Pyrazine dicarboxylate-bridged arsenotungstate: synthesis, characterization, and catalytic activities in epoxidation of olefins and oxidation of alcohols.

A praseodymium(iii)-containing arsenotungstate K16H15Li7[Pr2(H2O)3(pzdc)As3W29O103]2·38H2O (1) (pzdc = pyrazine-2,3-dicarboxylic acid) was synthesized by a conventional aqueous solution method and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), and single crystal X-ray diffraction. Structural analysis revealed that compound 1 was constructed by two identical subunits {Pr2(H2O)3(AsW9O33)3W2O4} bridged together by two pzdc ligands. In addition, compound 1 could act as an efficient catalyst for the epoxidation of olefins and oxidation of alcohols with hydrogen peroxide (H2O2) as the oxidant. In particular, the turnover frequency (TOF) in the oxidation of 1-phenylethanol reached up to 10 170 h-1, which is higher than that of previously reported catalysts.