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, [Ag4(H2O)(L)3(SiW12O40)] (1), [Zn(L)(H2O)]2[SiW12O40]·3H2O (2), [Cu(L)(H2O)]2[SiW12O40] (3), and [Cu2(L)2(HPWVI10WV2O40)]·4H2O (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 CrVI 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.