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Resonance Raman spectra of the N , N ‐ dihydro‐4,4′‐bipyridinium radical cation
Author(s) -
Barker David J.,
Cooney Ralph P.,
Summers Lindsay A.
Publication year - 1987
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/jrs.1250180612
Subject(s) - dication , chemistry , raman spectroscopy , delocalized electron , radical ion , photochemistry , resonance (particle physics) , resonance raman spectroscopy , adduct , solvent , molecule , ion , organic chemistry , physics , particle physics , optics
The Raman spectrum of diprotonated 4,4′‐bipyridine in the solid state as the dibromide salt is reported. The resonance Raman spectrum of the radical cation derived by one‐electron reduction of the dication is also reported. Viscous glycerol was employed as a solvent in order to protect the radical by inhibiting oxygen diffusion. The spectra are interpreted on the basis of a comparison with those of related compounds. A large shift in frequency (+70 cm −1 ) of the inter‐ring stretching vibration between the parent dication and radical monocation is observed. This has been interpreted in terms of a major contribution to the delocalized radical structure of a quinoid‐type form.