Decarboxylation of vinylene carbonate at triosmium clusters; X-ray crystal structure of the µ3-formylmethylidene compound [Os3(CHCHO)(CO)10]

Abstract

Vinylene carbonate [graphic omitted]O reacts at room temperature with [Os₂H₃(CO)₁₀] to give a good yield of the vinyloxy cluster [Os₃H(OCHCH₂)(CO)₁₀](1). A similar decarboxylation occurs on reaction with [Os₃(CO)₁₀(MeCN)₂] to give the formylmethylidene cluster [OS₃µ₃-CHCHO)(µ-CO)(CO)₉](2). The single-crystal X-ray structure of (2) is closely related to those of [Os₃(µ-CHR)(µ-CO(CO)₁₀](R = H or SiMe₃) with two osmium atoms bridged both by CO and an alkylidene group. In (2) this group is part of a four-electron-donating µ₃ bridge. Hydrogenation of (2) or decarbonylation of (1) leads to the formylmethylidene compound [Os₃H₂(CHCHO)(CO)₉](3).