Copper-carboxamide complex immobilized on nano NaY zeolite: an efficient catalyst for xanthenes synthesis

This paper describes the direct synthesis of carboxamide-functionalized nano NaY zeolite (CBA-Ze) to develop a new high-functionality nanocatalyst in one pot process. This surface functionalization was achieved using a four-component Ugi reaction. Afterward, copper ions were coordinated with Ugi-ligands decorated on the nano NaY zeolite surface. To characterize the synthesized catalysts, fourier transform-infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential thermal analysis, scanning electron micrograph, transmission electron microscopy, X-ray diffraction (XRD), dynamic light scattering, energy dispersive spectroscopy, inductively coupled plasma, and elemental analyses were used. The nature of the supported Ugi-ligand on the zeolite's surface improved the catalyst reactivity of the zeolite, made it more homogeneous, and increased its ability to coordinate with copper ions. The catalytic activity of the synthesized copper-carboxamide complex immobilized on nano NaY zeolite (Cu@CBA-Ze) was investigated in the synthesis of Xanthen derivatives, resulting in product yields of 85-98% Cu@CBA-Ze using only 20 mg in H2O:EtOH (1:1) at room temperature within 30 min. In addition to the ease of recovering and reusing catalyst, and the simple setup procedure, this method is an eco-friendly, benign procedure for synthesizing heterocycles. This study describes a catalytic system with the potential to produce other useful heterocyclic compounds under mild environmental conditions.