Synthesis and spectroscopic characterization of soluble mixed-ligand diruthenium complexes: potential application as anti-cancer agents.
Three mixed-ligand metal-metal bonded complexes containing one unsymmetrical anionic bridging ligand were successfully synthesized and characterized as to their electrochemical and spectroscopic properties. The investigated mono-substituted diruthenium complexes have the general formula, Ru2(OAc)3(L)Cl, where OAc = acetate anion and L = anilinopyridinate bridging ligand (ap, 2-Meap, 2-Fap). UV/Visible spectroscopy studies reveal that the investigated diruthenium complexes exist in the forms Ru2(OAc)3(L)Cl and [Ru2(OAc)3(L)]+ in solution. The two forms are observed as a split band in the 500 – 700 nm visible region. A collapse of one band is seen upon reaction of the complexes with excess halide (Cl-, Br-) indicating an equilibrium shift towards the neutral species in solution, whereas a reaction with AgBF4 precipitates the chloride as the AgCl salt, leaving only the cationic species in solution. Electrochemical characterization of the mixed-ligand diruthenium complexes conclusively reveals a stable Ru25+ oxidation state in all three complexes. Upon an applied potential in a non-coordinating solvent, each complex undergoes a reversible one-electron oxidation and reduction process accessing the Ru26+, and Ru24+ oxidation states respectively. The treatment of human breast adenocarcinoma MCF-7 cells with these water-soluble complexes results in a less than 50 % cell survival. This demonstrates significance of solubility in the development of metallodrugs for cancer treatment.
A dissertation submitted to the Faculty of Science, in partial fulfilment of the requirements for the award of Master of Science degree, University of the Witwatersrand, Johannesburg, 2018
Mashiloane, Karabo Concious (2018) Synthesis and spectroscopic characterization of soluble mixed-ligand diruthenium complexes: potential application as anti-cancer agents, University of the Witwatersrand, Johannesburg, https://hdl.handle.net/10539/24928