Two previously claimed results on the Vilsmeier-Haack formylation of triphenylamine were demonstrated to be in error and the unambiguous reproducible procedures were developed to prepare 4-formyltriphenylamine (3) and 4,4'-diformyltriphenylamine (4), respectively, in good yields.
"First, the starting material 4-(diphenylamino)benzaldehyde was synthesized from triphenylamine according to the Vilsmeiere Haack formylation reaction . Then 3,4-diaminobenzoic acid (0.3 g, 1.97 mmol) was suspended in 1:1 methanol water mixture (24 mL). "
[Show abstract][Hide abstract] ABSTRACT: Benzimidazole based metal free organic dyes (D-pi-A) with and without cyanovinyl unit have been designed and synthesized via one step processes and tested as sensitizers in the dye sensitized solar cells (DSSC). In such donor-n-bridge-acceptor dyes, N,N-diethylaniline and triphenylamine were act as donors and benzimidazole derivatives were act as pi-bridge as well as acceptor. The relationship between molecular structure and optoelectronic properties of the synthesized dyes as well as their DSSC performances were studied by UV-vis and fluorescence spectroscopy, cyclic voltammetry (CV) and Density Functional Theory (DFF) calculation. Introduction of cyanovinyl unit in between the donor and benzimidazole leads to the significant improvement in the optoelectronic properties and DSSC performance. In general, the cyanovinyl unit containing dyes based DSSCs show more than two times higher efficiency than the dyes without cyanovinyl unit based DSSCs. Among the fabricated DSSC, the dye contain triphenylamine donor and benzimidazole with cyanovinyl unit based DSSC shows maximum power conversion efficiency of 3.47% under AM 1.5 illumination (85 mW/cm(2)).
Dyes and Pigments 06/2014; 105:223–231. DOI:10.1016/j.dyepig.2014.02.010 · 3.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In this high-technology application, age functional dyes especially polymethine dyes have captured much attention of the researchers due to their immense potential for high-tech uses. Polymethine dyes show promising absorption spectra in the visible range, which can be easily exploited for the use of written text copying, photographic imaging, or photothermographic recording materials. Keeping this in mind, our research is composed of an investigation of two triphenylamino-based polymethine dyes, a known polymethine dye 3 and a new one polymethine dye 5, which have been synthesized by the reaction of 4-(diphenylamino) benzaldehyde 2 and 4,-(phenylazanediyl) dibenzaldehyde 4 with 4,-vinylidene-bis(N, N-dimethylaniline) 1. Based on bis-dimethylaminophenylethylene moiety, the new polymethine dye showed more high absorption spectra in the range of 600–700 nm than that of the known polymethine dye based on bis-dimethylaminophenylethylene moiety. Their maximum spectra were exhibited at 637 nm and 653 nm, respectively. Their leuco-converted reversible colored forms were also investigated.
"Dioxane and tetrahydrofuran (THF) were dried on sodium wire and distilled under nitrogen just before use. 4-Formyl triphenylamine  and 4,4′,4′′-triformyl triphenylamine [23–25] were obtained by formylation of TPA according to the reported methods. 4-Formyl-N,N′-bis(4-bromophenyl) aniline , tris (4-iodophenyl) amine  and vinyl triphenylamine  were synthesized and purified according to the literature procedures. "
[Show abstract][Hide abstract] ABSTRACT: Six star-shaped oligomers containing triphenylamine (
) and benzene unit (
) as cores have been synthesized by Wittig condensation or Heck coupling reaction using aromatic aldehydes and triphenylphosphonium salts or aromatic halogenated compounds with vinyl triphenylamine. All oligomers have well-defined molecular structure and high purity. Characterization of the oligomers was made by FT-IR,
H-NMR spectroscopy, UV-Vis, and fluorescence spectroscopy. The electrochemical behavior was studied by cyclic voltammetry (CV). The cyclic voltammograms have revealed that oligomers undergo quasireversible or irreversible redox processes. The irreversible process is associated with electrochemical polymerization of oligomers by dimerization of unsubstituted triphenylamine groups. Thermal characterization was accomplished by TGA and DSC methods and evidenced that all oligomers were stable materials until 250°C and have formed stable molecular glasses after first heating scan.
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