Copper(ii)-containing tungstotellurates(vi): syntheses, structures and their catalytic performances in selective oxidation of thioethers

We report the syntheses and structures of two new copper(ii)-containing tungstotellurates(vi) Na(12)[Te(VI)(2)W(8)O(38)Cu(2)(H(2)O)(2)]·7H(2)O (Te(2)W(8)Cu(2)) and Na(6)[Te(VI)W(6)O(24)Cu(NH(2)CH(2)CO(2))(2)]·6H(2)O (TeW(6)Cu). The two compounds were synthesized by a simple one-pot method and characterized by single-crystal X-ray diffraction (XRD), powder XRD, FT-IR spectroscopy, elemental analysis, and thermogravimetric analysis in the solid state. Furthermore, their catalytic properties for the selective oxidation of thioethers were also studied systematically. The catalytic experiment results indicate that the tungstotellurate(vi) Te(2)W(8)Cu(2) is an effective heterogeneous catalyst for the selective oxidation of thioethers to sulfoxides or sulfones by an H(2)O(2) oxidant at room temperature. Under the ambient conditions, Te(2)W(8)Cu(2) can convert 99% of methyl(phenyl)sulfane to sulfoxides or sulfones with 96% or 99% selectivity, respectively, and the utilization rate of H(2)O(2) is up to 80%. Furthermore, Te(2)W(8)Cu(2) as a heterogeneous catalyst is stable in the reaction and could be reused at least five cycles with conserved activity.