Mixed-metal chalcogenide tetrahedral clusters with an exo-polyhedral metal fragment

Abstract

The reaction of metal carbonyl compounds with group 6 and 8 metallaboranes led us to report the synthesis and structural characterization of several novel mixed-metal chalcogenide tetrahedral clusters. Thermolysis of arachno-[(Cp*RuCO)₂B₂H₆], 1, and [Os₃(CO)₁₂] in the presence of 2-methylthiophene yielded [Cp*Ru(CO)₂(μ-H){Os₃(CO)₉}S], 3, and [Cp*Ru(μ-H){Os₃(CO)₁₁}], 4. In a similar fashion, the reaction of [(Cp*Mo)₂B₅H₉], 2, with [Ru₃(CO)₁₂] and 2-methylthiophene yielded [Cp*Ru(CO)₂(μ-H){Ru₃(CO)₉}S], 5, and conjuncto-[(Cp*Mo)₂B₅H₈(μ-H){Ru₃(CO)₉}S], 6. Both compounds 3 and 5 can be described as 50-cve (cluster valence electron) mixed-metal chalcogenide clusters, in which a sulfur atom replaces one of the vertices of the tetrahedral core. Compounds 3 and 5 possess a [M₃S] tetrahedral core, in which the sulfur is attached to an exo-metal fragment, unique in the [M₃S] metal chalcogenide tetrahedral arrangements. All the compounds have been characterized by mass spectrometry, IR, and ¹H, ¹¹B and ¹³C NMR spectroscopy in solution, and the solid state structures were unequivocally established by crystallographic analysis of compounds 3, 5 and 6.