Study of Bimolecular Quenching Reactions of Coumarin Dye C1 by the Fluorescence Behavior in Toluene and Butanol Binary Mixtures

摘要

Inferable from the significance of solvent mixtures in practical chemistry,toluene(TL)and butanol(BL)mixtures are used to study fluorescence behavior of coumarin dye C1 namely 3-hydroxy-3-[2-oxo-2-(2-oxo-2H-chromen-3-yl)-ethyl]-1,3-dihydro-indol-2-one.Bimolecular quenching reaction studies of C1 with aniline as quencher are made in mixtures of TL-BL to know the effect of viscosity and dielectric constant variation at room temperature.The quenching process is studied in all solvent mixtures by steady state method.Quenching is characterized by Stern-Volmer(S-V)plots having upward curvature.Analysis of modified S-V equations which accounts both static and dynamic quenching allows calculating bimolecular quenching rate constant.The bimolecular quenching reactions are found to be significantly larger.Further finite sink approximation model is invoked so as to check whether reactions are diffusion limited.The extents of these rate parameters demonstrate that positive deviations in the S-V plot are because of the presence of apparent static and dynamic quenching process.