Home – Home – Jornals – Contemporary Problems of Ecology 2013 number 4

The carbonate sediments from the Vendian–Cambrian shelf of the Tuva–Mongolian microcontinent were dated by Sr and C isotope chemostratigraphy. Analysis of the Sr-isotopic characteristics (0.70725–0.70873) and δ ¹³C variations (+10.5 to –3.5‰), as well as their comparison with the data on the key sections of Siberia, Africa, Central Asia, Australia, South America, and Spitsbergen, showed that the carbonate sedimentary cover of the Tuva–Mongolian microcontinent accumulated at 600–520 Ma and the carbonate sediments of the Muren Formation and the basal horizons of the Bokson Group near the Ukha-Gol River are the oldest. Their sedimentation followed the Marinoan global glaciation.

Two intrusive complexes are recognized at the Shakhtama deposit: Shakhtama and ore-bearing porphyry. The U–Pb zircon dates (SHRIMP II) are 161.7 ± 1.4 and 161.0 ± 1.7 Ma for the monzonites and granites of the Shakhtama complex and 159.3 ± 0.9 and 155.0 ± 1.7 Ma for the monzonite- and granite-porphyry of the ore-bearing complex. The igneous complexes formed in a complex geodynamic setting in the late Middle Jurassic and early Late Jurassic, respectively. The setting combined the collision of continents during the closure of the Mongol–Okhotsk ocean and the influence of mantle plume on the lithosphere of the Central Asian orogenic belt. The intrusion of the Shakhtama granitoids took place at the end of the collision, and the intrusion of the porphyry of the ore-bearing complex, during the change of the geodynamic setting by a postcollisional (rifting) one. The complexes are formed by monzonite–granite series with similar geochemical characteristics of rocks. The performed geological, geochemical, and isotope-geochemical studies suggest that the sources of magmas were juvenile crust and Precambrian metaintrusive bodies. The juvenile mafic crust is considered to be the predominant source of fluid components and metals of the Shakhtama ore-magmatic system. The granitoids of both complexes include calc-alkalic high-K rocks with typical geochemical characteristics and with characteristics of K-adakites. These geochemical features indicate that the parental melts of the former rocks were generated at depths shallower than 55 km, and the melts of the latter rocks, at depths of 55–66 km. K-adakite melts resulted from the melting of crust submerged into the mantle during the lithosphere delamination, which was caused by the crust thickening as a result of the repeated inflow of basic magma into the basement of the crust and of tectonic deformations in its upper horizons. The high-Mg monzonitic magma produced under these conditions was mixed with melts in the upper horizons, which accounts for the high Mg contents of the Shakhtama granitoids. The similar compositions and petrogeochemical characteristics of the granitoids of the Shakhtama and porphyry complexes point to the same sources, transport paths, and evolution trend of their parental melts. This indicates that the igneous rocks of both complexes are products of the same long-living magmatic system, which produced Mo mineralization at the final stage. The favorable conditions for the ore production in the magmatic system during the formation of the porphyry complex were induced at the preceding stage — during the formation of the Shakhtama complex, which we regard as a preparatory stage in the evolution of the ore-magmatic system.

Global manifestations of Early Paleozoic granite formation in the Central Asian Mobile Belt and some other orogenic areas worldwide are considered. The work is based on the author’s studies of Early Paleozoic granitoids from the Altai–Sayan and West Transbaikalian orogenic areas as well as abundant literature data on other world provinces. Special attention is paid to the scales of granitoid magmatism in the Early Paleozoic, its geodynamic settings, periods, and stages, compositional evolution over time, lateral variability in structures of different types, relationship with LIPs, and, correspondingly, connection with mantle plumes and superplumes.

