Journal of Physical Chemistry B, Vol.113, No.19, 6826-6833, 2009
Photophysical Studies of a Hemicyanine Dye (LDS-698) in Dioxane-Water Mixture, in Different Alcohols, and in a Room Temperature Ionic Liquid
In this paper, we have investigated the photophysics of 1-ethyl-2-(4-(p-dimethylaminophenyl)-1,3-butadienyl)pyridinium perchlorate (LDS-698) molecule in dioxane-water mixture and in a room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]). Both photoisomerization and twisted intramolecular charge transfer (TICT) are possible in this molecule. We have shown that TICT is favorable in this molecule in the dioxane-water mixture and in neat [bmim][BF4]. The change in absorption energy of LDS-698 molecule with mole fraction of water is nonlinear in these systems. The Stern-Volmer plot also deviates from linearity in these systems. This nonlinearity is due to the specific solvation of water molecules in the mixture.