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Meerovich IG Jerdeva V Derkacheva VM Meerovich GA Lukyanets EA Kogan EA Savitsky AP 《Journal of photochemistry and photobiology. B, Biology》2005,80(1):57-64
The photodynamic activity of dibiotinylated aluminum sulfophthalocyanine was studied in vitro and in vivo. Dibiotinylated aluminum sulfophthalocyanine provided enhanced phototoxic action on OAT-75 cell monolayers as compared with the parent drug. Photodynamic therapy of mice with Ehrlich carcinoma using dibiotinylated aluminum sulfophthalocyanine (0.25 mg/kg) resulted in enhanced inhibition of tumor growth, pronounced vascular damage (thrombosis and destruction of vascular walls) and eventual tumor necrosis. 相似文献
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Anatoli I. Brusilovets V. Bdjhola T. Lis A. Savitsky 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):729-732
The interaction of 1,3,2,4 -oxaazaphosphatitanetidines with chlorides of aluminium and zirconium, alcohols, piperidine and R2NBr (R=SiMe3) has been studied. The reaction routes have been determined with NMR spectra and X-ray structure analyses. 相似文献
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A. Savitsky B. V. Trubitsin K. Möbius A. Yu. Semenov A. N. Tikhonov 《Applied magnetic resonance》2007,31(1-2):221-236
In this work, by using the respective advantages of W- and X-band electron paramagnetic resonance (EPR) spectroscopy techniques to investigate electron transport processes, we have studied the light-induced redox transients of the primary electron donor P700 and the secondary acceptor A1 in photosystem (PS) I complexes of intact cyanobacterial cellsSynechocystis sp. PCC 6803. We found that the kinetic behavior of the cation radical P700 ·+ generated by illumination with continuous light, and the EPR intensity of the radical pair P700 ·+A 1 ·? generated upon laser pulse illumination strongly depend on the illumination prehistory (either the sample was frozen in the dark or during illumination). Both these processes were sensitive to the presence of electron transport inhibitors which block electron flow between the two photosystems. In line with our X-band EPR data on the kinetics of light-induced redox transients of P700, our high-field W-band EPR study of the radical-pair state P700 ·+A 1 ·? shows that photosynthetic electron flow through the PS I reaction center is controlled both on the donor and on the acceptor side of PS I. 相似文献
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Evgenia G. Matveeva Marina I. Nelen Oleg I. Lobanov Alexander P. Savitsky 《Journal of fluorescence》2003,13(1):79-88
The antigen-antibody interaction between coproporphyrin I and anti-coproporphyrin antibodies was studied by a fluorescence method in water and a reverse micellar system: n-octane/Aerosol OT. Coproporphyrin fluorescence was quenched, and coproporphyrin emission maximum was shifted to the long-wavelength region after binding to the antibodies or Fab-fragments. The mechanism of this quenching is static, most probably, by a tryptophan residue (or maybe lysine or methionine). Apparent dynamic quenching, in this case, arises from protein backbone motion. A special kind of antibody Fab-Fab dimerization was proposed. 相似文献
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The kinetics of formation of nonstoichiometric ionic complexes of poly(octamethyleneacetamidine) with a low-molecular-mass chromophore (4-hydroxystyryl)-(4′-carboxystyryl)ketone and a block copolymer chromophore-poly(propylene oxide)-chromophore in dilute methanol solutions has been stud- ied by static and dynamic light scattering. The molecular masses of polyamidine and a poly(propylene oxide) spacer are 12000 and 2000, respectively. It has been shown that polyamidine-chromophore complexes have hydrodynamic radii comparable with those of polyamidine-(chromophore-poly(propylene oxide)-chromophore complexes (100–200 nm). The radii of gyration and the structural factors ρ of the complexes are estimated. In polyamidine-chromophore complexes, the chromophore is aggregated and the density of aggregates is high (ρ ≈ 1). The dependence of ρ for polyamidine-(chromophore-poly(propylene oxide)-chromophore) complexes on stoichiometry is related to a change in the ratio of dangling ends and the number of loops. With an increasing fraction of dangling ends, the complexes become less compact (ρ increases) and their aggregation proceeds at a higher rate. Moreover, a variation in the order of mixing of component solutions affects the size of complexes, the kinetics of structuring, and the change in their stoichiometry. 相似文献
