A Ruthenium(II) Phosphine Complex with a Phenanthroline Derivative: Synthesis and Biomolecular Interactions

The search for alternatives to platinum-based anticancer drugs has highlighted ruthenium complexes because of their favorable redox properties, structural versatility, and potential biological activity. In this work, the complex cis-[RuCl₂(dppz-Cl₂)(DPEPhos)] (dppz-Cl₂ = 7,8-dichloro-dipyrido[3,2-a:2’,3’-c]phenazine; DPEPhos = bis[(2-diphenylphosphino)phenyl]ether) was synthesized and comprehensively characterized by elemental analysis, molar conductivity, infrared and UV–Vis spectroscopy, ^31P{^1H} NMR, mass spectrometry, cyclic voltammetry, and single-crystal X-ray diffraction. The analyses confirmed the formation of a neutral octahedral Ru(II) complex with cis chloride ligands, while DMSO stability studies indicated the labilization of one chloride ligand. Biomolecular interaction studies revealed strong binding to human serum albumin through a spontaneous, predominantly hydrophobic process, whereas CT-DNA assays indicated moderate affinity. These findings provide valuable insights into biomolecular interactions and support the rational design of phosphine-containing ruthenium complexes as promising candidates for future anticancer applications and further biological investigation.