Metalloligand Hybrid Polyoxometalates for Efficient Selective Photocatalytic Oxidation of Sulfides to Sulfoxides under Visible-Light Irradiation

The development of novel high-efficiency photocatalysts to solve the bottleneck problems of low efficiency and harsh conditions of organic oxidation reactions is of vital significance. In this paper, a novel hybrid polyoxometalate (POM) crystal, (C2H8N)6[SiW11CdO39][Ru(bpy)(2)(dcbpy)]center dot DMF center dot 5.5H(2)O (RuCd-SiW), was synthesized by combining the metalloligand [Ru(bpy)2(dcbpy)] with the oxidation catalyst POM. The introduction of the metalloligand extended the light absorption range of RuCd-SiW to the visible region, while electrochemical measurements demonstrated its potential as an excellent photocatalyst. Under visible light (lambda > 400 nm) irradiation with O-2 as the sole oxidant, RuCd-SiW showed highly efficient photocatalytic activity for the selective oxidation of thioanisole to (methylsulfoxide)benzene with a yield of 99.5%, a turnover number of 497.5, and a turnover frequency of 103 h(-1). Particularly, the yield of (methylsulfoxide)benzene was still higher than 99% after five rounds of recycling, demonstrating its high stability and recyclability.