Showing papers in "Russian Chemical Reviews in 2004"
TL;DR: In this paper, a review of chemical studies of semiconducting clathrates belonging to a unique family of inclusion compounds is presented, and the prospects for fundamental research and the construction of new-generation materials based on semiconductor clathrate are discussed.
Abstract: The review surveys different aspects of chemical studies of semiconducting clathrates belonging to a unique family of inclusion compounds. The classification, crystal and electronic structures, properties and methods for the synthesis of semiconducting clathrates are considered on the basis of analysis of recent publications. The prospects for fundamental research and the construction of new-generation materials based on semiconducting clathrates are discussed. The bibliography includes 161 references.
150 citations
TL;DR: The published data on the structures and properties of crystalline actinide compounds having mutually coordinated AnO2+ or AnO22+ cations as structural elements are surveyed in this paper.
Abstract: The published data on the structures and properties of crystalline actinide compounds having mutually coordinated AnO2+ or AnO22+ cations as structural elements are surveyed. This cation—cation interaction is an important structure-forming factor for many crystalline compounds of Np(V) and U(VI). It strongly affects their UV-Vis and IR spectra as well as other properties. Differences and similarities between the cation—cation interactions of actinide ions in solutions and crystals are discussed. The bibliography includes 114 references.
131 citations
TL;DR: In this paper, various approaches to the formation of ordered structures of colloid particles are described, focusing on the formation by nanoparticles at interfaces, and the driving forces of the self-assembly of nanoparticles and the salient features of the ordered ensembles of such nanoparticles are analysed.
Abstract: Various approaches to the formation of ordered structures of colloid particles are described. The emphasis is placed on the formation of such structures by nanoparticles at interfaces. A number of processes involving the so-called self-assembly of particles are considered. Examples of the formation of ordered structures (two- and three-dimensional colloid crystals) are given. The driving forces of the self-assembly of nanoparticles and the salient features of the physicochemical properties of ordered ensembles of such nanoparticles are analysed. The bibliography includes 502 references.
108 citations
TL;DR: In this paper, the effect of chiral derivatives of phosphorous acid in coordination chemistry and enantioselective catalysis is discussed, and the prospects for the development of this field of research are demonstrated.
Abstract: The data published during the last five years on the application of chiral derivatives of phosphorous acid in coordination chemistry and enantioselective catalysis are summarised and discussed. The effect of the nature of these ligands on the structure of metal complexes and on the efficiency of catalytic organic syntheses is shown. Hydroformylation, hydrogenation, allylic substitution and conjugate addition catalysed by transition metal complexes with optically active phosphites and hydrophosphoranes are considered. The prospects for the development of this field of research are demonstrated. The bibliography includes 215 references.
85 citations
TL;DR: The state-of-the-art of research dealing with the development and perfection of metal corrosion inhibitors in aqueous solutions is analyzed in this article, where the main mechanisms involved in formation of protective layers on metals by inhibitors are discussed.
Abstract: The state-of-the-art of research dealing with the development and perfection of metal corrosion inhibitors in aqueous solutions is analysed. The main mechanisms involved in formation of protective layers on metals by inhibitors are discussed. Ways of creating mixed corrosion inhibitors with high protective properties are considered. The bibliography includes 150 references.
84 citations
TL;DR: In this article, the properties of lead difluoride are considered and phase equilibria in PbF2-MFn systems (n = 1−5) and data on compounds and solid solutions formed in these systems are analyzed.
Abstract: Properties of lead difluoride are considered. Phase equilibria in PbF2–MFn systems (n = 1–5) and data on compounds and solid solutions formed in these systems are analysed. The characteristic features of phase diagrams of systems involving lead difluoride are discussed. Composites of PbF2 with other inorganic compounds hold promise as a basis for the design of new functional materials. The bibliography includes 331 references.
77 citations
TL;DR: In this paper, the diversity of catalyst systems used for the copolymerisation of carbon monoxide is demonstrated and their influence on the structure and molecular mass of the resulting copolymers is analyzed.
Abstract: Characteristic features of the catalytic synthesis of alternating copolymers of carbon monoxide with various olefins, dienes, styrene and its derivatives are considered. The diversity of catalyst systems used for the copolymerisation of carbon monoxide is demonstrated and their influence on the structure and the molecular mass of the resulting copolymers is analysed. The data on the structure and physicochemical and mechanical properties of this new generation of functional copolymers are generalised and described systematically for the first time. The bibliography includes 296 references.
