stereo- and enantioselectivity are considered and illustrated by applications in various fields or organic synthesis. The impact of catalysis in oxydation, reduction, carbonylation reactions, carbene chemistry, in Ni and Pd promoted dimerizations, oligomerizations as well as fonctionalisations is stressed, quite often with special emphasis laid on reaction mechanisms. In this aspect, the last chapter examplifies the interest of high pressure NMR and IR when investigating the nature of reaction intermediates in homogeneous reactions.

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.

The focus of this thesis is the computational modelling of transition metal bimetallic (nanoalloy) clusters. More specifically, the study of Pd-Pt, Ag-Pt, Au-Au and Pd-Au as a few tens of atoms in the gas phase. The author used a combination of global optimization techniques - coupled with a Gupta-type empirical many-body potential - and Density Functional Theory (DFT) calculations to study the structures, bonding and chemical ordering, as well as investigate the chemisorptions of hydrogen and carbon monoxide on bimetallic clusters. This research is highly relevant to experimental catalytic studies and has resulted in more than seven publications in international journals.

Each chapter of "Phosphorus Compounds: Advanced Tools in Catalysis and Material Sciences" have been carefully selected by the editors in order to represent a state-of-the-art overview of how phosphorus chemistry can provide solutions in various fields of applications.

The editors have assembled an international array of world-renowned scientists and each chapter is written by experts in the fields of synthetic chemistry, homogeneous catalysis, dendrimers, theoretical calculations, materials science, and medicinal chemistry with a special focus on the chemistry of phosphorus compounds.
"Phosphorus Compounds: Advanced Tools in Catalysis and Material Sciences" is of interest to a general readership ranging from advanced university course students to experts in academia and industry.

Titanium dioxide photocatalysis is based on the semiconducting nature of its anatase crystal type. Construction materials with titanium photocatalyst show performances of air purification, self-cleaning, water purification, antibacterial action. This book describes principles of titanium dioxide photocatalysis, its applications to cementitious and noncementitious materials, as well as an overview of standardization of testing methods.

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.

Catalysis is a subject which draws upon many of the traditional scientific and technological disciplines, and its present structure has only been reached after many decades of detailed work. Nevertheless, in catalysis as in all other areas of science, experiments are carried out, new data are acquired, theories are proposed; and these things are done not in an intellectual vacuum, but in relation to previously established concepts and ideas. The history of how these guiding concepts have devel oped is nothing less than a skeletal history of the subject itself. In one respect at least, catalysis is similar to all other of mankind's endeavors: a failure to learn from history is a rejection of one's heritage. None of us should willingly plead guilty to this, and Professor O.-M. Schwab's opening chapter in this volume provides us with a ready means to avoid the need to re-invent what has been known for some time. Heterogeneous catalysis is dominated by the concept of a reactant molecule entering into some type of che mical interaction with the surface of a solid. Thus, to understand catalysis it is essential to understand as fully as possible the chemical nature of the solid. In the second chapter of this volume, Professor J. Haber provides a review of the majority of solid phases which are of catalytic interest. The framework for this review is chemical crystallography, and the author goes to some pains to draw attention to features that are of particular importance in catalysis."

This book provides the reader with the latest directions in the field of homogeneous catalysts for fine chemical production. Each theme is introduced from a broad perspective: materials, strategies, techniques and processes are presented both from a theoretical and a practical point of view. The focus is on those catalysts - particularly heterogenized homogeneous catalysts - and applications leading to the production of fine and speciality chemicals in a highly selective manner and with minimal environmental and economic impact. Each topic is treated critically so topics such as factors affecting the catalysts performance, the influence of the support, the catalysts' deactivation, the metal leaching or the issues on recycling are analyzed. Industrial and academic points of view are integrated and the feasibility and timeliness of industrial applications are illustrated. The reader is also provided with a comparison between parent heterogeneous and homogeneous systems.

