SYNTHESIS AND CHARACTERIZATION OF TETRANUCLEAR MIXED-METAL HYDRIDE COMPLEXES, LWM3(CO)11(MU-H)3, L = C5H5, C5ME5 AND M = RU, OS

[[abstract]]Hydrogenation of the tetranuclear mixed-metal clusters LWM3(CO)12(μ-H) (L = C5H5, M = Os, (1); L = C5Me5, M = Os, (2); L = C5H5, M = Ru, (3); L = C5Me5, M = Ru, (4)) in toluene solution has yielded the tetrahedral cluster complexes LWM3(CO)11(μ-H)3 (L = C5H5, M = Os, (5); L = C5Me5, M = Os, (6); L = C5H5, M = Ru, (7); L = C5Me5, M = Ru, (8)). Complex 8 was characterized by single crystal X-ray diffraction. Crystal data for 8: space group P21/n; a = 10.731(4), b = 16.275(4), c = 15.606(4) Å, β = 99.76(2)°, Z = 4; RF = 0.0255, Rw = 0.0245 and GOF = 1.19. Complexes 6 and 8, which possess a CpW(CO)2 fragment, are present solely as one isomer in solution. The structure of this isomer (denoted a) is consistent with the solid state structure of 8 in which the hydride ligands are located on the edges of a WM2 triangular face. For complexes 5 and 7, each containing a CpW(CO)2 fragment, variable temperature 1H NMR studies suggest the presence of two rapidly interconverting isomers (a and b) in solution. Isomer b contains a tetrahedral core similar to isomer a, but in b, the hydride ligands occupy two M---H---M sites and one W---H---M site, in a zigzag arrangement.[[fileno]]2010302010067[[department]]化學