General The making and breaking of carbon-metal bonds is fundamental to all the p- cesses of organometallic chemistry and moreover plays a significant role in - mogeneous as well as heterogeneous catalysis. This rather blunt statement - phasises the extent to which a proper understanding of the structure, energetics and reactivity of C-M bonds is at the core of the discipline. In order to accept it, a proper definition of the terms involved is required. Quite simply we define the metal-carbon bond in its broadest sense to embrace carbon linked to transiti- metals, lanthanides and actinides, and main group metals. We do not dist- guish between formally covalent single or multiple bonding on the one hand and q-bonding on the other. In the studies to be described in the following chapters, the emphasis will be on transition metal complexes and insofar as the fun- mentals come under scrutiny, simple metal alkyls or related species (metal al- nyl, alkynyl, aryl, or allyl) will play an emphatic part. The central role of metal alkyls and their congeners and especially the role of their metal carbon linkage in homogeneous catalysis may be appreciated by considering some key reaction steps leading to their formation or breakdown. There follows a few prominent examples of transition metal mediated stoichiometric or catalytic processes: - In homogeneous hydrogenation of double bonds, the stepwise reaction of an q2-coordinated alkene with dihydrogen gives first an alkyl metal hydride, and then the decoordinated alkane by elimination.

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.

1. R.G. Pearson Chemical Hardness - An Historical Introduction 2. P.K. Chattaraj Density Functional Theory of Chemical Hardness 3. J.L. Gazqu z Hardness and Softness in Density Functional Theory 4. L. Komorowski Hardness Indices for Free and Bonded Atoms 5. N.H. March The Ground-State Energy of Atomic and Molecular Ions and Its Variation with the Number of Elections 6. K. Sen Isoelectronic Changes in energy, Electronegativity, and Hardness in Atoms via the Calculations of 7. P. Politzer, J.S. Murray, M.E. Grice Charge Capacities and Shell Structures of Atoms 8. R. F. Nalewajski The Hardness Based Molecular Charge Sensitivities and Their Use in the Theory of Chemical Reactivity 9. B.G. Baekelandt, R. A. Schoonheydt, W.J. Mortier The EEM Approach to Chemical Hardness in Molecules and Solids: Fundamentals and Applications 10. J.A. Alonso, L. C. Balbas Hardness of Metallic Clusters

It is 25 years since the seminal papers describing the relationships between the skeletal geometrics and closed shell electronic requirements of metal clusters were originally published. The electron counting rules which developed from these papers, are now to be found in all undergraduate inorganic textbooks. This volume provides a contemporary account of recent applications of the methodology and the mathematical foundations of the rules. In addition it describes how it is possible to accomondate acception to the rules within a wider framework. The authors are the foremost authorities in the field and give a broad introduction to the area.

The French chemist Marcelin Berthelot put forward a classical and by now an often cited sentence revealing the quintessence of the chemical science: "La Chimie cree son objet." This is certainly true because the largest number of molecular compounds were and are continuously synthesized by chemists themselves. However, modern computational quantum chemistry has reached a state of maturity that one can safely say: "La Chimie Theorique cree son objet" as well. Indeed, modern theoretical chemistry is able today to provide reliable results on elusive systems such as short living species, reactive intermediates and molecules which will perhaps never be synthesized because of one or another type of instability. It is capable of yielding precious information on the nature of the transition states, reaction paths etc. Additionally, computational chemistry gives some details of the electronic and geometric structure of molecules which remain hidden in experimental examinations. Hence, it follows that powerful numerical techniques have substantially enlarged the domain of classical chemistry. On the other hand, interpretive quantum chemistry has provided a conceptual framework which enabled rationalization and understanding of the precise data offered either by experiment or theory. It is modelling which gives a penetrating insight into the chemical phenomena and provides order in raw experimental results which would otherwise represent just a large catalogue of unrelated facts.

Self-assembly is undoubtedly a topic of special interest in current chemistry and is related to very wide scientific areas. Recent progress in this field seems to be featured by the construction of well-defined discrete systems exploiting complementary hydrogen bonding as well as coordination bonding. Seven leading international experts introduce the current topics in this very interesting field, focusing on two major subjects: organic assemblies and inorganic assemblies. All researchers who are interested in molecular recognition, material science, nanotechnology, and supramolecular chemistry will welcome this book as an inspiring source for creative research ideas.