Conversion of the cluster [Os 3(CHCFc)(CO) 10] (CHCFc = ethynylferrocene) into [Os 3(S)(CHCFc)(CO) 9] by reaction with sulphur. Crystal structures of these clusters and of [Os 3H(C 2Fc)(CO) 9

Abstract

By application of a method established for various alkynes, the cluster [Os 3(CO) 10(MeCN) 2] was treated with ethynylferrocene (CHCFc) to give the alkyne cluster [Os 3(μ 3-CHCFc)(μ-CO)(CO) 9] ( 1). This cluster loses CO thermally and by visible irradiation to form the hydrido-ferrocenylethynyl cluster [Os 3H(μ 3-C 2Fc) (CO) 9] ( 2), but if the decarbonylation is carried out in the presence of sulphur at room temperature under visible irradiation, the cluster [Os 3(μ 3-S)(μ 3-CHCFc)(CO) 9] ( 3) is formed instead. The crystal structures of 1, 2, and 3 are reported. Clusters 1 and 3 are both 48-electron clusters containing μ 3-CHCFc ligands but, whereas 1 contains three OsOs bonds, 3 contains only two. In 3 the triply bridging ligands occupy opposite faces of the Os 3 triangle, with the osmium atoms at the open edge of the triangle having σ-bonds to the alkyne ligand. The structure of 1 and the known structure of [Os 3(PhC 2Ph)(CO) 10] are closely related, although cluster 1 contains one bridging CO ligand and the latter two semi-bridging CO ligands. The fluxionality of cluster 1 is considered in the light of these different structures.