Hydrogen peroxide assisted photorelease of an anthraquinone-based ligand from [Ru(2,2′-bipyridine)2 (9,10-dioxo-9,10-dihydroanthracen-1-olate)]Cl in aqueous solution

A new class of light-activated ruthenium(s) complex was designed as a potential blocker of biological functioning, especially for targeting redox reactions within mitochondria under light activation. Based on our concepts the complex [Ru(bipy)(2)(1-hydroxyanthra-9,10 quinone)]Cl (RU1) was prepared and studied to understand the preliminary reaction mechanisms and its excited state behaviour through a series of stability tests, electrochemistry, UV-Visible kinetics and femtosecond transient absorption spectroscopy experiments. Under white light in the presence of H2O2 two different reactions (fast and slow) appear to take place. The complex loses the quinone-based ligand and a resulting Ru(III) or Ru(V) species is produced. The complex RU1 shows potential to consume H2O2 from the one carbon metabolism in mitochondria, and hence may cut the energy cycle pathway of tumor cells.