Silica-supported molybdenum complex: A novel, selective and reusable organic–inorganic hybrid catalyst for eco-friendly oxidation of sulfides and olefins

A novel, highly efficient and reusable molybdenum based catalyst has been synthesized by covalent grafting of 2,6-diacetylpyridine-monosalicyloylhydrazone onto functionalized silica followed by complexation with MoO2(acac)2, and the resulting organic–inorganic hybrid material was found to be highly effective catalyst for oxidation of various sulfides and olefins to their corresponding sulfoxides/sulfones and epoxides, respectively. The catalyst was characterized by elemental analysis (CHN), diffuse reflectance UV–Vis, 13C CPMAS NMR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET surface area analysis, energy dispersive X-ray fluorescence (ED-XRF), Fourier-transform infrared (FT-IR) and atomic absorption spectroscopy (AAS). Mild reaction conditions, high turnover frequency, high selectivity, easy recovery and reusability of the catalyst render the present protocol very useful to address the industrial needs and environmental concerns.

An environmentally benign protocol for the synthesis of commercially important sulfoxides/sulfones and epoxides is described, where molybdenum complex covalently anchored onto the surface of functionalized silica gel is acting as an efficient heterogeneous catalyst. High turnover frequency, mild reaction conditions, high selectivity, and easy recovery and reusability of the catalyst render the present protocol very important to deal with the industrial prerequisites and environmental concerns.Figure optionsDownload as PowerPoint slideHighlights
► Synthesis of Silica-supported molybdenum complex.
► Characterizations and application of organic–inorganic hybrid catalyst.
► Efficient, recoverable and recyclable catalyst with consistent activity.
► Solvent-free synthesis of sulfoxides/sulfones and epoxides.