Organometallic reactions and homogeneous catalysis

The reverse reaction to reform the square planar complex is also well known. In contrast, it is generally not possible to isolate complexes made by adding a fifth ligand to traditional square planar complexes, such as [Pt(NH3)4] .  

The letter L will be used to represent die ligand P(C6H5)3, which is used frequently in organometallic complexes that are catalysts. 

However, such species are thought to be intermediates in substitution reactions. 

In a formal sense, these are oxidation reactions, because rhodium(l) is oxidized to rhodium(ni). These are also addition reactions because two ligands are added to square planar sixteen-electron systems which are transformed into octahedral eighteen-electron complexes. These reactions can also be viewed as an insertion reaction (see (4) below) in which a metal atom is inserted into a bond between two nonmetals. 

Studies on reaction (24) using labeled CO demonstrate that the CO inserted  

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Perspectives of Quantum Chemical Studies of Organometallic Reactions and Homogeneous Catalysis References... 

Tolman proposed two general rules relating to organometallic reactions and homogeneous catalysis. 

Whereas the CO insertion reaction has been investigated extensively in organometallic chemistry and homogeneous catalysis, there are only few first-principles investigations available for this reaction on transition metal surfaces (32,33,60). 

Organocatalysis is the study of reactions that employ catalysts based solely on organic compounds. This is a recent area of intense interest and complements traditional catalysts based on transition metal complexes. Organometallic chemistry and homogeneous catalysis were discussed earlier as a subarea of inorganic chemistry. Increasingly chemists seek to find catalytic methods for synthesis. 

Charles P. Casey (NAS) is Homer B. Adkins Professor of Chemistry at the University of Wisconsin, Madison. Dr. Casey s research lies at the interface between organometallic chemistry and homogeneous catalysis, and his group studies the mechanisms of homogeneously catalyzed reactions. He received his B.S. degree from St. Louis University and his Ph.D. from the Massachusetts Institute of Technology. 

These examples confirm that water as a solvent offers a number of variations to the possibilities offered by organic solvents in organometallic reactions and underline the importance of the analytical methods to characterization of organometallic compounds in water. There is still a huge potential for the use of water as the solvent of choice for homogeneous or biphasic catalysis. 

The outstandingly rapid scientific and technological development of metallocene-based catalysts for olefin polymerization is a perfect example of the successful application of organometallic chemistry to homogeneous catalysis and of the teaching that understanding reactions at the molecular level can provide to the more matter-of-fact fields of heterogeneous ca-... 

The coordination chemistry of the cobalt triad has received considerable attention in the areas of organometallic reaction mechanisms and homogeneous catalysis (82-84), Of particular interest have been processes such as hydrogenation, carbonylation, and hydroformylation, where the oxidative addition of substrate C-X or H-X bonds to coordinatively-unsaturated M(I) centers plays a critical role. Systems which have received the most attention thus far have been electron-rich... 

A concise summary of chemistry of technologically important reactions catalysed by organometallic complexes in solution. Cornils B and Herrmann W A (eds) 1996 Applied Homogeneous Catalysis with Organometallio Compounds (Weinheim VCH) A two-volume, multiauthored account with emphasis on industrial applications. 

Much of the recent interest in insertion reactions undeniably stems from the emphasis placed on development of homogeneous catalysis as a rational discipline. One or more insertion is involved in such catalytic processes as the hydroformylation (31) or the polymerization of olefins 26, 75) and isocyanides 244). In addition, many insertion reactions have been successfully employed in organic and organometallic synthesis. The research in this general area has helped systematize a large body of previously unrelated facts and opened new areas of chemistry for investigation. Heck 114) and Lappert and Prokai 161) provide a comprehensive compilation and a systematic discussion of a wide variety of insertion reactions in two relatively recent (1965 and 1967) reviews. 

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