Electrochemical and theoretical investigations of the reduction of [Fe-2(CO)(5)L{mu-SCH2XCH2S}] complexes related to [FeFe] hydrogenase

Capon, J. F., Ezzaher, S., Gloaguen, F., Petillon, F. Y., Schollhammer, P., Talarmin, J., Davin, T. J., McGrady, J. E. and Muir, K. W. (2007) Electrochemical and theoretical investigations of the reduction of [Fe-2(CO)(5)L{mu-SCH2XCH2S}] complexes related to [FeFe] hydrogenase. New Journal of Chemistry, 31(12), pp. 2052-2064. (doi: 10.1039/b709273c Univ Bretagne Occidentale, UFR Sci & Tech, UMR CNRS 6521 Chim Electrochim Mol & Chim Anal, F-29238 Brest 3, France. Univ Glasgow, Dept Chem, WestCHEM, Glasgow G12 8QQ, Lanark, Scotland.)

Full text not currently available from Enlighten.

Abstract

The complexes [Fe-2(CO)(6){mu-SCH2N(R)CH2S}] (R = CH2CH2OCH3, 1a; R= Pr-i, 1b) and [Fe-2(CO)(6)(mu-pdt)] 2 (pdt = S(CH2)(3)S) are structural analogues of the [2Fe](H) subsite of [FeFe]H(2)ases. Electrochemical investigation of 1 and 2 in MeCN-[NBu4][PF6] under Ar and under CO has demonstrated that the reduction can be resolved into two one-electron transfer steps by using fast scan cyclic voltammetry. At slow scan rates the reduction of 1 tends towards a two-electron process owing to the fast disproportionation of the anion, while the two-electron reduction of 2 is clearly favoured in the presence of CO. Substitution of a CO ligand in 2 by a N-heterocyclic carbene results in the destabilisation of the anion. Thus, in MeCN-, thf- or CH2Cl2-[NBu4][PF6], the electrochemical reduction of Fe-2(CO)(5)L-NHC(mu-pdt)] 3 (L-NHC = 1,3-bis(methyl)-imidazol-2-ylidene, 3a; 1,3-bis(2,4,6-trimethylphenyl)-imidazol-2-ylidene, 3b) occurs in a single-step, two-electron process at moderate scan rates; under appropriate conditions this process can be separated into two one-electron steps. Density Functional Theory calculations successfully rationalize the effects of the S-to-S linkage on the electrochemistry of the complexes.

Item Type:Articles
Keywords:ACTIVE-SITE MODELS ANION ATTAINING EXPONENTIAL CONVERGENCE CARBENE CO COMPLEX COMPLEXES DENSITY Density functional theory DENSITY-FUNCTIONAL THEORY ELECTROCATALYTIC PROTON REDUCTION ELECTROCHEMICAL REDUCTION ELECTROCHEMISTRY FINITE-DIFFERENCE EQUATIONS HYDROPHILIC PHOSPHATRIAZAADAMANTANE LIGAND IRON-ONLY HYDROGENASE LIGAND METAL-METAL BOND ONE-ELECTRON RATES RAY CRYSTAL-STRUCTURE REDUCTION STEP SUBSTITUTION UNEQUALLY SPACED GRIDS
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Muir, Dr Kenneth and McGrady, Prof John
Authors: Capon, J. F., Ezzaher, S., Gloaguen, F., Petillon, F. Y., Schollhammer, P., Talarmin, J., Davin, T. J., McGrady, J. E., and Muir, K. W.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:New Journal of Chemistry
ISSN:1144-0546

University Staff: Request a correction | Enlighten Editors: Update this record