DIMETHYLSULFIDE DERIVATIVES OF [RH6(CO)16] - CRYSTAL-STRUCTURES OF [RH6(CO)15(SME2)] AND [RH6(CO)12(SME2)4]

The decahexacarbonylhexarhodium cluster [Rh6(CO)16] reacts with dimethylsulfide to give a series of substituted clusters [Rh6(CO)16-x(SMe2)x], x = 1-4 (1-4). The crystal structures of 1 and 4 have been determined. The SMe2 ligands replace terminal carbonyls, otherwise the cluster structure is maintained. The four sulfide ligands in 4 replace four carbonyl groups at Rh atoms in the same plane of the Rh6 octahedron, with the SMe2 groups lying alternately above and below this plane. The di- and tri-substituted species have been characterized by ir spectroscopy and elemental analysis. The reactivity of [Rh6(CO)12(SMe2)4] toward hydrogen and carbon monoxide has been studied. Under CO it undergoes replacement of SMe2 by carbon monoxide to afford [Rh6(CO)16]. In a corresponding reaction with H2 [Rh6(CO)12(SMe2)4] is converted into a mixture of 2-4. Hydrogenation of 1-hexene using [Rh6(CO)12(SMe2)4] as a catalysts precursor was observed at 60-degrees-C with a highest rate of 2200 turnovers/h.