Photoprocesses of thiamonomethinecyanine monomers and dimers

Чибисов, А. К.; Захарова, Г. В.; Görner, Helmut

doi:10.1039/b005683i

Cited by 51 publications

(36 citation statements)

References 35 publications

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“…The behavior of cyanines in solutions was intensely studied in the presence of surfactants [7][8][9], in normal [10][11][12] and reverse micelles [8,9,13]. It has been shown on the basis of spectral data that the decomposition of the dimer and the conversion of the cis-monomer to the trans -isomer occurs in reverse AOT micelles [14].…”

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confidence: 99%

Spectral properties of carbocyanine dyes in solutions of reverse AOT micelles

et al. 2005

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Cyanine dyes are widely used in studies of various molecularly organized and biological systems [1][2][3][4]. Examples of such organized systems are microemulsions, normal and reverse micelles, lipid vesicles, and others. In these systems, individual stages of photosynthesis are modeled, and supramolecular systems for solar energy conversion are designed [3]. The formation of J aggregates in vesicles was observed in [5], when positively charged dye molecules were adsorbed on the negatively charged vesicle interface. In this case, strong Coulomb interaction between dye molecules and the vesicle interface can lead to the formation of J aggregates only at a very high concentration of dye molecules, and the minimum number of dye molecules necessary for J aggregate formation is 60 [6]. It has been shown that dye molecules are preferentially localized in the vesicles that already contain dye molecules rather than are uniformly distributed among all vesicles [3].The behavior of cyanines in solutions was intensely studied in the presence of surfactants [7][8][9], in normal [10-12] and reverse micelles [8,9,13]. It has been shown on the basis of spectral data that the decomposition of the dimer and the conversion of the cis-monomer to the trans -isomer occurs in reverse AOT micelles [14]. This cis -trans isomerization is due to strong electrostatic interaction of the dye with hydrophilic AOT groups at the interface between the organic phase and water, whereas the isomerization effect is much weaker in reverse micelles of neutral Triton X-100. Electrostatic interaction results in polarization and alignment of charged subunits in the dye molecule along the electric field, leading to conversion of the cis -to the transisomer. Hence, the absence of dye dimers in reverse micelles, as noted in [14], is due to the fact that the trans -isomer, unlike the cis -isomer, does not tend to form dimers in an aqueous medium.The preparation of monodispersed J aggregates of a given size, including those of an extremely small size, is a fundamental problem of great practical importance.One of possible ways of its solving seems to be the use of reverse micelles.Information on possible aggregated states of cyanine dyes in reverse micelles is rather controversial. For example, it has been established [13] that one dye molecule at the most can be present in the water pool of a single micelle, and the probability of occurrence of two dye molecules is of the order of 10 -5 . On the other hand, it is stated [14,15] that in water pools of reverse micelles with W ≥ 5 ( W = [H 2 O]/[AOT]), dye J aggregates are formed even at average dye concentrations much lower than one dye molecule per micelle. Zhang and Liu [13] believe that a dye molecule in micelles with a small water-pool radius is compressed by the surfactant shell, which results in distortion of planarity of the molecule, and molecule transforms into the nonfluorescent twisted monomeric state. In micelles of a greater size, the dye molecule exists in the planar fluorescent state in the water ...

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confidence: 99%

Spectral properties of carbocyanine dyes in solutions of reverse AOT micelles

et al. 2005

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“…Two types of aggregates, J (head-to-tail) and H (parallel), have been reported. H-type aggregates are frequently observed at low solution concentrations and in crystal structures [8]. The aggregation of hemicyanine dyes is extremely favored by strong attractive dispersion forces derived from the high polarizability of the chromophoric chain in aqueous solution [6].…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, the photostability of hemicyanine dyes increases with the electron-donating power of substituent in indoline moiety. It should be noted, that the high photostability of the developed hemicyanines is an advantage in biological imaging applications in which longer exposure times help to improve the image quality [8]. Taking into account, the kinetic of photobleaching process the quantum yield of this process (Ф bl ) was calculated using following equation: (Eq.…”

Section: Resultsmentioning

confidence: 99%

Hemicyanine dyes derived from 2,3,3-trimethyl-3H-indolium as candidates for non-covalent protein probes

Kabatc

Jurek

Kostrzewska

et al. 2015

Journal of Pharmaceutical and Biomedical Analysis

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“…Although the theory predicts no fluorescence from H-aggregate but weak fluorescence from Haggregates of various thiacyanine dyes has already been reported and attributed to the imperfect stacking of the dye molecules in the aggregates [27][28][29]. However, the most interesting observation of strong fluorescence with high fluorescence quantum yield from the H-aggregates of thiacyanine derivatives has been reported by C. Peyratont et.…”

Section: Spectroscopic Investigationmentioning

confidence: 98%

Fluorescence Resonance Energy Transfer between organic dyes adsorbed onto nano-clay and Langmuir–Blodgett (LB) films

Hussain

Chakraborty

Bhattacharjee

et al. 2010

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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Abstract:In this communication we investigate two dyes N N ′ , -dioctadecyl thiacyanine perchlorate (NK) and octadecyl rhodamine B chloride (RhB) in Langmuir and Langmuir-Blodgett (LB) films with or with out a synthetic clay laponite. Observed changes in isotherms of RhB in absence and presence of nano-clay platelets indicate the incorporation of clay platelets onto RhB-clay hybrid films. AFM image confirms the incorporation of clay in hybrid films. FRET was observed in clay dispersion and LB films with and without clay. Efficiency of energy transfer was maximum in LB films with clay.Keywords: Fluorescence Resonance Energy Transfer (FRET), Langmuir-Blodgett, pressure-area isotherm, clay, dyes, Atomic Force Microscope (AFM). IntroductionFluorescence Resonance Energy Transfer (FRET) is a physical phenomenon first described over 50 years ago [1,2]. Due to its sensitivity to distance, FRET has been used to investigate molecular level interaction. Fluorescence emission rate of energy transfer has wide applications in biomedical, protein folding, RNA/DNA identification and their energy transfer process [3][4][5][6][7][8][9]. Another important application of energy transfer is in dye lasers. Dye lasers have some limitations as the dye solution used as an active medium absorbs energy from the excitation source in a very limited spectral range and so the emission band also has these limitations. If a dye laser has to be used as an ideal source its spectral range needs to be extended. In order to extend the spectral range of operation, mixtures of different dye solutions/dye molecules embedded in solid matrices are being used. The work on energy transfer between different dye molecules in such mixtures in various solvents and solid matrices is, therefore, of great importance. The use of such energy transfer in dye lasers is also helpful in minimizing the photo-quenching effects and thereby, increasing the laser efficiency.FRET is the relaxation of an excited donor molecule by transfer of its excited energy to an acceptor molecule

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Photoprocesses of thiamonomethinecyanine monomers and dimers

Cited by 51 publications

References 35 publications

Spectral properties of carbocyanine dyes in solutions of reverse AOT micelles

Spectral properties of carbocyanine dyes in solutions of reverse AOT micelles

Hemicyanine dyes derived from 2,3,3-trimethyl-3H-indolium as candidates for non-covalent protein probes

Fluorescence Resonance Energy Transfer between organic dyes adsorbed onto nano-clay and Langmuir–Blodgett (LB) films

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