Home – Home – Jornals – 2013 number 5

Based on geological data and the geochemical and isotopic (Sr, Nd) parameters of the Devonian volcanic associations of the Minusa basin, the main regularities of volcanism development are considered, the composition of magmatic sources is studied, and the geodynamic mechanisms of their involvement in rifting are reconstructed. The early stage of formation of the Minusa basin was characterized by intense volcanism, which resulted in differentiated and, more seldom, bimodal volcanic complexes composed of pyroclastic rocks and dolerite sills. At the late stage, only terrigenous deposits accumulated in the basin. It has been established that the basites are similar in composition and are intermediate in geochemical characteristics between intraplate rocks (OIB) and continent-marginal ones (IAB). The basites, like OIB, have high contents of all lithophile elements, which is typical of enriched mantle sources, and, like IAB, show negative anomalies of Nb, Ta, Ti, and, to a smaller extent, Rb, Th, Zr, and Hf, selective enrichment in Pb and Ba (and, sometimes, Sr), and a weak REE differentiation (7 < (La/Yb) N < 17). In contrast to the basins in other segments of the Devonian Altai–Sayan rift area, the igneous-rock associations in the Minusa basin are characterized by a worse expressed geochemical inhomogeneity of rocks and lack of high-Ti (>2 wt.% TiO2) basites. The Sr and Nd isotope compositions of the Minusa basites deviate from the mantle rock series toward the compositions with high radiogenic-strontium and low REE contents. This points to the melting of a mantle substratum (PREMA-type) and carbonate-rich sedimentary rocks, which were probably assimilated by basaltic magma. The correlations between the contents of trace incompatible elements in rocks with SiO2 = 53–77 wt.% testify to the assimilation of crustal substrata by parental basaltic melts and the subsequent differentiation of contaminated magmas (AFC model). We propose a model for the formation of primary melts with the simultaneous participation of magmatic sources of two types: plume and fluid-saturated suprasubductional, localized beneath the active continental margin.

This paper presents mineral reactions in metapelites and estimations of PT -conditions of metamorphism for paragranulites of the Irkut block of the Sharyzhalgai uplift (Siberian Platform). The geothermometeric data based on exchange reactions and the contents of Na in cordierite and Ti in zircon indicate that the peak temperature of metamorphism reached ca. 800 °C at 6–7 kbar. The observed mineral reactions suggest that the pressure decreased to ca. 3 kbar at the retrograde stage of metamorphism.

We performed a thermomagnetic analysis of 91 samples and a probe microanalysis of five samples of sedimentary rocks from the lower zone of the borehole BDP-98 drilled at the bottom of Lake Baikal. The results show the scarcity of native iron: It was found only in five samples. Its concentration varies from ~10–5 to 7·10–4 %. The distribution of native-iron concentrations is bimodal, with a distinct “zero” mode. This scarcity of native iron in the Baikal sediments distinguishes them from continental (Eurasia) and oceanic (Atlantic) sediments of different ages. It is due to the high rate of sedimentation in the studied interval of BDP-98.

The chemical composition of bottom sediments in the Chukchi and, partly, East Siberian Seas was studied. In the south and west of the Chukchi Sea, a zone has been detected with the accumulation of sediments rich in organic carbon, an increased background content and anomalies of sulfophile metals (Mo, Zn, Hg, Ag, Au), iron group metals (V, Ni, Co), and some PGE (Ru, Pt). This zone is confined to the neotectonic active system of rift troughs extending fr om Bering Strait and the eastern Chukchi Peninsula to the continental slope, wh ere it is bounded by the Cenozoic Charlie rift basin of the Canadian hollow. The geochemical features of the carbon-enriched sediments evidence that they formed under oxygen-deficient conditions and, sometimes, in suboxic and anoxic environments near endogenic water and gas sources. The high carbon and metal contents suggest that the fine-grained sediments in the rift troughs of the Chukchi Sea are a possible analog of some types of ancient highly carbonaceous sediments belonging to black shales.

