Application of Fluorescence in Solvatochromic Studies of Organic Compounds

Abstract

In this review, we report the photophysical studies of selected heterocyclic compounds through solvatochromic approaches. The absorbance and fluorescence spectral characteristics of these compounds were recorded in different solvents of varying polarities. Ground state dipole moment was experimentally determined by Guggenheim method and solvatochromic approach proposed by Bilot-Kawski. The singlet excited state dipole moments were calculated experimentally based on different approaches of solvent polarity function proposed by Lippert--Mataga, Bakhshiev, Kawski-Chamma-Viallet, Reichardt and Bilot-Kawski. Greater singlet excited state dipole moment values in all the approaches can be ascribed to significant $π$-electron density redistribution. Multiple Linear Regression (MLR) analysis on the basis of Kamlet-Abboud-Taft and Catalan parameters were utilized to study solvent correlations and solute-solvent interactions. HOMO-LUMO energies of the compounds were estimated theoretically by TD-DFT computations and experimentally by cyclic voltammetry.