SYNTHESIS AND STRUCTURE OF MU-OXO-BIS[(ACETYLACETONATO)(THIOACETYLACETONATO)]DIOXO-DIMOLYBDENUM(V) AND MU-OXO-[TRIS(ACETYLACETONATO)(THIO-ACETYLACETONATO)]DIOXODIMOLYBDENUM(V)

In the reaction of Mo2O3 (acac)4 and Mo2O3 (OAc)4 with thioacetylacetone two new complexes of molybdenum(V), Mo2O3 (acac)2(Sacac)2 (complex I) and Mo2O3(acac)3(Sacac) (complex II), respectively, have been prepared. Their crystal structures have been determined from single crystal diffractometer data and refined to the final R values of 0.068 and 0.044, respectively. Both complexes crystallize in the tetragonal space group I4(1)/a with cell dimensions, (I): a = 21.646(3), c = 11.627(2) angstrom, D(calc) = 1.630 g cm-3, Z = 8 and (II): a = 21.240(3), c = 11.688(2)angstrom, D(calc) = 1.644 g cm-3, Z = 8 and have essentially the same structure. In the structure of (II) half of thioacetylacetone of (I) is statistically replaced by acetylacetone causing thus an occupational disorder in this region of the structure. Both complex molecules are dinuclear and have crystallographically imposed 1BAR symmetry with the bridging oxygen atom in the center of symmetry. Molybdenum atoms exhibit distorted octahedral coordinations. Sulfur atom of the Sacac ligand in (I) shows a considerably larger trans influence than the oxo-oxygen atom.