Home – Home – Jornals – Chemistry for Sustainable Development 2010 number 3

The paper focuses on the metamorphic geology of the oldest crustal eclogites discovered in the Late Archean tonalite-trondhjemite-granodiorite (TTG) complex of the Belomorian Mobile Belt on the Kola Peninsula. Eclogite bodies are, most likely, widespread. We studied one of the key objects, the Kuru-Vaara quarry, where several tens of retrogressed eclogite blocks randomly embedded in the TTG gneisses were stripped at the benches. Based on the field observations, two visually different types of eclogites have been recognized: "southern", strongly retrogressed coarse-grained, and "northern", well-preserved fine-grained. The southern eclogite blocks bear evidence for their partial melting with the formation of veins and melt percolation channels. The northern eclogite blocks show no evidence for melting. Despite the significant mineralogic difference, both types of eclogites can be assigned to amphibole eclogite facies. The applied jadeite solubility geobarometers yielded the minimum pressures of ~12 kbar for the northern eclogites and ~14-15 kbar for the southern ones. The used geothermometers yielded ~700 and ~750?C, respectively. But the presence of quartz lamellae in Na-clinopyroxenes in both types of eclogites and their bulk compositions corresponding to high-Mg basalts indicate that the Kuru-Vaara eclogites might have reached ultrahigh-pressure metamorphism. Analysis of the tentative P-T paths of metamorphic evolution for both types of eclogites showed that their burial-exhumation cycle might have taken as short as a few million years.
The set of presented data suggests that the formation of the Kuru-Vaara eclogites was related to the subduction of the Archean oceanic crust, which should have differed in composition and structure from the modern oceanic crust.

The Kataev volcanoplutonic association has been recognized in western Transbaikalia. It unites the volcanosedimentary rocks of the Kataev Formation and associated granites localized within the lower plates of the Buteel-Nuur and Zagan metamorphic-core complexes. The rocks of the Kataev association are dynamometamorphosed to different degrees, which is due to the tectonic exposure of metamorphic-core complexes in the Early Cretaceous. The U-Pb zircon dating of the Kataev Formation rhyolites yielded their age of 226 ± 3 Ma. The U-Pb zircon age of the granites intruding the Kataev Formation rocks is 223.4 ± 5.0 Ma. The volcanics of the Kataev Formation belong to the subalkalic basalt-andesite-dacite-rhyolite series. The trachybasalts and trachyandesite-basalts of the Kataev Formation have geochemical characteristics of igneous rocks formed as a result of subduction, e.g., they show distinct negative Nb and Ti and positive Ba and Sr anomalies on multielemental patterns. The specific composition of mafic volcanics points to their formation through the melting of a mantle source resulted from the mixing of depleted mantle and subduction components. Trachyandesites have higher Th and U contents than basaltoids. They can result from the contamination of a mantle source, similar in composition to the Kataev Formation basaltoids, with crustal material. The felsic volcanics of the Kataev Formation and granites inbruding them show nearly identical geochemical characteristics corresponding to both A - and I -type granites. These rocks might have formed through the melting of a moderately water-saturated magmatic source of diorite-tonalite composition at 742-833?C.
We have established that the rocks of the Kataev volcanoplutonic association in western Transbaikalia and northern Mongolia formed in the Late Triassic synchronously with the calc-alkalic granitoids of the Henteyn-Daurian batholith and the alkali granites and bimodal volcanic associations of the Kharitonovo and Tsagaan-Hurtey volcanoplutonic associations. The synchronous formation of volcanoplutonic associations of normal and high alkalinity agrees with the geodynamic setting of the Andean-type active continental margin existing in the area of present-day western Transbaikalia and northern Mongolia in the Early Mesozoic. This setting was the result of the subduction of the Mongolo-Okhotsk oceanic plate beneath the Siberian continent.

