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ABSTRACT: The interaction between carbazole and 2-chloro-3,5-dinitrobenzotrifluoride-ethylamines, (mono-, di-, and triethylamine) charge-transfer complex in DMSO was studied using fluorescence spectroscopy. The positive deviation from linearity has been observed in the Stern-Volmer plots. The experimental results showed that the fluorescence of carbazole was quenched by 2-chloro-3,5-dinitrobenzotrifluoride-ethylamines charge-transfer complex through a combined quenching procedure. The Stern-Volmer quenching constants, K(SV), have been determined and found to be greater quenching efficiency of ethylamine. Carbazole/2-chloro-3,5-dinitrobenzotrifluoride loaded PMMA film was exposed to ethylamine vapor, where the resulting absorption and emission changing properties were clearly monitored.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 11/2012; · 2.10 Impact Factor
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ABSTRACT: Simple hemicyanine dyes were synthesized by a classical condensation reaction. The structures of these dyes were characterized by (1)H NMR spectroscopy, elemental analysis, and FAB-Mass spectrometry. The sensing behavior of the hemicyanines towards a selection of anions was investigated by UV-vis absorption spectroscopy. These structurally simple dyes displayed a rapid response and high selectivity for cyanide ion over other common anions in the DMSO/H(2)O solution. Different sensing mechanism of the dyes to cyanide ion were confirmed by (1)H NMR studies, together with theoretical calculations based on DFT and PPP-MO methods. These dyes show no colorimetric response for other anions investigated.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 05/2012; 96:77-81. · 2.10 Impact Factor
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ABSTRACT: A highly selective colorimetric displacement assay for anions, F− and H2PO4
−, based on calix[4]arene-Reichardt’s dye was studied in DMSO. When calix[4]arene forms a complex with Reichardt’s, the absorption
peak at 386, 419 and 632 nm disappeared. Addition of anions to solution of calix[4]arene-Reichardt’s dye causes the blue color
of Reichardt’s dye to return as it is displaced from the calix[4]arene. These results demonstrate that this displacement assay
can be favorably utilized for the development of potential sensors for the detection of anion such as F− and H2PO4
− in relation to the other anions.
Fibers and Polymers 05/2012; 10(6):858-860. · 0.84 Impact Factor
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ABSTRACT: Intermolecular charge-transfer (CT) complexes between dichloronaphthoquinone (DCN) as acceptor and amine derivatives as donors
such as ethylamine, diethyl-amine, triethyl-amine were investigated using spectroscopic techniques. The colorimetric signaling
of CT complex from the point of view of their energy levels was carried out by theory calculation. The CT complexes were highly
colored with ethylamine, diethyl-amine, triethyl-amine sensing giving rise to a colorless to yellow, red, and blue, respectively.
A simple “OR” logic operation was successfully realized by ethylamine, diethyl-amine as input signals. Due to the dependence
of the CT complexes absorption intensity of added ethylamine and diethyl-amine, it is possible to mimic the function of the
truth table of an “OR” gate.
Fibers and Polymers 05/2012; 10(6):855-857. · 0.84 Impact Factor
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ABSTRACT: A squarylium (SQ) dye was synthesized by the reaction between squaric acid and 2,3,3-trimethylindolenine and its anion sensing properties were investigated using absorption and emission spectroscopy. This chemosensor exhibited high selectivity for CN(-) as compared with F(-), CH(3)CO(2)(-), Br(-), H(2)PO(4)(-), Cl(-), and NO(3)(-) in acetonitrile, which was attributed to the formation of a 1:1 squarylium:CN(-) coordination complex, the formation of which was supported by the calculated geometry of the complex.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 04/2012; 95:25-8. · 2.10 Impact Factor
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ABSTRACT: A new designed colorimetric and fluorescent dye chemosensor was synthesized, characterized and computationally calculated using MO theory calculation, which was based on donor-pi-acceptor electron charge transfer system. This particularly designed dye chemosensor displayed the selective Ni2+ ion chemo-sensing effects in optical properties with absorption and fluorescence emission. This dye chemosensor represented clear absorption spectra changes with Ni2+ ion and the dramatic fluorescence quenching effect with Ni2+ ion was determined. However it showed no significant optical spectra changes upon the addition of other metal ions such as Cd2+, Na2+, Mg2+, Pb2+, Fe2+, Fe3+, Ca2+, Cu2+, Hg2+, except Zn2+.
