Oxygenation of sulfides catalysed by SBA-15-immobilized molybdenum(VI) complex of a bis(phenol) diamine ligand using aqueous hydrogen peroxide as a green oxidant

A highly efficient and reusable molybdenum-based catalyst has been synthesized by covalent grafting of a bis(phenol) diamine ligand, namely 2-(((2-bromoethyl)(2-((3,5-di-tert-butyl-2-hydroxybenzyl)amino)ethyl)amino)methyl)-4,6-di-tert-butylphenol, onto functionalized ordered mesoporous silica (SBA-15) followed by complexation with MoO2(acac)(2). The resulting organic-inorganic hybrid material was found to be a highly effective catalyst for oxygenation of various sulfides to their corresponding sulfoxides or sulfones. The catalyst was characterized using transmission and scanning electron microscopies, X-ray photoelectron, Fourier transform infrared and atomic absorption spectroscopies, Brunauer-Emmett-Teller surface area analysis and thermogravimetric analysis. Mild reaction conditions, high selectivity and easy recovery and reusability of the catalyst render the presented protocol very useful for addressing industrial needs and environmental concerns.