Nanoporous Cu doped ZnS nanoparticles an efficient photo catalyst for the chemoselective synthesis of 2-substituted azoles via C-N arylation/ CSp3– H oxidation/ cyclization/dehydration sequence in visible light

Abstract

ZnS and Cu:ZnS nanoparticles were prepared by aqueous chemical method and characterized by several analytical tools. Nanoparticles have an average size of about ∼ 18 nm and possess highly open mesopores, moderate surface area, and uniform morphology. UV–vis spectra designate that doping of Cu shifted the optical response of the ZnS nanoparticles in to a visible region. These Cu:ZnS nanoparticles were employed as a photocatalyst for chemoselective synthesis of 2-substituted azoles by the reaction of benzyl bromides and 1,2-Diaminobenzene or 2-Mercaptoaniline in visible light. Analogous experiments confirmed that the reaction were proceeds through one pot C–N arylation/ CSp3– H oxidation/ cyclization/dehydration sequence. The enhanced catalytic activity by doping could be attributed to the presence of trapping level generated by copper doping which augments the relaxation time of electron and holes so that they are easily available for the reaction. The method was also applicable for the synthesis of quinazolin-4(3H)-ones.