The Conformations of Polymethine Dyes

Kolesnikov, A. M.; Mikhailenko, F. A.

doi:10.1070/rc1987v056n03abeh003270

Cited by 54 publications

(29 citation statements)

References 2 publications

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“…5-6 2012 typical in this case that the longer a wavelength of the absorption band maximum of the molecular form is, the longer the wavelength of the absorption maximum of the dimer is. As a rule, the absorption maximum of the trans form of the thiacarbocyanine monomer has a longer wavelength than the maximum of the cis form [14]. Therefore, a long wave absorption maximum with λ 1 = 510 nm can be assigned to a dimer formed from the trans form of the dye.…”

Section: Resultsmentioning

confidence: 97%

“…Since the equilibrium between the cis and trans forms of the dye shifts towards the trans form upon heating the solution [14], it can be suggested that the long wave D 1 band, which is more stable at elevated temperatures, belongs to dimers that are built up of the trans monomer forms (D trans ) and the D 2 and D 3 bands are attributed to dimers comprised of the cis monomer forms (D cis or D cis/trans ).…”

Section: Resultsmentioning

confidence: 99%

“…Equilibrium between the cis and the trans forms depends on temperature and medium polarity. It is assumed [14] that the main form of this kind of dyes in water at low temperatures is the mono cis form, although heating promotes a transi tion into the full trans conformation, the absorption maximum of which is observed at longer wavelengths.…”

Section: Introductionmentioning

confidence: 99%

“…It is known [5,8,14] that molecules of meso alkyl substituted thiacarbocyanines, both in the molecular form and in the form of dimers and aggregates, can be present in aqueous solutions as two stereoisomers: EEZE and EEEE, i.e., the mono cis form and the full trans form, respectively. Equilibrium between the cis and the trans forms depends on temperature and medium polarity.…”

Section: Introductionmentioning

confidence: 99%

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Effect of meso-alkyl substituents in the polymethine chain of thiacarbocyanines on the morphology of dye aggregates

et al. 2012

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Using the example of meso alkylsubstituted thiacarbocyanine dyes, it has been demonstrated that an ethyl substituent, as a rule, promotes the formation of long wave J aggreagtes in aqueous solutions and a methyl substituent favors the formation of short wave H* aggregates. The formation of dye aggregates pro ceeds through dimers by the block mechanism. The formation of three bands in the absorption region of dimers, which plausibly relate to three different forms of dimers and can be attributed to dimers consisting of the cis , cis /trans , and trans conformations of the dyes, has been recorded for the first time in meso CH 3 substituted thiacarbocyanines. The formation of three different types of H* aggregates from the three appro priate dimeric forms has also been shown for the first time. It has been established that introducing a multi charged Eu +3 cation into aqueous solutions of dyes shifts the equilibrium, nD aggregate, towards aggregates; meso CH 3 substituted dyes in this case shift towards H* aggregates and meso C 2 H 5 substituted dyes shift towards J aggregates. Hence it has been shown that an alkyl group in the meso position to the polymethine chain of thiacarbocyanines plays the role of a regulating agent in the aggregation process due to stereochemical effects and, by this means, predetermines the morphology and spectral properties of the formed aggregate.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of meso-alkyl substituents in the polymethine chain of thiacarbocyanines on the morphology of dye aggregates

et al. 2012

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“…Introduction of substituents in the meso position of the polymethine chain creates steric hindrances to the formation of the planar trans -isomer, and alltrans -and cis -isomers are simultaneously present at comparable concentrations in solutions of the substituted compounds [7,8].…”

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The Study of cis-trans Equilibrium and Complexation with DNA of meso-Substituted Carbocyanine Dyes

et al. 2005

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The effect of DNA was studied on cis-trans equilibrium and spectral and fluorescent properties of a number of meso -substituted carbocyanine dyes: 3,3'-diethyl-9-thiomethylthiacarbocyanine iodide (K1), 3,3'diethyl-9-methoxythiacarbocyanine iodide (K2), 3,3'-9-triethylthiacarbocyanine iodide (K3), 3,3'-dimethyl-9ethyloxacarbocyanine iodide (K4), 3,3'-9-triethyl-5,5'-dimethyloxacarbocyanine iodide (K5), and 3,3',9-triethyl-6,6'-dimethoxyoxacarbocyanine iodide (K6). Equilibrium between the cis and trans isomeric forms was detected for the thiacarbocyanine dyes in a number of organic solvents, with a shift of the equilibrium toward the cis -isomer caused by an increase in the solvent polarity. The oxacarbocyanines are present only in the form of trans -isomers in both polar and nonpolar solvents. Interaction of the dyes with DNA leads to the formation of stable noncovalent complexes. The complexation of the thiacarbocyanine dyes results in a shift of the isomeric equilibrium and occurs predominantly via the cis -form of the dye. The oxacarbocyanine dyes produce complexes with DNA in the initial trans -form.

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Polymethine Dyes

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Kirk‐Othmer Encyclopedia of Chemical Technology

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This article defines the specific molecular and electronic characteristics that qualify a colorant as a polymethine dye. It also delineates various subclasses of polymethine dye before going on to describe the spectroscopic characteristics associated with the polymethine chromogen, which has led to this class of colorant becoming so important to numerous sectors of industry and academia. The influences of molecular structure on spectroscopic properties that are peculiar to polymethine dyes form the subject of brief discussion before moving on to a survey of the chief commercial applications for this type of colorant. A short summary of nascent technologies for which polymethine dyes constitute key materials then follows, along with signposting of information sources on their synthesis.

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The Conformations of Polymethine Dyes

Cited by 54 publications

References 2 publications

Effect of meso-alkyl substituents in the polymethine chain of thiacarbocyanines on the morphology of dye aggregates

Effect of meso-alkyl substituents in the polymethine chain of thiacarbocyanines on the morphology of dye aggregates

The Study of cis-trans Equilibrium and Complexation with DNA of meso-Substituted Carbocyanine Dyes

Polymethine Dyes

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