A chitosan supported peroxidovanadium(V) complex: Synthesis, characterization and application as an eco-compatible heterogeneous catalyst for selective sulfoxidation in water

Anchoring of peroxidovanadium(V) (pV) species to chitosan, a natural chelating polymer, afforded a new and structurally defined immobilized complex, VO(O-2)(2)(NH2)-chitosan (ChpV) which was comprehensively characterized by elemental analysis (CHN, ICP-OES, energy dispersive X-ray spectroscopy), spectral studies (FT-IR, Raman, C-13 NMR, diffuse reflectance UV-Vis and XPS), SEM, XRD, Brunauer-Emmett-Teller (BET) and thermogravimetric analysis (TGA). Apart from being thermally stable, the compound is water-tolerant and non-hygroscopic. The compound effectively facilitated chemoselective oxidation of thioethers with H2O2 in aqueous medium to the respective high purity sulfoxide, in impressive yield (TOF 5628 h(-1)) and with high H2O2 efficiency, under mild reaction condition. In addition to water, the heterogeneous catalyst is highly compatible in a variety of organic solvents and is recyclable for several catalytic cycles without significant loss in selectivity. The catalytic procedure is amenable to ready scalability and is free from halogen, co-catalyst and acidic or any other hazardous additive. (C) 2018 Elsevier Ltd. All rights reserved.