In geologic objects of different characters and scales, the fractal properties of topography are related to the intensity of endogenic energy flows and the composition of geologic complexes. A good correlation between the topographic differentiation of the Khibiny pluton and the variables of different levels of its structural and compositional organization (mineral and chemical compositions of the rocks and minerals, rock texture, etc.) suggests that topography formation is an element of the self-organization of the Khibiny pluton. Analysis of the fractal dimensionality of topography in the Khibiny pluton, Primorye, and detailed areas in Transbaikalia revealed a coincidence of its maxima with the position of ore clusters, fields, and deposits, i.e., areas with the contents of elements significantly higher than their clarkes. All the above data suggest that the fractal properties of topography can be used as a prospecting criterion.

The Middle Oxfordian to lowermost Upper Kimmeridgian ammonite faunas from northern Central Siberia (Nordvik, Chernokhrebentnaya, and Levaya Boyarka sections) are discussed, giving the basis for distinguishing the ammonite zones based on cardioceratid ammonites of the genus Amoeboceras (Boreal zonation), and, within the Kimmeridgian Stage, for distinguishing zones based on the aulacostephanid ammonites (Subboreal zonation). The succession of Boreal ammonites is essentially the same as in other areas of the Arctic and NW Europe, but the Subboreal ammonites differ somewhat from those known from NW Europe and Greenland. The Siberian aulacostephanid zones – the Involuta Zone and the Evoluta Zone — are correlated with the Baylei Zone (without its lowermost portion) and the Cymodoce Zone/lowermost part of the Mutabilis Zone (the Askepta Subzone) from NW Europe. The uniform character of the Boreal ammonite faunas in the Arctic makes possible a discussion on their phylogeny during the Late Oxfordian and Kimmeridgian: The succession of particular groups of Amoeboceras species referred to successive subgenera is revealed by the occurrence of well-differentiated assemblages of typical normal-sized macro- and microconchs, intermittently marked by the occurrence of assemblages of paedomorphic “small-sized microconchs” appearing at some levels preceding marked evolutionary modifications. Some comments on the paleontology of separate groups of ammonites are also given. These include a discussion on the occurrence of Middle Oxfordian ammonites of the genus Cardioceras in the Nordvik section in relation to the critical review of our previous paper. The discussion shows that the oldest deposits in the section belong to the Middle Oxfordian, which results in the necessity for some changes in the foraminiferal zonal scheme of Nikitenko et al. The ammonites of the Pictonia involuta group are distinguished as the new subgenus Mesezhnikovia Wierzbowski and Rogov.

A theoretical study has been performed to check the possibility of using ultrabroadband nanosecond electromagnetic pulses as a geosteering tool for horizontal drilling to estimate the distance to the oil–water contact (OWC) in a floating oil accumulation. The voltage of a microwave-bandwidth pulse at the dipole receiver of a downhole radar was modeled for the case of a horizontal borehole near OWC in a formation saturated with oil and water. Numerical solutions to the boundary problem formulated on the basis of the Maxwell equations were obtained with the Microwave Studio software (www.cst.com). The frequency-dependent dielectric constants of the layered saturated formation and the drilling fluid were assumed according to experimentally tested models. The modeling has demonstrated that nanosecond electromagnetic pulses arriving from a layered oil–water contact can in principle be acquired and the distance from the wellbore to the OWC median can be inferred from the respective time delays recorded by a downhole radar. Additionally, the possible dynamic range and accuracy of sensing have been estimated.

The upper-mantle structure was studied from first-arrival data along the Meteorite profile, run using underground nuclear bursts. Unlike the layered, slightly inhomogeneous models in the previous works, emphasis was laid on lateral inhomogeneity at the minimum possible number of abrupt seismic boundaries. We used forward ray tracing of the traveltimes of refracted and overcritical reflected waves. The model obtained is characterized by considerable velocity variations, from 7.7 km/s in the Baikal Rift Zone to 8.0–8.45 km/s beneath the Tunguska syneclise. A layer of increased velocity (up to 8.5–8.6 km/s), 30–80 km thick, is distinguished at the base of seismic lithosphere. The depth of the layer top varies from 120 km in the northern Siberian craton to 210 km in its southeastern framing. It has been shown that, with crustal density anomalies excluded, the reduced gravity field is consistent with the upper-mantle velocity model.

