Silver(i) NHC complexes with antimicrobial and anticancer potential: synthesis, characterization, and DFT-derived...

Ag(i)-NHC complexes are well known as an important class of organometallic compounds widely used in organometallic chemistry and pharmaceutical chemistry. Herein, we report the synthesis, characterization, biological activity, and density functional theory (DFT) studies of a series of benzimidazolium salts and their Ag(i)-NHC complexes bearing 5,6-dimethylbenzimidazole cores. The antifungal activity of the synthesized complexes was investigated against Candida albicans and Candida glabrata, while their antibacterial potential was evaluated against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. In addition, the anticancer properties of the compounds were assessed using HCT116 (human colorectal carcinoma), A549 (human lung cancer), and BEAS-2B (human normal lung epithelial) cell lines to determine their cytotoxic and selective antiproliferative effects. Overall, among the synthesized Ag-NHC complexes, 3a and 3e appear to be the most promising candidates for further development. Furthermore, the stability of the complexes in the biological media and their protein binding properties were investigated and the results revealed that the complexes displayed satisfactory stability and albumin-binding properties. Finally, DFT calculations were employed to optimize the molecular geometries and to investigate the electronic, thermodynamic, and vibrational properties of the complexes. FMO, NBO, and MEP analyses provide insight into the distribution of electron density and the nature of metal-ligand interactions.