Reactivity of the Unsaturated Triosmium Cluster [Os3(CO)8{Ph2PCH2P(Ph)C6H4}(μ-H)] with Thiols

Abstract

The reaction of the unsaturated cluster [(μ-H)Os3(CO)8{Ph2PCH2P(Ph)C6H4}] 2 with C2H5SH, CH3CH(CH3)SH and C6H5SH are reported. The reaction of 2 with C2H5SH yields the new complexes [Os3(CO)8(μ-SC2H5)(η1-SC2H5){Ph2PCH2P(Ph)C6H4}(μ-H)] 9 and [Os3(CO)8)(SC2H5)(Ph2PCH2P)(Ph)C6H4}] 8 in 24 and 57% yields respectively and the known compound [(Os3(CO)8)(μ-SC2H5)(μ-dppm)(μ-H)] 7 in 5% yield. Compound 9, which exists as two isomers in solution, converts into 8 almost quantitatively in solution at 25°C and more rapidly in refluxing hexane. Compound8 reacts with H2 at 110°C to give 7 in high yield (86%). Treatment of 2 with propane-2-thiol yields [Os3(CO)8{μ-SCH(CH3)CH3}{Ph2PCH2P(Ph)C6H4}] 10 and [(Os3(CO)8{μ-SCH(CH3)CH3}{η1-SCH(CH3)CH3}{Ph2PCH2P(Ph)C6H4}(μ-H)] 11 in 75 and 3% yields respectively while with C6H5SH, [(Os3(CO)8(μ-SC6H5)(μ-dppm)(μ-H)] 6 is obtained as the only product in 75% yield. In both 8 and 10, the thiolato ligand bridges the Os–Os edge which is also bridged by the metallated phenyl group. The new compounds have been characterized by elemental analyses and spectroscopic methods (IR, 1H and 31P NMR). The molecular structures of 7, 8, 9 and 10 are reported as determined by X-ray diffraction studies.