Dikes of biotitic shonkinites and minettes of the complex Ryabinovyi alkaline massif (Central Aldan) have been studied. The dikes are localized in a neck of K-picrites in the northeast of the massif, which intrudes gold-bearing microcline–muscovite metasomatites (Muscovitovyi site). The obtained data on the chemical and trace-element compositions of the rocks and minerals and study of melt inclusions in clinopyroxenes indicate that the biotitic shonkinites and minettes crystallized fr om the same deep-seated high-pressure alkaline ultrabasic magma during its evolution. Apparently, at the early stage of crystallization of diopside in the biotitic shonkinites, homogeneous carbonate–silicate melt was separated into immiscible fractions of silicate, carbonate–salt, and carbonate melts. The temperature of melt immiscibility was >1120–1190 °C, i.e., higher than the homogenization temperature of silicate inclusions in the diopside. The contents of trace elements in the biotitic shonkinites and rock-forming clinopyroxenes were one or two orders of magnitude higher than the mantle values. The Eu/Eu* ratios of both the considered rocks and the clinopyroxenes were close to those of chondrites, which testifies to their crystallization from mantle magma. The HREE/LREE ratio indicates that the magma source was localized at the depths wh ere garnet-spinel assemblages existed. The negative Nb and Ti anomalies in the trace-element spectra and the high (>5) La/Nb ratios in the rocks and clinopyroxenes point to the influence of crustal material on the parental magma. Crystallization of magma took place in reducing conditions, which is evidenced by the low (4–7) Ti/V ratios in clinopyroxenes and the presence of chloride–sulfate inclusions in them. Since gold in the Ryabinovyi massif is associated with late sulfate–chloride and sulfate–carbonate fluids, it might have been transported by alkaline chloride–sulfate and carbonate (carbonatite) melts, found as inclusions in clinopyroxenes of the biotitic shonkinites, at the early stages of Mesozoic magmatism.

Some geological, petrochemical, and geochemical characteristics of carbonaceous shales as a new unconventional natural source of gold and PGE are considered by the example of the Kimkan and Sutyr’ units of the Bureya massif (southern Far East, Russia). It is shown that shales of the units belong to the terrigenous-carbonaceous and siliceous-carbonaceous formations. They accumulated in deep-water trenches, and the active continental margin was probably their main provenance. The carbonaceous terrigenous units and precious-metal ores in them show specific petrochemical characteristics different for complexes with predominantly PGE and gold mineralization. According to these characteristics, carbonaceous complexes with high Fe contents, low total contents of alkalies, and high K/Na ratios are promising for PGE-rich ores. Gold ores are usually localized in black-shale strata with high total contents of alkalies and low K/Na. In this respect, the shales and Fe-ores of the Kimkan unit obviously contain high-PGE mineralization, while the rocks of the Sutyr’ unit can bear gold deposits. We assume that the PGE mineralization is genetically related to the formation and transformation of carbonaceous rocks. At the same time, most of gold in the carbonaceous shales is native and is not related to carbon; it is present in mineral assemblages resulted from superimposed sulfidization and silicification.

Thermodynamic modeling of equilibria in the system water–rock–organic acids was used to study the influence of organic acids on Ca and Mg redistribution between a solution and a solid phase in connection with the use of calcites of variable composition Ca _x Mg _1–x CO ₃ as indicators of paleoclimatic environments. In the thermodynamic model, high-molecular humic substances (fulvic + humic acids) were represented by a set of independent metal-binding centers. Therefore, their number was preset based on the given density of proton- or metal-binding sites. The numerical implementation of several geochemical situations involving the dissolution/deposition of calcites with different Mg contents showed that the main effect of fulvic and humic acids is the acidification of solutions and the reduction of carbonate stability. Although humic substances can play an important role in fixing Ca and Mg and removing them from solution, their actual concentrations in natural media (<<1 g/L) do not cause significant changes in the composition of Ca_x Mg _1–x CO ₃ phases. On the other hand, there is quantitative evidence that variations in the Mg/Ca ratio in a solution and a solid phase are significantly influenced by the evaporative concentration of Mg-oversaturated solutions, alkalization/acidification during their evolution, or CO₂ content variations owing to changes in climate and lake activity.

