Synthesis of tetrazoles catalyzed by a new and recoverable nanocatalyst of cobalt on modified boehmite NPs with 1,3-bis(pyridin-3-ylmethyl)thiourea.

In the first part of this work, boehmite nanoparticles (BNPs) were synthesized from aqueous solutions of NaOH and Al(NO 3 ) 3 ·9H 2 O. Then, the BNPs surface was modified using 3-choloropropyltrimtoxysilane (CPTMS) and then 1,3-bis(pyridin-3-ylmethyl)thiourea ((PYT) 2 ) was anchored on the surface of the modified BNPs (CPTMS@BNPs). In the final step, a complex of cobalt was stabilized on its surface (Co-(PYT) 2 @BNPs). The final obtained nanoparticles were characterized by FT-IR spectra, TGA analysis, SEM imaging, WDX analysis, EDS analysis, and XRD patterns. In the second part, Co-(PYT) 2 @BNPs were used as a highly efficient, retrievable, stable, and organic-inorganic hybrid nanocatalyst for the formation of organic heterocyclic compounds such as tetrazole derivatives. Co-(PYT) 2 @BNPs as a novel nanocatalyst are stable and have a heterogeneous nature; therefore, they can be recovered and reused again for several consecutive runs without any re-activation.