Influence of length of the polymethine chain on width of absorption bands of symmetric cyanine byes

Ishchenko, A. A.; Derevyanko, N. A.; Zubarovskii, V. M.; Толмачев, А. И.

doi:10.1007/bf00516576

Cited by 26 publications

(24 citation statements)

References 6 publications

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“…It was shown [121] that annelation of terminal groups of the typical Brooker's cyanine dyes is accompanied by increasing of the effective lengths L by an order of magnitude 0.2-0.4. As an illustration, the spectral characteristics of indopentamethinecyanine 15 and imidacyanines 16 [122,123] via their annelated analogous 17 [124] and 18 [122] can be presented (the increasing of the effective length. ∆L is calculated by means of formulas presented in [118][119][120]).…”

Section: Benzannelations Of Heterocycles Used As Terminal Groupsmentioning

confidence: 99%

Molecular design of near infrared polymethine dyes: A review

et al. 2015

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Section: Benzannelations Of Heterocycles Used As Terminal Groupsmentioning

confidence: 99%

Molecular design of near infrared polymethine dyes: A review

et al. 2015

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“…Thus, a distinguishing feature of polymethine dyes is the transfer of electron density during the transition to the first excited state from the p centers at the odd positions in the chain to the atoms at the even positions, whereas in the neutral polyenes there are no changes in the charges during excitation, and only the orders of the p bonds change [12,[135][136][137][138]. Change in the charge distribution affects the intensity of the electronic transitions, while change in the bond orders and, accordingly, their lengths during subsequent vibrational relaxation in the excited state determines the width of the absorption bands [139][140][141], the magnitude of the Stokes shifts in the fluorescence spectra [142][143][144][145], and the paths for nonradiative degradation of the excited state [142,146]. A number of authors have postulated that the main reason for the decrease in the quantum yields of fluorescence is trans-cis conformational transformations both in the polymethine dyes [147][148][149][150][151][152][153][154][155] and in polyenes, stilbenes, and their substituted derivatives and hetero analogs [156,157].…”

Section: Soliton Waves In the Excited Statementioning

confidence: 99%

The Solitonic Nature of the Electronic Structure of the Ions of Linear Conjugated Systems

Kachkovskii

2005

Theor Exp Chem

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Features of the electron density distribution in the ground and excited states, the position of the energy levels, and the equilibrium molecular geometry of the ions of linear p-electron systems, including conjugated polymers and oligomers, cationic and anionic polymethine dyes, and the radical-ions of a,w-substituted polyenes, are reviewed. By using the soliton concept it was possible to explain many unusual properties of this type of organic compound: The quasimetallic conductivity, the marked change in the spectral characteristics of ionic dyes absorbing and emitting light in the near IR region of the spectrum, etc. It was shown on the basis of semiempirical and nonempirical calculations that the charges in collective p-electronic systems form soliton waves, the width of which does not depend on the length of the molecule. In the excited state the size of the solitons increases significantly. The introduction of donor and acceptor terminal groups can destroy the symmetry of the charge distribution and molecular geometry at a conjugation chain of critical length exceeding the dimensions of the soliton. It was established that the injection of electrons/holes not only leads to the appearance of a soliton level at the center of the energy gap but is also accompanied by significant displacement of the top of the valence band and the bottom of the conduction band.

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“…При такой длине цепи нарушается равномерность в распределении заряда в хромофоре красителя [19]. Особенно оно существенно в случае, когда его концевые группы отклоняются от средней электронодонорности [21]. Тиопирилиевые концевые группы красителей 1 и 2 обладают слабой электронодонорностью.…”

Section: результаты и их обсуждениеunclassified

“…В свою очередь, его нарушение обусловливает усиление специфических электростатических взаимодействий между распределенным зарядом хромофора и диполями молекул растворителя. В случае катионных красителей, к которым относятся соединения 1 и 2, главный вклад в эти взаимодействия вносит нуклеофильная сольватация положительно заряженных центров хромофора тиопирилоцианинов [21,22]. Это должно привести к падению селективности поглощения, сопровождающегося уширением полосы, уменьшением интенсивности длинноволнового максимума и ее ростом у коротковолнового мак-симума.…”

Section: результаты и их обсуждениеunclassified

“…Это должно привести к падению селективности поглощения, сопровождающегося уширением полосы, уменьшением интенсивности длинноволнового максимума и ее ростом у коротковолнового мак-симума. Действительно, такая картина наблюдается для большинства поликарбоцианинов, поглощающих свет в области более 1000 nm [21,22].…”

Section: результаты и их обсуждениеunclassified

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Электронное Строение И Спектрально-Флуоресцентные Свойства Лазерных Красителей Тиопирило-4-Трикарбоцианинов

Ищенко¹,

Курдюкова²,

Богданович³

et al. 2021

Оптика И Спектроскопия

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It was found that the long-wavelength absorption band of the laser dye IR 1061 and its analogue with an unsubstituted polymethine chain is strongly broadened and decreases in intensity in polar solvents, while the fluorescence band remains narrow and practically does not change in a wide range of solvent polarities. Based on the quantum-chemical calculations of these dyes by the ab initio DFT/B3LYP/6-31G (d,p) and TDDFT methods, taking into account the polarity of the medium by the PCM method, it is shown that the reason for this difference is the weakening of solvation in the fluorescent state as compared to the ground state due to the greater equalization of the charge in the first than in the latter. An increase in the alternation of bond orders in the polymethine chain in the fluorescent state was found, which causes an increase of vibronic interactions in the radiative transition as compared to the absorptive one. Spectral effects caused by a change in the angle of rotation of phenyl groups in the thiopyrylium cycle upon excitation have been analyzed.

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Influence of length of the polymethine chain on width of absorption bands of symmetric cyanine byes

Cited by 26 publications

References 6 publications

Molecular design of near infrared polymethine dyes: A review

Molecular design of near infrared polymethine dyes: A review

The Solitonic Nature of the Electronic Structure of the Ions of Linear Conjugated Systems

Электронное Строение И Спектрально-Флуоресцентные Свойства Лазерных Красителей Тиопирило-4-Трикарбоцианинов

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