The mechanism of protonation of carbyne complexes; X-ray crystal structure of [HMo(CCH2But){P(OMe)3}2(η-C5H5)][BF4] and [Mo(CF3CO2)(CF3CO2H){P(OMe)3}2(η-C5H5)]

Abstract

The carbyne hydride complex [HMo(CCH₂Bu^t){P(OMe)₃}₂(η-C₅H₅)][BF₄], structurally identified by X-ray crystallography, is formed on protonation of [Mo(CCH₂Bu^t){P(OMe)₃}₂(η-C₅H₅)]With HBF₄, whereas with CF₃CO₂H loss of the carbyne fragment occurs of give [Mo(OCOCF₃)(CF₃₀CO₂H){P(OMe)₃}₂(η-C₅H₅)], suggesting kinetic, charge-controlled attack by a proton on carbon.