Synthesis and spectroscopic characterization of new mixed-metal, mixed-chalcogenide clusters [Fe2W(CO)10(µ3-Se)(µ3-E)](E = Te or S). Structures of [Fe2M(CO)10(µ3-Se)(µ3-E)](M = W, E = Se or Te; M = Mo, E = Se)

Abstract

The room-temperature reaction of [Fe2(CO)6(µ-SeTe)] and [Fe2(CO)6(µ-SSe)] with freshly prepared [W(CO)5(thf)](thf = tetrahydrofuran) yielded the new mixed-metal, mixed-chalcogenide clusters [Fe2W(CO)10(µ3-Se)(µ3-E)](E = Te 1 or S 2). Compounds 1 and 2 were characterized by IR and 13C, 77Se and 125Te NMR spectroscopy. The crystal structure of 1 was elucidated by X-ray diffraction methods. The previously reported compounds [Fe2W(CO)10(µ3-Se)2]3 and [Fe2Mo(CO)10(µ3-Se)2]4 were further characterized by 77Se NMR spectroscopy and single-crystal X-ray analysis. Clusters 1, 3 and 4 are isostructural and isomorphous (in the solid state). The structure consists of square-pyramidal Fe2WSeTe, Fe2WSe2 and Fe2MoSe2 cores respectively, and in each case the heterometal atom (W for 1 and 3 and Mo for 4) occupies the apical site.