Design and synthesis of novel thiourea metal complexes with controllable antibacterial properties

Abstract

A new bidentate O,S donor thiourea ligand (L1), namely N‐(2‐hydroxyethyl)‐N′‐2‐chlorobenzoylthiourea, and its oxazolidine derivative (L2) were synthesized. Derivative L2 was used for the preparation of Ni(L2)2 and Cu(L2)2 complexes. The compounds were investigated using X‐ray crystallography and Fourier transform infrared, 1H NMR and UV–visible spectroscopies. Single‐crystal X‐ray analysis showed strong hydrogen bonding interactions between carbonyl oxygen and N(10) ─ H in the L1 ligand. In addition, the antibacterial activities of these compounds were evaluated against Gram‐positive and Gram‐negative bacteria, measured using the colony count method. The Cu(L2)2 complex exhibited a significant antibacterial activity while the activity of the other compounds was much lower. Finally, the relationship between the structure and antibacterial properties of these compounds was investigated using highest occupied and lowest unoccupied molecular orbital energies calculated by density functional theory method based on the 6‐31G*/LANL2DZ basis set.