New efficient and thermally stable NLO-chromophores 4-5 based on a thienylpyrrolyl donor πconjugated bridge and a benzimidazolyl acceptor moieties were developed by a one step Na 2 S 2 O 4 reduction of substituted o-nitroanilines in the presence of formyl-thienylpyrroles.
Abstract -A new series of thermally stable benzimidazole-based nonlinear optical (NLO)chromophores 4-5 has been developed. These chromophores possess a thienylpyrrolyl πconjugated system attached to functionalized benzimidazole heterocycles. This feature leads to robust chromophores with excellent solvatochromic properties, high thermal stabilities and good molecular optical nonlinearities.
The synthesis and full characterization of new chromophores with secondorder nonlinearities containing thienylpyrrolyl and benzothiazolyl moieties are reported. The solvatochromic behavior of the compounds was investigated. The hyperpolarizabilities β of derivatives 4-6 were measured using hyper-Rayleigh scattering and thermogravimetric analysis (TGA) was used to evaluate their thermal stability. The experimental results indicate that good nonlinearity-thermal stability is well balanced specially for chromophores 6b-c, making them good candidates for NLO applications.
New thermally stable heterocyclic chromophores 3-6 based on a (oligo)thiophene πconjugated bridge and a imidazo-phenanthroline moiety were synthesized in moderate to excellent yields by condensation of 5,6-phenanthroline-dione with formyl (oligo)thiophenes 1-2 in the presence of ammonium acetate in glacial acetic acid.
Novel colorimetric receptors for fluoride ion sensing containing anthraquinone as a chromogenic signaling unit and imidazo-2,2'-bithiophene binding sites are reported. Well-defined color change was observed upon addition of fluoride ions to acetonitrile solutions of receptors 2. Compounds 2a-c, deprotonated after fluoride ion addition, were studied as metal ion chemosensors in the presence of Zn(II), Hg(II), and Cu(II) in acetonitrile solutions, especially compound 2a which displayed a marked change from pink to yellow-gold colors upon complexation.
This manuscript describes the synthesis and characterization of five new organic–inorganic hybrid (OIH) sol-gel materials that were obtained from a functionalized siloxane 3-glycidoxypropyltrimethoxysilane (GPTMS) by the reaction with the new Jeffamine®, namely three different diamines, i.e., EDR-148, RFD-270, and THF-170, a secondary diamine, i.e., SD-2001, and a triamine, i.e., T-403. The OIH sol-gel materials were characterized by UV-visible absorption spectrophotometry, steady-state photoluminescence spectroscopy, and electrochemical impedance spectroscopy. The reported OIH sol-gel materials showed that, with the exception of the samples prepared with Jeffamine® SD-2001, the transmittance values ranged between 61% and 79%. Regarding the capacitance data, the values reported changed between 0.008 and 0.013 nF cm−2. Due to their optical and electrical properties these new OIH materials show promising properties for applications as support films in an optical sensor area such as fiber sensor devices. Studies to assess the chemical stability of the OIH materials in contact with cement pastes after 7, 14, and 28 days were also performed. The samples prepared with THF–170 and GPTMS, when compared to the samples prepared with RFD-270 and T-403, exhibited improved behavior in the cement paste (alkaline environment), showing promising properties for application as support film in optical fiber sensors in the civil engineering field.
-Bithienyl-1,3-benzothiazole derivatives were synthesised by reacting various 5-formyl-5'-alkoxy-or 5-formyl-5'-N,N-dialkylamino-2,2'-bithiophenes with ortho-aminobenzenethiol in good to excellent yields. Evaluation of the fluorescence properties of these compounds was carried out. They show strong fluorescence in the 450-600 nm region, as well as high quantum yields and large Stokes' shifts.
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