Synthesis, crystal structure, computational analysis and biological properties of 1-(4-chlorobenzoyl)-3-[2-(2-{2-[3-(4-chlorobenzoyl)-thioureido]-ethoxy}ethoxy)ethyl]-thiourea and its Ni(II) and Cu(II) complexes

Abstract

A new dianionic ligand, 1-(4-chlorobenzoyl)-3-[2-(2-{2-[3-(4-chlorobenzoyl)-thioureido]-ethoxy}ethoxy)ethyl]-thiourea(CBEDEA), and its Ni(II) and Cu(II) complexes have been synthesized. X-ray single crystal analysis of CBEDEA shows that the molecule crystallized in the triclinic crystal system, space group P-1, with two molecules per unit cell. The studied compounds were further characterized by FT-IR, UV-VIS,¹H NMR and mass spectroscopy. The metal complexes were isolated as four coordinated ML(M: Ni(II), Cu(II), L:CBEDEA) molecules. Computational studies on CBEDEA gave electrostatic potential energy isovalues which showed that there is a higher probability of metal coordination around the carbonyl and thione groups. Results of non-covalent interaction studies revealed the presence of significant amount of hydrogen bonding and other weak non-covalent interactions in the molecule. Docking calculations on CBEDEA and its Ni(II) and Cu(II) metal complexes revealed that they have affinity for beta-lactamase, a protein implicated in antibiotic drug-resistant mechanism. Complexation with the metal ion shrank the size of the molecule and enabled the metal complexes to fit more appropriately within the binding groove of the protein resulting in the improved affinity over CBEDEA ligand. Target-ligand binding interactions resulted from hydrophobicity and possibility of hydrogen bonding of the molecules. In vitro screening of the compounds against 17 bacteria and 4 yeasts confirmed their antimicrobial potency against more susceptible Gram-positive bacteria. Results of this study suggest that the metal complexes could be developed into novel antimicrobial compounds.