Gold–silver sulfoselenides of the series Ag₃ AuSe_x S_2–x (x = 0.25; 0.5; 0.75; 1; 1.5) were synthesized from melts on heating stoichiometric mixtures of elementary substances in evacuated quartz ampoules. According to X-ray single-crystal analysis, the compound Ag₃ AuSe_0.5S_1.5 has the structure of gold–silver sulfide Ag₃AuS₂ (uytenbogaardtite) with space group R 3 c . The volume of this compound is 1.5% larger than that of the sulfide analog. According to powder X-ray diffractometry, compounds Ag₃ AuSe_0.25S_1.75 and Ag₃AuSe _0.75S_1.25 also show trigonal symmetry. Compounds Ag₃AuSeS and Ag₃AuSe _1.5S_0.5 are structurally similar to the low-temperature modification of gold–silver selenide Ag₃AuSe ₂ (fischesserite) with space group I 4₁32. These data suggest the existence of two solid solutions: petzite-type cubic Ag₃AuSe₂–Ag ₃AuSeS (space group I 4 ₁32) and trigonal Ag₃AuSe_0.75S_1.25 — Ag ₃AuS₂ (space group R 3 c ). It was found that fischesserite from the Rodnikovoe deposit (southern Kamchatka) contains 3.5–4 wt.% S. At the Kupol deposit (Chukchi Peninsula), fischesserite contains up to 2.5 wt.% S and uytenbogaardtite contains up to 5.3 wt.% Se. At the Ol’cha and Svetloe (Okhotskoe) deposits (Magadan Region), uytenbogaardtite contains up to 0.5 and 1.8 wt.% Se, respectively. Literature data on the compositions of silver—gold selenides and sulfides from different deposits were summarized and analyzed. Analysis of data available on the S and Se contents of natural fischesserite and uytenbogaardtite confirms the miscibility gap near composition Ag₃AuSeS.

The procedure of the selection of halfwidths of absorption spectral lines measured in different works for intermolecular potential determination is proposed. The procedure is based on the analytical model for half-widths. Two examples connected with spectral lines of 2ν₁ + ν₂ + ν₃ vibrational band of H₂O molecule and ν₂ band of H₂S molecule broadened by helium pressure are discussed.

A technique for computer reconstruction of the pressure signal shape from the pulse microphone signal is offered. It is shown that the time of collisional relaxation of molecules from the excited state to the ground one can be measured on its basis with the use of a time-resolved photoacoustic spectrometer.

We present the observations results of aerosol disturbances in the stratosphere in the second half of 2011; the observations were performed at stations of CIS lidar network CIS-LiNet in Minsk (53.9°N; 27.60°E), Tomsk (56.5°N; 85.0°E), and Vladivostok (43.0°N; 131.9°E). Based on the lidar measurement data at the sensing wavelengths of 353, 355, and 532 nm, an increased aerosol content was observed in the lower stratosphere up to altitudes of 18 km from June–July and practically until the end of 2011. A well-defined and temporally stable aerosol layer was observed until October 2011 in the altitude range 13–17 km. An increased aerosol content in the lower stratosphere was observed until January 2012. The trajectory analysis of air mass transport in the stratosphere on the basis of NOAA HYSPLIT MODEL with the use of CALIPSO satellite data shows that the observed increased aerosol content was due to the transport of eruption products of Grimsvötn volcano (May 21, 2011, Iceland: 64.4°N; 17.3°W).

In the present paper, the potential capabilities of lidar measurements of the atmospheric density in the middle atmosphere are analyzed. Calculations are performed for a lidar with quite moderate specifications: transmitter comprising a solid Nd:YAG-laser with a wavelength of 532 nm, pulse energy of 0.8 J, and repetition frequency of 20 Hz; and receiving system comprising primary mirrors with radii of 0.3 and 0.5 m, field-of-view angles of 0.1 and 1 mrad, and spectral widths of the filter of 0.5, 1, and 10 nm. The signal acquisition time is 10 min for spatial resolution of 1 km. Three sensing options are analyzed: from the ground level, from an aircraft (at 10-km flight altitude), and from an ISS with orbit altitude of 414 km.

Algorithms for reconstruction of the Earth’s surface reflection coefficient from the data of satellite measurements are suggested. They allow the main components of radiation, forming an Earth’s surface image, to be taken into account with different degrees of accuracy. The algorithms involve a solution of the radiative transfer equation with the use of the linear system theory, Monte Carlo method, approximation formulas, and criterion of image isoplanarity. The algorithms are validated based on numerical experiments and comparisons with results of calculations by other authors.

