Estimation of Dipole Moments of New Coumarin Dye by Experimental and Theoretical Methods

Abstract

AbstractThe absorption and fluorescence emission spectra of coumarin dye, 4‐((4‐methoxyphenoxy) methyl)‐6‐methoxy‐2H‐chromen‐2‐one (4‐MPMMC) in different polarity solvents are recorded. The effects of solvent polarity on the spectral properties are discussed. It is found that, spectrum peak shifts toward higher wavelength, as the solvent polarity changes. The ground (µg) and excited state (µe) dipole moments are estimated using Lippert's, Bakshiev's, and Kawski‐Chamma‐Viallet's equations. The µe values are found to be higher than µg values for all solvents. This suggests that the dye is more polar in excited state than in ground state. Computational studies are done using Time Dependent Density Functional Theory (TD‐DFT), DFT, and Zindo methods with the help of Gaussian16W; Integral Equation Formalism Polarizable Continuum Model (IEFPCM). Further, the excited state dipole moments are estimated in different solvents and are compared with the experimental results. The reactive centers like electrophilic and nucleophilic sites are identified along with contour action using electrostatic potential (ESP) 3D map using DFT analysis.