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.

Graphical abstractA rare example of a dinuclear molybdenum complex exhibiting the {Mo2O6}0 core has been isolated from the hydrothermal reaction of MoO3 and 4,4′-di-tert-butyl-2,2′-bipyridine, and structurally characterized by single crystal X-ray diffraction. The complex is a particularly active and regioselective catalyst for the epoxidation of non-functionalized olefins using tert-butylhydroperoxide as oxidant.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The structure of a rare example of a dinuclear molybdenum complex exhibiting the {Mo2O6}0 core is described. ► Crystals of the complex were obtained after the hydrothermal reaction of MoO3 and 4,4′-di-tert-butyl-2,2′-bipyridine. ► The dioxo-bridged complex possesses catalytic activity for the epoxidation of non-functionalized olefins. ► The catalytic reaction is regioselective toward the epoxidation of internal double bonds.