An important but problematic component of nuclear geophysical technologies is computer inversion of measurement data based on the equation of particle transport. In this paper, we propose an approach and iterative methods for this inversion that are applicable to many problems of evaluation formation characteristics, including elemental composition, from data of corresponding logging methods. This approach is based on defining characteristic elements, interactions, and trajectories and using the superposition principle for transport processes, and linear a priori constraints on unknowns are used. In comparison with the previous publications of the author, this paper deals with a broader type of measurement data, including the reading ratio of detectors and normalized measurements. The iterative methods are specified for problems of determining the porosity and density from data of neutron–neutron and gamma–gamma logs, respectively. For the first of them, the results of numerical experiments are presented.

The article deals with problems and prospects of innovative activity of high schools within the processes of integration of a science and higher education. It is marked, that now there is an active inclusion of high schools as the major component in innovative sector of economy of Russia. It is shown that the increase in rates of scientific and technical process, automation of manufacture, increase in a share of sphere of services in an economic turn lead to growth of a demand not only experts with higher education, but innovatively prepared experts.

The results of the research of the computer typesetters training are presented in article. A model of formation of their professional competence in the process of vocational training is presented and described.

In the article the concepts of self-efficacy and the career self-efficacy are described. The authors describe the structural components and the sources of the career self-efficacy, perceived as the person’s ability to organize and carry out the actions necessary for the career realization. The author presents the results of research of the dynamics of career self-efficacy of the students during their studies at the higher education institution. On the basis of this research, there are described the features of the career self-efficacy of students of various years of studying. For example, the graduates, compared with freshmen, are more confident that they will be able to find information about the specifics of the companies, to carry out monitoring of the labor market and wages in their chosen profession. The graduates are increasingly anxious due to the drastic change in the social roles “student – expert.” Similar to the first-year students, the graduates underestimate such sources of career self-efficacy as indirect learning, verbal suggestion and positive emotional state.

The author analyzes the topicality and content of a model of formation of technological competence of the Bachelors of pedagogical education of the technological specialization. The article describes the interrelation between all the components of the model, the specific features of the educational process connected with the introduction of author’s integrative course «The foundations of the theory of technological training». Thus, there is justified the use of the model of formation of technological competence of the Bachelors of pedagogical education of the technological specialization, which can increase the level of technological competence of students and optimize the work of teachers.

The aim of this article is to consider the problems of teaching the professional ethics in higher education on the example of the “Public service ethics” course. The author discusses the topicality of this discipline in terms of the future specialist training. Also, based on the personal experience of teaching, the author provides a basis for her own vision of the content-related component of the course and the use of specific instructional techniques of the training activities.

The article interprets the phenomenon of the youth mentality generational transformation on the basis of sociological analysis of their value system. The emphasis of the research on the investigation of the youth value sphere is conditioned by positing values as a structural component of mentality. The article presents the results of an empirical study of the values of the Novosibirsk higher education students. The study was conducted by the method of filling in questionnaires. The research sample covered the students of four higher education institutions of the city. The obtained data made it possible to formulate conclusions about the main trends of formation of the student youth value system and, correspondingly, about a specific character of their mentality. One of its particular features is the synthesis of traditional and individualist values. The factors of formation of the youth value sphere are revealed.

The article describes a model of complex training tools application during chemistry and biology lessons, which helps to intensify the educational activity of the vocational school students. There are distinguished the criteria for the quality of educational activity components: the content-related, motivational and reflection-related ones. Also there are presented the research results and their description.

The article describes some of the historical aspects of distance education and its topicality due to the new needs of the society. Due to the fact that the way of e-learning changes with the advent of new technologies, it is possible to identify a number of stages of its development. The use of Internet technologies and e-learning in legal education opens up new opportunities for continuous learning and professional retraining of specialists, for getting a second education, and makes learning more accessible.

The modular principles of instruction originated in the middle of the 20th century and were actively developed in the theoretical works by the British, American, Russian methodologists involved in the field of professional education. The modular courses create the most favorable conditions for both the development of the person and the creation of the effective curriculum content. The module as a unit of the foreign language educational process has a number of specific features relevant for the technology of teaching. Modular instruction in foreign language classes is an effective means of modern educational management.

