Photosubstitution reactions of [W(η-C5H5)2(CH3)2][PF6]: some evidence for an α-elimination mechanism

Abstract

Irradiation of [W(η-C₅H₅)₂(CH₃)₂][PF₆] in the presence of L [L = pyridine (py), acetonitrile, or dimethylphenylphosphine] led to the isolation of the following products: [W(η-C₅H₅)₂(CH₃)L][PF₆], [W(η-C₅H₅)₂H(CH₂L)][PF₆](when L = PMe₂Ph), and [W(η-C₅H₅)₂HL][PF₆], [W(η-C₅H₅)₂(CH₃)L][PF₆](when L = py or MeCN). An α-elimination mechanism is proposed for these reactions. In a study of the related thermal reactions the products were the same as in the photochemical reactions for L = PMe₂Ph; for L = py the sole product isolated was [W(η-C₅H₅)₂(CH₃)L][PF₆]; and no reaction was observed with L = MeCN.