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In this minireview, modern multifrequency electron paramagnetic resonance (EPR) spectroscopy, in particular, at high magnetic fields, is shown to provide detailed information about structure, motional dynamics and spin chemistry of transient radicals and radical pairs occurring in photochemical reactions. Examples discussed comprise spin-polarized radicals and radical pairs in disordered systems, such as ultraviolet-irradiated quinone and ketone compounds in fluid alcohol solutions, green-light initiated electron transfer in biomimetic porphyrin?Cquinone donor?Cacceptor model systems in frozen solution, aiming at artificial photosynthesis, and red-light initiated electron transfer in natural photosynthetic reaction-center protein complexes. The transient paramagnetic states exhibit characteristic electron polarization (CIDEP) effects originating from a triplet mechanism, a radical-pair mechanism or a correlated coupled radical-pair mechanism. They contain valuable information about structure and dynamics of the short-lived reaction intermediates. Moreover, the CIDEP effects can be exploited for signal enhancement. Continuous-wave and pulsed versions of time-resolved high-field EPR spectroscopy, such as transient EPR and electron spin-echo experiments, are compared with respect to their advantages and limitations for the specific photoreaction under study. Furthermore, orientation resolving W-band pulsed electron-electron double resonance (PELDOR) experiments on the spin-correlated coupled radical pair $ {\text{P}}_{865}^{ \cdot + } $ $ {\text{Q}}_{\text{A}}^{ \cdot - } $ in frozen solution reaction centers from the purple photosynthetic bacterium Rb. sphaeroides reveal details of distance and orientation of the pair partners in their charge-separated transient state. The results are compared with those of the ground-state P865QA. In conjunction with Q-band proton electron-nuclear double resonance (ENDOR) experiments the W-band PELDOR results provide decisive evidence that the local structure of the QA binding site does not change under photoreduction of the quinone??in agreement with earlier FTIR studies. The examples given demonstrate that multifrequency EPR experiments on disordered systems add heavily to the capabilities of ??classical?? spectroscopic and diffraction techniques for determining structure?Cdynamics?Cfunction relations of biochemical processes, since short-lived intermediates can be observed in real time while staying in their working states at biologically relevant time scales. 相似文献
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A simple formula relating the electron-phonon coupling constant λ and 2Δ/kTC is proposed. The formula allows one to estimate λ on the basis of experimental Δ and TC. 相似文献
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Thermally Activated Delayed Fluorescence in a Y3N@C80 Endohedral Fullerene: Time‐Resolved Luminescence and EPR Studies 下载免费PDF全文
Dr. Michal Zalibera Denis S. Krylov Dimitrios Karagiannis Paul‐Anton Will Frank Ziegs Sandra Schiemenz Prof. Dr. Wolfgang Lubitz Prof. Dr. Sebastian Reineke Dr. Anton Savitsky Dr. Alexey A. Popov 《Angewandte Chemie (International ed. in English)》2018,57(1):277-281
The endohedral fullerene Y3N@C80 exhibits luminescence with reasonable quantum yield and extraordinary long lifetime. By variable‐temperature steady‐state and time‐resolved luminescence spectroscopy, it is demonstrated that above 60 K the Y3N@C80 exhibits thermally activated delayed fluorescence with maximum emission at 120 K and a negligible prompt fluorescence. Below 60 K, a phosphorescence with a lifetime of 192±1 ms is observed. Spin distribution and dynamics in the triplet excited state is investigated with X‐ and W‐band EPR and ENDOR spectroscopies and DFT computations. Finally, electroluminescence of the Y3N@C80/PFO film is demonstrated opening the possibility for red‐emitting fullerene‐based organic light‐emitting diodes (OLEDs). 相似文献