An adaptive educational environment can be adjusted both to the personality of student and to the alteration of the outer conditions. The article considers a model of adaptive educational environment of pre-higher professional education institution; its efficiency is estimated. Its quality features and the criteria of efficiency evaluation are described; the results of the model introduction are reviewed.

A distinctive feature of modern educational environment is the use of active methods of learning. The project method is one of them. The article reviews the experience of the project method use in the educational environment of the Academic College of the Vladivostok State University of Economics and Service in the sphere of basic and additional education. The author thinks that the formation of adaptive educational environment at the educational institution encourages the use of this method. The conditions for the successful project activities are stated in the article.

The action of a strong electric field on conjugated π-systems is studied within the method of full configuration interaction. The behavior of systems in the field is analyzed by means of the electron unpairing measure: the number N_eff of effectively unpaired electrons. For N_eff formal asymptotic rules are derived, which correspond to extreme values of the external field. Field induced biradicaloid π-states are studied in detail.

The phonon spectra of a series of А²В⁴С⁵₂ and А¹В³С⁶₂ crystals with the chalcopyrite structure are calculated in the Keating model in the basis set of polarization vectors of their sublattices. The dependences of frequency values and partial contributions of sublattices to the polarization vectors on the chemical composition are studied. The effect of the mass ratio and the strengths of covalent bonds between the compound components on the phonon spectrum formation is found.

The adsorption of CO and C₂H₂ molecules on the perfect basal surface of graphite is investigated by adopting cluster models in conjunction with quantum chemical calculations. The noncovalent interaction potential energy curves for three different orientations of CO and C₂H₂ molecules with respect to the inert basal plane of graphite are calculated via semi-empirical and Möller-Plesset ab initio methods. Then, we have considered the effects of interaction energies on the C≡O and C≡C bond lengths by performing the partial geometry optimization procedure on the CO-graphite and C₂H₂-graphite systems in various intermolecular distances. The computational analysis of all physical noncovalent potential energy curves reveals that the relative configurations in which CO and C₂H₂ molecules approach the graphite sheet from out of the plane have stronger interaction energy and so is more favorable from the energetic viewpoint. This means that the graphite layer prefers to increase its thickness via the chemical vapor deposition of CO and C₂H₂ on the graphite.

Within DFT (B3LYP) methods the potential surface of the interaction between 1-iodopropan-2-one and 1,2,3-benzotriazole resulting in the formation of 1,3-bis(2-oxopropyl)-3Н-1,2,3-benzotriazolium triiodide is studied. A mechanism consisting of four steps (N-1-alkylation of 1,2,3-benzotriazole, elimination of molecular iodine during partial reduction of 1-iodopropan-2-one with hydrogen iodide, formation of the triiodide structure, and formation of 1,3-bis(2-oxopropyl)-3Н-1,2,3-benzotriazolium) is proposed. Thermodynamic and kinetic parameters of these steps are obtained.

The molecular structure of chromium and cobalt tris-acetylacetonates is studied by the synchronous electron diffraction and mass spectrometric experiment and quantum chemically. It is found that molecules have the D₃ symmetry with internuclear distances r_h1(Cr–O) = 1.960(4) Å and r_h1(Co–O) = 1.893(4) Å. Quantum chemical calculations by the DFT methods with different basis sets yield a structure well consistent with that found in the experiment. Changes in the structural parameters of chromium and cobalt b-diketonate complexes whose ligands differ in –CH₃, –C(CH₃)₃, –CF₃ substituents are considered.

The ferromagnetic resonance (FMR) method in situ is used to study the initial stages of the formation of ε iron oxide nanoparticles deposited on silica gel at temperatures up to 600°C. It is shown that at high-temperature treatment of starting samples obtained by impregnation with an iron(II) sulfate solution, supermagnetic ε-Fe₂O₃/SiO₂ nanoparticles form with a narrow size distribution. An analysis of the FMR data in comparison with the data of other methods enables the formulation of the formation conditions for systems of deposited ε-Fe₂O₃ nanoparticles without other polymorph impurities.

