Photoprocesses in Transition Metal Complexes, Biosystems and Other Molecules. Experiment and Theory


Book Description

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.




Vanadium Catalysis


Book Description

Vanadium is one of the more abundant elements in the Earth’s crust and exhibits a wide range of oxidation states in its compounds making it potentially a more sustainable and more economical choice as a catalyst than the noble metals. A wide variety of reactions have been found to be catalysed by homogeneous, supported and heterogeneous vanadium complexes and the number of applications is growing fast. Bringing together the research on the catalytic uses of this element into one essential resource, including theoretical perspectives on proposed mechanisms for vanadium catalysis and an overview of its relevance in biological processes, this book is a useful reference for industrial and academic chemists alike.




Introduction to Metal π-Complex Chemistry


Book Description

The Plenum Press series, Monographs in Inorganic Chemistry, is intended to fill an obvious need for high-level surveys of recent research in that area, particularly in matters which go beyond the traditional or classical bound aries of the subject. The study of n-bonding of hydrocarbon groups (and their derivatives) to metals is exactly that kind of subject, for it provides a new way of understanding the behavior of metals (which constitute four-fifths of all the chemical elements). In addition, n-bonding has expanded the intriguing area of organometallic chemistry threefold, bringing in all the transition metals, the lanthanides, and the actinides. So much has been discovered and developed in the area of n-bonded "complexes" of the metals that important new industrial processes based on such substances have been developed. A truly comprehensive review of all n-bonded compounds of the metals would now result in an impossibly large and expensive volume, and would require monthly revision. Instead, the present authors have wisely decided to write a survey which outlines the general aspects of preparation, properties, structure, reactions, and uses of such compounds-a survey which can serve as a textbook, but which can also lead the more experienced practitioner to the most advanced literature on the subject. They have clarified and condensed the subject by means of good organization and a liberal use of diagrams-features which will please the general reader.




Metal Π-complexes


Book Description




Metal [pi]-complexes


Book Description




Olefin Upgrading Catalysis by Nitrogen-based Metal Complexes I


Book Description

This book highlights key advances that have occurred in the field of olefin conversion in recent years. The role of homogenous transition metal catalysts which contain an imine functionality is emphasized; their potential applications in the processing and upgrade of olefins to a wide variety of commodity products of very high industrial value is also explored. On the threshold of the fiftieth anniversary of the Noble Prize to Ziegler and Natta, this book gives a critical summary of the state of the art developments in the fascinating and rapidly developing field of the olefin polymerization, oligomerization, and co-polymerization catalysis.




Surface Organometallic Chemistry: Molecular Approaches to Surface Catalysis


Book Description

Surface organometallic chemistry is a new field bringing together researchers from organometallic, inorganic, and surface chemistry and catalysis. Topics ranging from reaction mechanisms to catalyst preparation are considered from a molecular basis, according to which the "active site" on a catalyst surface has a supra-molecular character. This. the first book on the subject, is the outcome of a NATO Workshop held in Le Rouret. France, in May. 1986. It is our hope that the following chapters and the concluding summary of recommendations for research may help to provide a definition of surface organometallic chemistry. Besides catalysis. the central theme of the Workshop, four main topics are considered: 1) Reactions of organometallics with surfaces of metal oxides, metals. and zeolites; 2) Molecular models of surfaces, metal oxides, and metals; 3) Molecular approaches to the mechanisms of surface reactions; 4) Synthesis and modification of zeolites and related microporous solids. Most surface organometallic chemistry has been carried out on amorphous high-surf ace-area metal oxides such as silica. alumina. magnesia, and titania. The first chapter. contributed by KNOZINGER. gives a short summary of the structure and reactivity of metal oxide surfaces. Most of our understanding of these surfaces is based on acid base and redox chemistry; this chemistry has developed from X-ray and spectroscopic data, and much has been inferred from the structures and reactivities of adsorbed organic probe molecules. There are major opportunities for extending this understanding by use of well-defined (single crystal) oxide surfaces and organometallic probe molecules.




Catalysis and Electrocatalysis at Nanoparticle Surfaces


Book Description

Illustrating developments in electrochemical nanotechnology, heterogeneous catalysis, surface science and theoretical modelling, this reference describes the manipulation, characterization, control, and application of nanoparticles for enhanced catalytic activity and selectivity. It also offers experimental and synthetic strategies in nanoscale surface science. This standard-setting work clariefies several practical methods used to control the size, shape, crystal structure, and composition of nanoparticles; simulate metal-support interactions; predict nanoparticle behavior; enhance catalytic rates in gas phases; and examine catalytic functions on wet and dry surfaces.




Advances in Catalytic Activation of Dioxygen by Metal Complexes


Book Description

The subject of dioxygen activation and homogeneous catalytic oxidation by metal complexes has been in the focus of attention over the last 20 years. The widespread interest is illustrated by its recurring presence among the sessions and subject areas of important international conferences on various aspects of bioinorganic and coordination chemistry as well as catalysis. The most prominent examples are ICCC, ICBIC, EUROBIC, ISHC, and of course the ADHOC series of meetings focusing on the subject itself. Similarly, the number of original and review papers devoted to various aspects of dioxygen activation are on the rise. This trend is due obviously to the relevance of catalytic oxidation to biological processes such as dioxygen transport, and the action of oxygenase and oxidase enzymes related to metabolism. The structural and functional modeling of metalloenzymes, particularly of those containing iron and copper, by means of low-molecular complexes of iron, copper, ruthenium, cobalt, manganese, etc., have provided a wealth of indirect information helping to understand how the active centers of metalloenzymes may operate. The knowledge gained from the study of metalloenzyme models is also applicable in the design of transition metal complexes as catalytsts for specific reactions. This approach has come to be known as biomimetic or bioinspired catalysis and continues to be a fruitful and expanding area of research.