Asymmetric acetylenic thioethers in ruthenium cluster chemistry

The compounds [Ru₃(CO)₉(μ,η²-SCCR)(μ₃,η²-CCR^′)] (R=SiMe₃, R^′=SiⁱPr₃ (1); R=SiⁱPr₃, R^′=SiMe₃ (2); R=SiⁱPr₃, R^′=H (3); R=H, R^′=SiⁱPr₃ (4)) have been obtained by cleavage of one S-C bond of the thioethers ⁱPr₃SiCCSCCR (R=H, SiMe₃) in the presence of Ru₃(CO)₁₂. Thermal treatment of [Ru₃(CO)₉(μ,η²-SCCSiⁱPr₃)(μ₃,η²-CCH)] yields to the cluster [Ru₄(CO)₉(μ-CO)₂(μ₄-S)(μ₄-η²-C(H)C)(CCSiⁱPr₃)] (5) which contains a bridging sulfur atom and a polycarbon chain as a consequence of the rupture of the S-C bond and a C-C coupling reaction. All derivatives have been characterized by spectroscopic data. An X-ray diffraction study was carried out on the species [Ru₃(CO)₉(μ,η²-SCCSiⁱPr₃)(μ₃,η²-CCSiMe₃)] and of [Ru₃(CO)₉(μ,η²-SCCSiⁱPr₃)(μ₃,η²-CCH)].