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The influence of tritium aerosol transport on radioactive contamination on the territory of the Krasnoyarsk region influenced by the mining–chemical combine of the Rosatom State Corporation was studied. Snow cover, foliage, and needles collected at various distances from the mining–chemical combine were selected as the object of this study. A new methodology of liquid extraction from plant material (leaves and needles) was worked out. As a result, the maximal concentrations of tritium (15 kBk/m3 in snow, 11 and 15 Bk/m2 for leaves and pine-tree needles, respectively) were determined. However, the results obtained are not anomalous. Consequently, contamination with tritium may not be accounted for entirely due to the low concentrations.

The high-temperature heat capacity of YbVO4 in the range 381–1054 K has been measured by differential scanning calorimetry for the first time, and thermodynamic functions of the solid compound—changes in enthalpy and entropy, reduced Gibbs energy—have been determined using this data.

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала. Structures and relative energies of binuclear iron-manganese complexes with the phosphine ligand L, which exist in vinylidene Cp(CO)(L)MnFe(μ-C=CHPh)(CO)4 (2) and benzylidene ketene η4 -{C[Mn(CO)(L)Cp]⋅ ⋅(CO)CHPh}Fe(CO)3 (3) forms are calculated by the B3LYP density functional method. Four isomers with different positions of ligand L relative to the phenyl ring (conformers a and b) and the substituent Ph relative to the С=С bond (conformers E and Z) are considered for each form and their relative stability is determined. It is shown that all isomers of 2 have approximately the same energy (within 4 kcal/mol) whereas the energies of isomers of 3 differ within 21 kcal/mol. Isomer 3Ea in which the PPh3 ligand contacts with the phenyl substituent of the vinylidene group is most energetically favorable. It is found that with an increase in the L ligand size in the order PH3 < PH2Ph < PHPh2 < PPh3 the Mn–P bond length increases to 2.37 Å in the most stable isomer of form 3 and to 2.43 Å in the isomers of 2 and three conformers of 3. A more substantial increase in the Mn–P bond length in complexes 2 and 3 correlates with their lower stability as compared to isomer Ea of 3, which is consistent with experimental data on the presence of only one conformer 3Ea in solution.

The electrochemical reactions of carbonyl cluster compounds M3(CO)12 (M = Fe, Ru, Os) were compared with those of [Fe5C(CO)14]2− and [Fe6C(CO)16]2− in different aprotic solvents. The stability of electrochemically generated products of these clusters in the studied solvents was shown to grow in the following order: tetrahydrofuran < acetone < dichloromethane < acetonitrile.

This study is devoted to investigating the content of uranium isotopes in water of the Yenisei River and its tributaries within the territories affected by the operation of Rosatom plants (mining chemical combine, and electrochemical plant). Long-term monitoring of the 238U content by mass spectrometry carried out in two institutes of the Siberian Branch of the Russian Academy of Sciences first revealed the multiple excess of 238U over the background content in different areas of the Yenisei River basin, such as the region of the Yenisei River near the effluents of the mining and chemical combine (MCC), and the territories of the Bol’shaya Tel’ and Kan rivers. In these regions, the 238U content in water reaches 2.1–4.0 μg/l, which exceeds its content upstream from the MCC (0.3–0.6 μg/l) by almost an order of magnitude. The studies of the isotopic composition of uranium in water samples, which were carried out at the Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, showed the presence of a technogenic isotope of uranium 236U in the samples from the Bolshaya Tel’ River and revealed the deviation of the isotope ratio 238U/235U (167 ± 3 and 177 ± 3) from the equilibrium natural ratio (238U/235U = 138). These facts attest to the technogenic origin of part of the uranium in water of the Bol’shaya Tel’ River connected with the activity of MCC. The excess uranium content in the Kan River requires additional studies to ascertain the fraction of uranium of technogenic origin connected with the activity of the electrochemical plant (ECP) (Fig. 1, Table 4).

A version of capillary electrophoresis with indirect spectrophotometric detection and the hydrodynamic suppression of electroosmotic flow is studied. It is shown that, to improve the reliability of ion identification, one should calculate electrophoretic mobilities of ions or migration times corrected with regard to the electroosmotic flow rate. Correlations between electrophoretic peak areas of ions and their electrophoretic mobilities are derived. In the studied version of capillary electrophoresis, the accuracy of measuring anion concentrations can be improved using the internal standard method.

The electrochemical behavior of the heteronuclear dimeric vinylidene complex [Cp(CO)2MnCu(μ-C=CHPh)(μ-Cl)]2 (I) is studied using polarography, cyclic voltammetry, and controlled-potential electrolysis on mercury and platinum electrodes in acetonitrile. The dimer is reduced in two two-electron stages: at the first stage, metal-halogen bonds are broken and binuclear monomers [Cp(CO)2MnCu(μ-C=CHPh)(Cl)]− are formed; at the second stage, mononuclear manganese complexes Cp(CO)2Mn=C=CHPh, metallic copper, and chloride ions are formed. The two-electron oxidation of dimer [Cp(CO)2MnCu(μ-C=CHPh)(μ-Cl)]2 also results in the formation of binuclear monomers, which decompose to complex Cp(CO)2Mn=C=CHPh, Cu2+ ions, and Cl− ions.

Schemes of redox transformations were proposed for osmium carbonylhydride clusters: trinuclear (μ-H)Os3(μ-CR = CHR')(CO)10 (R = R' = H, Ph; R = H, R' = Ph), (μ-H)2Os3(μ3-L)(CO)9 (L = C = CHPh, CH≡CPh), tetranuclear CpMnOs3 (μ-CH = CHPh)(μ-H)(μ-CO)(CO)11, and trinuclear Os3(μ3-C = CHPh)(CO)9. Two-electron reduction of the trinuclear clusters results in elimination of the unsaturated ligand with preservation of the metal framework.

