Showing papers in "Russian Chemical Reviews in 2009"
TL;DR: The main methods of studying the electronic structure of merocyanines are considered in this paper, where the dependence of the dye properties on their chemical structure, the solvent nature and the aggregation type is analyzed.
Abstract: Key approaches to the synthesis of merocyanine dyes are summarised. The dependence of the dye properties on their chemical structure, the solvent nature and the aggregation type is analysed. The main methods of studying the electronic structure of merocyanines are considered. Attention is focused on polyene–polymethine electron transitions. The applications of merocyanines in modern research, including the design of new materials and technologies (non-linear optics, photovoltaics, holography, etc.) are presented.
182 citations
TL;DR: In this paper, a review is devoted to heterogeneous catalysts for selective hydrogenation of highly unsaturated impurities (dienes and acetylenes) in hydrocarbonic streams.
Abstract: The review is devoted to heterogeneous catalysts for selective hydrogenation of highly unsaturated impurities (dienes and acetylenes) in hydrocarbonic streams. The most promising systems are nanocomposites on the basis of palladium or gold.
176 citations
TL;DR: In this article, the results of modern studies of physicochemical properties and biological activities of nanocrystalline cerium dioxide are generalized and the key methods for its preparation are considered and the prospects for its application in biological research and in medicine are analyzed.
Abstract: The results of modern studies of physicochemical properties and biological activities of nanocrystalline cerium dioxide are generalized. The key methods for its preparation are considered and the prospects for its application in biological research and in medicine are analyzed.
146 citations
TL;DR: The methods of isolation of fucoidans and determination of their chemical structures are reviewed in this article, where a variety of the biological activities of these biopolymers are briefly summarised.
Abstract: The methods of isolation of fucoidans and determination of their chemical structures are reviewed. The fucoidans represent sulfated polysaccharides of brown algae, the composition of which varies from simple fucan sulfates to complex heteropolysaccharides. The currently known structures of such biopolymers are presented. A variety of the biological activities of fucoidans is briefly summarised.
122 citations
TL;DR: In this article, the use of mediator oxidation systems activated by electric current (anodic or parallel anodic and cathodic) in organic electrosynthesis is considered and generalised.
Abstract: The data on the use of mediator oxidation systems activated by electric current (anodic or parallel anodic and cathodic) in organic electrosynthesis are considered and generalised. Electrochemical activation of these systems permits successful application of catalytic versions and easy scaling of mediator-promoted processes. Chemical and environmental advantages of electrochemical processes catalysed by mediator oxidation systems are demonstrated. Examples of the application of organic and inorganic mediators for the oxidation of various classes of organic compounds under conditions of electrolysis are given.
121 citations
TL;DR: The theoretical and practical aspects of the use of atomic energy in R Bader's theory 'Atoms in Molecules' for solving problems of physical and structural chemistry are considered in this article.
Abstract: The theoretical and practical aspects of the use of atomic energy in R Bader's theory 'Atoms in Molecules' for solving problems of physical and structural chemistry are considered
110 citations
TL;DR: In this paper, a review devoted to the application of organocatalysis for the asymmetric aldol reaction is presented, which is one of the most important methods for carbon-carbon bond formation in organic compounds.
Abstract: The review is devoted to the application of organocatalysis for the asymmetric aldol reaction, which is one of the most important methods for carbon–carbon bond formation in organic compounds The mechanism of enamine catalysis and the main types of organocatalysts for the aldol reaction are considered, data on this type of reactions involving carbonyl compounds with various electronic and spatial structures are classified The effects of organocatalyst structure on the regio-, stereo- and enantioselectivity of intramolecular and intermolecular aldol reactions are reviewed
100 citations
TL;DR: In this paper, the potential of using nano-sized TiO2 in medicine and nanobiotechnology is considered, focusing on its sol-gel synthesis from different precursors.
Abstract: The published data on the preparation and the dispersion-structural properties of nano-sized TiO2 are considered. Attention is focused on its sol–gel synthesis from different precursors. The possibilities for the purposeful control and stabilization of properties of TiO2 nanopowders and sols are analyzed. Information on physicochemical methods used in studies of the particle size and the phase composition of nanodisperse TiO2 is presented. The prospects of using nano-sized TiO2 in medicine and nanobiotechnology are considered.
94 citations
TL;DR: The state of the art of the chemistry of nitroxide radicals promising for the design of molecular magnets is considered in this article, where the state-of-the-art of the physics of magnet design is discussed.
Abstract: The state of the art of the chemistry of nitroxide radicals promising for the design of molecular magnets is considered.
