Reactions of [(μ-H)Os3(CO)10(μ-OMe)] and [(μ-H)Os3(CO)9(μ-OMe)(MeCN)] with dppm, dppe, dppp, and PPh2H:: X-ray crystal structures of [(μ-H)Os3(CO)8(μ-OMe)-(μ2-η2-dppm)] and [(μ-H)Os3(CO)9(μ-OMe)(PPh2H)]

Treatment of [(mu-H)Os-3(CO)(10)(mu-OMe)] (1) with dppm {dppm = bis(diphenylphosphino)methane} at 110 degrees C gave the known compound [Os-3(CO)(10)(mu(2)-eta(2)-dppm)] (2) and the new compound [(mu-H)Os-3(CO)(8)(mu-OMe)(mu(2)-eta(2)-dppm)] (3). A similar reaction of 1 with dppe {dppe=bis(diphenylphosphino)ethane} afforded two products, [(mu-H)Os-3(CO)(8)(mu-OMe)(mu(1)-eta(2)-dppe)] (5) and [(mu-H)Os-3(CO)(8)(mu-OMe)(mu(2)-eta(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 degrees C gave exclusively [(mu-H)Os-3(CO)(8)(mu-OMe)(mu(2)-eta(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 [(mu-H)Os-3(CO)(8)(mu-OMe)(MeCN)] (4) with the appropriate diphosphine at ambient temperature. The reaction of 1 with PPh2H at 110 degrees C gave the new compounds [(mu-H)Os-3(CO)(9)(mu-OMe)(PPh2H)] (8) and [(mu-H)Os-3(CO)(7)(mu-PPh2)(2)(PPh2H)](10) and the previously reported compound [(mu-H)Os-3(CO)(8)(mu-OMe)(PPh2H)] (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 PPhH ligand occupies a 'pseudo' axial site on one of the osmium atoms bearing the bridging hydride and methoxide ligand. (c) 2005 Elsevier Ltd. All rights reserved.