Ground state and photophysical properties of Ru(phen)(2)quo(+): a strong excited state electron donor

We prepared the complex Ru(phen)(2)quo(+) (phen = 1, 10-phenanthroline, quo (-) = 8-quinolate) and investigated its photophysical and redox properties. The absorption and emission of Ru(phen)(2)quo(+) are red-shifted relative to Ru(phen)(3)(2+), and the former is easier to oxidize than the latter. Ru (phen)(2)quo(+) possesses an Ru --> phen MLCT (metal-to-ligand charge trans fer) excited state (E-oo similar to 1.85 eV) that is a better reducing agen t than the parent complex Rut phen)(3)(2+). Transient absorption results ar e consistent with the formation of reduced methylviologen upon Ru(phen)(2)q uo(+) excitation with visible light in water. (C) 1999 Elsevier Science S.A . All rights reserved.