Synthesis and photophysical properties of fluorescent dyes based on triphenylamine, diphenylamine, diphenyl sulfone or triphenyltriazine derivatives containing an acetylene linkage group

In this study, ten fluorescent dyes were prepared based on three different kinds of central moiety, such as triphenylamine, diphenylsulfone or triphenyltriazine, which was coupled to either carbazole or naphthalimidinyl group via an acetylene linkage group. N-n-Butyl-carbazole, N-phenyl-carbazole or N-n-butyl-naphthalimide was coupled to the individual central moiety of triphenylamine, diphenyl sulfone, 2,4,6-triphenyl-1,3,5-trazine or diphenylamine using a Sonogashira coupling reaction in the final step. All dyes were confirmed their chemical structure by 1H NMR, GC-Mass and elemental analyses. The absorption properties and thermal stabilities of the fluorescent dyes were examined. Density Functional Theory (DFT) and Time-Dependent DFT calculations were carried out, in addition to geometry simulation, by using the Gaussian 09 program. In terms of fluorescence properties in this series, two dyes based on diphenyl sulfonyl and three dyes based on triphenylamine substituted by 1–3 of N-n-butyl-carbazole exhibited a blue emission, whereas three dyes based on triphenylamine substituted by 1–3 of N-n-butyl-naphthalimide were observed by a red emitter which can be attributable to both effects the bathochromic shifts in absorption maxima and larger Stokes shifts. In case of corresponding 2,4,6-triphenyl-1,3,5-trazine central moiety coupled to a carbazole ring, a green fluorescence was emitted. Results revealed that the fluorescence of the dyes is affected by the electron-donating strength of the acetylene linkages involved in the π-conjugation systems of the dyes. •Fluorescence dyes to provide three ranges of emission, blue, green, and red fluorescence.•Dyes containing an acetylene linkage group between N-butyl carbazole or naphthalimidyl moiety.•Improved thermal stability.