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151.
Transient absorption spectra in the photocolouration and photobleaching of the indoline 6-nitrosubstituted spiropyran have been investigated with picosecond spectroscopy. The cis—cisoid intermediate stereoisomer at 440 nm and some of the final coloured forms are produced in less than 10 ps in the photocolouration. 相似文献
152.
Petrov NKh Gulakov MN Alfimov MV Busse G Frederichs B Techert S 《Journal of fluorescence》2004,14(1):87-89
It was found that preferential solvation of cyanine dyes in binary mixtures can strongly affect both their isomerization and aggregation; the comparison of absorption and fluorescence excitation spectra might be a useful tool for studying these nonradiative processes. 相似文献
153.
R. V. Markov A. I. Plekhanov Z. M. Ivanova N. A. Orlova V. V. Shelkovnikov A. A. Ivanov M. V. Alfimov 《Journal of Experimental and Theoretical Physics》2004,99(3):480-486
Thin films of J-aggregates of a new amphiphilic thiacarbocyanine dye of the benthiazole series are prepared and the nonlinear optical response of molecular J-aggregates is studied for femto-and nanosecond exciting radiation pulses. It is found that the nonlinear optical response of J-aggregates exhibits substantial enhancement upon an increase in the pulse duration, which cannot be described by the saturation effect in the model of a two-level system. This effect is considered using a three-level model taking into account the formation of self-trapped exciton states in molecular J-aggregates. 相似文献
154.
Nazarov V. B. Avakyan V. G. Alfimov M. V. Vershinnikova T. G. 《Russian Chemical Bulletin》2003,52(4):916-922
Naphthalene-d8—-cyclodextrin—adamantane triple complexes were prepared in an aqueous solution at room temperature. Irradiation ( = 285 nm) of the solution in the presence of molecular oxygen results in the long-lived ( = 10.3 s) room temperature phosphorescence (RTP). The removal of oxygen from the solution increases the RTP intensity and phosphorescence lifetime by 1.5 times. The RTP spectrum contains a well-resolved vibrational structure, whose bands are assigned to full symmetric vibrations of naphthalene, their overtones, and the combination tones of full symmetric vibrations. The quantum-chemical calculation of the triple complex structure confirms that both naphthalene and adamantane can simultaneously be included into the -cyclodextrin cavity and suggests that the role of the latter as the third component is the more efficient shielding of naphthalene from the oxygen effect due to both the formation of three-component complexes and their aggregation to form submicronic particles. 相似文献
155.
156.
A. K. Chibisov M. V. Alfimov G. V. Zakharova L. S. Atabekyan V. G. Avakyan V. G. Plotnikov 《High Energy Chemistry》2017,51(6):440-448
Thiacarbo- and thiadicarbocyanine indolenine and thiazoline polymethine dyes form host?guest complexes with cucurbit[7,8]urils in water. Cucurbit[7]uril forms preferentially 1: 1 and 1: 2 monomeric complexes and cucurbit[8]uril forms 2: 1 and 2: 2 dimeric complexes. On the basis of quantum-chemical calculations, the structure of monomeric and dimeric complexes has been suggested. The complexation manifested itself in absorption, prompt and thermally activated delayed fluorescence spectra, as well as in the triplet?triplet absorption spectra. Dimeric complexes in the triplet state are involved in one-electron oxidation and participate in triplet?triplet energy transfer. 相似文献
157.
V. A. Livshits I. V. Demisheva B. G. Dzikovskii V. G. Avakyan M. V. Alfimov 《Russian Chemical Bulletin》2006,55(12):2161-2173
The ternary inclusion complexes of two spin-labeled pyrrolidine-and piperidine-containing indole derivatives (1 and 2, respectively) and two hydrocarbons, benzene and cyclohexane, with γ-and β-cyclodextrins (CD) (altogether eight complexes)
were prepared and studied by ESR in the solid phase over a broad temperature range. For most ternary complexes, the hydrophobicity
of the NO group environment is much higher than for binary complexes devoid of hydrocarbons. The rotational mobility of both
spin-labeled indoles in the ternary complexes of γ-CD is much greater than in binary complexes of γ-CD, which is due to transition
to the stoichiometry 2γ-CD-1(2)-C6H6(C6H12) from 1: 1 stoichiometry. The guest rotational mobility in the complexes with either of the CD is higher for 2 than for 1. The saturation transfer ESR spectra show that the rotational mobility of 1 in γ-and β-CD in the presence of C6H6 or C6H12 has a character of fast librations in an angular cone, whose amplitude increases with temperature, whereas for radical 2, the rotation occurs in the full solid angle. The structures and energies of all complexes were calculated for different
modes of inclusion of guest molecules using the PM3 method with the standard set of parameters. The calculation results are
in qualitative agreement with experimental data. The results demonstrate the possibility of substantial modification of the
molecular dynamics and hydrophobicity of the environment of “functional” guest molecules by introducing a second regulatory
guest molecule into the CD cavity.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2081–2093, December, 2006. 相似文献
158.
S. P. Gromov S. A. Sergeev S. I. Druzhinin M. V. Rusalov B. M. Uzhinov L. G. Kuz'mina A. V. Churakov J. A. K. Howard M. V. Alfimov 《Russian Chemical Bulletin》1999,48(3):525-536
Crown-containing butadienyl dyes containing various heterocyclic moieties and azacrown ether fragments were synthesized for
the first time. The spatial structures and the absorption and fluorescence spectra of crown-containing butadienyl dyes and
their complexes with metal cations were examined. The effects of the nature of the heterocyclic and crown ether fragments
on fluorescence and generation of dyes and their complexes with metal cations were revealed based on the spectral data.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 530–541, March, 1999. 相似文献
159.
160.
Turshatov AA Möbius D Bossi ML Hell SW Vedernikov AI Lobova NA Gromov SP Alfimov MV Zaitsev SY 《Langmuir : the ACS journal of surfaces and colloids》2006,22(4):1571-1579
Amphiphilic 4-(3',4'-dimethoxystyryl)-N-octadecylpyridinium perchlorate and bromide form stable monolayers at the air/water interface. Small differences in the surface pressure-area and surface potential-area isotherms depending on the anion indicate interactions between the chromophore and the anions on the pure water subphase. The monolayer behavior is considerably modified on 10 mM aqueous solutions of KI, KClO4, KCl, and KF as revealed by isotherm measurements, reflection spectroscopy, and Brewster angle microscopy. The phase transition observed in the isotherms is shifted to higher surface pressure because of variation of the salt according to the Hofmeister series. Upon monolayer compression, the chromophores are increasingly tilted, and a shift of the band to longer wavelengths is attributed to the environment becoming less polar. However, in the case of KCl at small areas per molecule, relaxation is observed at constant area with the appearance of a new band shifted to shorter wavelengths. This band is assigned to small associates of about four chromophores (H aggregates). In the case of KI, a new band shifted to longer wavelengths is found. Theoretical calculations did not yield a transition in the observed range, even for large aggregates (J aggregates). Therefore, other interactions may be responsible for the appearance of this band. 相似文献