Formation of a cationic alkylidene complex via formal hydride abstraction: synthesis and structural characterization of [W(PMe3)4(η2-CHPMe2)H]X (X = Br, I)

Abstract

W(PMe₃)₄(η²-CH₂PMe₂)H reacts with aryl halides to give the alkylidene complex, [W(PMe₃)₄(η²-CHPMe₂)H]⁺, which reacts with LiAlD₄ to give selectively W(PMe₃)₄(η²-CHDPMe₂)H, in which the deuterium resides in the methylene group; subsequent migration of deuterium from the methylene group provides a means to measure the rate constant for the formation of the 16-electron species [W(PMe₃)₅] from W(PMe₃)₄(η²-CH₂PMe₂)H.