We present paleomagnetic data on the Cambrian volcanosedimentary complexes of the Bateni Ridge, which correspond to the evolution of the Kuznetsk Alatau island arc. The paleomagnetic poles which served as the basis for the apparent polar-wander path (APWP) were determined. The paleomagnetic data were compared with those on the Cambrian poles for other fragments of the Kuznetsk Alatau island arc. For example, the APWP the Bateni fragment corresponds to that for the Kiya (Martaiga) fragment of the eastern slope of the Kuznetsk Alatau. The distribution of the paleomagnetic poles suggests that the relative drift of the Kuznetsk Alatau arc fragments and the entire island-arc system resulted from large-amplitude strike-slips. In the Cambrian, this paleoarc moved from ~10? N to ~10? S and rotated more than 50? clockwise. In the paleomagnetic record, its accretion is reflected in the coincidence of the Late Cambrian-Early Ordovician poles on the eastern slope of the Kuznetsk Alatau with one another and the coeval poles for the Siberian craton. This coincidence also suggests that the general structure of the present Kuznetsk Alatаu formed as early as the Early Caledonian. Nevertheless, the differences in the position of the poles on the western and eastern slopes of the Kuznetsk Alatau suggest that strike-slip activity along the Kuznetsk-Altai deep fault (the major one in the region) continued in the Hercynian and, probably, in the Mesozoic.

To elaborate physicochemical models for the origin of crystalline rocks, experimental studies of the field of high-alumina assemblages of the system CaO-MgO-Al₂O₃-SiO₂ were carried out at 10-30 kbar and 1250-1535 ?C. We have determined the phase relations between the melt (L) and An, Sp, Cpx, Cor, and Ga, the slope of the rays of the monovariant reactions An + Sp = Cpx + Cor (+ Ga) and L = Cpx + Ga + Cor + Sp, the position of the nonvariant point (An, Sp, Cpx, Cor, Ga, L), and the compositions of phases participating in these reactions.
Based on a topological analysis of the studied site of the system CaO-MgO-Al₂O₃-SiO₂, we have substantiated that "eclogitization" must follow the reaction Opx + An + Sp = Cpx + Ga. A fundamental continuous series of eutectic monovariant equilibria was observed: L = Cpx + Opx + Fo + An, L = Cpx + Opx + An + Sp, L = Cpx (+ Ga) + An + Sp, and L = Cpx + Cor (+ Ga) + An. A change in the melt composition in this series of eutectic reactions depending on pressure must reflect the most likely magma genesis trend in nature. Composition fields in which the above series of reactions is observed with the composition fields of the rocks of magmatic formations showed that this series is most similar to the alkali-earth series of rocks. The mineralogical compositions of cumulates and phenocrysts found in the effusive and dike varieties of these rocks correspond to unique sets of subsolidus phase associations and individual subsolidus phases crystallizing in this fundamental eutectic series.

During serpentinization and subsequent alteration in the absence of brucite, kimberlites accumulate uncompensated silica. Its amount can be calculated from the average compositions of the rock-forming minerals (olivine, calcite, phlogopite) and the chemical compositions of the rocks. The contents of rock-forming oxides and REE were determined in 12 kimberlite pipes of the Yakutian kimberlite province, in 413 samples from secondary-alteration zones and of unaltered kimberlites. Columns of successive kimberlite alterations were constructed for each pipe on the basis of secondary-quartz data; here, the behavior of rock-forming oxides and REE was assessed. All the studied rocks had experienced different degrees of postmagmatic hydrothermal metasomatism at different depths in all the pipes. The changes were reflected in the supply/loss of rock-forming oxides and REE. During the hydrothermal metasomatism, the supply of REE enriched the kimberlites with TiO₂, P₂O₅, and CaO. During the removal of REE, most of the rock-forming oxides were partially lost. The maximum REE supply was 67% in the Udachnaya-Vostochnaya pipe and 59% in the Nyurbinskaya pipe as compared with the unaltered kimberlites. The maximum REE loss was 87% in the Aikhal pipe and 81% in the Internatsional'naya pipe as compared with the unaltered kimberlites. The initial REE contents of postmagmatically altered kimberlites changed considerably in all the studied cases. This conclusion has been drawn owing to the use of normative-quartz content as a criterion for secondary alteration.