Single crystal XRD is used to determine the structures of the complexes (H₂TMEDA)[Mg(ptac)₃]₂ (1, TMEDA = Me₂N(CH₂)₂NMe₂, ptac = ^tBuCOCHCOCF₃) and (H₂TMEDA)[Mg(hfac)₃](hfac) (2, hfac = CF₃COCHCOCF₃) at a temperature of 150 K. The crystallographic data for complex 1: a = 10.2919(3) Å, b = 10.9492(4) Å, c = 15.4159(6) Å, α = 87.117(1)°, β = 89.686(1)°, γ = 79,864(1)°, space group Z = 1, R = 0.0573; for complex 2: a = 12.9446(2) Å, b = 23.0035(4) Å, c = 13.1473(3) Å, α = 90°, β = 98.779(1)°, γ = 90°, space group P2₁/n, Z = 4, R = 0.0605. The structures are ionic; the metal atom coordinates six oxygen atoms of three β-diketonate ligands. The distances Mg–O in complex 1 are in the range 2.036(2)-2.0920(19) Å; the same distances in complex 2 are in the range 2.051(2)-2.076(2) Å. The spatial packing is determined by the system of hydrogen bonds between the (H₂TMEDA)²⁺ cations and [Mg(ptac)₃]^– (1) or hfac^– (2) anions. A thermogravimetric study of complex 1 is carried out.

The structure of supports (ceria and zirconia) for supported copper catalysts for the processes of hydrogen obtaining and purification is studied. The formation features of the structure of zirconia annealed at 300-1000°C are identified at different levels: the atomic one and the level of the structural arrangement of secondary particles when the formation of agglomerated block structures with large number of grain interfaces occurs. The formation process of copper oxides on different supports is studied.

N1s and O1s X-ray photoelectron spectra of stable nitroxyl radicals (substituted piperidine-1-oxyl, 2-imidazoline-1-oxyl, and 2-imidazoline-3-oxide-1-oxyl) and also diamagnetic derivatives with a {ONCNO} fragment are measured. It is shown that the structure of N1s and O1s X-ray photoelectron spectra of nitroxyls is determined by charge transfer processes between different parts of the molecule to screen the X-ray hole and the spin-spin interaction of unpaired electrons on the HOMO and 1s level.

An X-ray photoelectron and X-ray emission study of the charge state of thiacalix[4]arenes is performed with a comparison with the data of quantum chemical calculations. Relaxation corrections between the Kohn–Sham orbital energies calculated by the DFT method and experimental parameters of the X-ray emission and photoelectron spectra of the studied compounds are estimated. It is shown that the formation of a cyclic aromatic system in thiacalixarenes results in a decrease in the energy of orbitals involving р–π interactions of the bridging sulfur atoms and aromatic moieties, which determines the features of the X-ray emission spectra of the studied compounds.

In the samples of the Na₂MoO₄–MgMoO₄ system quenched in the air at above 600°C, by powder X‑ray diffraction two double molybdates of variable composition are detected: monoclinic alluaudite-like Na_4–2xMg_1+x(MoO₄)₃ (0.05 ≤ x ≤ 0.35) and triclinic Na_{2–2 y}Mg_2+y(MoO₄)₃ (0.10 ≤ y ≤ 0.40) isostructural to previously studied Na₂Mg₅(MoO₄)₆. Sodium-magnesium molybdate of the Li₃Fe(MoO₄)₃ structure type is not revealed in this system. By spontaneous flux crystallization, the crystals are obtained and the structures of two triclinic double molybdates of the Na₂Mg₅(MoO₄)₆ structure type (space group P1, Z = 1) containing magnesium and manganese are determined. The results of the refinement of site occupancies made it possible to determine the composition of the studied crystals: for the compound with magnesium (Na)_0.5(Na_0.25⟩_0.75)(Na_0.75Mg _0.25)Mg₂(MoO₄)₃ or Na_1.50Mg_2.25(MoO₄)₃ (a = 6.9577(1) Å, b = 8.6330(2) Å, c = 10.2571(2) Å, α = 106.933(1)°, β = 104.864(1)°, γ = 103.453(1)°, R = 0.0188); for the compound with manganese (Na)_0.5(Na_0.32⟩_0.68)(Na_0.82Mn_0.18)Mn₂(MoO₄)₃ or Na _1.64Mn_2.18(MoO₄)₃ (a = 7.0778(2) Å, b = 8.8115(2) Å, c = 10.4256(2) Å, α = 106.521(1)°, β = 105.639(3)°, γ = 103.233(1)°, R = 0.0175). The Na₂Mg₅(MoO₄)₆ structure is redetermined and it is shown that actually it corresponds to the composition Na_1.40Mg_2.30(MoO₄)₃.

