Browsing Публикации в изданиях других стран by Author "Zenkevich, E. I."

Now showing items 21-33 of 33

    • Photoinduced electron transfer dynamics for self-assembled porphyrin arrays in solutions and films 

      Zenkevich, E. I.; Kilin, D. S.; Willert, A.; Bachilo, S. M.; Shulga, A. M.; Rempel, U.; Borczyskowski, C. von (2001)
      Electronic excitation energy deactivation in self-assembled porphyrin triads has been studied by the time correlated single photon counting technique as a function of the solvent polarity (toluene-acetone mixtures), temperature (77-350 K), and mutual spatial arrangement of the donor and acceptor subunits. The donor (Zn-octaethylporphyrin chemical dimer) fluorescence quenching ...
      2017-05-26

    • Photoinduced relaxation processes in self-assembled nanostructures: multiporphyrin complexes and composites "CdSе/ZnS quantum dot-porphyrin" 

      Zenkevich, E. I.; Borczyskowski, C. von (2009)
      Here, we discuss self-assembled multicomponent organic/inorganic nanostructures. Self-assembled multiporphyrin triads were formed via non-covalent interactions of meso-phenyl bridged ZnOEP chemical dimer, (ZnOEP)₂Ph, with dipyridyl substituted tetrapyrrole extra-ligand. In tetrads, the dimer (ZnOEP)₂Ph is covalently linked via 5-mesoposition to additional electron acceptors ...
      2017-05-27

    • Radiationless intermolecular energy transfer with participation of acceptor excited triplet states 

      Gurinovich, G. P.; Zenkevich, E. I.; Sagun, E. I. (1982)
      Radiationless energy transfer between like and unlike molecules has been experimentally studied under conditions where acceptor molecules have been excited to the triplet state. Homogeneous singlet—triplet—triplet migration has been discovered in higbly concentrated chlorophyll “a” and pheophytin “a” solutions in castor oil at 183 K by measuring the variation of pigment relative ...
      2017-05-18

    • Regularities of intermolecular interactions and energy transfer in mixed associates of chlorophyll and its analogs 

      Zenkevich, E. I.; Losev, A. P.; Kochubeev, G. A.; Gurinovich, G. P. (Elsevier Scientific Publishing Company, 1978)
      Regularities of intermolecular interactions and energy transfer in mixed associates of chlorophyll and its analogs / E. I. Zenkevich [et al.] // Journal of Molecular Structure. – 1978. Vol. 45. – P. 423-436.
      2017-05-18

    • Resonant Raman Scattering of ZnS, ZnO, and ZnS/ZnO Core/shell quantum dots 

      Milekhin, A. G.; Yeryukov, N. A.; Sveshnikova, L. L.; Duda, T. A.; Himcinschi, C.; Zenkevich, E. I.; Zahn, D. R. T. (2012)
      Resonant Raman scattering by optical phonon modes as well as their overtones was investigated in ZnS and ZnO quantum dots grown by the Langmuir–Blodgett technique. The in situ formation of ZnS/ZnO core/shell quantum dots was monitored by Raman spectroscopy during laser illumination.
      2017-05-27

    • Resonant Raman studies of compositional and size dispersion of CdS₁₋ₓSeₓ nanocrystals in a glass matrix 

      Azhniuk, Yu. M; Milekhin, A. G.; Gomonnai, A. V.; Lopushansky, V. V.; Yukhymchuk, V. O.; Schulze, S.; Zenkevich, E. I.; Zahn, D. R. T. (2004)
      Resonant Raman scattering spectra of glass-embedded CdS₁₋ₓSeₓ nanocrystals are measured and complemented with TEM and optical absorption as well as photoluminescence data. The selectivity of the resonant Raman process not only for the size, but also for the composition of nanocrystals within the ensemble, is directly observed in the dependence of phonon band frequency, linewidth ...
      2017-05-27

