The stable radical cation [Mo2(µ-C8Me8)(η-C5H5)2]+: an intermediate in the redox activation of an alkyl C–H bond and a probe of metal–alkene bonding

Abstract

An X-ray structure determination has shown that oxidation of [Mo₂(µ-C₈Me₈)(η-C₅H₅)₂]1 to [Mo₂(µ-C₈Me₈)(η-C₅H₅)₂]⁺1⁺ results in geometric changes consistent with the presence of a three-electron metal–alkene interaction; cation 1⁺ undergoes both H-atom abstraction (with the CPh₃ radical) and oxidative deprotonation {on addition of [Fe(η-C₅H₅)₂]⁺} to give [Mo₂(µ-C₈Me₇CH₂)(η-C₅H₅)₂]⁺2⁺ showing that the mechanism of the redox-activation of one C–H bond of 1(EC or EEC) is critically dependent on the nature of the chemical oxidant.