Fluorescence spectroscopic studies on preferential solvation and bimolecular quenching reactions of Quinolin-8-ol in binary solvent mixtures

Abstract

On account of the importance towards solvent mixtures in practical chemistry, binary solvent mixtures of acetonitrile (AN) and 1, 4-dioxane (DX) are used to study fluorescence behavior of this organic compound namely Quinolin-8-ol (QO). At the outset, preferential solvation is examined in AN-DX for this QO, in order to understand specific and nonspecific interactions. Further Suppan’s dielectric enrichment model is implemented to identify the non-ideality and dielectric enrichment in AN-DX for preferential solvation. Bimolecular quenching reaction studies of Quinolin-8-ol have been carried out in mixtures of AN-DX to study the effect of dielectric constants and viscosity at room temperature. The quenching process is studied in all solvent mixtures by Steady state and Transient state method. Quenching is characterized by Stern-Volmer (S-V) plots having downward curvature. Interestingly, for moderate quenching concentration, downward curvature has been observed for the title molecule. The inter and intra molecular hydrogen bonding has profound role in the formation of different conformers in QO. Further, modified S-V equation is applied to analyze the fluorescence quenching reactions of QO molecule.