76 citations
TL;DR: A review of cyclopalladated compounds of the PC- and PCP-type can be found in this paper, with a focus on the structural factors and experimental conditions that determine the feasibility of direct PC-alladation of mono-and bidentate phosphines, phosphites, and phosphinites.
Abstract: The review considers methods of synthesis of cyclopalladated compounds of the PC- and PCP-type including intramolecular activation of the C–H bonds in the P-donor ligands, oxidative addition of preliminarily functionalised substrates to palladium(0), transmetallation of lithiated compounds, chelation of phosphine-substituted phosphorus ylides, and some non-standard processes resulting in a new ligand formation on a metal template. Particular attention has been given to the structural factors and experimental conditions that determine the feasibility of direct cyclopalladation of mono- and bidentate phosphines, phosphites and phosphinites. The bibliography includes 384 references.
70 citations
TL;DR: In this article, the synthesis of functional nanocomposites based on zero-, one-and two-dimensional solid-state nanoreactors formed by zeolite cages, pores of mesoporous matrices, or interlayer cavities in layered compounds are considered.
Abstract: Approaches to the synthesis of functional nanocomposites based on zero-, one- and two-dimensional solid-state nanoreactors formed by zeolite cages, pores of mesoporous matrices, or interlayer cavities in layered compounds are considered. It is demonstrated that the use of solid-state nanoreactors opens up extensive opportunities for designing nanocomposites with specified physicochemical properties and makes it possible to avoid the aggregation of nanoparticles and to protect them from exposure to external factors, thus essentially facilitating the practical utility of these materials. The bibliography includes 304 references.
68 citations
TL;DR: A class of conformationally rigid cyclic α-amino acids that can be used in the synthesis of peptidomimetics, peptide models and biologically active compounds is surveyed.
Abstract: A class of conformationally rigid cyclic α-amino acids that can be used in the synthesis of peptidomimetics, peptide models and biologically active compounds is surveyed. The rigid frameworks of such amino acids enable 'fixation' of strictly defined torsion angles and hence prediction and deliberate tuning of the conformation of a polypeptide chain. Recent data on the structures and methods of the synthesis of such amino acids are presented. The bibliography includes 259 references.
66 citations
TL;DR: In this paper, the results of X-ray photoelectron spectroscopy (XPS) studies of the structures of the outer and inner electron shells of compounds of light actinides (Th, U, Np, Pu, Am, Cm, Bk, Cf) in the binding energy (Eb) range of 0-1250 eV are generalised.
Abstract: The results of X-ray photoelectron spectroscopy (XPS) studies of the structures of the outer and inner electron shells of compounds of light actinides (Th, U, Np, Pu, Am, Cm, Bk, Cf) in the binding energy (Eb) range of 0–1250 eV are generalised. The regularities of formation of the fine structure in the X-ray photoelectron (XPS) spectra of these compounds are considered. The mechanisms of appearance of such structure are analysed, and the correlations between the fine structure parameters and actinide oxidation states and local environment, the magnetic properties of compounds, the nature of the chemical bond and secondary electronic processes that accompany photoemission of electrons are discussed. Experimental evidence for effective formation of the outer (Eb = 0–15 eV) and inner valence (Eb = 15–50 eV) molecular orbitals, in particular, from the fully occupied An6p and Lns orbitals of the neighbouring actinide (An) and ligand (L) atoms in the compounds in question is presented. The use of fine spectral structure parameters, together with the electron binding energies and line intensities extends significantly the scope of application of the XPS method in structural studies.
The bibliography includes 276 references.
TL;DR: In this article, a review of polymeric nanocomposites containing encapsulated nanoparticles formed in nanostructured polymeric systems including block copolymers, dendrimers, nanoporous polymers, polyelectrolyte gel-surfactant complexes and multilayered films is presented.
Abstract: The review concerns the syntheses of polymeric nanocomposites containing encapsulated nanoparticles formed in nanostructured polymeric systems including block copolymers, dendrimers, nanoporous polymers, polyelectrolyte gel–surfactant complexes and multilayered films. Nanostructures in amphiphilic block copolymers can form spontaneously both in the bulk (block microsegregation) and in solution (block copolymer micelle). In polymeric systems, nanostructures play the role of nanoreactors for the growing nanoparticles. The nanoparticle size, shape and size distribution are controlled by the nanostructure characteristics and synthesis conditions. The catalytic, magnetic and optical properties of these nanostructured polymeric nanocomposites are discussed. The bibliography includes 131 references.
