Resonance Raman Spectrum of the Phenanthroline Anion:  Implications on Electron Delocalization in the MLCT Excited State of Ru(phen)₃²⁺

Electron Localization or Delocalization in the MLCT Excited States of Ru(bpy)32+ and Ru(phen)32+. Consequences to Their Photochemistry and Photophysics in Fluid Solution

“…We conclude that even if the natures of the excited states of *Ru(phen) 3 2+ and *Ru(bpy) 3 2+ were very different, i.e., delocalized vs localized, such differences do not manifest themselves in their photophysics and electron-transfer photochemistry in fluid solution at and near room temperature. The paper by Turró et al 4 proposes that differences exist on the vibrational time scale, but the results presented here indicate that these differences, were they to exist, do not affect the observed excited-state decay and electron-transfer chemistry. …”

Origin of electronic absorption spectra of MLCT-excited and one-electron reduced 2,2′-bipyridine and 1,10-phenanthroline complexes

“…For example, observation of dpp ÅÀ (dpp = 2,3-bis(2-pyridyl)pyrazine) UV-Vis features in the excited-state spectrum of a dinuclear complex [(bpy) 2 Ru(l-dpp)Ru(bpy) 2 ] 2+ provided an evidence that MLCT excitation is directed to the bridging ligand instead of bpy [19]. The similarities between UV-Vis spectroscopic effects of reduction and MLCT excitation are less obvious in complexes of 1,10-phenanthroline (phen) such as [Ru(phen) 3 ] 2+ [20] and [W(CO) 4 (phen)] [15]. The very notion of the analogy between excited-and reducedstate spectra is based on the assumption that the same N,N ÅÀ chromophore is present in both states.…”

Long‐Lived, Emissive Excited States in Direct and Amide‐Linked Thienyl‐Substituted RuII Complexes

“…We have previously reported that contributions to positive absorption features at higher energies (≈ 420 nm) may arise from triplet states localized on peripheral bithienyl moieties, as well as reduced phenanthroline groups. [56][57][58] By comparison, the higher energy feature observed in the excited spectrum of [Ru(bpy) 2 (2) is also attributed to a triplet state localized on bithienyl moieties appended to the bipyridine. [42] This is additionally supported by the exceedingly long excited state lifetime (τ = 15 μs) observed for this complex.…”