The Karchiga copper massive sulfide deposit is located in the Kurchum block of high-grade metamorphosed rocks. This block is part of the Irtysh shear zone, which belongs to the largest transregional fault in Central Asia. The deposit is associated with the gneiss-amphibolite middle unit of the metamorphic complex, which is distinct in the geochemical fields. The mineralization is spatially and paragenetically related to the amphibolite beds, which are ore-bearing together with terrigenous rocks.
The deposit contains two spatially isolated ore lodes, in which all the discovered commercial reserves concentrate. They conformably overlie the host rocks and are tabular and ribbon-like. The mineralization has a close spatial relationship with Mg-rich anthophyllite-containing rocks. The sulfide ores are disseminated or massive and comprise pyrite, chalcopyrite, pyrrhotite, sphalerite, and magnetite. The ore is of Zn-Cu composition, in which Cu dominates considerably over Zn (average contents 2 and 0.4%, respectively; Cu/(Cu + Zn) = 0.83). The ores are rich in Co (up to 0.16%, averaging 0.02%), poor in Au and Ag (0.3 and 7.2 ppm, respectively), and almost free of Pb and Ba.
All the rocks and ores experienced epidote-amphibolite metamorphism. Meanwhile, the ores experienced recrystallization and partial regeneration, but the initial shape of the accumulations remained unchanged.
The essentially chalcopyritic ores, the volcanosedimentary ore-bearing rocks, and the spatial and genetic relationship of the mineralization with undifferentiated basaltoids suggest that this deposit belongs to the Besshi type, formed in a back-arc environment, near large uplifts.
The studies show that Besshi-type chalcopyrite deposits differ from most of the complex (Kuroko-type) deposits in Rudny Altai in the composition of volcanic rocks and geodynamic settings but belong to the same evolutionary series in this pyrite-bearing province. Both types of deposits might have formed in the Middle-Late Paleozoic, during the longest peak of pyritization in the Earth's history.

The VES method was used to determine the geoelectric parameters of Cenozoic rocks in the Chuya intermontane basin. It was shown that the polyfacies and polychromous sediments filling the basin are well differentiated by their electrical parameters. A combination of methods used in data acquisition and processing, due to their high resolution capacity at shallow depths, provided information on the structure and physical properties of the Chuya rocks from surface to depths of 250-300 m. Despite a reasonable consistence among these methods to the above depths, the VES method is a more effective tool for detecting shallower layers. Interpretation of the VES data proved the existence of a large outburst channel as new geological evidence for an ice-dammed origin of the Middle Neopleistocene lake. A more detailed layering of the topmost part of the geoelectrical section across the Irbistu-Kokozek interfluve using the VES data revealed a number of fine-grained lenticular structures of the ancient lakes in the Chuya depression, which are hidden beneath a cover of fluvioglacial and lacustrine bouldery pebbles and moraine diamictons.

The study is devoted to the possibilities of MTS in the case of arbitrary medium and electromagnetic-field inhomogeneity. It has been shown that the local tensor impedance and admittance ratios between the field components are differential. Useful information about the study region, with complex behavior of sounding curves, can be obtained by unconventional processing techniques, with the help of nonlocal medium response functions (component matching). Experiments can be considerably more cost-effective if we divide the study area into several small zones of synchronous observations and perform independent experiments in each of them at different time.

