Co(III)@Fe3O4@SiO2 salen complex as a highly selective and recoverable magnetic nanocatalyst for the oxidation of sulfides and benzylic alcohols

In this study, Co (III) salen complex was synthesized and immobilized onto the surface of Fe3O4@SiO2 magnetic nanoparticle. The heterogeneous nanocatalyst was characterized by different techniques including X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), nitrogen adsorption−desorption isotherm (BET), vibrating sample magnetometer (VSM), and atomic absorption spectroscopy (AAS). The oxidation reaction of sulfides to sulfoxide with hydrogen peroxide (30%) was investigated in the presence of catalytic amount of heterogeneous magnetic Co (III) salen complex at room temperature in water, and corresponding products were achieved with excellent yields and selectivity. This catalyst was also used for the oxidation of benzyl alcohol derivatives with tert-butyl hydroperoxide (TBHP) as an oxidant in acetonitrile at reflux conditions and excellent yields, and selectivity was observed. Magnetic Co (III) salen complex showed good stability, and magnetic properties without significant loss in the activity and selectivity.