93 citations
TL;DR: Experimental and theoretical data on new compounds, nitrides and carbides of the platinum group 4d and 5d metals (ruthenium, rhodium, palladium, osmium, iridium, platinum), published over the past five years are summarized in this article.
Abstract: Experimental and theoretical data on new compounds, nitrides and carbides of the platinum group 4d and 5d metals (ruthenium, rhodium, palladium, osmium, iridium, platinum), published over the past five years are summarized. The extreme mechanical properties of platinoid nitrides and carbides, i.e., their high strength and low compressibility, are noted. The prospects of further studies and the scope of application of these compounds are discussed.
73 citations
TL;DR: In this paper, a general information on composite materials with ionic conductivity including inorganic composites and hybrid polymeric ion exchange membranes containing inorganic or polymeric nanoparticles is generalized.
Abstract: Information on composite materials with ionic conductivity including inorganic composites and hybrid polymeric ion exchange membranes containing inorganic or polymeric nanoparticles is generalized. The nature of the effect of increase in the ionic conductivity in this type of materials and the key approaches used for theoretical estimation of the conductivity are considered. Data on the ionic conductivity and some other important properties of composites and membrane materials are presented. Prospects for utilization of composite materials and hybrid membranes in hydrogen power engineering are briefly outlined.
TL;DR: In this paper, data on the metal complexes with bis(hydrazones) obtained from various classes of dicarbonyl compounds are generalized and described systematically, and the structure and complexing properties of these compounds are considered.
Abstract: Data on the metal complexes with bis(hydrazones) obtained from various classes of dicarbonyl compounds are generalized and described systematically. The structure and complexing properties of bis(hydrazones) are considered and the factors influencing structures of the metal complexes are analyzed. The relationships between the structures and physicochemical properties of the considered compounds are discussed.
TL;DR: In this article, published data on stereodynamic processes in the coordination units of di-and tetravalent silicon, germanium, tin and lead compounds are summarized and analyzed.
Abstract: Published data on stereodynamic processes in the coordination units of di- and tetravalent silicon, germanium, tin and lead compounds are summarized and analyzed.
TL;DR: In this paper, the state-of-the-art methods for filling single-walled carbon nanotubes (SWNTs) are analyzed systematically, based on both intercalation of inorganic substances from the gas phase, solution or melts inside SWNTs and the formation of nanocrystals inside the channels as a result of chemical reactions.
Abstract: The state-of-the-art methods for filling single-walled carbon nanotubes (SWNTs) are analyzed systematically. In situ and ex situ approaches for filling SWNTs are addressed. They are based on both intercalation of inorganic substances from the gas phase, solution or melts inside SWNTs and the formation of nanocrystals inside the channels as a result of chemical reactions. A comparative evaluation of these methods is performed, and major requirements for successful formation of '1D-crystal@SWNT' nanocomposites are formulated. The functional properties of the intercalated single-walled nanotubes and their possible applications in modern nanotechnologies are discussed.
TL;DR: In this article, the key trends in basic and application-oriented research on nanomaterials are considered, and it is noted that some studies are now carried out abroad and in domestic laboratories, while some other are to be initiated in the near future.
Abstract: Key trends in basic and application-oriented research on nanomaterials are considered. It is noted that some studies are now carried out abroad and in domestic laboratories, while some other are to be initiated in the near future. It is emphasized that effective research in the field in question is possible only provided that laboratories are equipped with advanced instrumentation.
TL;DR: A retrospective of modern approaches to the synthesis of natural butano- and butenolides based on the use of recent achievements of synthetic organic chemistry is given in this article, where natural sources and biological activities are indicated.
Abstract: A retrospective of modern approaches to the synthesis of natural butano- and butenolides based on the use of recent achievements of synthetic organic chemistry is given. For most of the considered compounds, natural sources and biological activities are indicated.
TL;DR: In this paper, the authors describe data on the mechanisms of gas-phase monomolecular decomposition of nitro compounds using modern quantum chemical methods, focusing on the discussion of multistage decomposition for elementary experimentally observed products.
Abstract: Data on the mechanisms of gas-phase monomolecular decomposition of nitroalkanes, nitroalkenes and nitroarenes obtained using modern quantum chemical methods are described systematically. The attention is focused on the discussion of multistage decomposition of nitro compounds to elementary experimentally observed products. Characteristic features of competition of different mechanisms and the effect of molecular structure on the change in the Arrhenius parameters of the primary reaction step are considered.
TL;DR: In this paper, the asymmetric synthesis of chiral biologically active sulfoxides by oxidation of appropriate sulfides catalyzed by titanium and vanadium complexes was studied and a generalized version of this paper was published.
