Mi. Knyazhansky et al., Light-induced adiabatic structural relaxation and electronic energy deactivation in Pyridinium bications, J PHOTOCH A, 132(1-2), 2000, pp. 59-66
Citations number
16
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
The comparative detailed investigation of the Bication pyridinium systems (
BCP) and corresponding model pyridinium cations (CP) has been carried out b
y the spectral luminescent methods. BCP consist of the two identical moieti
es bound by the various space bridges ensuring their very weak interaction
in the ground state. The Adiabatic Structural Relaxation (ASR) followed by
the photocyclization reaction is realized only in one of BCP fragments in a
ccordance with the general scheme typical for CP. The ASR is not realized i
n another BCP fragment owing to the S-1 state deactivation by the extremely
fast Interfragmental Intramolecular S-S Energy Transfer from the unchanged
fragment to the cyclized one. The ASR mechanism, luminescent properties an
d photoproduct structures depend strongly on the solvent temperature (visco
sity) and on the steric interactions typical for the BCP. The additional in
formation concerning the N phenyl role in the fluorescence and photo-chemic
al properties' formation in CP has been obtained by the study of the BCP. (
C) 2000 Elsevier Science S.A. All rights reserved.