Modeling with Transition-metal Complexes

Molecular modelling of transition metal complexes (TMC), reproducing characteristic features of their stereochemistry and electronic structure, is in high demand in relation with studies and development of various processes of complex formation with an accent on ion extraction, ion exchange, isotope separation, neutralization of nuclear waste, and also when studying structure and reactivity of metal-containing enzymes. Solving these techno-... 

Metal-fragment substituted silanols are known to be stable towards self-condensation due to the strongly reduced acidity of the Si-OFI proton [2], However, these species show ready reaction with organochlorosilanes RsSiCl, which gives access to metallo-siloxanes [2], constituting attractive models for transition metal complexes anchored on silica surfaces. 

Kozelka, J. "Molecular Modeling of Transition Metal Complexes with Nucleic Acids and Their Constituents." In Metal Ions in Biological Systems Sigel A., Sigel. H., (eds.) Marcel Dekker, Inc. New York, Basel, Hong Kong, 1996 Vol. 33 pp 2. 

Reactions of Cu (aq) with Transition Metal Complexes Redox Reaction with N02 as a Model for Copper Nitrite Reductases (CuNIR)... 

Deeth, R. J. Anastasi, A. Diedrich, C. Randell, K. Molecular modelling for transition metal complexes Dealing with d-electron effects. Coord. Chem. Rev. 2009, 253, 795. 

Molecular Modeling of Transition Metal Complexes with Nucleic Acids and Their Consituents... 

Deeth R, Anastasi A, Diedrich C, Randell K (2009) Molecular modelling fin transition metal complexes dealing with d-electron effects. Coord Chem Rev 253 795... 

However, donor-acceptor interactions are affected not only by the Lewis acid and base strengths, but also by other, steric and electron structural, factors. Thus, even in systems where either solely the donor or the acceptor property of the solvent is manifested, solvents with different space requirements may interact to different extents because of the steric properties of the reference solute and a reference acceptor with a tendency for dative 7c-bonding (back-coordination) will interact more strongly with jr-acceptor solvent molecules (e.g., acetonitrile) than would be expected from their basicity. The solvent donicity investigations by Burger et al [Bu 71, 74] with transition metal complex reference acceptor model systems have clearly shown the great extent to which such secondary effects may distort the solvent scale. 

Matieiiko, L. L Mosolova, L. A. Zaikov, G. E. The Modeling of Transition Metal Complex Catalysts in the Selective Alkylarens Oxidations with Dioxygen. The Role of Hydrogen - Bonding Interactions, Oxid. Commun., 2009,32, 731. 

Electron transfer in biological systems where the electron donor and acceptor are separated by a long molecular distance is encountered in very important processes such as photosynthesis and respiration [54]. As natural systems are not appropriate for such studies. Gray et al. have employed proteins chemically labeled with transition metal complexes to measure ET rates in metaUoproteins. In particular, they have shown that long-lived luminescent probes enabled a wider range of ET measurements than is possible with non-luminescent complexes [55]. The blue copper protein azurin is a convenient model for the study of ET in p-sheet proteins. 

Calculations show that the high valent d -d dimer, (Re(sCH)(OH)2l2, contains a Re-Re double bond with a diamagnetic metal-metal bonding configuration.554 a theoretical study, based on CASSCF/CCI calculations, of the lowest part of the electronic spectra of [RMn(CO)3(a-diimine)] is reported. These systems serve as models for transition metal complexes with low-lying MLCT states.- - - ... 

The same M-L potential functions used with transition metal complexes have been successfully parametrized to reproduce the experimental variation in M-L bond lengths found in the more ionic alkali and alkaline earth complexes and lanthanide complexes." The results refute a common misconception that equations (1) and (2) are inappropriate for modeling these M-L bonds. 

To date, most of the photochemical data available for transition metal complexes comes from condensed phase studies (1). Recently, the primary photochemistry of a few model transition metal carbonyl complexes has been investigated in gas phase (5.). Studies to date indicate that there are many differences between the reactivity of organometallic species in gas phase (5.6) as conq>ared with matrix (7-10) or solution (11-17) environments. In most cases studied, photoexcitation of isolated transition metal... 

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