Gum Acacia Stabilized Ag-TiO 2 and Ag-SiO 2 : Sustainable Nanocatalysts for Direct and Convenient Synthesis of 5-Substituted 1 H -tetrazoles

We describe the use of biocompatible gum acacia (GA)-as-sembled Ag-TiO2 and Ag-SiO2 nanostructures as effective heteroge-neous catalysts for the synthesis of 5-substituted 1H-tetrazoles throughthe traditional [3+2] cycloaddition of aryl nitriles with sodium azides. Characterization of the prepared catalysts employing TEM, XPS, FE-SEM, FT-IR, XRD, and TGA-DTG reveals silver nano particles encapsulatedin the GA matrix amidst modified nano titania or silica. A variety of structurally divergent aryl nitriles were converted into the correspond-ing tetrazoles in a short reaction time. Other advantages include lowcatalytic load, easy handling of catalyst, limited use of toxic reagents,and desirable conversion yields, making this protocol a viable and practical alternative for this cyclization. The catalysts can be easily recov-ered and reused over multiple cycles without significant loss of catalyticactivity