Cyclopentadienyl and indenyl ruthenium(II) complexes containing diazafluorenone derivative ligands: Syntheses, characterization, antibacterial and cytotoxicity studies

Abstract

We have successfully synthesized a series of eight versatile, half-sandwich ruthenium(II) cationic complexes [(Cp/Ind)Ru(к2(N∩N)L)(PPh3)]PF6 (1–8), where L represents a 4,5-diazafluorenone derivative ligand. These complexes were isolated as their hexafluorophosphate salts and subjected to thorough characterization using various spectroscopic techniques such as FT-IR, NMR, UV and Mass. Furthermore, single-crystal X-ray diffraction studies determined the molecular structures of representative complexes 1, 7, and 8. We screened the synthesized complexes and ligands in vitro to assess their potential antibacterial activity against three bacterial strains: the Gram-positive Staphylococcus aureus, the Gram-negative Escherichia coli and Klebsiella pneumoniae. Remarkably, all the compounds exhibited potent antibacterial activity against the tested organisms. In addition, we conducted a cell viability assessment to evaluate the cytotoxicity of the free ligands. The results indicated that the ligands did not demonstrate statistically significant cytotoxicity. However, it is noteworthy that complex 1 displayed more pronounced cytotoxic effects on the DL cell line, followed by complexes 3, 5, and 7.