ESR spectroscopic characterisation of a coordinated alkyne radical, and redox-induced vinylidene–alkyne complex isomerisation
Abstract
One-electron oxidation of [Cr(CO)2(RC2R)(η-C6Me6)]1 gives paramagnetic [Cr(CO)2(RC2R)(η-C6Me6)]+1+ in which the unpaired electron in highly delocalised onto the alkyne; the radical cation (1+; R = SiMe3) is an intermediate in the oxidative isomerisation of the vinylidene complex [Cr(CO)2{CC(SiMe3)2}(η-C6Me6)]2 to [Cr(CO)2(Me3SiC2SiMe3)(η-C6Me6)](1; R = SiMe3).