TL;DR: In this article, the synthesis and structures of β-diketonates and their N,P-containing structural analogues are generalised and described systematically, and the possibility of creating diverse metal complexes with various modes of coordination of typical chelating ligands is discussed.
Abstract: Data on the synthesis and structures of β-diketonates and their N,P-containing structural analogues are generalised and described systematically. The possibility of creating diverse metal complexes with various modes of coordination of typical chelating ligands is discussed. The bibliography includes 200 references.
TL;DR: The results of recent studies in the field of self-propagating high-temperature synthesis of nanosized materials are surveyed in this paper, where the possibilities of the synthesis of nano-materials in the combustion mode are demonstrated.
Abstract: The results of recent studies in the field of self-propagating high-temperature synthesis of nanosized materials are surveyed. The possibilities of the synthesis of nanomaterials in the combustion mode are demonstrated. Examples of applications of the self-propagating high-temperature synthesis for the preparation of nanopowders, films and compact materials are given. The bibliography includes 116 references.
TL;DR: In this paper, the thermodynamic model and the theory of the epitaxial stabilisation phenomenon are outlined, the role of thermodynamic and structure-geometric factors determining the possibility of epitaxially stabilisation of unstable phases is interpreted.
Abstract: The methods of synthesis of new oxide compounds and thin-film materials based on the use of heteroepitaxy are considered. The thermodynamic model and the theory of the epitaxial stabilisation phenomenon are outlined, the role of thermodynamic and structure-geometric factors determining the possibility of epitaxial stabilisation of unstable phases is interpreted. The use of epitaxial stabilisation for the design of heterostructures with specific electric properties is demonstrated. The characteristic features of the structural relations between the film and substrate materials, resulting in the formation of thin films with different numbers of variants, are discussed. The bibliography includes 128 references.
TL;DR: The state-of-the-art in structural investigations into fullerene derivatives is surveyed in this article, where the crystal structures of individual fullerenes and of their derivatives determined experimentally by single-crystal X-ray diffraction are systematised.
Abstract: The state-of-the-art in the structural investigations into fullerene derivatives is surveyed The crystal structures of individual fullerenes and of their derivatives determined experimentally by single-crystal X-ray diffraction are systematised The results of powder X-ray diffraction and EXAFS spectroscopy are overviewed for those classes of derivatives that have been insufficiently studied by single-crystal X-ray diffraction Patterns of packing of the fullerene spheres encountered in crystal structures are described and representative examples of the most typical motifs are given Reasons for the rotational disorder, which often hampers structure determination for fullerene derivatives, and its classification are considered A model of the 'rubber cavity' is introduced, which allows prediction of typical mutual orientations of disordered molecules The redistribution of bond lengths upon σ- and π-functionalisation of the carbon core is analysed based on the information retrieved from the Cambridge Structural Database Factors affecting the molecular packing density in crystalline derivatives of fullerenes are discussed in relation to the quality of the diffraction data attainable for them The bibliography includes 282 references
TL;DR: A review of recent data on synthesis methods, physicochemical properties and crystal chemistry of silicate microporous materials containing transition elements (amphoterosilicates) can be found in this paper.
Abstract: The review surveys and generalises recent data on synthesis methods, physicochemical properties and crystal chemistry of silicate microporous materials containing transition elements (amphoterosilicates). The frameworks of these materials, unlike those of usual aluminosilicate zeolites, are built from tetrahedrally coordinated atoms along with atoms of various elements (Ti, Nb, Zr, Ta, Sn, W, Fe, Mn, Zn, etc.) with coordination numbers of 6 or 5. Many amphoterosilicates possess ion-exchange properties and can serve as catalysts for redox reactions, sorbents, etc. The structural diversity of synthetic and natural amphoterosilicates provides the basis for the preparation of microporous materials with different properties. The bibliography includes 195 references.
TL;DR: In this paper, data on the synthetic methods, reactivities, biological activities and other practically important properties of 1,8-naphthyridine derivatives published over the last 15 years are analyzed.
Abstract: Data on the synthetic methods, reactivities, biological activities and other practically important properties of 1,8-naphthyridine derivatives published over the last 15 years are analysed. The bibliography includes 759 references.
TL;DR: In this paper, substitution reactions at boron atoms in 10-12-vertex metallacarboranes are studied. But the authors focus on the possible mechanisms of substitution reactions and the influence of the metal fragment on substitution positions in the polyhedron.
