REACTIONS OF SOLID H2OS3(CO)(10) WITH GASEOUS CO, NH3, AND H2S

The coordinatively unsaturated H2Os3(CO)(10) (1) cluster reacts readily in the solid state with gaseous reactants L (L = CO, NH3, H2S) to afford the electron-precise adducts H2OS3-(CO)(10)L (2, L = CO; 3, L = NH3; 4, L = H2S). In the case of the reaction with CO, the solid product 2 was unambiguously characterized by means of H-1 magic angle spinning NMR spectroscopy. Upon longer reaction times compound 2 releases H-2 and transforms into OS3(CO)(12) (5). The novel NH3 adduct 3 exists in solution as a mixture of two isomers, differing in the relative orientation of the ammonia and the terminal hydride ligands with respect to the OS3 plane (syn and anti). Variable-temperature (VT) H-1 and C-13 NMR spectroscopy revealed that these isomers interconvert in solution. The novel H2S adduct 4 was much less stable than the other two, and upon dissolution in dichloromethane, it immediately transformed into the known compound H2Os3(CO)(9)S (6).