Novel Twisted Intramolecular Charge Transfer (TICT) Extended Fluorescent Styryl Derivatives Containing Quinoline Electron Releasing Moiety

Novel extended fluorescent styryl derivatives were synthesized from (E)-3-(2-cyclopropyl-4-(4-fluorophenyl)quinolin-3-yl)acrylaldehyde containing quinoline ring with 4-fluorophenyl ring at the 4-position as an electron donor and different active methylene compounds as electron acceptors by conventional Knoevenagel condensation reaction. The UV-Visible absorption and fluorescence emission spectra of the dyes were studied in solvents of differing polarity and the compounds showed polarity sensitive emission properties. The dyes were characterized by the spectral analysis. Thermogravimetric analysis showed these dyes are thermally stable up to 250 °C. Density Functional Theory computations have been used to derive more understanding of structural, molecular, electronic and photophysical parameters of the push-pull dyes. The computed absorption wavelength values are found to be in good agreement with the experimental results. The second order hyperpolarizability (βo) values were computed by Density Functional Theory and found to be in the range of 116.61 × 10−31 to 898.48 × 10−31 e.s.u.