Time-resolved resonance Raman spectroscopy has been employed to examine the location of the promoted electron the metal-to-ligand charge-transfer (MLCT) excited state of Ru(bpy)_2(dpphen)^(2+) (bpy) = 2,2'-bipyridine; dpphen = 4,7-diphenyl-1,10-phenanthroline). Variations in the environment about Ru(bpy)_2(dpphen)^(2+) shift the localization charge in the MLCT excited state from bpy in neutral micelles (Brij 35) to dpphen in the presence of DNA and surfactants (C_(12)H_(25)OSO_3Na, C_(10)H_(23)OSO_3Na, and C_8H_(21)OSO_3Na), whereas in water the electron is localized on both ligands. The shifts in the electronic absorption spectrum and the dependence of the ground-state resonance (rR) signal with excitation wavelengths coincident with the high- and low-energy sides of the MLCT absorption band are consistent with a lowering of the energy of the Ru(II)-dpphen transition with respect to that of bpy in anionic micelles.
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Turró et al. (1994) studied this question.