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Avakyan V.G.,Russian Academy of Sciences | Shapiro B.I.,Lomonosov Moscow University of Fine Chemical Technology | Alfimov M.V.,Russian Academy of Sciences
Dyes and Pigments | Year: 2014

Quantum-chemical calculations for monomers, dimers, and tetramers of 3-ethyl-2-[(1E,3E)-3-(3-ethyl-1,3-thiazol-2(3H)-ylidene)prop-1-en-1-yl]-1, 3-thiazol-3-ium chloride and 3-ethyl-2-[(E)-(3-ethyl-1,3-benzothiazol-2(3H)- ylidene)methyl]-1,3-benzothiazol-3-ium chloride were performed. Both dyes were found capable of forming two kinds of π-stacking-dimers with various degree of overlap. Three kinds of tetramers: four-deck ladder, three-deck brickwork, and two-deck linear, can be formed without destruction of the dimers of the cyanine dyes. The energy of tetramer formation was found to decrease in the order brickwork > linear > ladder configurations. For dimers of the first dye and its tetramer (brickwork, ladder and linear) configurations, the energies of the first S0 → S1 singlet transitions, oscillator strengths, and structures of frontier MO have been calculated. The spectral shifts in dimers and tetramers were found to depend only on mutual orientation of components: brickwork and linear tetramers show red shift (+Δλ) while ladder tetramers, blue shift (-Δλ) of absorption bands (with respect to monomer). © 2014 Elsevier Ltd. All rights reserved.

Nikitina P.A.,Lomonosov Moscow University of Fine Chemical Technology | Kuz'Mina L.G.,RAS Kurnakov Institute of General and Inorganic Chemistry | Perevalov V.P.,Lomonosov Moscow University of Fine Chemical Technology | Tkach I.I.,Lomonosov Moscow University of Fine Chemical Technology
Tetrahedron | Year: 2013

A series of novel derivatives of imidazole containing a chromenyl moiety in position 2 of the ring has been synthesized. A characteristic response of the chromenyl ring H-2 proton to its environment allows the study of the prototropic tautomerism of novel 1-hydroxyimidazoles in solution using 1H NMR spectroscopy. It has been shown that the predominance of one or another tautomer depends on the nature of the substituents of the imidazole ring, and the proton-donating/proton-withdrawing properties of a solvent. X-ray diffraction data for two of the compounds has revealed that in the solid state these 1-hydroxyimidazole derivatives exist as N-oxide tautomers. © 2013 Elsevier Ltd. All rights reserved.

Kuz'Micheva G.M.,Lomonosov Moscow University of Fine Chemical Technology | Ivleva L.I.,RAS A.M. Prokhorov General Physics Institute | Kaurova I.A.,Moscow State University | Rybakov V.B.,Moscow State University
Acta Materialia | Year: 2014

Crystals of strontium barium niobate solid solutions, both nominally pure Sr0.61Ba0.39Nb2O6 and doped with transition metal (Cr3+ and Ni3+) ions, have been investigated by X-ray diffraction. The chemical composition of the undoped crystal was determined taking into consideration vacancies in niobium Nb(2) and oxygen sites and the statistical distribution of strontium in two (Sr(1) and Sr(2)) sites in the tetragonal tungsten bronze type crystal structure. It was established that the introduction of chromium or nickel oxides into the melt initial composition greatly influences the strontium and barium content in the crystals obtained and the distribution of these species in the crystallographic structure. The probability of finding the transition metal ions in regular and interstitial positions depending on their concentration and valence state is discussed. © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Khlebtsov B.,Russian Academy of Sciences | Panfilova E.,Russian Academy of Sciences | Khanadeev V.,Russian Academy of Sciences | Bibikova O.,Russian Academy of Sciences | And 7 more authors.
ACS Nano | Year: 2011

We describe novel composite nanoparticles consisting of a gold-silver nanocage core and a mesoporous silica shell functionalized with the photodynamic sensitizer Yb-2,4-dimethoxyhematoporphyrin (Yb-HP). In addition to the long-wavelength plasmon resonance near 750-800 nm, the composite particles exhibited a 400-nm absorbance peak and two fluorescence peaks, near 580 and 630 nm, corresponding to bound Yb-HP. The fabricated nanocomposites generated singlet oxygen under 630-nm excitation and produced heat under laser irradiation at the plasmon resonance wavelength (750-800 nm). In particular, we observed enhanced killing of HeLa cells incubated with nanocomposites and irradiated by 630-nm light. Furthermore, an additional advantage of fabricated conjugates was an IR-luminescence band (900-1060 nm), originating from Yb3+ ions of bound Yb-HP and located in the long-wavelength part of the tissue transparency window. This modality was used to control the accumulation and biodistribution of composite particles in mice bearing Ehrlich carcinoma tumors in a comparative study with intravenously injected free Yb-HP molecules. Thus, these multifunctional nanocomposites seem an attractive theranostic platform for simultaneous IR-luminescence diagnostic and photodynamic therapy owing to Yb-HP and for plasmonic photothermal therapy owing to Au-Ag nanocages. © 2011 American Chemical Society.

