Cu/ZnO@GO promoted green synthesis of novel dipyridopyrimidines: evaluation of biological activity and theoretical study of the mechanism using a DFT method

This investigation presents a single-step reaction performed at ambient temperature in aqueous media, involving acetylacetone, aldehydes, guanidine, and activated acetylenic compounds, employing a catalytic system consisting of small quantities of Cu/ZnO@GO. Currently, the antioxidant potential of select synthesized dipyridopyrimidines is evaluated via diphenyl-picrylhydrazine (DPPH) radical scavenging assays. Furthermore, the antimicrobial efficacy of the synthesized compounds was systematically assessed using the disk diffusion method, which involved testing against two distinct strains of Gram-negative bacteria and Gram-positive bacteria. In a separate vein, the catalytic efficacy of the Cu/ZnO@GO catalyst was rigorously assessed in the reduction of organic pollutants, specifically 4-nitrophenol (4-NP), in aqueous solutions under benign conditions. The data revealed that nanocomposites prepared via a biosynthetic method demonstrated remarkable catalytic performance in the remediation of organic contaminants, achieving substantial reduction within mere seconds. The synthetic methodology employed for the generation of dipyridopyrimidines was characterized by a confluence of advantageous attributes, encompassing accelerated reaction kinetics, elevated product yields, and facile recovery of the catalyst from the reaction milieu. Density Functional Theory (DFT) calculations at the B3LYP/6-311G(d,p) level were conducted to explore the reaction mechanism, employing the total energy of reactants and products as a basis for its determination.