L-proline covered N doped graphene quantum dots modified CuO/ZnO hexagonal nanocomposite as a robust retrievable catalyst in synthesis of substituted chiral 2-amino-4H-chromenes

Abstract

Nitrogen-doped Graphene Quantum Dots (N-GQDs) is a significant carbon nanomaterial that can be used to design various metal-organocatalyst. Modification of N-GQDs plays a serious role in catalytic activity, recyclability, thermal stability, and so on. Also, finding revealed that homogeneity, morphology, and size of nanocomposites can be intensively influenced via various procedures and precursors. Hence, CuO/ZnO hexagonal nanocomposites with morphological engineering have been prepared by the hydrothermal method for improving performance. On the other hand, the study of the effect of amino acid as a chiral organic group on the surface of modified N-GQDs is essential for expanding new inorganic-organic hybrid catalysts. In this work, we introduced l-proline assisted CuO/ZnO@N-GQDs hexagonal nanocomposites as a robust recyclable nanocatalyst in multicomponent reactions (MCRs) for the preparation of 2-amino-4H-chromenes. As-prepared CuO/ZnO@N-GQDs@l-proline nanocatalyst has been investigated by High-resolution Transmission electron microscope (HRTEM), Transmission electron microscope (TEM), Field emission scanning electron microscopy (FE-SEM), Brunauer-Emmett-Teller (BET), Energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetric analysis (TGA), and X-ray diffraction analysis (XRD). High atom economy (95%), recyclability catalyst (8 runs), avoided the utilization of further reagents such as additives, and excellent yield of products (80–94%) are a few vital highlights of this method.