Papers by Keyword: Solvatochromism

Abstract: Solvatochromic compounds attracted more and more attentions in the application of fluorescent probe, indicator, chromogenic reagent, molecular recognition field and so on. Although sovatochromic effects have been discovered for more than a century, they are still difficult to understand and even more difficult to predict. This review introduced organometallic complexes and organic compounds of solvatochromic materials and highlight the latest progress in recent years, and the molecular structure design and solvatochromic properties are discussed.

Abstract: 2, 6-Diaminoanthraquinone is used in drug delivery. The absorption and fluorescence spectral properties of 2,6-Diaminoanthraquinone (DAAQ) have been investigated in a series of organic solvents with different polarity functions ranging from 0.207 to 0.762.The different solvents used are Tetrahydrofuran (THF) (0.207), Dimethylformamide (DMF) (0.404), ethanol (0.654) and Methonal (0.762).The fluorescence shifts are more pronounced than the absorption shifts indicating that the change in dipole moment is positive. The change in dipole moment and the ratio of the dipole moments are determined and discussed by Solvatochromism method. The third order nonlinearity of 2,6-DAAQ in PVA dissolved in DMF solution is determined using Electroabsorption. Higher order nonlinearities can be deduced on successful recording of the stark spectrum at the higher order of the applied electric field.

Abstract: C3-symmetrical tristriazolotriazines substituted with phenylene rings carrying lateral flexible alkoxy side chains were prepared via condensation/ring transformation of cyanuric chloride and tetrazoles. These star-shaped, planar compounds can form broad thermotropic mesophases. Due to the extensive π-conjugation, these compounds are highly emissive and the octupolar donor-acceptor electronic structure results in non-linear optical properties like solvatochromism. Brønstedt acids provoke halochromism of the absorption and of the fluorescence.

Abstract: This research aimed to study the use of curcumin as a natural dye for dyeing poly(lactic acid) and poly(ethylene terephthalate) fabrics. The study found that curcumin was dyeable on PLA and PET, providing a brilliant yellow color on the fabric. Curcumin could build up very well on PLA, while lower build up was on PET. At the same applied concentration, higher color yield was observed on the dyed PLA fabric. To achieve the same visual color yield, a significantly lower concentration of curcumin was required for PLA as compared with PET. The color shade of curcumin-dyed PLA differed from the PET analogue. A bathochromic shift of the K/S curve was found when the substrate was changed from PLA to PET. The influence of polymer media on the spectroscopic properties of curcumin could be elucidated by measuring absorbance properties of curcumin in ethyl acetate and methyl benzoate, being representatives of PLA and PET, respectively. At the same concentration, curcumin solution in ethyl acetate exhibited higher absorbance than that in methyl benzoate, corresponding to the deeper shade obtained when dyed on PLA as compared with PET. Bathochromic shift of absorbance curve was also observed when the solvent was changed from ethyl acetate to methyl benzoate.

Abstract: Red fluorescence was widely applied in full color organic light-emitting display and anti- counterfeit technology. Due to concentration quenching red fluorescence was weak and even no luminescence in a solution or solid state. Therefore, novel red fluorescent pigment bis(4-(N-(9, 9- diethyl-2-fluorenyl)phenylamino)phenyl)fumaronitrile (EFPAFN) with non-planar fluorenylamino group and fumaronitrile core was prepared. The compound existed a pair of antiparallel dipole limiting molecular interaction, showed strong red photoluminescence which centralized at 657 nm in solid film. The decomposition temperature of EFPAFN was observed at around 422 °C. In different polarity of solvents the absorption and emission peaks of EFPAFN showed positive and then negative solvatochromic shifts. EFPAFN in water/tetrahydrofuran (v/v, 9:1) mixture was adjusted and aggregated into small size particles in the range of 141-531 nm or big size particles of 255-825 nm as fluorescent organic nanoparticles (FONs). FONs of EFPAFN with donor-acceptor group showed strong emission at 653 nm and had potential applications in nano-sized fluorescence and optoelectronic device.

Abstract: Compounds 1 were synthesized, in good to excellent yields (72-87%), through condensation of formyl-arylthiophene precursors 2 with 1,2-diaminoanthraquinone in ethanol at reflux, followed by cyclisation of the imine intermediate with Pb(OAc)4 in acetic acid at room temperature. Evaluation of the thermal, linear and NLO properties of these compounds was carried out. The  values of chromophores 1, measured by hyper-Rayleigh scattering (HRS) technique, are several times larger (49-67) than that of the standard reference molecule p-nitroaniline (pNA). Due to their excellent thermal stability, (Td = 341-446 oC), and good NLO properties, arylthienyl-imidazo-anthraquinones 1 could be used as new efficient and thermally stable NLO materials.

Abstract: New push-pull thiobarbituric (oligo)thiophene derivatives 1 were synthesized, in good to excellent yields (60-98%), through Knoevenagel condensation of the corresponding formyl-(oligo)thiophenes 2 with 1,3-diethylthiobarbituric acid in dichloromethane, under basic conditions. Evaluation of the thermal and solvatochromic properties of these compounds was carried out and their NLO response was estimated. The values obtained suggest that these (oligo)thiophenes have good potential to be used as novel NLO materials.

Abstract: Fluorescent dyes with a high sensitivity of their optical spectra towards changes of the environment were prepared via aldol condensation or Horner olefinations. The main chromophore is a quadrupolar N-substituted 1,4-distyrylbenzene which allows protonation and complexation at various positions resulting in a series of different and significant changes of the optical spectra. The sensitivity of the absorption and emission spectra on solvent polarity, acid, and cations is reported.

Abstract: The synthesis of 5-arylazo- substituted bithiophenes and their UV-visible, solvatochromic and nonlinear optical properties (NLO) are described. In agreement with the solvatochromic data and also with the second-order molecular NLO characterization, the new donor-acceptor systems could find application as suitable solvatochromic probes and also as new NLO materials.

Abstract: A new series of oligothienyl-imidazo-phenanthrolines 3 were synthesised in good to excellent yields by condensation of 5,6-phenantroline-dione 2 with formyl-thiophene derivatives 1 in the presence of ammonium acetate in glacial acetic acid. Furthermore, their solvatochromism and molecular optical nonlinearities were determined and comparatively studied. The experimental results indicate that phenanthrolines 3, due to their moderate solvatochromic properties and good optical nonlinearities, could be used as suitable probes for the determination of solvent polarity and as nonlinear optical materials.