The results of numerical simulation of aerosol radiative forcing for three regions of the Ocean are presented: the coastal area of Antarctica, the Sea of Japan, and the Sea of Darkness. In the simulation of aerosol radiative forcing in these regions the results of ship measurements of aerosol optical depth and water vapor content are used. Data on the single scattering albedo and asymmetry factor are represented by the model (coastal Antarctica – model OPAC) and long-term observations at AERONET photometric stations (Sea of Japan – Noto site and the Sea of Darkness – Cape Verde site). Calculations showed that cooling effect of aerosol over the Japan Sea/Sea of Darkness on the borders of atmosphere increases by about an order of magnitude as compared to the clear atmosphere near Antarctica. In this case, the daily averaged values of the aerosol radiative forcing change as follows: at the level of the underlying surface from –2.3 (Antarctica) to –30.3/–32.6 W/m² (Japan Sea/Sea of Darkness), at the top of the atmosphere from –1.9 to –16.1/–18 W/m². The estimates obtained are in good agreement with the results of other authors.

The low clouds conditions over the territory of the Siberian region are researched, using the 47-year (1966-2012) observation data of 25 meteorological stations. The spatial distribution of the seasonal average values of the amount of low-level clouds and their frequency according to five gradations (amount of clouds: 0, 1-3, 4-6, 7-9, and 10), as well as the cloud base heights and its standard deviations was analysed for four seasons (winter, spring, summer, autumn).

The results of the analysis of climatic changes of the amount of low clouds over the territory of Siberia for the last 47 years (1966-2012) are presented according to the data of ground-based meteorological observations of 25 stations with annual and seasonal averaging. It has been found that the significant long-term fluctuations of the lower clouds are typical for the concerned period (relative to the standard of the 1966-1975 or 1976-2005). The amount of low clouds increased everywhere at the end of the XX century and at the beginning of the XXI (from 1976 to 2005), when global warming was observed over the territory of the Northern hemisphere. Over the period of the started cooling (2006-2012) a significant decrease of the amount of low clouds has been observed over the Western Siberia, and the marked weakening of its growth has been observed over the Eastern Siberia.

The description of an automated multi-wavelength path photometer, which serves for the convenience of transparency measurements of the atmospheric surface layer (the total length of optical path is 1000 meters) at 13 discrete points of the wavelength range 0.45÷4.6 mm. The fundamental difference of the photometer from the previous version is that all receiving modules with their interference filters and optimally matched optical radiation detectors are rigidly fixed in a circle on the fixed panel. At the center of this panel on the axis of a step motor, a small flat mirror is fastened, directing the incoming radiation to the appropriate collecting module according to the program.

The simple and effective method (technique) of the leakage test of the respiratory system using medical ventilation apparatus and laser photoacoustic leak detector “LaserGasTest” was suggested. The technique was tested in model experiments and experiments on animals. Sulfur hexafluoride is inert and biologically harmless gas and its concentration in medical ventilation apparatus does not exceed 5000 mg/m³ (0.077%). The proposed technique provides precise location and size of leakage.

In this paper the dependence of snow water dielectric characteristics on pollutants accumulated in snow cover for all the period of snow accumulation is defined. The results of calculation of dielectric characteristics considering the accumulated pollutants are presented. A technique that characterizes the impacts of accumulates pollutants in snow cover on the dielectric properties of snow water using regression analysis is suggested.

The dependence of energy characteristics of a CuBr laser of an average active volume with and without HBr addition on the rate of the current rise is under study. The variation of the energy characteristics is conditioned by connecting an additional inductance in the discharge circuit. It is shown that at the increase of the inductance up to 4 mH, the average lasing power of the CuBr laser decreases tenfold. Under similar conditions, the average generation power of the CuBr laser with HBr addition decreases by less than two orders of magnitude. The portion of yellow line generation also changes by a less degree. Thus, the presence of the electronegative addition to the CuBr laser active medium decreases requirements to the pulse power supply.

The interaction of the Tunguska cosmic body and the Chelyabinsk object (Chebarkul meteorite) with the atmosphere has many common characteristics. The water vapor, caused by fragmentation of objects before their penetration in the atmosphere, was registered at the altitude of the mesopause in both events. The rainbow bands, which were seen in the tail of the Tunguska body, are connected with refraction and reflection of sunny rays in horizontal (parhelic) ring. A forming of explosion rejections of the substance from the Chelyabinsk object with a speed of ~ 1 km/s (which is typical for comets) and a fragmentation of the object outside the atmosphere lead to conclusion about the comet nature of the Chelyabinsk object.

