GQDs@SiO3Pr Schiff-base complexes Co (II); As an eco-friendly environmental nanocatalyst for the synthesis of the amino carbonitrile chromenes

Abstract

An effective nanocomposite comprising functionalized graphene quantum dots has been developed for the rapid, one-step production of amino carbonitrile chromenes. To this end, the surface of graphene quantum dots (GQDs) was functionalized with a novel synthetic Schiff-base complex of cobalt (II) prepared by post-synthetic surface modification of the graphene quantum dot surface with a silane coupling agent (3-chloropropyl trimethoxysilane, SiO₃PrCl) in order to synthesize GQDs@SiO₃PrCl. Then, the Schiff base ligand synthesized from the condensation reaction of 4-aminoantipyrine with ortho-phenylenediamine was immobilized on the surface of the silane-linker grafted GQDs to synthesize the GQDs@SiO₃Pr-Schiff base. Finally, the cobalt particles were stabilized on the surface of the graphene quanta functionalized with Schiff bases (GQDs@SiO₃Pr-Schiff Base/Co (II)). The GQDs@SiO₃Pr-Schiff Base/Co (II) nanocatalyst demonstrated exceptional performance in the synthesis of amino carbonitrile chromenes derivatives, facilitating high product yields using various aromatic aldehydes, 4‑hydroxy coumarin and malononitrile under mild conditions. Additionally, the catalyst exhibited reusability up to seven times without significant loss of productivity, showcasing its environmental friendliness and sustainability in organic synthesis. This versatile nanocatalyst holds promising for efficient and economically viable catalysis in diverse chemical applications.