A new azido-coordinated nickel(II) complex [NiL¹(N₃)] (1) and a new thiocyanato-coordinated nickel(II) complex [NiL²(NCS)] (2), where L¹ and L² are the monoanionic forms of Schiff bases 2-[(2-isopropylaminoethylimino)methyl]-6-methylphenol and 2-[(2-dimethlaminoethylimino)methyl]-6-methylphenol respectively, are prepared and structurally characterized by elemental analysis, IR spectra, and single crystal X-ray crystallography. Complex 1 crystallizes in the triclinic space group P-1 with unit cell dimensions a = 8.812(2) Å, b = 9.433(3) Å, c = 9.488(2) Å, α = 81.933(2)°, β = 69.925(2)°, γ = 84.591(2)°, V = 732.5(3) ų, Z = 2, R₁ = 0.0291, and wR₂ = 0.0734. Complex 2 crystallizes in the monoclinic space group P2₁/n with unit cell dimensions a = 7.4497(4) Å, b = 6.1933(3) Å, c = 31.5126(18) Å, β = 92.484(2)°, V = 1452.57(13) ų, Z = 4, R₁ = 0.0307, and wR₂ = 0.0668. The Ni atom in each of the complexes is coordinated by three donor atoms of the Schiff base ligand and by one N atom of the azide or thiocyanate ligand, forming a square planar geometry. The azide and thiocyanate anions readily coordinate to the complexes as secondary ligands.

X-ray crystallographic analysis is used to determine the crystal structures of [Ru(NH₃)₆](MoO₄)Cl×3H₂O and [М(NH₃)₆](ReO₄)₃×2H₂O (M = Ru, Ir) complex salts. The features of the fragment packing are studied.

Complex rhodium(III) salts with the composition trans-М[Rh(NH₃)₂(NO₂)₄], where М = K⁺, Cs⁺, Ag⁺, and N(CH₃)₄⁺, are prepared and characterized. The molecular and crystal structures are determined by X-ray crystallography.

A coordination polymer {[Cu(C₁₁H₂₀N₄O₂)₂(H₂O)]²⁺×2(NO₃^–)}_n (I) is synthesized and analyzed using single-crystal XRD. The crystals are monoclinic: space group P2/c, a = 12.5237(6) Å, b = 7.3310(3) Å, c = 16.8926(8) Å, β = 92.569(4)°, V = 1549.38(13) ų, r_calc = 1.47 g/cm³, and Z = 2. The copper atom is in a special position in the second-order axis. The coordination polyhedron of the metal is a trigonal bipyramid. In the axial direction, it is coordinated by two oxygen atoms O(1) of the organic ligand molecules connected by the symmetry operation [–x, y, 0.5–z]; the angle O(1)Cu(1)O(1)ⁱ is 175.16(15)°. In the equatorial direction, the copper atom is coordinated by oxygen atoms O(2) of two ligand molecules connected with the reference molecule by the symmetry operations [–x, y, 0.5–z] and [x, 1–y, –0.5+z] and the water molecule О(6) in a special position on the twofold axis. The OCuO angles between the equatorial oxygen atoms are 96.80(16)-131.60(8)°, and those between the axial and equatorial atoms are 87.58(8)-91.60(10)°. It is noteworthy that the length of the Cu–O(1) bond (1.955(2) Å) with the axial carbonyl oxygen atom is somewhat shorter than the bond (2.060(3) Å) with the equatorial atom. Nitrate anions are outside the coordination sphere of the metal. The Cu…Cu distance in the polymer is 8.33 Å. To confirm the purity of the sample of I, the powder X-ray pattern is refined by the Rietveld method; the lattice parameters at room temperature are: a = 12.535(4) Å, b = 7.3161(13) Å, c = 16.841(5) Å, β = 92.11(2)°, and V = 1543.4(7) ų.

