Abstract:

The monomer and excimer fluorescence bands recorded in aqueous solution of a new kind of fluorescence chemosensor which have the ability of recognition exhibit an "isosbestic" point over certain limited ranges of temperatures. The temperature dependence of their excimer formation was studied. The mechanism of the transformation between monomer and excimer and the excimer geometrical configuration have been proposed. From the temperature conefficient of the ratio of excimer to monomer fluorescence intensities at the isosbestic wavelength the value of enthalpy and entropy in the process of transformation can be estimated. The repulsive energy between unexcited molecule in the excimer configuration contributes to the excimer formation of these fluorescence chemosensor. These results provide a base for their applications.

Key words: Excimer, Temperature dependence, Geometrical configuration, Repulsive energy