Experimental and DFT studies of 2-methyl-quinoxaline and its silver (I) complex: Non-covalent interaction analysis, antimicrobial activity and molecular docking study

Abstract

The current study describes the characterization and vibrational spectra (elemental analysis, FT-IR, 1H NMR and UV–Visible absorption) of 2-Methyl-quinoxaline (2-MQ) and synthesized [Ag(2-Methyl-quinoxaline)(NO3)]. The experimental investigation is supported by theoretical calculations at the DFT level. The frontier molecular orbitals (HOMO and LUMO), the global reactivity descriptors, MEP, and thermodynamic analysis are also computed to investigate the reactivity of the ligand and the complex. The intermolecular interactions in the title compound were analyzed by topological AIM and RDG approaches. The chemical structure of the ligand and its Ag(I) complex were elucidated by the ELF analysis. In addition, a molecular docking study was implemented to look into the studied compounds for their antibacterial activity. According to the molecular docking study used to evaluate the inhibitory effect on target proteins for antimicrobial drugs, the metal complex has a greater binding affinity than the free ligand. These compounds might thus be effective antibacterial candidates. Thus, antimicrobial studies have been performed with 2-MQ and Ag(I) complex against various Gram-positive and Gram-negative bacteria. The 2-MQ proved to be the most active compound in this study and showed the highest antimicrobial activity against S. aureus ATCC 29213, B. cereus 709 Roma, V. anguillarum ATCC 43312 and C. albicans ATCC 90028. Antimicrobial activity against Ag(I) complex, L. monocytogenes, V. anguillarum, A. hydrophila, E. aerogenes, S. dysenteria, B. cereus and C. albicans was determined. © 2022