α–γ-Type [Mo8O26]4–-Containing Metal–Organic Complex Possessing Efficient Catalytic Activity toward the Oxidation of Thioether Derivatives

In this work, a new α–γ-type [Mo8O26]4– anion was first synthesized and characterized by single-crystal X-ray diffraction analysis and was obtained by introducing molybdate to the synthesis of metal–organic complex (MOC) under hydrothermal conditions. An octamolybdate-based MOC, namely, {[Cu8(H2O)6](dpyh)4(α–γ-Mo8O26) }·(β-Mo8O26)·8.5H2O (H2dpyh = N,N-bis(3-pyrazolamide)-1,2-hexahydrobenzene), was obtained. The α–γ-type [Mo8O26]4– anion was composed of four MoO6 octahedra and four MoO5 trigonal bipyramids by sharing their edges and corners. The title complex exhibited a 1D structure in which an α–γ-type [Mo8O26]4– anion was connected with [Cu4(dpyh)2] units in a staggered manner. Under optimized conditions, complex 1 as the catalyst can achieve a highly efficient conversion (more than 99%) of thioanisole within 30 min and above 99% selectivity toward sulfoxide. Furthermore, efficient catalytic oxidation of thioether derivatives was also performed with 1 as the catalyst. In addition, the stable electrochemical sensing performance and adsorption capacity toward organic dyes were tested.