Catalytic epoxidation of olefin over supramolecular compounds of molybdenum oxide clusters and a copper complex

The catalytic epoxidation of olefin was investigated on two copper complex-modified molybdenum oxides with a 3D supramolecular structure, [Cu(bipy)]4[Mo15O47]·2H2O (1) and [CuI(bix)][(CuIbix)(δ-MoVI8O26)0.5] (2) (bipy = 4,4′-bipyridine, bix = 1,4-bis(imidazole-1-ylmethyl)benzene). Both compounds were catalytically active and stable for the epoxidation of cyclooctene, 1-octene, and styrene with tert-butyl hydroperoxide (t-BuOOH) as oxidant. The excellent catalytic performance was attributed to the presence of stable coordination bonds between the molybdenum oxide and copper complex, which resulted in the formation of easily accessible Mo species with high electropositivity. In addition, the copper complex also acted as an active site for the activation of t-BuOOH, thus improving these copper complex-modified polyoxometalates. Copper complex-modified polyoxometalates showed high catalytic activity and stability in the catalytic epoxidation of olefin with tert-butyl hydroperoxide (t-BuOOH) as oxidant.