Journal of Nanoscience and Nanotechnology 02/2012; 12(2):1503-6. · 1.56 Impact Factor
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ABSTRACT: A dual mode chemosensor dye 3 for detection of fluoride ion, based on the D-π-A molecular framework by one-step condensation, presents high selectivity and sensitivity both in colorimetric and fluorometric analyses. Upon the addition of F(-) anion, the absorption band shows a remarkable red shift along with fluorescent intensity decreasing. The absorption and fluorescent intensities of the dye 3 can be reversibly selected by deprotonation/protonation of the amine moiety via control of intramolecular charge transfer (ICT), leading to a molecular switch with "on" and "off" states. (1)H NMR titration analysis and DMol(3) calculation were employed to reveal the intermolecular charge transfer system of dye 3-F(-) complex.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 10/2011; 86:294-8. · 2.10 Impact Factor
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ABSTRACT: This research focuses on the preparation of polyion complex having spironaphthoxazine and their photochromic behaviors including absorbance and fluorescence switching. The polyion complex was prepared by the ion complex formation between spironaphthoxazine 3 (cationic monomer) and poly(styrene-sulfonic acid) (anionic polymer). Spironaphthoxazine group showed reversible photoisomerization in this polyion complex upon UV irradiation. It reversibly changed the fluorescent intensity by alternative irradiation with ultraviolet and visible light. The photoinduced ionic conductivity in polyion complex solution gradually increased upon UV irradiation and subsequently decreased in the dark.
Molecular Crystals and Liquid Crystals 12/2010; 520(1):151/[427]-157/[433]. · 0.58 Impact Factor
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ABSTRACT: A new donor-π-acceptor (D-π-A) type isophorone dye was synthesized by the condensation reaction between 2-(3,5,5-trimethylcyclohex-2-enylidene)-malononitrile and indole-3-carboxaldehyde. The chemical structure of the dye was characterized by 1H NMR, EA and MS. A novel, chromogenic, fluorescent dye based on indol as donor unit and isophorone as acceptor unit displayed marked UV-visible absorption changes and highly selective fluorescence quenching in the presence of fluoride ion. The dye also exhibited sizeable colour changes when used as a pH-induced molecular switch and as a detector for volatile organic compounds. The absorption and fluorescent intensity of the dye can be reversibly selected by protonation/deprotonation of the amine moiety via control of intramolecular charge transfer (ICT), leading to a molecular switch with "on" and "off" states.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 10/2010; 78(1):234-7. · 2.10 Impact Factor
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ABSTRACT: An investigation of the photo- and electrophysical properties of curcumin (1,7-bis[4-hydroxy-3-methoxyphenyl]-1,6-heptadiene-3,5-dione) revealed well-defined color changes upon the addition of Hg(2+) or OH(-). Curcumin exhibited high selectivity for Hg(2+) ions, as compared with Cu(2+), Fe(2+), Fe(3+), Zn(2+), Na(+) and Ni(2+) ions in DMSO/H(2)O (5:1, v/v) which was attributed to the formation of a 4:1 Hg(2+)-curcumin coordination complex. Spectral responses at lambda(max)=434nm revealed that curcumin can function as a NOR logic gate with OH(-) and Hg(2+) as input variables. The electrochromic properties of curcumin were studied using an ITO/curcumin-Bu(4)NClO(4)/ITO cell. The electrochromic cell colored red at 3V, but changed to yellow in open-circuit condition.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 08/2010; 76(3-4):384-7. · 2.10 Impact Factor
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ABSTRACT: A highly selective chemosensor based on fluoran dye for Fe(2+), 2'-anilino-3'-methyl-6'-dibuthylamino-N-((2'-(2''-ethylimino) methyl) naphthalen-2-ol) iso-indolin-1-one-fluoran (5), was designed and synthesized. The chemical structures of all the intermediates and the fluoran dye 5 are characterized by (1)H NMR, (13)C NMR, Ms and elemental analysis. Upon addition of Fe(2+), the fluoran dye 5 shows a new peak around 658nm in its absorption spectra, and the color of solution changed from colorless to greenish black. Whereas other ions including Mg(2+), Pb(2+), Ni(2+), Hg(2+), Cd(2+), Fe(3+), Cu(2+), Zn(2+) and Al(3+) and so on induced basically no spectral change, which constituted a Fe(2+) highly sensitive and selective colorimetric chemosensor by "naked eyes".
