Reply to the Comment on "Resonance Raman Investigation of Ru(phen)_2dppz^(2+) and Related Complexes in Water and in the Presence of DNA"

Abstract

Our recent paper describes the rR spectra of Ru(phen)_2dppz^(2+), Ru(phen)_2(F_2-dppz)^(2+), and Os(phen)_2(dppz)^(2+) (phen = 1,10-phenanthroline, dppz = dipyrido[3,2-a:2',3'-d]phenazine, F_2-dppz = 7,8-difluoro-dppz) obtained utilizing 354.7 nm excitation (fwhm ∼ 10 ns). The spectra collected for Ru(phen)_2(F_2-dppz)^(2+) and Os(phen)_2(dppz)^(2+) were assigned to the ground state of the complexes at both high and low pulse energies. In the case of Ru(phen)_2dppz^(2+), the power dependence of the peaks at 1365 and 1453 cm^(-1) were consistent with an excited state. Our interpretation described below and on the recent paper was not based on the assumption that the ^3ππ* state of the dppz ligand lies below the MLCT in Ru(phen)_2dppz^(2+), but rather that pumping directly into the dppz ^1ππ* manifold could lead to trapping of the excitation at short time scales on the lowest LC dppz state (^3ππ*) if crossing to the MLCT required activation. Lowering of the MLCT relative to the ^3ππ* in Ru(phen)_2(F_2-dppz)^(2+) and Os(phen)_2(dppz)^(2+) would result in lowering the activation barrier and much faster crossing to the MLCT.

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