This book comprises the proceedings of a NATO sponsored Advanced Research Workshop held from 1st November to 6th November 1992 in the delightful Chateau de Florans, Bedoin, Vaucluse, France and entitled 'Elementary Reaction Steps in Heterogeneous Catalysis. ' The organisers are grateful to the Science Committee of NATO for their support of this meeting. This is believed to be the first wide ranging NATO ARW in the field of heterogeneous catalysis for 20 years, following a previous venture organised in Sardinia by Basolo and Burwell, of Northwestern University, Illinois, USA [1]. This volume collects the lecture presentations and reports on the lively Panel discussions. The idea for the meeting evolved from a series of International Symposia on Quantum Chemistry and Mechanism in Heterogeneous Catalysis. The first of these was held in Lyon, France in 1986, the second in Krakow, Poland in 1988 and the third in Berkeley, California in 1990. The organising committee of the present meeting was Bernard Bigot, France, Tony Farragher, Netherlands, Richard Joyner, UK, Mme. Danielle Olivier, France, and Rutger van Santen, Netherlands, (Chairman). We wish to thank all members of the committee but in particular Bernard Bigot, who undertook the very extensive work involved in the local organisation with consummate skill and made our stay in Provence a great pleasure. Bernard Bigot's secretary, Mme. Marie-Noelle Coscat and Richard Joyner's secretary, Mrs. Pat Gibbs, also deserve our considerable thanks. There were fifty-four participants from eleven countries.

Materials Chemistry is rapidly emerging as a key component of contemporary science. The strongly interdisciplinary nature of the field requires input from all branches of chemistry, from crystallography, from solid state physics and from computational and theoretical techniques. This book aims to give a coherent survey of the field by considering all the major aspects of the current study of the chemistry of materials. Early chapters emphasise basic principles and techniques. Strong emphasis is given to new techniques and technologies, for example, the opportunities opened up by new synchrotron sources in crystallography, and new computational techniques in simulation studies of complex materials. Characterisation techniques including crystallographic, microscopic and spectroscopic techniques are then described. Key contemporary themes such as atomic transport, reactivity and catalysis are reviewed. Later chapters focus on specific dasses of material, induding solid state ionics, ceramics (induding giant magneto-resistance and high temperature superconducting solids), microporous and molecular materials. We hope that the book provides a snapshot of the scientific and technological challenges in this fast developing field. The editors would like to thank the NATO Scientific Affairs Division for funding the School on which this volume is basedj financial contribution from Johnson Matthey Technology Centre is also gratefully acknowledged. We are most grateful to Mrs Jean Conisbee for all her efforts in preparing the manuscript.

1. INTRODUCTION Although quite spectacular results have been obtained in the last few decades in the field of homogeneous transition metal catalyzed transformations of olefins and alkynes [1], reactions which could lead to heterocycles have been partly neglected. An obvious reason for this is that substrates containing heteroatoms such as N, 0 or S could coordinate the metal and suppress the catalytic activity. Nevertheless, some interesting early examples of transition-metal-catalyzed syntheses of heterocyclic compounds have been reported and these have been reviewed by C. W. Bird [2] . More recently the incorporation of CO , which enables esters and lactones 2 to be synthesized from olefinic starting materials, has begun to attract attention (see, for example, ref. [3]). The dominant role of palladium as the catalyst for the formation of O-containing heterocycles has been suggested to be associated with the relatively low strength of the Pd-O bond. Among the first examples of a nitrogen-containing heterocycle to be formed by homogeneous catalysis is the triazine shown in Equation 1 which is the product of the trimerization of benzonitrile in the presence of iron penta carbonyl or Raney nickel [4] .

