Cobalt-nickel supported on magnetic mesoporous silica hollow spheres for efficient synthesis of tetrazole derivatives under solvent-free conditions.

This study presents the synthesis and characterization of a Co-Ni anchored magnetic mesoporous silica hollow sphere as an efficient and eco-friendly nanocatalyst for the preparation of 1-substituted 1H-1,2,3,4-tetrazole derivatives. The hollow and mesoporous architecture of the catalyst provides a large active surface area, enhancing its catalytic performance. The synergistic interaction between cobalt and nickel on the catalyst surface significantly improves its efficiency. The catalyst was thoroughly characterized using FT-IR, XRD, FE-SEM, TEM, EDS, elemental mapping, BET, ICP-OES and VSM techniques. Its magnetic properties facilitate easy separation and recyclability, with minimal loss of activity over multiple cycles. The nanocatalyst was applied in a solvent-free, three-component reaction involving triethyl orthoformate, sodium azide, and aromatic amines at 80 °C, affording the desired 1-substituted tetrazole derivatives in excellent yields (up to 98%). Reaction parameters, including catalyst loading, temperature, and solvent effects were optimized. Additionally, the obtained tetrazole derivatives were identified by their melting points, FT-IR, 1H NMR and 13C NMR analyses. The key advantages of this catalytic system include its reusability, high efficiency under mild conditions, short reaction times, and production of pure products in high yields.