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چکیده
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In this project, the L-arginine salen Schiff-base (ASS) complex of lanthanum on the functionalized surface of mesoporous MCM-41 (MCM-41@ASS-La) was synthesized for the first time. To prepare MCM-41@ASS-La, the surface of MCM-41 was modified with 3-iodopropyl trimethoxysilane (IPTMS) and then L-arginine salen Schiff-base ligand anchored om modified MCM-41. Then, lanthanum ions were stabilized on its surface. Then, MCM-41@ASS-La was characterized by different techniques e.g. Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray Spectroscopy (EDX), scanning electron microscopy (SEM), wavelength dispersive X-ray spectroscopy (WDX), energy-dispersive X-ray spectroscopy (EDS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and N2 adsorption–desorption isotherms. Next step, the synthesized MCM-41@ASS-La was investigated as an efficient and reusable nanocatalyst for the chemoselective synthesis of sulfoxides and tetrahydrobenzo[b]pyrans. In these studies, the reaction conditions for the synthesis of tetrahydrobenzo[b]pyrans were optimized, and the best results were obtained in H2O as an ideal, available and, green solvent in the presence of MCM-41@ASS-La nanocatalyst. Also, the reaction conditions for the oxidation of sulfides to sulfoxides were optimized, and the best results were obtained under solvent-free conditions using hydrogen peroxide (H2O2) in the presence of MCM-41@ASS-La nanocatalyst. Then, several derivatives of sulfoxides and tetrahydrobenzo[b]pyrans were synthesized in the presence of MCM-41@ASS-La nanocatalyst under optimized conditions. In addition, MCM-41@ASS-La nanocatalyst can be recovered (about 96%) and reused for several cycles without metal leaching or reactivation.
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