Complexes of Zinc(II) Chloride with N-Vinyl-, N-Allyl- and N-Propargylimidazoles: Structural, Theoretical and Biological Studies.

Background/Objectives: Transition metal complexes of imidazoles exhibit a variety of biological activities. This makes them promising metal-based drugs for use in medicine. The aim of this research is to investigate the complexes of zinc(II) with N-vinyl, N-allyl, and N-propargylimidazoles, represented by the formula [ZnL2Cl2], as potential drug candidates. Methods: Structural studies of the obtained complexes were performed using single-crystal X-ray diffraction analysis, IR and NMR spectroscopy. DFT calculations were used to determine structural, electronic and thermochemical parameters of the complexes. QSAR analysis was performed using PASS. The wound-healing and antihypoxic activities were studied in vivo using models of wounds and acute hypoxia of various origins. The antimicrobial activity of the complexes was evaluated against Staphylococcus aureus Wood 46, Escherichia coli M-17, and the yeast fungus Candida albicans 927. The cytotoxic activity was tested using several cell lines, including monkey kidney (Vero) cells, human cervical cancer cells (Hep2C and HeLa), human lung carcinoma (A549), and human embryonal rhabdomyosarcoma (RD). Results: New complexes of N-allylimidazole and N-allyl-2-methylimidazole with ZnCl2 were synthesized and characterized. All the studied complexes possess diverse biological activities. While the antimicrobial activity was modest, a distinct antifungal activity was observed. The cytotoxicity of the complexes was found to be mainly in relation to Hep2c and RD cell lines. Conclusions: Based on the results of QSAR analysis and experimental findings, the diverse biological activities of the compounds indicate that they are promising lead structures for further optimization in drug development.