Abstract: Published data on the asymmetric synthesis of chiral biologically active sulfoxides by oxidation of appropriate sulfides catalyzed by titanium and vanadium complexes are generalized. Bibliography — 87 references.
TL;DR: In this paper, the authors focused on the method proposed by the authors for controlling the catalytic activity of transition metal complexes in hydrocarbon (in particular, alkylarene) oxidation with molecular oxygen.
Abstract: The methods used to increase the catalytic activity of transition metal complexes in hydrocarbon (in particular, alkylarene) oxidation with molecular oxygen are briefly considered The attention is focused on the method proposed by the authors for controlling the catalytic activity of the complexes MLn1 (M=Ni(II), Fe(II,III); L=acac, enamac, n=2, 3) used in alkylarene oxidation to hydroperoxides by introducing additional electron-donating mono- or polydentate modifying ligands L2 The role of H-bonds in the mechanisms of homogeneous catalysis is discussed A strategy for controlling the catyalytic activity of Fe(II,III)(acac)n?L2 complexes (L2=R4NBr or 18-crown-6) by adding low concentrations of H2O is proposed The activities of Ni and Fe catalysts in the microstages of chain initiation and propagation in a radical chain process of ethylbenzene oxidation are estimated
TL;DR: In this article, the regularities of isotope fractionation in natural photochemical processes and in living tissues are discussed, showing that both chemical and biochemical transformations of mercury compounds (outside and inside living organisms) follow radical spin-selective mechanisms.
Abstract: Mercury isotope effects in environmentally significant chemical and biochemical reactions are considered. The recently discovered anomaly for the 199Hg and 201Hg magnetic nuclei proves that both chemical and biochemical transformations of mercury compounds (outside and inside living organisms) follow radical spin-selective mechanisms. The regularities of isotope fractionation in natural photochemical processes and in living tissues are discussed.
TL;DR: In this paper, the authors focused on the mechanism of polymer chain growth control during reversibly inhibited radical homopolymerization and the effect of structure of precursors and regulating additives on the polymerization kinetics of monomers of different nature and the molecular-mass characteristics of the polymers thus formed.
Abstract: Published data on controlled synthesis of macromolecules using nitroxide radicals, formed in situ during polymerization, as polymer chain growth regulators are systematized and generalized. The attention is focused on the mechanism of polymer chain growth control during reversibly inhibited radical homopolymerization and the effect of structure of precursors and regulating additives on the polymerization kinetics of monomers of different nature and the molecular-mass characteristics of the polymers thus formed. The key methods for generation of nitroxide radicals directly during polymerization are considered. The prospects for development and practical use of these approaches for the synthesis of new polymeric materials are evaluated.
TL;DR: In this paper, a pseudopotential approach to the electronic structure simulation of superheavy elements (SHE) compounds is presented, leaving both valence and outer-core electronic shells for explicit treatment.
Abstract: Relativistic pseudopotential approach to the electronic structure simulation of superheavy elements (SHE) compounds is presented. Advanced formulations of this approach leaving both valence and outer-core electronic shells for explicit treatment give rise to simple and efficient computational techniques ensuring highly accurate description of most chemical properties of SHE. At present, the errors due to the use of approximate methods for solving the correlation problem for a subsystem of valence electrons are much larger than those stemming from the pseudopotential approximation itself. Recent applications to the studies of the chemistry of elements 112 (eka-Hg) and 114 (eka-Pb) are reviewed; properties of these elements and their lighter homologues, Hg and Pb, are compared.
TL;DR: In this paper, the role of size effects in the structure, composition and properties of nano-sized silicon carbide systems is analyzed and the potential application fields of nanocrystalline and amorphous silicon carbides are outlined.
Abstract: Characteristic features of the synthesis of particles, fibres (wires), tubes, films and bulk materials based on nanocrystalline and amorphous silicon carbide are considered. The role of size effects in the structure, composition and properties of these systems is analyzed. The potential application fields of nano-sized silicon carbide are outlined.
TL;DR: The advances in the synthesis and study of derivatives of cyclopentadienyltricarbonylmanganese (cymantrene) are considered in this article.
Abstract: The advances in the synthesis and study of derivatives of cyclopentadienyltricarbonylmanganese (cymantrene) are considered. The bibliography includes 356 references.
TL;DR: In this article, a review of physicochemical data of natural phenols published in recent years is presented, including physicochemical properties of peroxyl, alkyl and thiyl radicals with natural compounds.
