Facile synthesis of 5-substituted-1H-tetrazoles and 1-substituted-1H-tetrazoles catalyzed by recyclable 4′-phenyl-2,2′:6′,2″-terpyridine copper(II) complex immobilized onto activated multi-walled carbon nanotubes

5-Substituted-1H-tetrazoles can conveniently be synthesized from the corresponding nitriles by reaction with NaN3 using the efficient and recyclable heterogeneous catalyst prepared by immobilization of copper(II) complex of 4′-phenyl-2,2′:6′,2″-terpyridine on activated multi-walled carbon nanotubes [AMWCNTs-O–Cu(II)–PhTPY]. Excellent results were obtained in each case affording the corresponding tetrazole adducts in good to excellent yields. In general, aromatic nitriles with electron-donating group could be accomplished as well as that with electron-withdrawing groups. By leaving out nitrile from the reaction and adding CH(OEt)3 and amines bearing various substituents, 1-substituted-1H-tetrazoles formed in water in high yields. The reported protocols have the advantages of rapid assembly of a host of heterocyclic systems in high yields with the added advantage of recycling and reuse of the catalyst.