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 08/2010; 76(3-4):293-6. · 2.10 Impact Factor
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ABSTRACT: 2-[[3-Cyano-4-(N-ethyl-N-(2-hydroxyethyl)amino)styryl]-5,5-dimethylfuran-2(5H)-ylidene]malononitrile styryl dye was prepared by the condensation of 4-[(2-hydroxy-ethyl)-methyl-amino]-benzaldehyde (donor moiety) with 2-cyanomethylene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran (acceptor moiety). The corresponding design, synthesis and solvatochromic characteristics of the intramolecular charge-transfer (ICT) dye chromophore were discussed and determined. Optical properties such as absorption and fluorescence emission spectra were monitored in several solvent media with different polarity. In this determination, the prepared dye chromophore showed positive solvatochromism effect and the resulting solvatochromic characteristics were studied with semiempirical calculations. The energy potentials of this dye chromophore such as HOMO and LUMO values were calculated by computational simulation approaches using Material Studio 4.3. Furthermore, the functions as a molecular switching sensor with pH stimulation of alkali-acid addition were determined in DMSO, which was operated by deprotonation/protonation effects based on intramolecular charge-transfer system.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 10/2009; 75(1):225-9. · 2.10 Impact Factor
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ABSTRACT: A highly selective colorimetric chemosensor based on fluoran dye for iron cations, 2′-anilino-3′methyl-6′-dibuthylamino-N-(2′-(2″-hydroxybenzylideneamino)ethyl) iso-indolin-1-one-fluoran (5), was designed and synthesized. The chemical structures of all the intermediates and fluoran dye 5 were characterized by 1H-NMR, 13C-NMR, MS and elemental analysis. And its sensing behavior toward metal ions was investigated by UV-visible absorption spectroscopes. The fluoran dye 5 chemosensor showed an extreme selectivity for Fe2+ and Fe3+ in acetonitrile solution. Whereas other ions including Mg2+, Pd2+, Ni2+, Hg2+, Cd2+, Ag+, Cu2+, Zn2+ and Al3+ induced basically no spectral change, which constituted a Fe2+ highly sensitive and selective colorimetric chemosensor from colorless to black by “naked eyes.” Spectral responses at λmax = 653 nm reveals that dye 5 can function as OR logic gate with Fe2+ and Fe3+ as input variables.
Molecular Crystals and Liquid Crystals. 07/2009; 504(1):155-163.
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ABSTRACT: A novel semisquarylium dye was synthesized by the reaction between 3,4-dibutoxy-3-cyclobutene-1,2-dione and a benzothiazolium salt and its metal ion sensing properties were investigated using absorption and emission spectroscopy. These misquarylium exhibited high selectivity for Hg2+ ions, as compared with Ca2+, Pb2+, Al3+, Ce2+, Ba2+, Ni2+, Cd2+, Zn2+ and Mg2+ ions in DMSO/H2O (9:1, v/v), which was attributed to the formation of a 2:1 BSQ:Hg2+ coordination complex, the formation of which was supported by the calculated geometry of the complex.
Dyes and Pigments 83(3):324-327. · 3.13 Impact Factor
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ABSTRACT: An azine dye and its boron complex were synthesized and their structures were confirmed using elemental analysis, UV–Vis, fluorescence, mass and 1H NMR spectroscopic techniques. The effects of protonation/deprotonation on the absorption and emission characteristics of the two dyes were determined. The observed effects of pH upon the colour of the dyes were interpreted in terms of electron density distribution and intramolecular charge transfer.
Dyes and Pigments 87(3):268-271. · 3.13 Impact Factor
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ABSTRACT: A particular chromogenic and fluorophoric dye chemosensor was designed and synthesized, which was based on the stimuli-responsive D–π–A charge transfer system. Indole moiety as a donor unit and furan moiety as an acceptor unit were used. This prepared dye sensor showed the selective fluoride ion sensing effects in UV–vis absorption and fluorescence emission properties. Clear absorption changes and highly selective fluorescence quenching effects with fluoride ion were determined. Experimental data and images were collected and supported to provide a better understanding of this particular dye sensor.
Journal of Photochemistry and Photobiology A: Chemistry. 217(1):224-227.
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ABSTRACT: A colorimetric displacement assay system for F− and H2PO4− anions based on a 2,6-dichlorophenol-indo-o-cresol sodium salt:calix[4]arene-p-sulfonate complex was studied in 1:1 DMSO:water solution. When calix[4]arene-p-sulfonate formed the complex with the blue 2,6-dichlorophenol-indo-o-cresol sodium salt dye, the absorption peak of the dye at 625 nm disappeared and the DMSO:water solution of the complex was colourless. However, the initial blue colour of the dye returned with the addition of both F- and H2PO4− anions which bound to the calix[4]arene-p-sulfonate and, in doing so, displaced the 2,6-dichlorophenol-indo-o-cresol sodium salt from the 2,6-dichlorophenol-indo-o-cresol:calix[4]arene-p-sulfonate complex. The findings imply that this displacement assay could be used to develop potential optical signalling systems for the detection of anions such as F− and H2PO4−.
Dyes and Pigments 88(1):84-87. · 3.13 Impact Factor
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ABSTRACT: The preparation and solvatochromic behavior of novel, intramolecular charge transfer dyes obtained by the condensation of 2-cyanomethylene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran with 4-dimethylamino benzaldehyde and 9-formyljulolidine are described. The absorption and fluorescence emission spectra of the dyes were studied in solvents of differing polarity. The dyes exhibited positive solvatochromism and their solvatochromic properties are discussed with the aid of semiempirical calculations. The HOMO and LUMO values of the dyes were obtained using both cyclic voltammetry and theoretical calculations; the electrochemical results were in agreement with both observed values and theoretical calculations. pH molecular switching was achieved by modulation of intramolecular charge transfer by means of protonation/deprotonation in DMSO solution.
Dyes and Pigments 84(2):169-175. · 3.13 Impact Factor