In the differentially normalized method of electromagnetic sounding (DNME), the transmitter and receiver are grounded electrical circuits. The conduction and polarization properties of a section are studied by measuring the electrical potential difference (Δ U ( t )) and the second potential difference (Δ² U ( t )); the latter characterizes the spatial inhomogeneity of the electromagnetic field. Measurements of Δ² U ( t ) are strongly influenced by three-dimensional inhomogeneities within the receiver spread. To reduce this effect, measurements are made in two positions (left and right) of the transmitter circuit relative to receiver with subsequent averaging of the measured data. Often in field studies, the transmitter and receiver circuits are at an angle to each other, and the use of two transmitters in measurements leads to the need to determine a generalized transmitter for one-dimensional forward numerical modeling of field data.
The effect of the off-axis (diagonal) position of the transmitter and receiver circuits on the data of electromagnetic pulse sounding and their inversion for a one-dimensional polarizable conducting medium have been studied in real and numerical experiments. In modeling, the effect of induced polarization (IP) is taken into account by introducing the resistivity frequency dispersion (Cole-Cole equation). Validity of the calculation of the generalized transmitter is estimated for the solution of the one-dimensional forward problem with the inversion of field diagonal measurements. The effect of three-dimensional objects on the results of measurements using the above observation system is estimated by solving the 3D forward problem for a polarizable conducting medium.

The use of the products formed in combustion of the mineral part of coal (cenospheres) that are close in the ratio SiO₂/Al₂O₃ to crystalline aluminosilicates of the structural type of rock-forming granitoid minerals, in processing and burying radioactive wastes (RAW) allows one to solve the problems of waste minimization both in nuclear and fuel power engineering. Due to the application of microspehric zeolites and porous materials based on cenospheres of the ash from the combustion of the Kuznetsk coal for solidification of liquid RAW containing cesium and strontium radionuclides, it becomes possible to obtain glass crystal compounds under rather soft conditions (750-900 °С). Under these conditions, mineral-like phases of feldspar and feldspathoids fixing radionuclides in their lattice are formed. The target phases content reaches 66-80 %.

Sorption of methylene blue, vitamin B₁₂ and gelatine on the enterosorbent made of the bast of birch bark from aqueous solutions modeling the medium of stomach and intestines was investigated. The corresponding kinetic curves allowing one to estimate the completeness of the use of the sorption potential of enterosorbent in differentmodel media were obtained. Efficient curative and prophylactic action of the enterosorbent for the therapy of esherichiosis in mice was demonstrated.

Features of physicochemical processing of the natural gas of Eastern Siberia for the purpose of obtaining valuable products are considered. Special attention is paid to the processes based on the microspherical components of energy ash: non-cryogenic process of helium isolation using cenospheres, and the process of oxidative dimerization of methane (ODM) into ethane and ethylene in the presence of ferrospheres. A scheme of natural gas processing taking into account the features of composition and involving the stages of ODM is proposed.

Results of investigations, carried out at the Institute of Chemistry and Chemcial Technology SB RAS, concerning the problem of search and development of methods to synthesize new complex compounds of platinum possessing biological activity are presented. Two series of compounds representing the analogues of cisplatin and oxplatin, respectively, are presented. New efficient synthesis procedures were developed, X-ray structural studies of the majority of compounds were performed. Thernal stability and solubility of compounds were established. The data obtained may serve as the basis for the industrial production and arrangement of the modern physicochemical monitoring of the composition and properties of these preparations.

Results of investigations carried out in the Institute of Chemistry and Chemcial Technology in the area of mastering the technologies for obtaining synthetic solid, gaseous and liquid fuel from the brown Kansk-Achinsk coal are generalized. The technologies under development are based on the processes of autothermal pyrolysis and gasification of brown coal in the reactors with the boiling bed of catalytically active slag, and on the processes of thermal dissolution of coal and its mixtures with carbon-contaiing wastes in the presence of activated iron ore catalysts that provide obtaining liquid fuel and binders for road construction.