Connections between the vegetation zone boundaries and some climatic indexes are discussed. Possible changes of the boundaries of vegetation subzones at the territory of European Russia and West Siberia are predicted within the framework of one of the scenarios of global warming. The revealed regularities allow us to propose a mathematic-cartographical model of vegetation zonality for the period of 2046–2065.

The present situation in the systematics of such a widespread genus as birch (Betula L.) involves complications. The attempts to study a large number of the species of this genus, described in Siberia and in the Russian Far East, strike on an insurmountable obstacle – impossibility to detect them for the second time, or, relying on the described characters, to find the species identical to the type samples. Very high variability of all the characters is typical for these species. In the southern regions of West Siberia, this relates to Betula pendula and B. microphylla, while in East Siberia and in the northern regions of Russian Far East this relates to Betula pendula (=B. platyphylla) and B. lanata. Intense and widespread hybridization exists between these species; in this connection, studies of this species over the whole territory of Northern Asia began. The studies were carried out for more than 40 years. By present, many works in periodical issues and several monographs have been published on the basis of the results obtained in numerous expeditions. In the present paper, the role of natural hybridization in plant systematics is demonstrated for Siberian birch species as example, and the necessity to have a distinct notion of hybridization processes over large territories that include the ranges of contacting species is stressed. It is a hopeless matter to solve the problems of systematics studying only small local populations.

Accumulating evidence has shown that the scaling exponent (α) of the aboveground biomass-density relationship is not a constant value. Debate continues over what determines the variation in α. By measuring foliar stable carbon isotope, plant morphological traits and α along an aridity gradient from eastern to Western China, we confirmed that the variation in α was accounted for by changes in plant morphological traits which are adaptive strategies for enhancing water use efficiency during drought stress. This information can be crucial for understanding and predicting community and ecosystem processes.

The leaf mesostructure of several Araliaceae species has been investigated in the plants growing in the Russian Far East. Araliaceae species reveal variability in quantitative traits of the leaf, which is dependent on the ecological conditions of their habitats and life forms. Comparative description of their adaptive capacity in relation to the light and water regimes is given.

Large-scale studies of the mycocomplex of Eurasian Arctic were carried out, with the model group of macromycetes – clavarioid fungi as an example. The species composition was revealed in all longitudinal sectors and latitudinal subzones; its comparative analysis was carries out. It was established that the clavarioid life form is best adapted to the extremal psychrophilic conditions of Arctic among other groups of aphyllophorous fungi. It is demonstrated that ocean-side sectors are most rich, while the continental ones are essentially scanty. The distribution of the species composition of fungi agrees with the similar distribution for flowering plants, especially for hemicryptophytes. The annual amount of precipitation appears as the leading climatic factor. The established differences allow one to subdivide the Eurasian Arctic into four mycogeographic regions: Atlantic (European), Siberian, Chukotka (Bering) region, and the High Arctic.

Polypore fungi in the forest-steppe zone of West Siberia were studied, their ecological features were revealed. The xylobiont complex is represented by 128 polyporoid species, among them 120 species develop on the basic forest-forming woody plants. The distribution of polypores species over the breeds of substrate-forming plants was studied, the features of species distribution, their relations on living trees and on dead wood were analyzed, as well as the features of species distribution over topical niches.

Results of the studies of pathogenic micromycetes developing on the leaves of woody plants in the urban ecosystems of the southern part of the West Siberian region are presented. The number of pathogenic species revealed was 101. The existence of common regularities in the structure of micromycete complexes for five Siberian cities and for different gardening objects was established.

Geostatistical techniques were used to assess the spatial patterns of spores densities and biovolume of arbuscular mycorrhizal fungi (AMF) in soils from two contrasting vegetation communities: an Ephedra distachya -ephemeral plant vegetation community and an Eremurus anisopteris vegetation community. Also evaluated was the relationship between the spatial distribution of spore densities and biovolume of AMF and soil properties. Spatial dependence of spore densities and biovolume of AMF were exhibited further by kriged maps. The results showed spore density and biovolume indicated strong spatial autocorrelation and a patchy distribution within both sites. However, the patch size of genera and biovolume of AMF differed between the two communities. The correlation between distribution of spore and biovolume of AMF and distribution of soil parameters was expressed by Spearman rank-correlations coefficients. These results suggest that spore or biovolume distribution of AMF was affected significantly by some soil properties.

