Application of novel and reusable Fe3O4@CoII(macrocyclic Schiff base ligand) for multicomponent reactions of highly substituted thiopyridine and 4H-chromene derivatives

In this research study we designed and synthesized Co^II(macrocyclic Schiff base ligand containing 1,4-diazepane) immobilized on Fe₃O₄ nanoparticles as a novel, recyclable, and heterogeneous catalyst. The nanomaterial was fully characterized using various techniques such as Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy-dispersiveX-ray spectroscopy, thermogravimetric analysis, vibrating sample magnetometry, differential reflectance spectroscopy, Brunauere–Emmette–Teller method, inductively coupled plasma, and elemental analysis (CHNS). Then, the catalytic performance was successfully investigated in the multicomponent synthesis of 2-amino-4-aryl-6-(phenylsulfanyl)pyridine-3,5-dicarbonitrile and 2-amino-5,10-dioxo-4-aryl-5,10-dihydro-4H-benzog]chromene-3-carbonitrile derivatives. Furthermore, the catalyst was isolated using a simple filtration, and recovery of the nanocatalyst was demonstrated five times without any loss of activity.