Visible light photodegradation of organic dyes, reduction of CrVI and catalytic oxidative desulfurization by a class of polyoxometalate-based inorganic-organic hybrid compounds

A new family of polyoxometalates-based inorganic-organic hybrid compounds, namely, [Ag-4(H2O)(L)(3)(SiW12O40)] (1), [Zn(L)(H2O)](2)[SiW12O40]center dot 3H(2)O (2), [Cu(L)(H2O)](2)[SiW12O40] (3), and [Cu-2(L)(2)((HPW10W2O40)-W-VI-O-V)]center dot 4H(2)O (4), have been synthesized (L = 1,4 bis(3-(2-pyridyl)pyrazol)butane). This series of inorganic-organic hybrid compounds exhibit variable supramolecular architectures. The photodegradation of organic dyes malachite green and methylene blue with the use of compounds 1-4 as photocatalysts was studied under visible light irradiation. Strikingly, the photocatalytic result demonstrates that compound 1 is an efficient photocatalyst for the removal of malachite green and methylene blue. Remarkably, compound 1 serves as an active and recyclable photocatalyst for the reduction of Cr-VI with isopropanol as scavenger at ambient temperature. The catalytic oxidative desulfurization of thioanisole was also investigated with the use of compounds 1-4 as catalysts and tert-butyl hydroperoxide as oxidant. The catalytic results indicate that compounds 3 and 4 behave high catalytic performance for the oxidation of the thioanisole. (C) 2016 Elsevier Ltd. All rights reserved.