Reactions of [(μ-H)Os 3(CO) 10(μ-OMe)] and [(μ-H)Os 3(CO) 9(μ-OMe)(MeCN)] with dppm, dppe, dppp, and PPh 2H: X-ray crystal structures of [(μ-H)Os 3(CO) 8(μ-OMe)(μ 2-η 2-dppm)] and [(μ-H)Os 3(CO) 9(μ-OMe)(PPh 2H)

Abstract

Treatment of [(μ-H)Os 3(CO) 10(μ-OMe)] ( 1) with dppm {dppm = bis(diphenylphosphino)methane} at 110 °C gave the known compound [Os 3(CO) 10(μ 2-η 2-dppm)] ( 2) and the new compound [(μ-H)Os 3(CO) 8(μ-OMe)(μ 2-η 2-dppm)] ( 3). A similar reaction of 1 with dppe {dppe = bis(diphenylphosphino)ethane} afforded two products, [(μ-H)Os 3(CO) 8(μ-OMe)(μ 1-η 2-dppe)] ( 5) and [(μ-H)Os 3(CO) 8(μ-OMe)(μ 2-η 2-dppe)] ( 6) which differ in the mode of bonding of the dppe ligand. The reaction of 1 with dppp {dppp = bis(diphenylphosphino)propane} at 110 °C gave exclusively [(μ-H)Os 3(CO) 8(μ-OMe)(μ 2-η 2-dppp)] ( 7) which exists as two isomers in solution. Compounds 2, 3, and 5– 7 are also obtained in almost similar yields from reactions of [(μ-H)Os 3(CO) 9(μ-OMe)(MeCN)] ( 4) with the appropriate diphosphine at ambient temperature. The reaction of 1 with PPh 2H at 110 °C gave the new compounds [(μ-H)Os 3(CO) 9(μ-OMe)(PPh 2H)] ( 8) and [(μ-H) 2Os 3(CO) 7(μ-PPh 2) 2(PPh 2H)] ( 10) and the previously reported compound [(μ-H) 2Os 3(CO) 8(μ-PPh 2) 2] ( 9). The molecular structures of 3 and 8 were determined by single crystal X-ray diffraction. In compound 3, the dppm ligand bridges the same Os–Os edge as the hydride and the methoxide ligand. In 8, the PPh 2H ligand occupies a ‘pseudo’ axial site on one of the osmium atoms bearing the bridging hydride and methoxide ligand.