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Registration Number

0221U103433, 0120U101178 , R & D reports

Title

Fluorescent cyanine and squarine dyes with halogen atoms in terminal heterocyclic moieties.

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Head

Tatarets Anatolii L.,

Registration Date

20-02-2021

Organization

State Scientific Institution "Institute for Single Crystals" of National Academy of Sciences of Ukraine

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 The aim of the work is to develop methods for the synthesis of halogenated cyanine and squaraine dyes and to elucidate the influence of halogen atoms in terminal heterocyclic moieties on the spectral and photophysical characteristics of fluorescent dyes. The main objectives of the project: - to find out the availability of starting compounds and to develop methods for the synthesis of corresponding intermediates and dyes; - study of the "structure - properties" relationship; - Determining the reason of the anomalous effect of "heavy" halogens (bromine, iodine) on the increase in the fluorescence quantum yield of cyanine dyes. The objects of research are squaraine and cyanine dyes containing halogen atoms in terminal heterocyclic fragments. Research methods - organic synthesis, spectral and other physical and photophysical research methods - NMR, mass spectrometry, electron absorption and fluorescence spectroscopy. The project results in a series of new fluorescent heptamethinecyanine and squaraine dyes with terminal indolenine (3,3-dimethyl-3H-indolium) moieties, which contain different quantity of halogen substituents in the aromatic cycles of indoles. It was found that the introduction of halogen atoms (chlorine, bromine or iodine) in position 4 and 6 of indolenine has almost no effect on the positions of maxima of absorption and fluorescence of cyanine dyes, but unexpectedly causes a significant increase in quantum yield of dye fluorescence (up to 38%) that is 1.4 times more than for the unsubstituted dye. In this case, bromine atoms have a more significant effect on theincrease of the quantum yield of dyes fluorescence than iodine atoms. Using the 4,5,6-triiodindolenenine intermediate, a new long-wave hexaiodoquinonocyanine photosensitizer IQCy was developed, which demonstrates more pronounced photodynamic inactivation of S. aureus compared to existing photosensitizers Ce6 and HITC.

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2021-02-20