Search

Fine nanoparticles of CuO, generated in‐situ by the chemical reduction method, were immobilized on cucurbit[6]uril support to afford nanocomposite CuO@CB[6] as an air‐stable green powder. The nanocomposite was fully characterized by various physicochemical techniques, such as FTIR, PXRD, XPS, FESEM, EDX, Elemental mapping, HRTEM, TGA, and ICP‐AES. It has been found to be an efficient heterogeneous nanocatalyst for the synthesis of a series of 2H‐indazoles from aldehyde, amine, and azide, under base‐ and ligand‐free conditions, at a low concentration of the metal (0.2 mole %). The augmented catalytic activity of the CuO NPs is attributed to the fine size of the nanoparticles. The nanocatalyst was retrieved from the reaction mixture by simple filtration and reused up to five times with insignificant deprivation in its catalytic activity. All synthesized 2H‐indazoles were isolated in good to excellent yield (55‐96%) and characterized by 1H and 13C NMR studies. Three new indazoles are additionally characterized by DEPT 135 spectroscopy and HRMS spectra. [ABSTRACT FROM AUTHOR]

Abstract: Two new Chitosan‐supported Schiff base complexes (CS@L1‐Cu) and (CS@L2‐Cu) have been synthesized. They are characterized by various spectroscopic and instrumental techniques such as Fourier transform infrared spectroscopy (FT‐IR), Ultravoilet‐visible spectroscopy (UV‐Vis), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), Field emission scanning electron microscopy (FESEM), Energy dispersiveX‐ray microscopy (EDX), Thermo gravimetric analysis/Differential thermal analysis (TGA/DTA), and atomic absorption spectroscopy (AAS) analysis.Thecomplex CS@L2‐Cu have been found to be efficient heterogeneous catalyst for the synthesis of 5‐substituted 1H‐tetrazoles from a series of oximes and sodium azide and also for oxidative homo‐coupling of terminal alkynes. The catalyst could be easily recovered from reaction mixture by simple filtration and recycled up to five times with no significant loss in its catalytic activity. The mercury poisoning test indicated that the catalysts are heterogeneous in nature. All products were isolated as white to off‐white and light yellow solids and characterized by1H and 13C NMR spectroscopy. [ABSTRACT FROM AUTHOR]