Ms. Antonious, SOLVENT POLARITY INDICATORS - FLEXIBLE STYRYLPYRIDINIUM AND QUINOLINIUM FLUORESCENCE PROBES FOR MEDIUM FREE-VOLUME, SPECT ACT A, 53(3), 1997, pp. 317-324
Fluorescence properties are studied for four structurally related flex
ible styrylpyridinium and quinolinium dyes of electron donor-acceptor
type in glycerol at different temperatures. The response of the fluore
scence quantum yield (phi(f)) to viscosity-temperature changes (eta(T)
function) is a sensitive function of dye structure. Probe rotational
relaxation dynamics are accurately described in terms of the free-volu
me hypothesis. An intriguing gauge of the interplay between average me
dium microviscosity/free-volume and some molecular properties such as
rotor size and flexibility is developed for potential analytical appli
cation as fluorescence probes for medium viscosity. (C) 1997 Elsevier
Science B.V.