Synthesis, spectral characterization, DFT calculations, antimicrobial activity and molecular docking of 4-bromo-2-((2-hydroxy-5-methylphenylimino)methyl)phenol and its V(V) complex

Abstract

VO(acac)2 reacted with a new ONO tridentate Schiff base, 4-bromo-2-((2-hydroxy-5-methylphenylimino)methyl)phenol, (H2L) in methanol to afford a new V(V) complex, [VO(L)(MeO)(MeOH)]. Characterization by elemental analysis, molar conductivity, FT-IR, electronic spectroscopy, 1H NMR, single crystal X-ray and TGA studies indicated that the free ligand existed as its keto tautomer in solid state, while in the complex it was coordinated to the regular VO core in its deprotonated form (enol), as a tridentate anionic ligand. The vanadium center was also found to be 6-coordinated, in a distorted octahedral fashion with a deprotonated ligand and an oxygen atom of the methoxy group in the equatorial plane and an oxido ligand and an oxygen from methanol in the apical sites. DFT and NBO calculations were additionally performed and confirmed the experimental data. The synthesized ligand and its oxido-vanadium(V) complex exhibited satisfactory antimicrobial activities against some tested Gram-positive and Gram-negative bacteria, and fungus strain. In addition, the potential of these compounds as antimicrobial agents was investigated using molecular docking to glucosamine-6-phosphate (GlcN-6-P) synthase.