The regularities of the typical stages of self-recovery (regeneration) of the subpopulation structure of Soldanella hungarica Simonk. after rigid local destructions were generalized relying on the results of multi-year (1974–2011) monitoring on permanent test grounds of the Institute of Carpathian Ecology, NAS of Ukraine, situated near the upper boundary of spruce forest in the Carpathian mountains. It was revealed that under the experimental conditions the point impacts of this kind do not cause general destabilization of population processes. However, they initiate behavioral reactions aimed at the mobilization of population reserve of S. hungarica at closely located territories. Unequal roles of individual and group effects in this phenomenon were revealed. The conclusion concerning the determining importance of the vitality composition for the results of the local regeneration of S. hungarica population was made. It was stated that self-recovery of the structure of S. hungarica on experimental grounds is a long-standing process requiring several ten years.

Evaluation of state of 22 cenopopulations of Hedysarum theinum situated in the sub-alpine and alpine vegetation belts in Kazakhstan and the Republic of Altay was made according to the set of traits. It was revealed that the most favorable conditions for this species are those of the sub-alpine belt (12 CP), where the sums of scores for organism and population features vary from high to medium values. The pessimal state, which is characterized by the smallest values of the majority of parameters of the species, was revealed in the alpine vegetation belt at the altitude of about 2000 m above the sea level in the Rudniy Altay (Kazakhstan) and in scrub communities at the joint of the alpine and subalpine belts at the edge of the range of H. theinum in Russian Altay. The reactive-tolerant type of the population strategy of H. theinum was revealed.

Results of the studies of 20 natural cenopopulations (CP) of the rare species Althaea officinalis L.in the Republic of Bashkortostan, growing at the northern boundary of the range, are reported. The demographic structure, morphometric parameters and the vital state of individuals were studied, the optimal conditions of existence were determined. The majority of the studied cenopopulations A. officinalis are distinguished by the low density (1–4 individuals/m²) and incomplete ontogenetic spectrum. The vitality type of the cenopopulations of A. officinalis changes from prosperous to depressive. The ecological and phytocenotic optimua do not coincide for the majority of CP. The optimal growing conditions for A. officinalis occur in reed near-bank communities, along the periphery of Phragmites australis stand. Worsening of the vital state of A. officinalis CP is observed in the communities perturbed by depasturage.

Results of the studies of the flavonoid content and structure of Bistorta vivipara (L.) Delarbre from the natural habitats of Siberia are discussed. The plants growing under the conditions of enhanced insolation at the altitude of 1500 m above the sea level and higher accumulate a significant amount of flavonoids, even the conditions of superfluous humidity, low temperature of air and soil in a high-mountain tundra zone do not counteract their biosynthesis. The flavonoid content in the plants of shaded habitats is lower. It is quite probable that these pigments play a role of filters protecting plant tissues from the unwholesome influence of ultraviolet radiation, and the altitude of locality above the sea level is one of the leading ecological factors. Adaptation of plants to the UV radiation occurs due to the shielding compounds of the epidermal cells. Flavonol aglycones in the plants collected at the territory of the Altay were studied for the first time by means of HPLC. Three aglycons have been detected: myricetin, quercetin and kaempferol. The major aglycone of B. vivipara is quercetin (to 5,8 % in flowers, 6,8 % in leaves).

Results of the comparative analysis of lipid and fatty acid composition of the roots, leaves and fruit of the dwarf and tall forms of Siberian apple growing under the conditions of different water supply are described. It was discovered that adaptation to decreased water supply in different ecological forms of apple within the same species involves biochemical changes in the amount and quality of total lipids and phospholipids. Noticeable differences in the chemical composition of the two forms of apple were demonstrated in the level of unsaturation of fatty acids and phospholipids. The most significant differences in the fatty acid composition were detected between the root tissues of the two apple forms. It is assumed that these differences are caused by differences in water supply, which can be one of the reasons of the formation of the dwarf status of Siberian apple; possible participation of the lipid pool in this process is also assimed.