Abstract: Data on substitution reactions at boron atoms in 10–12-vertex metallacarboranes, which are of fundamental and applied significance, are generalised. The possible mechanisms of substitution reactions and the influence of the metal fragment on substitution positions in the polyhedron are discussed. The bibliography includes 161 references.
TL;DR: A review of the main lines of research in thermooptical spectroscopy related directly or indirectly to analytical chemistry is presented in this article, where the advantages and drawbacks of these methods are considered.
Abstract: The review surveys the main lines of research in thermooptical spectroscopy related directly or indirectly to analytical chemistry. The advantages and drawbacks of thermooptical spectroscopy methods are considered. Particular attention is given to the coupling of thermooptical spectroscopy to chromatography, flow analysis techniques, capillary electrophoresis,
etc. Prospects for the development of analytical thermooptical spectroscopy are discussed. The bibliography includes 606 references.
TL;DR: In this paper, a review of the pathways of formation of crystalline oligomeric oxoalkoxides is presented, which are products of partially controlled (or uncontrolled) hydrolysis, oxidation, thermal decomposition of mono-and bimetallic alkoxides of the ortho series.
Abstract: The review surveys the pathways of formation of crystalline oligomeric oxoalkoxides M
mO
n(OR)
p, which are products of partially controlled (or uncontrolled) hydrolysis, oxidation, thermal decomposition of mono- and bimetallic alkoxides of the ortho series M(OR)
n and M
mM
'n(OR)
p or elimination of ethers from these compounds. The physicochemical properties of oxoalkoxides (solubility, the behaviour in solutions, volatility,
etc.) differ considerably from the properties of the corresponding alkoxides. Hence, oxoalkoxides can be considered as immediate precursors of oxide materials produced by sol–gel technology. The M
mO
n(OR)
p compounds are classified according to the sizes of associates. The crystal chemistry of alkoxides is discussed. The bibliography includes 249 references.
TL;DR: In this paper, the physicochemical factors responsible for contact interactions are considered in relation to the bulk structural-rheological properties of disperse systems, and the bibliography includes 114 references.
Abstract: Results of studies of physicochemical dynamics of disperse systems, which is a new and rapidly developing field of physical chemistry, are generalised. Most attention is given to frequently occurring disperse systems composed of a solid phase and a liquid dispersion medium. The dynamics of contact interactions between particles of disperse solid phases is a key element of the dynamics of such systems. The physicochemical factors responsible for contact interactions are considered in relation to the bulk structural—rheological properties of disperse systems. The bibliography includes 114 references.
TL;DR: The physical and chemical mechanisms of spin catalysis are discussed in this paper, where the nature of spin catalysts, the quantitative measure of catalytic effects, and the types of chemical reactions susceptible to spincatalysis are considered.
Abstract: A new phenomenon, spin catalysis,
i.e., stimulation of chemical reactions by removing the prohibitions imposed for reasons of electron angular momentum (spin) of reactants is considered. The physical and chemical mechanisms of this phenomenon are discussed. The nature of spin catalysts, the quantitative measure of catalytic effects and the types of chemical reactions susceptible to spin catalysis are considered. The bibliography includes 37 references.
TL;DR: In this article, the results of pulse radiolysis studies of the kinetics and mechanism of fast one-electron redox reactions of halide ions, metal ions, actinides and other compounds with hydrated electrons, hydroxyl and other radicals and hydrogen atoms and the properties of intermediates formed in these reactions are analysed.
Abstract: The results of pulse radiolysis studies of the kinetics and mechanism of fast one-electron redox reactions of halide ions, metal ions, actinides and other compounds with hydrated electrons, hydroxyl and other radicals and hydrogen atoms and the properties of intermediates formed in these reactions are analysed. The oxidation of a mixture of chloride and bromide ions yields mixed radical anions ClBr-·. Data on the formation of metal atoms and ions in unusual and unstable oxidation states by the reduction of metal ions in aqueous solutions and on the reactions involving such ions are presented. It is shown that the reduction of compounds in aqueous solutions with organic radicals takes place through outer- or inner-sphere electron transfer. The bibliography includes 116 references.
TL;DR: In this article, the results of modern theoretical and experimental studies of components of the long-range surface forces which determine the properties of dispersions and wetting liquid films are generalised, and the bibliography includes 113 references.