Reduction of a series of palladium-containing complexes with MnPd, Fe2Pd, and Fe3Pd skeletons was studied by classical polarography, cyclic voltammetry, and controlled-potential electrolysis in acetonitrile. The electrochemical behavior of these complexes was compared to that of relared platinum complexes.

The potential energy profile of the full catalytic cycle of methanol carbonylation catalyzed by [Rh(CO)2I2]- complex was explored computationally using a gradient-corrected density functional method. The equilibrium structures of all isomers of the intermediates involved in the catalytic process have been calculated. The transition states of CH3I oxidative addition, the CO migratory insertion, and the CH3COI reductive elimination were also located. The rate-determining step of the reaction, CH3I oxidative addition, was found to proceed via a back-side SN2 mechanism. The activation barrier of CO migratory insertion is calculated lower than that of CH3I reductive elimination; this finding confirms the hypothesis that the unstable nature of the complex [RhCH3(CO)2I3]- is mainly due to its fast decomposition into the acyl species. The trans conformers of the six-coordinated intermediates [RhCH3(CO)2I3]- and [Rh(CH3CO)(CO)2I3]- are more stable than their cis conformers. The activation barriers of CO migratory ...

Details of the irreducible-tensors approach are presented and applied to connect macroscopic parameters of uniaxial Liquid Crystals (LC) with their molecular orientational distribution function and microscopic molecular characteristics. Special attention is paid to higher (up to fourth) rank tensors used for description of LC optical nonlinearities.

The tautomeric state of methylated phenols was evaluated experimentally and by quantumchemical calculations. The values of ΔH t and K t are presented.

Dealumination of type Y zeolite using SiCl4 produces a statistically averaged distribution of Al and Si atoms in the framework. The action of H4EDTA causes defects in the backbone and partial amorphization of the zeolite. Extracellular particles containing Al form due to dealumination with SiCl4. The maximum number of these occurs at nalbb=5–16 atoms/unit cell. Treatment with H4EDTA has practically no effect on the composition of the particles, which are largely sodium cations. The extracellular particles localize both in sodalite cells and in large voids after dealumination with SiCl4.

A new simple and environmentally friendly synthetic method for 2-(1-adamantyl)-4-bromophenol that did not use catalysts and solvents was developed. A new simplified preparation method for 2-(1-adamantyl)-4-bromoanisole in one step instead of two was proposed. Both compounds are intermediates in the first and second synthetic steps to 6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid (adapalene).

A reaction of 2-iodophenol and 2-iodoanisole with 1-adamantanol in trifluoroacetic acid gives the corresponding 4-(1-adamantyl) derivatives. Similar adamantylation of 4-iodophenol and 4-iodoanisole is accompanied by migration of the iodine atom from para- to ortho-position, giving 4,6-di(1-adamantyl)-2-iodophenol and 4-(1-adamantyl)-2-iodoanisole, respectively, as the reaction products.

4-(1-Adamantyl)-, 5-(1-adamantyl)-, and 4,6-bis(1-adamantyl)pyrogallols were obtained by the reaction of adamantan-1-ol with pyrogallol in trifruoroacetic acid. The reaction of pyrogallol with adamantan-1-ol at 200 °C in a solvent-free medium without catalysts resulted in 5-(1-adamantyl)pyrogallol.

1. In the complex (Ph3P)(CO)PtFe2(CO)8 the CO groups on the Pt atom are easily replaced when the complex is reacted with P-, As-, and Sb-containing compounds. 2. A number of new trinuclear PtFe2 complexes were obtained, which contain two different n-donor substituants attached to the Pt atom.

1. A comparative polarographic study of the phenylvinylidene compounds Cp(CO)2Mn=C= CHPh (I), Cp2(CO)4Mn2(Μ-C=CHPh) (II), and Cp (CO)2MnPt (Μ-CHPh)LL' (III–IX), where L and L′ may be P(OR)3 or CO, has shown that the coordination of the Mn=C bond to a second metal atom results in transposition of the electrophilic center from the α-C atom of the vinylidene group in I to the Mn atoms in II and the Pt atom in III–IX. 2. A correlation between the potential for the electrochemical reduction of the complexes Cp(CO)2MnPt(Μ-C=CHPh)LL' and the energy of the σ → σ* transition of the metal-metal bond in their UV spectra has been established. 3. The attachment of the donor substituents L and L′ to the Pt atoms in compounds III–IX results in an increase in the strength of the Mn-Pt bond. The donor interaction between the Pt atom and the semibridging carbonyl group causes the opposite effect.

1. The heterometallic complexes (Ph3P)(L)PtFe2(CO)8, like the homometallic compounds M3(CO)12 (M=Fe or Os), successively add two electrons under the conditions of electrochemical reduction in MeCN, being converted into radical anions and dianions, respectively. The reduction process is controlled by diffusion, and the value of the formation potential of the radical anion depends on the nature of L, decreasing along the series L=CO=PhsAs≅Ph3Sb≅Ph3P>(PhO)3P > (EtO)3P. 2. The electronic absorption spectra of the complexes (Ph3P)(L)PtFe2(CO)8 display bands which correspond to σ → σ* transitions between levels which are responsible for the formation of the metal-metal bonds, and it has been discovered that their position is influenced by the charge of the ligands attached to the Pt atom.