Results of the investigation of composition features of brown coal from Siberian deposits and the major factors determining its structural properties are presented. Methods of stimulating destructive reactions of hydrogenation into liquid hydrocarbons by means of preliminary activation tratment and the use of catalysts are considered. Investigation was carried out with different coal samples from the Kansk-Achinsk and Lensk basins; for comparison, the data on brown coal from the large deposit Yallourn (Australia) are described. The general regularities of the changes of structural properties are established, as well as the features of the interaction with solvents depending on the content of ion-exchange cations among which calcium cations are prevailing and play the part of ion cross-links in the structure. It is shown that cation removal with diluted HCl solutions, mechanochemical treatment and irradiation with accelerated electrons under optimal conditions allow one to enhance the activity int eh interaction with solvents and to elevate the reactivity during hydrogenating destruction into liquid hydrocarbons.
Results of the investigation of the effect of conditions of mechanochemical treatment of iron ore concentrates on their phase composition and parameters of the fine crystal structure are presented. The conditions of the preparation, on this basis, of dispersed active hydrogenation catalysts providing thorough decomposition of the organic mass of brown coal to form liquid hydrocarbons were developed. The individual and group composition of the obtained light-coloured hydrocarbon fractions of coal hydrogenates was determined. The data were compared with the composition of the corresponding fractions of oil from the major promising deposits of Eastern Siberia. Suitability of liquid coal hydrogenates for obtaining synthetic motor fuel, other oil products and their use as petrochemical raw material was substantiated.

Results of systematic investigation of the physicochemical features of the formation and isomerizing activity of catalysts based on zirconium dioxide modified with sulpahte and tungstate anions and various trivalent cations, depening on the composition and preparation conditions, are presented.

Methods of synthesis of betulin diacetate and dipropionate from birch bark are proposed. The methods are based on combined extraction of betulin from birch bark and its acylation with acetic and propionic acids. The structure of the resulting betulin derivatives was confirmed by means of chromatography - mass spectrometry, FTIR and NMR spectroscopy.

Problems connected with processing of underground polycomponent brines of the Krasnoyarsk Territory are to a large extent due to the remoteness of deposits and the absence of developed infrastructure. The version involving direct extraction recovery of valuable elements in the form of salts is considered. It is shown that the highest salt concentrating degree may be achieved for extraction of calcium bromide and lithium chloride (by a factor of 20 and 40, respectively). A scheme of extraction recovery of calcium bromide with a mixture of tributylphosphate and molecular iodine is proposed. Problems of lithium chloride extraction are considered. For the example of extraction of lithium tetraphenylborate, LiFeCl₄ and Li(ClI₂) in the systems with tributylphosphate, it is established that the growth of steric hindrance for the formation of extracted complexes promotes the recovery of lithium from calcium chloride brines.

Technological problems of processing rare metal ores of the Chuktukon deposit (Krasnoyarsk Territory) are considered. Oxide ferrimanganese ores contain 3-7 % earth oxides in the form of phosphates (monazite, florencite) and 0.5-1 % niobium oxide (chalcolamprite) and are practically undressable. The possibility of their direct chemical processing was studied. A scheme including autoclave nitric acid leaching and extraction of rare earth elements, reductive treatment of leaching tailings and isolation of niobium concentrate into the non-magnetic fraction was proposed. According to this scheme, nitrate solutions are subjected to thermal decomposition in order to recover nitric acid. The pyrometallurgical process of ore reduction leading to cast iron and rare metal products was analyzed. Process realization requires solution of complicated technological problems in obtaining high-quality products.

¹⁹F NMR, IR, Raman and impedance spectroscopy are used to study the ionic mobility, structure, and conductivity of 45ZrF₄-35BiF₃-20CsF bismuth fluorozirconate glass. With the increase in temperature from 150 K to 500 K the fluorine-containing groups pass from the rigid lattice to local movements (reorientations), and then to diffusion. According to the results of IR and Raman spectroscopy, the lattice of this glass consists of ZrF₈ polyhedra linked by their vertices into chains. The glass has high ionic conductivity: σ ≈ 1.8×10^-4 S/cm in a temperature range of 480-485 K.

An analysis of the literature data on the partial molar volume of glycine in an aqueous urea solution at 298 K is performed. The mentioned value linearly increases with the increase in the urea concentration (wt.%). The hydration number of glycine decreases by a factor of 2 when passing from water to the saturated (20m) urea solution.

