L-cysteine complex of palladium onto mesoporous channels of MCM-41 as reusable, homoselective and organic–inorganic hybrid nanocatalyst for the synthesis of tetrazoles

In this study, ordered structure with a hexagonal arrangement MCM-41 was synthesized and functionalized with L-cysteine group and further palladium particles has been supported on its surface (L-cysteine-Pd@MCM-41). The prepared catalyst is well characterized by various techniques such as low-angle X-ray diffraction (XRD), thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), N2 adsorption–desorption measurement isotherms, energy-dispersive X-ray spectroscopy (EDS), X-ray Mapping (WDX), scanning electron microscopy (SEM) and inductively coupled plasma (ICP) techniques. The collected data from all techniques provided evidence that palladium complex was immobilized onto MCM-41 pores. The obtained nanocatalyst demonstrated excellent activity as a new heterogeneous catalyst for the homoselective synthesis of 5-substituted 1H-tetrazole derivatives. This method has the advantages of simple methodology, eco-friendly and simplicity in the separation of catalyst, shorter reaction times, and high yields of the product. Finally, easy catalyst recovery was achieved and the catalyst could be recycled for six times without a significant decrease in activity and selectivity.