Synthesis, characterization, solvatochromic, and electrochemical investigation of novel 4-methyl coumarin fused azo dyes as an NLO material and their biological studies

Herein, we synthesized novel 4-methyl coumarin-incorporated heterocyclic azo dyes, and structures were confirmed by analytical and spectroscopic approaches. Computational studies were performed using the DFT method with a B3LYP/ 6–31 G (d, p) basis set used to explore the molecular geometry, Mullikan atomic charges, global reactive descriptors, MEP, and RDG. Nonlinear optical (NLO) analysis revealed that the first-order hyperpolarizability of 1d was 18 times greater than that of urea. Natural bond orbital (NBO) analysis showed that all the compounds had greater stability due to internal charge transfer. Solvatochromic behavior was analyzed using UV–Vis spectroscopy, and the absorbance was observed in the range of 380–445 nm. The electrochemical behavior was determined by cyclic voltammetry, which exhibited two reduction peaks and was used to calculate the energy of the molecules (E_HOMO-E_LUMO). The antimicrobial activity was studied against different pathogens Viz., E. coli, S. aureus, and A. flavus, and the results showed that the compounds had good antimicrobial efficacy. “Furthermore, in silico molecular docking results revealed that compounds 1b and 1a have good binding site energies against the target enzymes DNA gyrase and O-methyltransferase, respectively”.