Synthesis and structural characterisation of some new triosmium alkylidyne clusters containing sulfur-donor ligands. The formation of C-S and C-C bonds

The neutral clusters [Os3(μ-H)2(CO)9{μ3-CS(CH 2)4CH2}] 1 and [Os3(μ-H)2(CO)9{μ3-CS(CH 2)2SCH2C-H2}] 2 were synthesised in good to moderate yields respectively by the reaction of [Os3(μ-H)3(CO)9-(μ3-CCl)] with 1 equivalent of 1,8-diazabicyclo[5.4.0]undec-7-ene, in the presence of a 10-fold excess of thiane or 1,4-dithiane. Under ambient conditions, complex 2 in solution slowly rearranges to a novel ketenylidene-bridged cluster [Os3(μ-H)2(CO)8{S(CH2) 2SCH2CH2}(μ3-CCO)] 3, which is formed by exchange of S(CH2)2SCH2CH2 and CO at the μ3-carbon. All complexes were fully characterised by spectroscopic methods and their molecular structures established by single-crystal X-ray analyses.