Functional transition metal chemistry

Functionalized polyethylene would be of great industrial importance, and if synthetic methods to control the microstructure of functionalized polymers using transition-metal-based catalysis are developed, it would significantly broaden the utility and range of properties of this class of polymers. Recent progress in the field of late transition metal chemistry, such as Brookliart s use of nickel-based diimine catalysts, has enabled the copolymerization of ethylene with functional a-olefins.29 However, these systems incorporate functionalized olefins randomly and with limited quantity (mol percent) into the polymer backbone. 

Transition-metal chemistry in particular was the field where pioneering density functional results have been of unprecedented accuracy for larger systems and impressive to any researcher in the field. Today, it seems that density functional theory has adopted the role of a standard tool for the prediction of molecular structures. 

Ziegler, T., 1997, Density-Functional Theory as a Practical Tool in Studies of Transition Metal Chemistry and Catalysis , in Density Functional Methods in Chemistry and Materials Science, Springborg, M. (ed.), Wiley, Chichester. 

Transition-metal chemistry is currently one of the most rapidly developing research areas. The record of investigation for compounds with metal silicon bonds is closely comparable to that for silicones it was in 1941 when Hein discovered the first metal silicon complex, followed by Wilkinson in 1956. A milestone in the development of this chemistry was Speier s discovery of the catalytic activity of nobel metal complexes in hydrosilylation reactions in 1977. Hydrosilylation is widely used in modem organic syntheses as well as in the preparation of organo functionalized silicones. Detailed investigations of the reaction mechanisms of various catalysts continue to be subject of intense research efforts. 

In summary, the Lewis-like model seems to predict the composition, qualitative molecular shape, and general forms of hybrids and bond functions accurately for a wide variety of main-group derivatives of transition metals. The sd-hybridization and duodectet-rule concepts for d-block elements therefore appear to offer an extended zeroth-order Lewis-like model of covalent bonding that spans main-group and transition-metal chemistry in a satisfactorily unified manner. 

This survey of theoretical methods for a qualitative description of homogeneous catalysis would not be complete without a mention to the Hartree-Fock-Slater, or Xot, method [36]. This approach, which can be formulated as a variation of the LDA DFT, was well known before the formal development of density functional theory, and was used as the more accurate alternative to extended Hiickel in the early days of computational transition metal chemistry. 

Many reviews touching on aspects of computational inorganic chemistry have appeared in fact, too many to list here. Several special thematic issues can be highlighted Chem. Rev. 2000,100 (2), 351-818 on computational transition metal chemistry Coord. Chem. Rev. 2003, 238/239, 1-417 on theoretical and computational chemistry Struct. Bond. 2004, 112/113, on principles and applications of density functional theory in inorganic chemistry J. Comput. Chem. 2006, 27 (12), 1221-1475 on theoretical bioinorganic chemistry, and no doubt many others. 

Life processes also depend on inorganic molecules, and a classic example includes the so-called transition metals , key to the function of many molecules (e.g. enzymes). As such, when considering biomolecules it is imperative to understand fundamental features of transition metals and their interaction with biomolecules. Indeed, transition metal chemistry is an effective means of learning... 

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