Thisbookistalkingabouthowtousesupercriticalwater(SCW)torapidlyproduce micro- and nano-particles of metal oxides, inorganic salts, metals and organics. Itcoversbasicprinciples,experimentalmethodologiesandreactors,particlep- duction,characterizationsandapplicationsaswellastherecentadvancement. Fine particlescanbeproducedbybothchemicalandphysicalprecipitationofproducts from SCW. They can be used as catalysts, materials in ceramics and electronic devices andcompositematerials. Particlesareeasilyproduced continuouslyina owreactorinshortreactiontimes(0. 4s?2min)butcanalsobesynthesizedin batchreactorsforlongreactiontimes(e. g. ,12h). Theycanbeeasilystudiedin-situ microscopically(optical/IR/Raman/SR-XRD)inanopticalmicro-reactor,diamond anvilcell. Thesize,sizedistribution,crystalgrowth&structure,andmorphologyof particlescanbecontrolledbychangingtheconcentrationsofstatingmaterials,pH, pressures,temperatures,heating&coolingrates,organicmodi cations,reducingor oxidizingatmospheres, owratesandreactiontimes. Thisisthe rstbooktosystematicallyintroduceusingSCWforproductionof neparticles. Itisanidealreferencebookforengineers,researchersandgraduate studentsinmaterialscienceandengineering. vii Acknowledgments I would like to thank Drs. T. Ogi & T. Minowa (Biomass Technology Research Center,NationalInstituteofAdvancedIndustrialScienceandTechnology,Japan), and Profs. K. Arai, H. Inomata, R. L. Smith Jr. and T. Adschiri (Chemical Engineering,TohokuUniversity,Japan),whoinitiallyintroducedthehydrothermal andsupercritical uidsareastomewhenIworkedinJapanfrom1996to1999. Thanks are also due to Profs. J. A. Kozinski, R. I. L. Guthrie (Materials Engineering,McGillUniversity,Canada)andI. S. Butler(Chemistry,McGill)for theirguidanceinmyworkonhydrothermalprocessduringmyworkinCanadafrom 1999to2007. Profs. W. Bassett (Geological Sciences, Cornell University) and D. Baker (Earth&PlanetarySciences,McGill)forinstructionsregardingDAC,Dr. I-Ming Chou(U. S. GeologicalSurvey)forusefuldiscussionsofthepressurecalculation procedure. Drs. M. Watanabe and T. Sato (Research Center of Supercritical Fluid Technology, Tohoku University, Japan) for discussions about the experimental set-upofthebatchand owreactors. Drs. S. Xu,H. Assaaoudi,R. HashaikehandA. Sobhy,whoworkedwithmeat McGillinCanada. ix Contents 1 Introduction...1 1. 1 Background ...1 1. 2 RapidExpansionofSupercriticalSolution(RESS)Process ...4 1. 3 SupercriticalAntisolvent(SAS)Process ...4 1. 4 OtherPhysicalProcesses ...5 1. 5 SupercriticalWaterProcess ...5 References...8 2 Supercritical Water Process...11 2. 1 Introduction ...11 2. 2 BatchReactor ...15 2. 3 FlowReactor...18 2. 4 DiamondAnvilCell(DAC)...20 References...25 3 Metal Oxides Synthesis...29 3. 1 Introduction ...29 3. 2 Boehmite(AlOOH) ...30 3. 3 Ferrites...31 3. 4 Phosphor(YAG) ...32 3. 5 LiCoO /LiMn O ...33 2 2 4 3. 6 Ce Zr O (x =0?1)...33 1?x x 2 3. 7 PotassiumHexatitanate,PotassiumNiobateandTitania ...35 3. 8 ZincOxide...38 3. 9 Nickel,Nickel/CobaltOxide...

As we are moving ahead into the 21st century, our hunger for cost effective and environmentally friendly energy continues to grow. The Energy Information Administration of US has forecasted that only in the first two decades of the 21st century, our energy demand will increase by 60% compared to the levels at the end of the 20th century. Fossil fuels have been traditionally the major primary energy sources worldwide, and their role is expected to continue growing for the forecasted period, due to their inherent cost competitiveness compared to non-fossil fuel energy sources. However, the current fossil energy scenario is undergoing significant transformations, especially to accommodate increasingly stringent environmental challenges of contaminants like sulfur dioxide, nitrogen oxides or mercury, while still providing affordable energy. Furthermore, traditional fossil fuel utilization is inherently plagued with greenhouse gas emissions from combustion, especially carbon dioxide from stationary sources as well as from mobile sources. Should worldwide government policies dictate a reduction of greenhouse gas emissions, such as proposed by the Kyoto Protocol and the implementation of carbon taxes, fossil fuels would lose their significant competitive appeal in favor of nuclear energy and renewable energy sources. However, the current non-fossil fuel energy share of the worldwide energy market is merely below 15%, and therefore, it is more likely that fossil fuel energy producers would adapt to the new requirements by developing and implementing emission control technologies, and emission trades among other strategies."

