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Your search keyword '"Glebov, Evgeni M."' showing total 130 results
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130 results on '"Glebov, Evgeni M."'

16. Photophysics and photochemistry of (n-Bu4N)2[Pt(NO3)6] in acetonitrile: ultrafast pump-probe spectroscopy and quantum chemical insight.

Author

Fedunov, Roman G., Grivin, Vjacheslav P., Pozdnyakov, Ivan P., Melnikov, Alexei A., Chekalin, Sergei V., Vasilchenko, Danila B., and Glebov, Evgeni M.

Subjects
ACETONITRILE, CHARGE exchange, RADICALS (Chemistry), PHOTOCHEMISTRY, SPECTROMETRY, PHOTOEXCITATION
Abstract

The ultrafast processes caused by photoexcitation of (n-Bu4N)2[Pt(NO3)6] complex in acetonitrile were studied by means of transient absorption (TA) pump-probe spectroscopy and verified by quantum chemical calculations. The primary photochemical process was found to be an inner-sphere electron transfer followed by an escape of an •NO3 radical to the bulk solution. The reaction occurs via the dissociative triplet excited LMCT state of the initial complex. Based on the experimental data and quantum chemical calculations, the mechanism of ultrafast photophysical and photochemical processes is proposed. [ABSTRACT FROM AUTHOR]

Published
2024
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29. Photochemistry of (n-Bu4N)2[Pt(NO3)6] in acetonitrile.

Author

Grivin, Vjacheslav P., Matveeva, Svetlana G., Fedunov, Roman G., Yanshole, Vadim V., Vasilchenko, Danila B., and Glebov, Evgeni M.

Subjects
FLASH photolysis, ACETONITRILE, PHOTOCHEMISTRY, CHARGE exchange
Abstract

Photochemistry of the (n-Bu4N)2[Pt(NO3)6] complex in acetonitrile was studied by means of stationary photolysis and nanosecond laser flash photolysis. The primary photochemical process was found to be an intramolecular electron transfer followed by an escape of an •NO3 radical to the solution bulk. The spectra of two successive Pt(III) intermediates were detected in the microsecond time domain, and their spectral and kinetic characteristics were determined. These intermediates were identified as PtIII(NO3)52− and PtIII(NO3)4− complexes. Disproportionation of Pt(III) species resulted in formation of final Pt(II) products. [ABSTRACT FROM AUTHOR]

Published
2024
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41. Multifunctional fluorescent diarylethene: time-resolved study of photochemistry.

Author

Semionova, Veronica V., Pozdnyakov, Ivan P., Grivin, Vjacheslav P., Plyusnin, Victor F., Tsentalovich, Yuri P., Shirinian, Valerii Z., Melnikov, Alexei A., Chekalin, Sergei V., Lvov, Andrey G., and Glebov, Evgeni M.

Abstract

A study of luminescence and photochromic properties of (E)-2,3-bis(2,5-dimethylthiophen-3-yl)-5-(4-(pyrrolidin-1-yl)benzylidene)cyclopent-2-en-1-one, which is a diarylethene with a push–pull system between carbonyl and dimethylamino groups, was performed using time-resolved methods. The intramolecular charge transfer (ICT) process as well as 6π-electrocyclization and E-/Z-isomerization contribute to the complex light-induced properties of this molecule. Formation of unexpected short-lived intermediates was detected in the time range from 100 fs to 100 μs. A model based on two processes (additional photocyclization and interconversion between conformers) was proposed to rationalize this result. The key intermediates existing in the picosecond time domain are so-called precursors, which are proposed for both parallel (p) and anti-parallel (ap) isomers of the open form. In general, fast light-induced processes for the fluorescent diarylcyclopentenones are much more complicated than for the parent cyclopentenone-based DAE. [ABSTRACT FROM AUTHOR]

Published
2023
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43. Recombination of X-ray-Generated Radical Ion Pairs in Alkane Solution Assembles Optically Inaccessible Exciplexes from a Series of Perfluorinated para -Oligophenylenes with N , N -Dimethylaniline.

Author

Nikul'shin, Pavel V., Fedunov, Roman G., Kuibida, Leonid V., Maksimov, Alexander M., Glebov, Evgeni M., and Stass, Dmitri V.

Subjects
RADICAL ions, EXCIMERS, ION pairs, ION recombination, IRRADIATION, ABSORPTION coefficients
Abstract

We demonstrate that a series of perfluorinated para-oligophenylenes C6F5-(C6F4)n-C6F5 (n = 1–3) produce exciplexes with N,N-dimethylaniline (DMA) in degassed X-irradiated n-dodecane solutions. The optical characterization of the compounds shows that their short fluorescence lifetimes (ca. 1.2 ns) and UV-Vis absorption spectra, overlapping with the spectrum of DMA with molar absorption coefficients of 2.7–4.6 × 104 M−1cm−1, preclude the standard photochemical exciplex formation pathway via selective optical generation of the local excited state of the donor and its bulk quenching by the acceptor. However, under X-rays, the efficient assembly of such exciplexes proceeds via the recombination of radical ion pairs, which delivers the two partners close to each other and ensures a sufficient energy deposition. The exciplex emission is completely quenched by the equilibration of the solution with air, providing a lower bound of exciplex emission lifetime of ca. 200 ns. The recombination nature of the exciplexes is confirmed by the magnetic field sensitivity of the exciplex emission band inherited from the magnetic field sensitivity from the recombination of spin-correlated radical ion pairs. Exciplex formation in such systems is further supported by DFT calculations. These first exciplexes from fully fluorinated compounds show the largest known red shift of the exciplex emission from the local emission band, suggesting the potential of perfluoro compounds for optimizing optical emitters. [ABSTRACT FROM AUTHOR]

Published
2023
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