A Crown-Shaped Ru-Substituted Arsenotungstate for Selective Oxidation of Sulfides with Hydrogen Peroxide

Chemistry. 2018 Aug 1;24(43):11059-11066. doi: 10.1002/chem.201800748. Epub 2018 Jul 3.

Abstract

An acetate-bridged Ru-substituted arsenotungstate [H2 N(CH3 )2 ]14 [As4 W40 O140 {Ru2 (CH3 COO)}2 ]⋅22 H2 O (1) has been synthesized and structurally characterized. Four Ru atoms occupy the respective lacunary S2 sites of the crown-shaped polyanion [As4 W40 O140 ]28- , and each Ru atom is coordinated by one As atom and five μ2 -O atoms, comprising four from the S2 site and one from the acetate ligand. To the best of our knowledge, this coordination of the Ru atom, with an Ru-As bond length of 2.377(3)-2.387(3) Å, is unprecedented in polyoxometalate (POM) chemistry. Notably, 1 exhibits high efficiency, excellent selectivity, and good recyclability for the oxidation of sulfides with hydrogen peroxide (H2 O2 ). Catalytic oxidation of various sulfides in the presence of 1 gives superior conversion and selectivity for sulfones in acetonitrile, whereas sulfoxides are obtained in methanol.

Keywords: arsenotungstate; catalysis; polyoxometalates; ruthenium; sulfoxidation.