A green one-pot three-component syntheses of tetrazole under microwave irradiation using Ni Schiff base complex of mixed ligands on MCM-41 as an efficient heterogeneous catalyst

Abstract Syntheses of 5-substituted tetrazole derivatives have been reported by one-pot three-component reaction of various aldehydes (aryl, aryl with fused ring, aryl with extended conjugation, heterocyclic and aliphatic), hydroxylamine hydrochloride and sodium azide in the presence of potent, reusable, low cost and thermally stable catalyst, Ni-complex MCM-41 under conventional heating / microwave irradiation. The prepared materials were characterized by FT-IR, PXRD analysis, N₂ adsorption and desorption, EDX, SEM and TEM microscopy, ICP-OES and TGA. The effect of solvent, temperature, catalyst loading and time for the syntheses of tetrazoles were optimized. The efficiency of Ni-MCM-41 catalyst is compared and discussed against the literature reports. The catalyst can be successively recovered by simple filtration method and reused upto five times with excellent yields upto 94%. In general, microwave irradiation technique gave better yields when compared to conventional heating irrespective of the nature of the substrate and their substituents.