M@Si/Al (where M ¼ Mn(III), Co(II) and Fe(III) supported on nanosized SiO2/Al2O3) is applied as an efficient, highly reusable and heterogeneous catalyst for the regiospecific synthesis of 1-aryl-5-amino-1Htetrazole in DMF (dimethylformamide) as a solvent. The arylaminotetrazoles were efficiently synthesized from the reaction of cyanamides and sodium azide in the presence of a catalytic amount of nano metal catalyst under thermal conditions. 1-Aryl-5-amino-1H-tetrazoles (B isomer) can be obtained from the arylcyanamides carrying electron releasing substituents on the aryl ring, while with electron withdrawing groups, 5-arylamino-1H-tetrazole (A isomer) will be obtained. The advantages of this method include high yields, relatively short reaction times, easy work-up, recovery and reusability of the catalyst and high TON of catalyst. The nano catalyst can be easily recovered and reused several times without considerable loss of activity. The quantum theoretical calculations for the synthesized components were performed by density functional theory (DFT) methods using the 6-31G basis set, geometry and thermodynamic parameters, frontier molecular orbitals (FMOs) as well as by using molecular electrostatic potentials (MEPs).
