| Abstract |
Complexes [MHCpBz(CO)(2)(PR3)] (R = CH3, M = Mo (1); M = W (2); R = Ph, M = Mo (3); Cp-Bz = C-5(CH2Ph)(5)) were prepared by thermal decarbonylation of the corresponding [MHCpBz(CO)(3)] in the presence of trimethyl- or triphenyl-phosphine. In solution the NMR spectra of all compounds show the presence of cis and trans isomers that interconvert at room temperature. In the solid state the molecular structures obtained for compounds 1 and 2 correspond to the trans isomers, while for 3 the cis isomer is present. The electrochemistry of [MoHCpBz(CO)(2)(PMe3)] (1), [MoHCpBz(CO)(3)] (5), [WHCpBz(CO)(3)] (6), [WCpBz(CO)(3)](2) (7), and [MCpBz(CO)(3)(CH3CN)]BF4 (8), is described. The cleavage of M-H bonds takes place upon oxidation or reduction. Cations [MCpBz(CO)(2)L(CH3CN)](+) form in solvent-assisted M-H bond breaking upon oxidation of [MHCpBz(CO)(2)L] (L = PMe3, CO). Reduction of [MHCpBz(CO)(3)] gives [MCpBz(CO)(3)] and H-2. The presence of one PMe3 ligand lowers the reduction potential and precludes the observation of reduction waves. (C) 2010 Elsevier B.V. All rights reserved. |
