Effects of chromophore interaction in photophysics and photochemistry of cyanine dyes

Spectral and fluorescent properties of ketocyanine dyes (polyenic bis-ω,ω′-aminoketones) and cation-anionic polymethine dyes of various structures were studied. The symmetric ketocyanines were shown to have a long-wavelength absorption band bathochromically shifted in comparison with that of the asymmetric ketocyanines with the same total length of the polyenic chain. The nonlinear ketocyanines exhibit the additional short-wavelength band in their absorption spectra, which can be more intense than the longwavelength band. The absorption spectra of ion pairs of cation-anionic dyes with overlapping cation and anion bands contain a new intense short-wavelength band inactive in fluorescence excitation. These spectral peculiarities are explained on the basis of chromophore interaction model. It has also been shown that theT1levels of ketocyanine chromophores do not essentially interact with each other in a ketocyanine molecule in nonpolar solvents; in polar solvents this interaction becomes appreciable due to lowering the potential barrier for conjugation.

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Aggregation of cation-anionic and related polymethine dyes

International Journal of Photoenergy ◽

10.1155/s1110662x00000039 ◽

2000 ◽

Vol 2 (1) ◽

pp. 17-21 ◽

Cited By ~ 5

Author(s):

A. S. Tatikolov ◽

G. Ponterini ◽

Zh. A. Krasnaya

Keyword(s):

Absorption Spectra ◽

Ion Pairs ◽

Wavelength Region ◽

Polymethine Dyes ◽

Gradual Transition ◽

Solvent Mixtures ◽

Anionic Dyes ◽

Excitation Spectra ◽

Absorption Bands ◽

Fluorescence Excitation

Absorption, fluorescence, and fluorescence excitation spectra were studied for a number of cation-anionic and related anionic polymethine dyes in weakly polarand nonpolarsolvents, as well as in binary mixtures of solvents of different polarity. For some dyes, aggregation is observed in toluene or acetonitrile-toluene mixtures with low amounts of acetonitrile, which is revealed as appearance of new absorption bands and/or broadening of the initial bands of a monomeric dye. Solvent mixtures butyronitrilehexane with low butyronitrile content were found to greatly stimulate the formation of dye aggregates for most of the dyes studied. The absorption spectra of the aggregates are often blue-shifted with respect to the corresponding absorption spectra of parent monomeric dyes and/or represent broad continuums located both in the blue and red regions. For one of the cation-anionic dyes studied, which consists of3,3′-diethylthiamonomethinecyanine cation and trimethinebenzoxanine anion, fluorescent aggregates were observed; their broad fluorescence band is located in the long-wavelength region. For this dye, gradual transition from nonfluorescent aggregates to fluorescent ones and then to monomeric ion pairs and dissociated ions was observed in butyronitrile-hexane mixtures with growing butyronitrile content.

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Characterization of Low Noise TES Detectors Fabricated by D-RIE Process for SAFARI Short-Wavelength Band

Journal of Low Temperature Physics ◽

10.1007/s10909-014-1131-7 ◽

2014 ◽

Vol 176 (3-4) ◽

pp. 363-369 ◽

Cited By ~ 9

Author(s):

P. Khosropanah ◽

T. Suzuki ◽

R. A. Hijmering ◽

M. L. Ridder ◽

M. A. Lindeman ◽

...

Keyword(s):

Short Wavelength ◽

Low Noise ◽

Wavelength Band ◽

Short Wavelength Band ◽

Tes Detectors

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Performance of SAFARI Short-Wavelength-Band Transition Edge Sensors (TES) Fabricated by Deep Reactive Ion Etching

IEEE Transactions on Terahertz Science and Technology ◽

10.1109/tthz.2014.2298376 ◽

2014 ◽

Vol 4 (2) ◽

pp. 171-178 ◽

Cited By ~ 6

Author(s):

T. Suzuki ◽

P. Khosropanah ◽

R. A. Hijmering ◽

M. Ridder ◽

M. Schoemans ◽

...

Keyword(s):

Short Wavelength ◽

Reactive Ion Etching ◽

Transition Edge Sensors ◽

Wavelength Band ◽

Short Wavelength Band ◽

Ion Etching ◽

Deep Reactive Ion Etching ◽

Transition Edge ◽

Band Transition

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Nature of Lowest Electron Transitions in Anionic Polymethine Dyes With Keto-Containing Terminal Groups

10.21203/rs.3.rs-164583/v1 ◽

2021 ◽

Author(s):

A. P. Naumenko ◽

V. I. Borisyuk ◽

Olexiy Kachkovsky ◽

Yu. L. Slominskii ◽

N. V. Obernikhina

Keyword(s):

Absorption Spectra ◽

Energy Gap ◽

Dipole Moments ◽

Spectral Band ◽

Electron Transition ◽

Polymethine Dyes ◽

Polymethine Chain ◽

Local Electron ◽

Fluorescence Excitation ◽

Electron Transitions

Abstract The complex quantum-chemical and spectral study of the anionic polymethine dyes with the simplest symmetrical terminal groups and with different length polymethine chain is performed. It was shown that these dyes produce the specific molecular orbitals positioned nearly the energy gap and located only within the terminal groups. By investigation of the absorption spectra, it was established that the typical highly intensive longwawelength spectral band is observed which are bathochromically shifted upon lengthening of the open conjugated chain; this polymethine band is connected with the electron transition between the frontier levels of the opposite symmetry. In the contrast, the local MOs take part in so-called quasi-local electron transitions involved also one the frontier orbital. The local transitions have small dipole moments and hence they do practically not appear in the absorption spectra, however, the local transitions cause the appearance of the non-deep minima in the spectra of the fluorescence excitation anisotropy.

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