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Electronic absorption, resonance Raman and excited‐state resonance Raman spectroscopy of rhenium(I) and copper(I) complexes, with substituted dipyrido[3,2‐ a : 2′,3′‐ c ]phenazine ligands, and their electron reduced products
Author(s) -
Waterland Mark R.,
Gordon Keith C.
Publication year - 2000
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/(sici)1097-4555(200004)31:4<243::aid-jrs536>3.0.co;2-y
Subject(s) - phenazine , raman spectroscopy , excited state , chemistry , resonance (particle physics) , resonance raman spectroscopy , ligand (biochemistry) , rhenium , photochemistry , absorption spectroscopy , photoexcitation , analytical chemistry (journal) , crystallography , atomic physics , inorganic chemistry , organic chemistry , biochemistry , receptor , physics , quantum mechanics , optics
The electronic absorption and resonance Raman spectra of a series of rhenium(I) and copper(I) complexes with substituted dipyrido[3,2‐ a : 2′,3′‐ c ]phenazine (dppz) ligands were investigated. The ligands were ben[ i ]dipyrido[3,2‐ a : 2′,3′‐ c ]phenazine, 11,12‐dimethyldipyrido[3,2‐ a : 2′,3′‐ c ]phenazine, 10‐methyldipy‐ rido[3,2‐ a : 2′,3′‐ c ]phenazine and 11‐methyoxydipyrido[3,2‐ a : 2′,3′‐ c ]phenazine. The spectroelectrochemistry of the reduced complexes and the emission and resonance Raman spectra of the excited states are reported. Vibrational wavenumber calculations of the unsubstituted ligand suggest the presence of normal modes that are localized to various sections of the ligand structure; the resonance Raman spectra of the complexes are interpreted with reference to these calculations. The analysis of the spectra revealed that the Franck–Condon state initially formed by visible photoexcitation (450 nm) is metal‐to‐ligand charge‐transfer in nature. Spectroelectrochemical resonance Raman and electronic absorption measurements revealed the spectral signatures for the radical anions of each of the ligands used in this study. These spectral features were used to assign the excited states formed by the complexes. Most of the complexes studied show spectral features in their excited‐states that suggest that the predominant state formed within 5 ns of excitation is ligand‐centred. Copyright © 2000 John Wiley & Sons, Ltd.