Investigations Of The Mechanism Of DNA Cleavage Using Ruthenium Polypyridyl Complexes

We have synthesized a ruthenium complex, [(phen)2Ru(tatpp)Ru(phen)2]4+ (P4+), which has been shown to undergo various redox and protonation steps to form different species that can be monitored by UV-Vis spectroscopy. In Chapter 2, the photochemistry of P4+ in the presence and absence of DNA was studied. It was hypothesized that the lifetime (t1/2) of the excited state of P4+, P*, would be extended in the presence of DNA. However, studies conducted showed that the lifetime of P* was diminished in the presence of DNA as compared to P4+ alone. Experiments have also shown that P4+ is capable of damaging DNA both in the presence and absence of oxygen. This damage is potentiated under anaerobic conditions. In Chapter 3, we uncovered the chemical species responsible for damaging plasmid DNA as the doubly reduced, doubly protonted H2P4+ species and a carbon-based radical species.