Abstract: The results of modern theoretical and experimental studies of components of the long-range surface forces which determine the properties of dispersions and wetting liquid films are generalised. The bibliography includes 113 references.
TL;DR: The lines of research in the field of inorganic chemistry that are closely related to the design of novel functional materials are analyzed in this paper, where special attention is given to areas of the inorganic materials chemistry that have been developed most intensely at the Division of Inorganic Chemistry and at the Department of Materials Science of the Moscow State University over the past decade.
Abstract: The lines of research in the field of inorganic chemistry that are closely related to the design of novel functional materials are analysed. Special attention is given to areas of inorganic materials chemistry that have been developed most intensely at the Division of Inorganic Chemistry of the Department of Chemistry and at the Department of Materials Science of the Moscow State University over the past decade. The bibliography includes 135 references.
TL;DR: In this paper, the synthesis and chemical properties of complexes of Group 4-10 transition metals (d elements) with η 6-tetramethylfulvene and η 7-trimethylallyldiene ligands, formed from the pentamethylcyclopentadienyl complexes of these metals, are described systematically.
Abstract: Published data on the synthesis and chemical properties of complexes of Group 4–10 transition metals (d elements) with η 6-tetramethylfulvene and η7-trimethylallyldiene ligands, formed from the pentamethylcyclopentadienyl complexes of these metals, are described systematically. A description of the structures of these complexes in terms of a 'specific' resonance hybrid of fulvene and methylenecyclopentadienyl (or allyldiene and dimethylenecyclopentadienyl) structures is proposed. It is noted that similar properties or behaviours of the fulvene and allyldiene complexes can be followed both for compounds formed by metals of the same Group and for compounds of elements of the same transition row with identical electron configurations. The bibliography includes 102 references.
TL;DR: In this paper, structural features and methods for the synthesis of complex manganese oxides with the brownmillerite structure A2MnB'O5+δ (A = Ca, Sr; B' = Ga, Al) and of their derivatives are surveyed.
Abstract: Structural features and methods for the synthesis of complex manganese oxides with the brownmillerite structure A2MnB'O5+δ (A = Ca, Sr; B' = Ga, Al) and of their derivatives are surveyed. Modern approaches to the description of crystal structures containing various types of chains of tetrahedra are considered and possible ordering patterns of these chains are discussed. The effects of the electronic structure and crystal chemical properties of the B' cations on the possibility of formation of a layered ordered structure is noted. The emphasis is placed on the anion non-stoichiometry of the brownmillerite phases and the influence of the excess oxygen (fluorine) on the structure of the compounds. A comparative analysis of properties of oxygen- and fluorine-doped brownmillerites is given. The data on the magnetic structures, transport and magnetoresistive properties of Mn-containing brownmillerites are generalised. The bibliography includes 74 references.
TL;DR: The use of chiral 1,3,2-oxazaborolidines in asymmetric organic synthesis, particularly in enantioselective reduction of ketones, imines and oxime ethers, asymmetric Diels-Alder reactions, aldol condensation and atroposelectively reduction of lactones is reviewed in this paper.
Abstract: The use of chiral 1,3,2-oxazaborolidines in asymmetric organic synthesis, particularly, in enantioselective reduction of ketones, imines and oxime ethers, asymmetric Diels–Alder reactions, aldol condensation and atroposelective reduction of lactones is reviewed. Reactions of immobilised 1,3,2-oxazaborolidines are also considered. The bibliography includes 266 references.
TL;DR: In this paper, the same model is used to discuss the results of analysis of cyclisation of alkyl radicals; the ring strain energy is shown to play an important role in the activation of these reactions.
Abstract: Kinetic data on intramolecular abstraction of hydrogen atoms in alkyl, alkoxyl and peroxyl radicals are generalised and analysed. It is shown that the activation energies of these reactions are affected by ring strain. The kinetic parameters of mono- and bimolecular elimination reactions are compared. The difference between the activation energies of these reactions is interpreted using the model of intersecting parabolas. The same model is used to discuss the results of analysis of cyclisation of alkyl radicals; the ring strain energy is shown to play an important role in the activation of these reactions. It is noted that the difference between the electron affinities of the C, N and O atoms is clearly manifested in the cyclisation of aminyl and ω-formylalkyl radicals. The kinetic parameters of cyclisation and bimolecular radical addition reactions are compared. The experimental data on the transfer of the vinyl and aryl groups in alkyl radicals are analysed. The bibliography includes 146 references.