Proceedings of the NATO Advanced Study Institute on New Trends and Applications of Photoelectrochemistry and Photocatalysis for Environment Problems, Cafelu, Palermo, Italy, September 6-18, 1987

Enzymes perform the executive role in growth, energy conversion, and repair of a living organism. Their activity is adjusted to their en vironment within the cell, being turned off, switched on, or finely tuned by specific metabolites according to demands at the physiologi cal level. Each enzyme discovered in the long history of enzymology has revealed its own individuality. Even closely related members of a family differ in specificity, stability or regulatory properties. Despite these, at first sight overwhelming aspects of individuality, common factors of enzymic reactions have been recognized. Enzymes are stereospecific catalysts even when a nonspecific process would yield the same product. Knowledge of the detailed stereochemistry of an enzymic reaction helps to deduce reaction mechanisms and to ob tain insight into the specific binding of substrates at the active site. This binding close to catalytically competent groups is related to the enormous speed of enzyme-catalyzed reactions. The physical ba sis of rate-enhancement is understood in principle and further exploit ed in the design of small organic receptor molecules as model enzymes. These aspects of enzyme catalysis are discussed in Session 1. Session 2 emphasizes the dynamic aspects of enzyme substrate inter action. Substrate must diffuse from solution space to the enzyme's surface. This process is influenced and can be greatly facilitated by certain electrostatic propterties of enzymes. The dynamic events during catalysis are studied by relaxation kinetics or NMR techniques."

The field of organometallic chemistry has emerged over the last twenty-five years or so to become one of the most important areas of chemistry, and there are no signs of abatement in the intense current interest in the subject, particularly in terms of its proven and potential application in catalytic reactions involving hydrocarbons. The development of the organometallic/ catalysis area has resulted in no small way from many contributions from researchers investigating palladium systems. Even to the well-initiated, there seems a bewildering and diverse variety of organic reactions that are promoted by palladium(II) salts and complexes. Such homogeneous reactions include oxidative and nonoxidative coupling of substrates such as olefins, dienes, acetylenes, and aromatics; and various isomerization, disproportionation, hydrogenation, dehydrogenation, car bonylation and decarbonylation reactions, as well as reactions involving formation of bonds between carbon and halogen, nitrogen, sulfur, and silicon. The books by Peter M. Maitlis - The Organic Chemistry of Palladium, Volumes I, II, Academic Press, 1971 - serve to classify and identify the wide variety of reactions, and access to the vast literature is available through these volumes and more recent reviews, including those of J. Tsuji [Accounts Chem. Res. , 6, 8 (1973); Adv. in Organometal. , 17, 141 (1979)], R. F. Heck [Adv. in Catat. , 26, 323 (1977)], and ones by Henry [Accounts Chem. Res. , 6, 16 (1973); Adv. in Organometal. , 13, 363 (1975)]. F. R. Hartley's book - The Chemistry of Platinum and Palladium, App!. Sci. Pub!.

It is now IS years since the first patents in polymer supported metal complex catalysts were taken out. In the early days ion-exchange resins were used to support ionic metal complexes. Soon covalent links were developed, and after an initially slow start there was a period of explosive growth in the mid to late 1970s during which virtually every homogeneous metal complex catalyst ever reported was also studied bound to a support. Both polymers and inorganic oxides were studied as supports, although the great preponderance of workers studied polymeric supports, and of these polystyrene was by far the commonest used. This period served to show that by very careful design polymer-supported metal complex catalysts could have specific advantages over homogeneous metal complex catalysts. However the subject was a complicated one. Merely immobilising a successful metal complex catalyst to a functionalised support rarely yielded other than an inferior version of the catalyst. Amongst the many discouraging results of the 1970s, there were more than enough results that were sufficiently encouraging to demonstrate that, by careful design, supported metal complex catalysts could be prepared in which both the metal complex and the support combined together to produce an active catalyst which, due to the combination of support and complex, had advantages of activity, selectivity and specificity not found in homogeneous catalysts. Thus a new generation of catalysts was being developed.