Red emitting solid state fluorescent triphenylamine dyes: Synthesis, photo-physical property and DFT study

In this work, four red-emitting push–pull chromophoric dyes containing triphenylamine are reported. The synthesis and solvatochromic behavior of novel triphenylamine based Y-shaped dyes obtained by the condensation of 4-(diphenylamino) benzaldehyde and 4,4′-diformyltriphenylamine with (1-phenylethylidene) propanedinitrile and ethyl-2-cyano-3-phenyl-2-butenoate are reported. The UV–Visible absorption and fluorescence emission spectra of these dyes were studied in solvents of different polarities. The photophysical behavior and the relation between structure and properties of the chromophores were investigated experimentally. These dyes exhibited positive solvatochromism and solvatofluorism in solution. The dyes were characterized by FT-IR, 1H NMR and Mass spectral analysis. Thermal analysis showed that, these dyes are thermally stable up to 300 °C. Density Functional Theory [B3LYP/6-31G(d)] computations have been used to have more understanding of structural, molecular, electronic and photophysical parameters of push–pull dyes. The absorption wavelength values are found to be in good agreement with the experimental results. Non-linear properties (βo) were calculated by theoretical method and found in the range of 196.45 × 10−30 to 222.18 × 10−30 e.s.u.

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► Synthesis of push–pull triphenylamine based solid state red-emitting fluorescent dyes.
► A good agreement between the experimental and theoretical methods (DFT) results.
► Electronic spectra are highly sensitive to the polarity of solvent medium.
► Also, the quantum yields of these dyes were responsive to solvent polarity.
► Synthesized dyes are thermally stable up to 300 °C.