The new co-crystal copper(II) melamine complex poly[bis(μ-methacrylato)μ-(1,3,5-triazine-2,4,6-triamine)], C₁₉H₂₆Cu₂N₆O₈ (1) crystallizes in the triclinic P-1 space group with a = 8.9670(2) Å, b = 9.4108(2) Å, c = 15.4476(3) Å, α = 96.6090(10)°, β = 100.6270(9)°, γ = 95.5950(10)°. Each Cu(II) exhibits a pseudooctahedral geometry. Four coplanar carboxylate oxygen atoms coordinated to the Cu(II) ion define the basal plane, whereas the apical position is occupied by one nitrogen atom from the melamine ligand. Here, the carboxylato-bridged two dinuclear copper(II) complexes are linked through melamine giving a 1D alternating chain. The structure of 1 consists of a two-dimensional supramolecular layer constructed by intermolecular N-H…N hydrogen bonds of the melamine ligands from adjacent one-dimensional [Cu₂(C₄H₅O₂)₄(C₃H₆N₆)] chains.

The structure of a nickel(II) complex with 2-amino-4-iminopentane is determined by X-ray crystallography at 150 K. Crystal data for C₁₀H₁₈N₄Ni are: a = 10.9802(3) Å, b = 13.5780(4) Å, c = 8.0935(2) Å, β = 107.304(1)°, space group P2₁/c, V = 1152.04(5) ų, Z = 4, d_x = 1.459 g/cm³, R = 0.0283. The structure is molecular; the metal atom is coordinated by four nitrogen atoms of two β-diimine ligands. The Ni-N distances in Ni(NacNac)₂ fall within 1.8571-1.8623 Å. The molecules in the crystal are joined by only van der Waals interactions.

Counter-diffusion of the aqueous solution of Cs_2.75K_1.25[Re₆Se₈(CN)₄(OH)₂] and a water-ammonia solution of NiCl₂ afforded crystals of a rhenium cluster complex trans-{[Ni(NH₃)₅]₂[Re₆Se₈(CN)₄(OH)₂]}·6H₂O. The structure of the complex is determined by single crystal X-ray diffraction. In the structure, nickel atoms have an octahedral coordination environment involving nitrogen atoms of five NH₃ ligands and one CN ligand of the cluster anion. The anion has two bridging CN ligands in the trans-positions.

Reaction of zinc iodide, sodium azide and 2-[(3-dimethylaminopropylimino)methyl]-6-ethoxyphenol (HL) results in the formation of a trinuclear complex [Zn₃L₂(μ_1,1-N₃)₂I₂]. The complex is characterized by elemental analysis, IR spectroscopy, and X-ray crystallography. The complex possesses crystallographic two-fold rotation axis symmetry and crystallizes in the monoclinic system, C2/c space group, a = 23.241(2) Å, b = 10.849(1) Å, c = 17.384(2) Å, β = 120.868(1)°, V = 3762.4(6) ų, Z = 4. The molecule consists of two [ZnL(N₃)I] units connected together by a central Zn atom. The terminal Zn atom is five-coordinated in a trigonal-bipyramidal geometry, and the central Zn atom is six-coordinated in an octahedral geometry. The Zn⋯Zn separation between the terminal and the central Zn atoms is 3.257(2) Å.

The Schiff-base compound N,N′-Bis-(2,5-dimethoxybenzylidene)-1,3-diaminopropan, (2,5-MeO-ba)₂pn, is synthesized and characterized by elemental analysis, FT-IR and ¹H NMR spectroscopy. The crystal structure of (2,5-MeO-ba)₂pn is determined by X-ray single crystal diffraction analysis. The X-ray diffraction analysis at 120 K reveals that (2,5-MeO-ba)₂pn crystallizes in the orthorhombic system, Fdd2 space group with a = 29.339(9) Å, b = 29.4073(11) Å, c = 4.4524(2) Å, V = 3840.8(3) ų, μ = 0.72 mm^-1, and Z = 8.