    • Self-assembled nanoscale photomimetic models: structure and related dynamics 

      Zenkevich, E. I.; Borczyskowski, C. von; Shulga, A. M.; Bachilo, S. M.; Rempel, U.; Willert, A. (2002)
      Using static and time-resolved measurements, dynamics of non-radiative relaxation processes have been studied in self-assembled porphyrin triads of various geometry, containing the main biomimetic components, Zn–porphyrin dimers, free-base extra-ligands (porphyrin, chlorin or tetrahydroporphyrin), and electron acceptors A (quinone or pyromellitimide). The strong quenching of the ...
      2017-05-26

    • Self-organization principles in the formation of multiporphyrin complexes and “semiconductor quantum dot-porphyrin” nanoassemblies 

      Zenkevich, E. I.; Borczyskowski, C. von (2014)
      In this paper, we review several aspects of molecular recognition (based on non-covalent binding interactions) occurring between meso-pyridyl substituted tetrapyrrole extra-ligands and chemical dimers of tetrapyrrolic macrocycles containing central Zn ions and spacers of various nature and flexibility. Experimental results obtained by us earlier are analyzed using a novel approach ...
      2017-05-27

    • Size-Dependent Non-FRET Photoluminescence Quenching in Nanocomposites Based on Semiconductor Quantum Dots CdSe/ZnS and Functionalized Porphyrin Ligands 

      Zenkevich, E. I.; Blaudeck, T.; Milekhin, A.; Borczyskowski, C. von (2011)
      We review recent experimental work to utilize the size dependence of the luminescence quenching of colloidal semiconductor quantum dots induced by functionalized porphyrin molecules attached to the surface to describe a photoluminescence (PL) quenching process which is different from usual models of charge transfer (CT) or Foerster resonant energy transfer (FRET). Steady-state ...
      2017-05-27

    • Spectral Рeculiarities of NH-Tautomerism in Isocycle-Containing Porphyrins and their Covalently Linked Dimers 

      Zenkevich, E. I.; Shulga, A. M.; Chernook, A. V.; Gurinovich, G. P. (1984)
      It has been found experimentally that a whole class of isocycle-containing porphyrins, including synthetic and natural objects and their covalently linked dimers, shows NH-tautomerism which manifests itself in isotropic solutions in normal electronic spectra both at 77 K and higher temperatures (up to 500 K).
      2017-05-18

    • Spectroscopy of interchromophoric interactions in self-organized porphyrin and chlorin complexes 

      Zenkevich, E. I.; Shulga, A. M.; Chernook, A. V.; Rempel, U.; Borczyskowski, C. von (1995)
      Spectral-luminescent properties of multimolecular complexes (triads and pentads, complexation constants range from 5∙10⁶ to 5∙10⁷ M⁻¹) formed by two-fold coordination of dipyridyl and tetra-pyridyl substituted porphyrin or related molecules with Zn-porphyrin and Zn-chlorin dimers having various spacers between macrocycles (-CH₂-CH₂- or phenyl ring) have been studied in methylcyclohexane ...
      2017-05-18

    • Steric interactions influence on electron transfer efficiency in meso-nitrophenylporphyrins and their chemical dimers 

      Knyukshto, V. N.; Zenkevich, E. I.; Sagun, E. I.; Shulga, A. M.; Starukhin, D. A.; Bachilo, S. M. (2001)
      Steric interactions upon mono- and di-meso-phenyl substitution in octaethylporphyrins (OEP) and their chemical dimers with the phenyl spacer manifests itself in the dramatical T₁-state lifetimes shortening at 293 K (from ms down to μs in degassed toluene solutions) without any influence on spectral-kinetic parameters of S₀- and S₁-states. This effect is explained by non-planar ...
      2017-05-26

    • Structural Dynamics and Relaxation Processes with Participation of Excited Singlet and Triplet States in Sterically Hindered Porphyrins and Their Chemical Dimers 

      Zenkevich, E. I. (2014)
      Paper presents an overview of mutual Belarussian-Russian collaboration in the field of sterically hindered porphyrins compared with the relevant literature data. Typically, the conformational dynamics of a non-planar tetrapyrrole macrocycle at 295 K manifests itself in bathochromic absorption and fluorescence shifts (∆ν ~ 1100 cm⁻¹), the increase of the Stokes shift (∆νₛ ~ 900 ...
      2017-05-27