A new Schiff base cobalt(III) complex with the formula [CoL¹L²(N₃)]×NO₃ (L¹ is 2-[1-(2-phenylaminoethylimino)ethyl]phenolate, L² is N-phenylethane-1,2-diamine) is prepared and characterized by physicochemical methods and single crystal X-ray determination. The complex crystallizes in the triclinic system space group P-1, with a = 8.504(2) Å, b = 14.973(3) Å, c = 20.676(4) Å, α = 100.021(3)°, β = 90.005(3)°, γ = 103.084(2)°, V = 2523.0(9) ų, Z = 4, R₁ = 0.0732, and wR₂ = 0.1182. Single crystal X-ray diffraction analysis reveals that the complex contains two mononuclear [CoL¹L²(N₃)]⁺ cations and two nitrate anions. The Co atom is six-coordinated in an octahedral geometry. The ligands and the cobalt(III) complex are screened in vitro for their antibacterial activity against Bacillus subtillis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aereuguinosa.

Molecular and crystal structures of dimephosphone nicotinoylhydrazone and dimephosphone iso-nicotinoylhydrazone exhibiting antiphthisic activity are studied. In contrast to aroylhydrazones of arylaldehydes, existing in the crystalline state as a mixture of two amide conformers, the studied hydrazones exist in the crystalline state in the single geometrical form E_C=NE_N—NZ_N—C(О).

The origin of the magnetic field effect on the dimerization of aluminum(III) and gallium(III) phthalocyanine chloride films is revealed. The EPR technique is employed to demonstrate that the dimerization of the above coordination compounds occurs via a free radical pathway with the formation of phthalocyanine and OH radicals, thus resulting in the appearance of the magnetic moment in the studied compounds.

[Pt₃S₂(P(CH₂OH)₃)₆](PF₆)(OH)×H₂O (1) is obtained by a reaction of [Pt₃S₂(P(CH₂OH)₃)₆]Cl₂ with NH₄PF₆. The crystal structure of 1 was determined by a single crystal X-ray diffraction analysis (space group R3c a = 12.0042(2) Å, c = 52.6879(11) Å, V = 6575.2(2), Z = 6, C₁₈H₅₇F₆O₂₀P₇Pt₃S₂, d_x = 2.385 g/cm³, T = 150 K, R₁ = 0.044 for 2123 F₀ > 4δ(F) until 2θ_max = 63°). The cations contain a {Pt₃(μ₃-S)₂}²⁺ core with nonbonding Pt…Pt distances of 3.1536(6) Å. The Pt atoms are in a square planar environment; the Pt–S and Pt–P bond lengths are 2.3586(16) Å and 2.260(2) Å respectively.

Single crystal X-ray diffraction is used to determine the crystal structure and conformational features of 9-(furan-2-yl)-4,5,6,7,8,9-hexahydro[1,2,3,4]tetrazolo[5,1-b]quinazoline obtained by three-component cyclocondensation of furfurol, 5-amino-1Н-1,2,3,4-tetrazole, and cyclohexanone.

The title compound C₂₄H₂₂ClNO₂ belongs to the orthorhombic system, space group Pca2₁ with a = 12.1771(10) Å, b = 4.9305(4) Å, c = 34.419(3) Å, α = β = γ = 90°, V = 2066.5(3) ų, Z = 4, D_c = 1.260 g/cm³, F(000) = 824, R = 0.0402 and wR = 0.1144, S = 1.034, T = 293 K. The compound is a chalcone with 4-chlorophenyl and [(5-ethyl-pyridin-2-yl)-ethoxy]-phenyl substituents bonded at the opposite ends of a propenone group, the biologically active region. The propenone bridge makes dihedral angles of 10.61(23)° and 62.75(22)° respectively, with 4-chlorophenyl and the [(5-ethyl-pyridin-2-yl)-ethoxy]-phenyl group.

A co-crystal is obtained in a methanolic solution from methyl 2-(3-chloro-4-methyl-2-oxo-2H-chromen-7-yloxy)acetate and 2-(2-aminophenyl)benzothiazole. In the crystal these molecules are connected via usual N—H…O and weak C—H…O H-bonds. The co-crystals are very stable.