Ultrasonic velocity and density values are measured for aqueous solutions containing 2.00 mol.%, 4.00 mol.%, and 5.00 mol.% glycine in a temperature range of 15-65°C, 5.50 mol.% glycine (20-65°C), and 6.00 mol.% glycine (25-65°C). Adiabatic compressibilities (κ_S) and molar adiabatic compressibilities (Κ_S) are calculated. The values of κ_S and Κ_S decrease monotonically with an increase in glycine concentrations up to saturation at all the temperatures. The temperature dependences of κ_S and Κ_S have minima that are typical of water and aqueous solutions; the positions of the minima depend on the glycine concentration. The temperature coefficients of the molar compressibility, ∂Κ_S/∂T, change their signs from negative to positive at lower temperatures (by approximately 10 deg) than ∂κ_S/∂T.

The Monte Carlo method is used to calculate the radial distribution functions (RDFs) of Na⁺Cl⁻, Na⁺Na⁺ , and Cl⁻Cl⁻ ion pairs in water clusters that differ both in composition and size. An analysis of the RDFs shows that like-charged ions can approach one another at extremely small distances (direct ion contact) without the participation of a third ion of the opposite sign. The Na⁺Na⁺ (interionic distance 3.5 Å) and Cl⁻Cl⁻ (interionic distance 5.25 Å) ion pairs are most likely to form in very dilute solutions. The composition of ionic associates changes with increasing concentration of ions in the solution (it is indicated by the emergence of the RDF peak at 4.25 Å and its further growth with concentration and by a selective visual analysis of instantaneous cluster configurations) so that groups of three, five, etc. ions of the opposite sign bearing a net charge of 1+ or 1- appear.

The dielectric relaxation spectra (DRS) of 1,2-ethanediol, 1,2-propanediol, and 1,2,6-gexanetriol are analyzed in terms of the Dissado-Hill (DH) model in a wide range of temperatures, with all parameters required for calculating the cluster dipole moments being determined within the DH molecular model itself. The dependence of the equilibrium and relaxation properties of DRS on the hydrocarbon radical length and the number of OH groups is studied. The dipole moments of the clusters are calculated. It is shown how the roles of the processes of intracluster rearrangement are redistributed due to the break of hydrogen bonds and fluctuation processes of synchronous exchange of molecules between the clusters.

Chemical modification of polyethylene glycols by antioxidants belonging to the class of sterically hindered phenols is used to obtain water-soluble conjugates differing in the structure of the joined antioxidant and molecular weight. The inclusion of hydrophobic end groups in polyethylene glycol molecules leads to a decrease in the lower critical mixing point of the solution as compared to the original polymer. Dilute solution viscometry and light scattering are used to determine the molecular-mass characteristics of the polymers and the hydrodynamic radii of single conjugate molecules. The mass fraction of single molecules in aqueous solutions of the conjugates is greater than 95%. The aggregates are micellar-type particles whose core is formed by the hydrophobic moieties of sterically hindered phenols. It is shown that the antiradical activity of the antioxidants 3-(3-tert-butyl-4-hydroxy-5-methylphenyl)-propionic acid and 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid, which are used for the modification, differs only slightly, whereas the activity of the relevant conjugates increases significantly.

Electron microscopy and dynamic light scattering are used to investigate the structuring process of a supramolecular system based on the aqueous solutions of L-cysteine and silver nitrate diluted with liquid water-soluble nonelectrolytes. The gel formation mechanism is discussed.

The physicochemical characteristics of single and mixed zirconia and silica gels produced by the sol-gel technique at different synthesis pH and sequence of introducing the reagents in the mother liquid are presented. As a result of comparing the data obtained by different research methods, it is found that in the mixed gels, irrespective of the synthesis technique, Si-O-Zr bonds are present. The introduction of a zirconium salt in the mother liquid containing a silicate salt leads to the preferred formation of zirconia gel granules of 20-30 nm in diameter enclosed in the matrix of silica gel. The inverse sequence of introducing the gel-forming components in the reaction mixture promotes the formation of large gel aggregates containing the particles of less that 10 nm and having a high degree of polymerization. Mixed gels of zirconium oxyhydrate and silicic acid have an order higher sorptive capacity for yttrium (III) and calcium cations, as compared to single silica gels and zirconia gels.

