Abstract

A new series of Schiff base ligands derived from 4H-chromen-3-ol and substituted aromatic amines were synthesized and subsequently complexes with Zn(II) ions to afford structurally well-defined zinc(II) complexes. The synthesized ligands and their zinc complexes were characterized using elemental analysis, FT‑IR, UV–Visible, ¹H and ¹³C NMR spectroscopy, mass spectrometry, molar conductance, magnetic susceptibility and thermal (TGA/DTA) studies. Spectral data confirmed bi dentate coordination of the ligands through azomethyl nitrogen and phenolic oxygen atoms, leading to tetrahedral or distorted octahedral geometries around the Zn(II) center. Antimicrobial activity was evaluated against selected Gram‑positive, Gram‑negative bacteria and fungal strains using the disc diffusion and MIC methods. The Zn(II) complexes exhibited significantly enhanced antimicrobial activity compared to free ligands, attributed to increased lipophilicity and chelation effects. Reaction mechanisms for ligand formation and metal complexation are discussed in detail. The results suggest that Zn(II) chromen‑based Schiff base complexes are promising candidates for antimicrobial drug development.