Pestryakov A.N.,Tomsk Polytechnic University | Lunin V.V.,Moscow State University | Bogdanchikova N.,National Autonomous University of Mexico | Temkin O.N.,Lomonosov Moscow University of Fine Chemical Technology | Smolentseva E.,National Autonomous University of Mexico
Fuel | Year: 2013

(Graph Presented) Role of small and big gold particles in CO oxidation and methanol selective oxidation to formaldehyde has been studied by the methods of diffuse reflectance electron spectroscopy, XRD, XPS, HRTEM and catalytic testing. By comparison of catalytic and spectroscopic data it was concluded that states Auδ+ with certain effective charge (δ < 1) are active sites in low-temperature CO oxidation as well as in alcohol partial oxidation. These states can be formed under the action of different factors, such as metal-support interaction, redox treatments, and modifying additives. Modifiers stabilizing the ionic states of gold (Ce and Zr oxides) increase the selectivity of the catalyst in alcohol partial oxidation, whereas electron-releasing additions (La and Cs oxides) impair the catalyst properties. © 2012 Elsevier Ltd. All rights reserved.

Frolkova A.K.,Lomonosov Moscow University of Fine Chemical Technology | Raeva V.M.,Lomonosov Moscow University of Fine Chemical Technology
Theoretical Foundations of Chemical Engineering | Year: 2010

This article is a survey of the present-day methods of dehydration of ethanol resulting from fermentation processes. The existing separation techniques for water-ethanol mixtures of various compositions are compared, and the conditions under which each particular technique is preferable are formulated. © 2010 Pleiades Publishing, Ltd.

Temkin O.N.,Lomonosov Moscow University of Fine Chemical Technology
Kinetics and Catalysis | Year: 2012

The state-of-the-art in the theory of routes for multi-route reactions in the homogeneous catalysis with metal complexes is reviewed. Key problems and the possible approaches to their solution based on the Horiuti-Temkin theory of steady-state reactions, which are useful in constructing the kinetic algebraic mod- els of multi-route processes, are discussed. A classification of the mechanisms of real processes involved in the homogeneous catalysis with metal complexes is presented. The chain mechanisms of catalytic processes, conjugated and associated reactions, and critical phenomena in the dynamics of homogeneous reactions are considered. © Pleiades Publishing, Ltd., 2012.

Ezinkwo G.O.,Lomonosov Moscow University of Fine Chemical Technology | Tretjakov V.F.,Lomonosov Moscow University of Fine Chemical Technology | Talyshinky R.M.,RAS Topchiev Institute of Petrochemical Synthesis | Ilolov A.M.,RAS Topchiev Institute of Petrochemical Synthesis | Mutombo T.A.,Lomonosov Moscow University of Fine Chemical Technology
Catalysis Communications | Year: 2014

One of the major constraints to the efficiency of Lebedev's process for butadiene production is the deposition of soot on the active sites of the catalyst which results to the reduction of catalyst activity and the periodic regeneration of catalyst thereby increasing time and energy spent on the process and subsequently, cost. The use of a process initiator has been found to be a possible solution to the above mentioned challenges. A synergetic effect was observed during the initiation of the catalytic process. Furthermore, the interdependence between the efficiency of the process initiator and the morphology of Al2O3, linear velocity of the feed stream and other process parameters was observed. © 2013 Elsevier B.V.

Temkin O.N.,Lomonosov Moscow University of Fine Chemical Technology
Kinetics and Catalysis | Year: 2014

Three possible mechanisms of the direct hydration of α-olefins under conditions of catalysis with metal complexes in solution are considered, and information that confirms the possible realization of the reaction steps of various types is presented. Factors determining the regioselectivity of reaction steps are considered in the framework of various mechanisms, and the available published data about catalytic systems capable of ensuring the direct hydration of α-olefins are analyzed. New approaches to organization of the synthesis of n-alcohols from olefins and dienes are discussed, which are based on the systems of consecutive reactions, conjugated, and combined (associated) processes. © 2014 Pleiades Publishing, Ltd.

Serafimov L.A.,Lomonosov Moscow University of Fine Chemical Technology | Chelyuskina T.V.,Lomonosov Moscow University of Fine Chemical Technology
Russian Journal of Physical Chemistry A | Year: 2011

A new equation for two-phase systems in integer units is obtained by transformations of the Serafimov equation. The total number of types of phase portraits for biazeotropic ternary mixtures is determined on the basis of this equation. © 2011 Pleiades Publishing, Ltd.

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