By means of a variant of the Monte Carlo method (entropic sampling within the Wang-Landau algorithm) the models of the interaction of a neutral polymer with a flat surface are studied. The method yields distribution functions over the energy and the distance from the polymer to the surface. Based on these distributions, excess entropies of the systems and their thermal properties are calculated: internal energy, heat capacity, average radius of gyration, average chain end-to-end distance, and average distance from the polymer to the surface. Continuous and lattice models are considered.

The capacities of the wetting method for the characterization of the surface structure of polymers and surfactant adsorption layers on polymer surfaces and also the determination of the energy characteristics of polymer surfaces at different interfaces, which are used to optimize the choice of polymers in the solution of actual practical problems, are demonstrated.

A method to develop DNA fibrils with a length more than a few tens of micrometers, oriented in one direction on the n- and p-type silicon surface is described. A new simple and effective technique is proposed to produce silver nanowires by electrochemical reduction of silver ions bound to DNA using the obtained fibrils as a template, as a result of which DNA molecules fixed on the surface of the n-type silicon single crystal are uniformly covered by silver clusters with a size of about 30 nm. The proposed metallization procedure of DNA on the n-type silicon surface has an advantage in comparison with a similar one for macromolecules fixed on freshly cleaved mica, glass surface, and р-type silicon. n-Type silicon is not only a substrate, but also a source of electrons for silver reduction. The absence of an additional chemical component (reducer) principally distinguishes the proposed method from the others currently known. Atomic force microscopic images of fixed DNA molecules and prepared nanowires are obtained.

The methods of circular dichroism, ultraviolet spectrophotometry, dynamic light scattering, viscometry, dynamic birefringence, and atomic force microscopy are employed to study the conformational properties of the DNA molecule during its complexation with oligopeptides. Samples with с 2, 3, and 5 monomeric L-lysine residues are used. Experimental data evidence that in the diluted solutions (with a low ionic strength) of DNA with oligopeptides (with 3 and 5 monomeric units) the condensation of the macromolecule is observed at specific peptide concentrations. For the bipeptide the DNA condensation in the solution is not observed. In the DNA solutions with a high ionic strength (1 M NaCl), oligopeptides do not affect the macromolecule size.

The radioprotective action of caffeine upon γ irradiation of DNA solutions is demonstrated by means of low gradient viscometry, flow birefringence, atomic force microscopy and UV spectroscopy. In the presence of caffeine, a decrease in the radiation effect on the DNA coil size in the solution, in the number of double-stranded breaks and damaged nitrogen bases, and in the degree of radiation-induced denaturation is observed.

Methods of spectrophotometry, spectropolarimetry, and viscometry are used to study the self-organization in the solution of crown-containing actinocin derivative (I) exhibiting antitumor activity and the interaction of the formed aggregates with a DNA molecule. The presence of the 4′-benzo-15-crown-5 radical in the structure of the studied compound determines the observed differences in its complexation with Na⁺ and K⁺ ions. The process of aggregation in the presence of K⁺ ions is accompanied by a shift of the long-wave band in the absorption spectrum to short-wave (the formation of H type aggregates) or long-wave (the formation of J type aggregates) regions depending on the K⁺ ion concentration in the solution. In the presence of Na⁺ ions, regardless of their concentration in the solution, J type aggregates form. A scheme of complex formation and their mutual transformations with changes in the ionic composition of the medium is proposed. A study of the interaction of this compound with DNA shows that in the presence of K⁺ ions it binds to the DNA molecule in the form of monomers and/or dimers without producing large supramolecular aggregates. The H and J structures formed in K⁺-containing solutions of compound I are broken in the interaction with DNA. If a solution of compound I is added to a DNA solution containing Na⁺ ions, the J type aggregates are formed directly on the surface of the DNA molecule. At the same type, the J structures originally formed in the Na⁺-containing solution of compound I practically do not interact with DNA. A study of this system shows that the introduction of the crown group in the compound molecule with a heterocyclic chromophore provides the opportunity to affect its affinity and binding to the DNA molecule by means of the ionic composition of the medium.