Exploring the chemical and biological landscape of a Nickel (II) schiff base complex via azomethine linkage

Nickel(II) complexes incorporating azomethine-derived Schiff-base ligands were synthesized and characterized using UV-Vis, FT-IR and ¹H NMR spectroscopy, supported by DFT calculations at the B3LYP/6-311++G(d, p) level. The spectral data confirmed square-planar coordination with Ni-N and Ni-O bonding. Frontier molecular orbital and topological analyses revealed efficient metal-ligand charge transfer, strong electron delocalization and favorable molecular stability. The reduced HOMO-LUMO gap (2.724 eV) and high electrophilicity index suggest enhanced reactivity and biological potential. Molecular docking studies against the 2BL8 receptor showed high binding affinity (-9.1 kcal/mol), surpassing chloramphenicol, while ADMET predictions confirmed good solubility (-3.860), oral bioavailability (0.85) and pharmacokinetic safety. Antibacterial assays demonstrated superior inhibition against E. coli, K. pneumoniae and B. subtilis, with moderate activity toward S. aureus. Overall, the combined experimental and computational results establish the Ni(II) Schiff-base complex as a thermodynamically stable and biologically active molecule, which highlights its promise as a lead scaffold for antimicrobial drug design.