Abstract: This review surveys physicochemical data of natural phenols published in recent years. The structures of some compounds of this class are given. A complete set of the dissociation energies of the O–H bonds for 71 natural phenols is presented. Kinetic characteristics of the reactions of peroxyl, alkyl and thiyl radicals with natural phenols, exchange reactions of phenoxyl radicals with phenols and reactions of phenoxyl radicals with lipids, hydroperoxides, cysteine and ascorbic acid are compiled and described systematically. The reactivity of phenols in radical reactions and the factors that determine the reactivity (the enthalpy of reaction, triplet repulsion, the electronegativities of atoms at the reaction centre, the presence of π-electrons adjacent to the reaction centre, the radii of atoms at the reaction centre, steric hindrance, the force constants of the reacting bonds) are discussed. An important role of hydrogen bonding between surrounding molecules and the OH groups of natural phenols in decreasing their reactivities is noted.
TL;DR: The nuclear shell model predicts that the next doubly magic shell-closure beyond 208Pb is at the proton number Z=114, 120, or 126 and at the neutron number N=172 or 184.
Abstract: The nuclear shell model predicts that the next doubly magic shell-closure beyond 208Pb is at the proton number Z=114, 120, or 126 and at the neutron number N=172 or 184. The outstanding aim of experimental investigations is the exploration of this region of spherical 'Super Heavy Elements' (SHEs). Using cold fusion reactions which are based on lead and bismuth targets, the new elements from 107 to 112 were synthesized at GSI in Darmstadt, Germany. Some of these results were confirmed at RIKEN in Wako, Japan, where also a relatively neutron-deficient isotope of element 113 was synthesized. In hot fusion reactions of 48Ca projectiles with actinide targets, a more neutron-rich isotope of element 112 and the new elements from 113 to 116 and even 118 were produced at FLNR in Dubna, Russia. Recently, part of these hot fusion data, which represent the first identification of nuclei located on the predicted island of SHEs, were confirmed in two independent experiments. The decay data reveal that for the heaviest elements, the dominant decay mode is α emission rather than fission. The decay properties as well as reaction cross-sections are compared with results of theoretical studies.
TL;DR: In this paper, the main achievements in the field of synthesis of sulfonated polynaphthylimides and their precursors, namely, sulphonated aromatic diamines, are analysed.
Abstract: The main achievements in the field of synthesis of sulfonated polynaphthylimides and their precursors, namely, sulfonated aromatic diamines, are analysed. The relationship between the structure of sulfonated polynaphthylimides and their physicochemical characteristics such as chemical and thermal stability, moisture uptake, ion-exchange capacity and proton conductivity is studied. The prospects of using polynaphthylimides containing pendant sulfo groups for the development of proton-conducting polymeric electrolyte membranes for fuel cells are demonstrated.
TL;DR: The mechanisms of oxidation of nucleosides, nucleotides and DNA with reactive oxygen species including singlet oxygen, superoxide and hydroxyl radicals and high-valence metal oxo complexes are considered.
Abstract: The mechanisms of oxidation of nucleosides, nucleotides and DNA with reactive oxygen species including singlet oxygen, superoxide and hydroxyl radicals and high-valence metal oxo complexes are considered.
TL;DR: In this article, the relationship between the structures and thermolysis mechanisms of compounds based on differentiation of the structural fragments depending on the functional surrounding of nitro groups is identified using the RRN (Recombination Reaction Network) strategy and original CASB (Computer Assisted Structure Building) softwere.
Abstract: Data on the experimental and theoretical studies of thermal decomposition of C- and N-nitro compounds of aliphatic, alicyclic, aromatic and heteroaromatic compounds, which formed the grounds for the develpment of ab initio appoach to the prediction of the mechanisms of thermolysis of energetic compounds, are described systematically. The relationships between the structures and thermolysis mechanisms of compounds based on differentiation of the structural fragments depending on the functional surrounding of nitro groups are identified. Using the RRN (Recombination Reaction Network) strategy and original CASB (Computer Assisted Structure Building) softwere, full reaction mechanisms for the thermal destruction of nitro compounds at different thermal decomposition levels (including extensive ones) are simulated. The full set of possible mechanisms of thermal decomposition of 38 chemically different nitro compounds is presented
TL;DR: In this article, state-of-the-art data on the methods of synthesis, properties and transformations of nitro- and dinitrocyclopropanes of different structure is generalized and described systematically.
Abstract: State-of-the-art data on the methods of synthesis, properties and transformations of nitro- and- dinitrocyclopropanes of different structure is generalized and described systematically. The attention is focused on stereoselective cyclopropanation methods, new approaches to the synthesis of natural products and their synthetic analogues with diversified biological activities, in particular, of aminocyclopropane acids based on nitrocyclopropanes, and the formation of structures of energetic compounds.