Adiabatic structural relaxation in heterocyclic nitrogen-containing cations - The structure, absorption and fluorescence of the 2,4,6-triarylsubstituted pyridinium cations
Mi. Knyazhansky et al., Adiabatic structural relaxation in heterocyclic nitrogen-containing cations - The structure, absorption and fluorescence of the 2,4,6-triarylsubstituted pyridinium cations, J PHOTOCH A, 118(3), 1998, pp. 151-156
Citations number
19
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
The detailed studies of the 2,4,6-(N-alkyl)triarylsubstituted pyridinium ca
tions I as well as the large series of the model structures have been carri
ed out by absorption, fluorescent and polarization methods in the solvents
of various polarity and viscosity at different temperatures. The localizati
ons of the lowest electron transitions are determined. It is shown that the
fluorescence with anomalous Stokes shift (ASS-fluorescence) arises owing t
o the adiabatic structural relaxation (ASR) with the formation of the flatt
ened (but not twisted) structure. The advantages of I as the objects for AS
R study are discussed. The crude determination of the ASR kinetic parameter
s has been conducted. A data assume that the ASS fluorescence quantum yield
s of the cations I are conditioned mainly by deactivation processes in the
final flattened structure. (C) 1998 Elsevier Science S.A. All rights reserv
ed.