New Schiff base complex of zirconium on mesoporous MCM-41 as highly efficient nanocatalyst for the synthesis of tetrazoles and sulfoxides

Heterogeneous catalysts have used in various organic reactions and industrial processes due to their stability, recoverability and recyclability. Nanomaterials can be applied as a bridge between homogeneous and heterogeneous catalysis due to their high surface area to volume ratio, remarkable efficiency, stability and recoverability. For example, MCM- 41 is great and useful material for the heterogenization of homogeneous catalysts because of its unique properties such as large specific surface area, ease of functionalization, homogeneous hexagonal pore arrays with pore diameters, stability in high temperature, and versatile separation from reaction media. In this work, a zirconium Schiff‑base complex was anchored on functionalized MCM-41 (Zr-Schiff‑base@MCM-41) and applied as efficient and reusable nanocatalyst for the synthesis of 5-substituted 1Htetrazoles using [2+3] cycloaddition reaction of various organic nitriles with sodium azide (NaN3) in green solvent. Also this catalyst was applied as a versatile catalyst for selective oxidation of sulfides to sulfoxides using hydrogen peroxide as oxidant. Characterization of the catalyst was performed using N2 adsorption–desorption isotherms, SEM, EDS, XRD, TGA, FT-IR, and AAS techniques [1-3].