Research Article

Design, Synthesis and In Silco studies of Metal Complexes with a Novel O, N, O-Donor Schiff Base Ligand

Abstract

This study reports the design, synthesis, and characterization of a novel tetradentate O, N, O-donor Schiff base ligand (m1), and its transition metal complexes with Ni(II), Pd(II), and Pt(II). The ligand was synthesized via acid-catalyzed condensation of 3-formyl-4-hydroxybenzoic acid and 3,4-diaminophenol, yielding a crystalline product (85% yield, mp 165–168°C) characterized by FT-IR (C=N at 1649 cm⁻¹, O-H at 3365 cm⁻¹) and NMR spectroscopy. The metal complexes (C1–C3) were prepared in high yields (74–76%) and exhibited shifts in IR spectra (e.g., C=N at 1665–1674 cm⁻¹) and new M–N/M–O vibrations (466–608 cm⁻¹), confirming N₂O₂ coordination. In silico molecular docking studies with the 6COX protein revealed strong binding affinities (MolDock scores: −6.6 to −8.3 kcal/mol), with Pd(II) and Pt(II) complexes forming hydrogen bonds with PHE 518. Antibacterial assays demonstrated significant activity against Staphylococcus aureus (inhibition zones up to 41 mm) and moderate efficacy against Escherichia coli, highlighting structure-dependent selectivity. These results underscore the ligand’s versatility in forming stable metal complexes with potential applications in antimicrobial therapy and bioinorganic chemistry.