In situ synthesis of CuO nanoparticles over functionalized mesoporous silica and their application in catalytic syntheses of symmetrical diselenides.

A versatile and novel catalyst, CuO nanoparticles immobilized over functionalized mesoporous silica (nCuO-FMS), has been synthesized over an organically modified mesoporous silica framework following a facile synthetic route. The surface of the silica support (SBA-15) is first grafted with the 3-aminopropyl silane group and then further functionalized with tris(4-formylphenyl)amine. The reaction is performed in such a way that a few -CHO groups remain free for further functionalization. Finally, the CuO nanoparticles immobilized on mesoporous silica are obtained by a one pot reaction between the functionalized silica, 2-aminophenol and CuCl2. The product obtained has been used as a catalyst for the syntheses of symmetrical diselenides in the presence of KOH as the base and dimethyl sulphoxide (DMSO) as the solvent. The materials have been characterized thoroughly by X-ray powder diffraction, nitrogen adsorption-desorption studies, transmission electron microscopy, thermal analysis and different spectroscopic techniques. The Cu content of the sample has been determined by atomic absorption spectrophotometry (AAS). The products of the catalytic studies have been identified and estimated by NMR spectroscopy. Almost 78% isolated yield could be achieved at 363 K within 3 hours of the reaction and the catalyst, nCuO-FMS, can be recycled at least up to five catalytic cycles.