Syntheses and reactivities of hydrosulfido- or sulfido-bridged heterobimetallic complexes containing Group 6 and Group 9 metals

Abstract

Reactions of [Cp₂M(SH)₂] (M = Mo 1, W 2) with one equiv of [IrH₂(PPh₃)₂(Me₂CO)₂][PF₆] in acetone at room temperature under 1 atm of H₂ afforded the hydrosulfido–hydrido complexes [Cp₂M(μ-SH)₂IrH₂(PPh₃)₂][PF₆] (M = Mo 4, W 5), whereas those of 1 and 2 with [RhH₂(PPh₃)₂(Me₂CO)(EtOH)][PF₆] 6 resulted in the formation of [Cp₂Mo(μ-SH)₂Rh(PPh₃)₂][PF₆] 7 and [Cp₂W(μ-S)₂Rh(PPh₃)₂][PF₆] 8. X-Ray analyses have been undertaken to clarify the detailed structure of [Cp₂Mo(μ-SH)₂IrH₂(PPh₃)₂][BPh₄] derived from 4 along with 7 and 8. Bimetallic complexes 4, 5, 7, and 8 catalysed the hydrogenation of alkynes such as 1-octyne and tert-butyl propiolate at room temperature under 1 atm of H₂, yielding 1-octene and tert-butyl acrylate as the major products, respectively. In both reactions, the Mo–Rh complex 7 showed the highest catalytic activity, although even the reactions using 7 are much slower than those catalyzed by the mononuclear Rh complex 6.