Green Approach for Preparation of New Hybrids of 5‐Substituted‐1 H ‐Tetrazoles Using Novel Recyclable Nanocatalyst based on Copper(II) Anchored onto Glucosamine Grafted to Fe 3 O 4 @SiO 2

Abstract The novel copper(II) ions decorated Fe 3 O 4 @SiO 2 composite magnetic spheres were synthesized by grafting copper(II) ions onto glucosamine modified Fe 3 O 4 @SiO 2 NPs. The magnetic Fe 3 O 4 @SiO 2 −TCT−GA−Cu(II) catalyst were characterized by varies physicochemical techniques such as FT‐IR, FE‐SEM, TEM, DLS, XRD, EDX, VSM, TGA, VSM, ICP, and UV‐Vis. The catalytic performance of this novel catalyst was studied in the green preparation of 5‐substituted 1 H ‐tetrazole based hybrids via three‐component and one‐pot reaction of sodium azide, hydroxylamine hydrochloride, and various aldehydes in water and ethylene glycol, as a green solvent mixture. This green protocol provides significant advantages such as non‐vigorous conditions, short reaction times, outstanding yield of desired tetrazoles, minimizing of chemical waste, wide‐ranging substrate, quick and efficient work‐up procedure and using environmentally benign, durable, cost effective, magnetically separable, reusable nanocatalyst.