A dinuclear oxomolybdenum(VI) complex, [Mo2O6(4,4′-di-tert-butyl-2,2′-bipyridine)2], displaying the {MoO2(μ-O)2MoO2}0 core, and its use as a catalyst in olefin epoxidation

The dinuclear complex [Mo2O6(di-tBu-bipy)2] (1) (di-tBu-bipy = 4,4′-di-tert-butyl-2,2′-bipyridine) was obtained as a minor product of the hydrothermal reaction of MoO3 and di-tBu-bipy, and structurally characterized by single-crystal X-ray diffraction. In the molecular structure of 1 two distorted MoO6 octahedra share a common edge to form a dioxo-bridged Mo2O6 unit which is coordinated by di-tBu-bipy ligands. The catalytic performance of 1 for the epoxidation of non-functionalized olefins using tert-butylhydroperoxide as oxidant compares favorably with that reported for other oxomolybdenum(VI) complexes bearing the same organic ligand. The catalyst exhibits regioselectivity toward internal olefin epoxidation over external olefin epoxidation.