1'-Phthalazinylhydrazones of salicylaldehyde, its substituted derivatives, and 2-diphenylphosphinebenzaldehyde are synthesized and studied. A description is given of the structures salicylaldehyde 1'-phthalazinylhydrazone (1а) and 2-diphenylphosphinebenzaldehyde 1'-phthalazinylhydrazone (2), which exist in the crystal in the hydrazonophthalazone tautomeric form. Molecules of hydrazone 1а form in the crystal infinite stacks of hydrogen bonded dimers with intermolecular π-stacking interactions. A quantum chemical calculation is made of the geometry and total energy of the possible tautomers in vacuum and in aqueous and chloroform solutions. The hydrazonophthalazone tautomers are shown to be the most stable in all cases. The X-ray crystallography results are compared with the calculated data.

By quantum chemical DFT M06-2X/6-31G(d,p) method, the equilibrium parameters of rigid and stable hydrocarbon clusters of icosahedral symmetry with a dodecahedron structure whose sites are occupied by 20 adamant-1,3,5-triyl moieties linked with each other either directly or through bridges containing two or four carbon atoms are determined. The radius of the smallest studied quasispherical molecules is 1.05 nm and that of the largest one is 1.76 nm. The radius of the inner cavity in them varies from 0.37 nm (C₂₀₀H₂₆₀) to 1.06 nm (C₃₂₀H₂₆₀). Perfluorination increases the outer and decreases the inner radius of super dodecahedrane.

In the structure of Tl₂S, the pseudo translational sublattice of Tl and S atoms with a rhombohedral primitive subcell a_P = 3.09 Å, α_P = 81.87° is determined. As opposed to the common PbS structure type, in which single (close-packed) layers of cations and anions alternate, in the structure of Tl₂S, there is an alternation of double cationic layers with single anionic layer, while the general geometry of atomic positions (skeleton) of the PbS structure type is retained. Therewith, the atoms of a part of cationic layers occupy the atomic sites of the anionic layers and vice versa.

The crystal structure of catena-di(μ₂-2-thiobarbiturato-O,S)aqualead(II) C₈H₈N₄O₅S₂Pb (C₄H₄N₂O₂S is 2-thiobarbituric acid, H₂TBA) is determined. Crystallographic data for catena-[Pb(H₂O)(μ₂-HTBA-O,S)₂] are as follows: a = 6.5972(1) Å, b = 9.8917(2) Å, c = 10.0893(2) Å, α = 106.702(1)°, β = 93.395(2)°, γ = 107.48(1)°, V = 593.82(2) ų, space group P1, Z = 2. The Pb²⁺ ion is linked with six monodentate HTBA ⁻ ligands through two O atoms and four S atoms and also connected with a water molecule. Additionally, there is a shortened Pb–S contact (3.622 Å), given which the complex polyhedron represents a distorted square antiprism. Hydrogen bonds N–H⋯O and O–H⋯O form a branched three-dimensional network. The structure is also stabilized by the π–π-interaction of heterocyclic HTBA⁻ ions.

A novel Zn(II) coordination polymer [Zn₂(phen)₂]L₄×3H₂O(1) is synthesized by the reaction of Zn(NO₃)₂, Phen(1,10-phenanthroline), and L(2-mercaptonicotinic acid) at room temperature and structurally characterized by X-ray single crystal diffraction along with IR spectra and elemental analysis. Title complex 1 belongs to the triclinic system with the space group ( P-1), a = 10.9373(11) Å, b = 11.6201(12) Å, c = 13.1371(14) Å; α = 116.100(1)°, β = 97.717(2)°, γ = 108.652(2)°, V = 1344.4(2) ų; Z = 2, ρ_calcd = 1.596 g×cm^–3, F(000) = 664, R₁ = 0.0708 and wR₂ = 0.1823 independent reflections for 18523 observed ones (I > 2σ(I)), and the zinc atom is rendered five-coordinated in a distorted tetragonal pyramid coordination geometry by two nitrogen atoms from the phen molecule, two oxygen atoms from two L molecules, and an oxygen atom from the H₂O molecule. Complex 1 forms a 1D chain by O—H⋯O hydrogen bonds from free-water, while the 2D layer structure is formed by C—H⋯O hydrogen bonds through the L ligand of adjacent chains. These compounds further result in a 3D network structure by the intermolecular π⋯π stacking interaction of the neighbouring layers.