Vol 62, No 4 (2017)

(Me₂NH₂)₅H[ZnW₁₂O₄₀] · 3.5H₂O (I) has been synthesized by the reaction between Zn(NO₃)₂ · 4H₂O, Na₂WO₄ · 2H₂O and (Me₂NH₂)NO₃ under hydrothermal conditions with a yield of 79%. The crystal structure of complex I has been characterized by single-crystal X-ray diffraction. Crystals of complex I are monoclinic, space group Cc, a = 13.165(1) Å, b = 19.370(1) Å, c = 20.987(2) Å, α = 84.81°, V = 5145.9(0) ų, Z = 4, C₁₀H₄₈N₅O_43.5ZnW₁₂. The Zn–O and W–O bond lengths are 1.86(2)–1.89(3) and 1.697(1)–2.030(2) Å, respectively. Na₂K₆[PtW₆O₂₄] · 11H₂O (II) has been synthesized by a slow reaction between (Me₂NH₂)₅H[ZnW₁₂O₄₀] · 3.5H₂O and [Pt(OH)₄(H₂O)₂] in H₂O at room temperature. Crystals of complex II are trigonal, space group R\(\bar 3\)m, a = 13.138(1) Å, c = 20.987(2) Å, V = 2742.9(1) ų, Z = 3, H₂₂O₃₅Na₂K₆PtW₆. The crystal structure of complex II contains [PtW₆O₂₄]^6– anions linked to K⁺ cations via oxygen atoms. The Na⁺ cation is coordinated to water molecules. The Pt atom is in a standard octahedral surrounding (Pt–O and W–O are 2.018(6) and 1.762(5)–2.151(4) Å, respectively).

The previously unknown effect of emergence of an associated non-autonomous phase upon heating of zinc pyrovanadate Zn₂V₂O₇ within the region of negative volume expansion is detected. Comparison of the data of high-temperature X-ray diffraction of the Zn₂V₂O₇ samples synthesized via solution and solid-phase routes shows that the grain size affects the stabilization of the non-autonomous phase. The presence of a non-autonomous phase results in self-dispersion of the substance upon phase transition in heating–cooling cycles.

A series of heteroligand copper(I) complexes with 3-pyridin-2-yl-5-(4-R-phenyl)-1H-1,2,4-triazoles (R = H, CH₃, CH₃O) and PPh₃ of general composition CuIL(PPh₃) have been synthesized and studied. The compounds have been characterized by elemental analysis, IR spectroscopy, and diffusion reflectance spectra. The structure of the complex with 3-pyridin-2-yl-5-phenyl-1H-1,2,4-triazole has been determined by single-crystal X-ray diffraction analysis. The complex is mononuclear and has a tetrahedral environment of the central atom. The compounds exhibit strong visible photoluminescence (λ_max = 599–609 nm). Quantum-chemical calculations at the B3LYP/DGDZVP level have demonstrated that the short phosphorescence life-time of the CuIL(PPh₃) compounds is caused by intensity transfer from the S₀–S₂ transition through spinorbit coupling induced by the rotation of the iodine 5p orbital upon the T₁–S₂ transition.

Two new copper and nickel complexes with triethanolamine (TEA) and 4-hydroxybenzoic acid (L) have been synthesized within the framework of systematic studies into the formation of mixed-ligand metal complexes on the basis of commercially available compounds with the simplest structure, such as ethanolamines and benzoic acid monoderivatives (hydroxy-, amino-, and nitrobenzoic acids). According to X-ray diffraction data, the complexes have the compositions [Cu₂(L)₂(TEA)₂] · [Cu(TEA)₂] · 2H₂O (I) and [Ni(TEA)₂] · 2L (II). Compound I is a mixed-ligand complex, while complex II is a supramolecular compound consisting of a nickel–TEA monoligand complex anion and non-coordinated L. TEA molecules in complex I are coordinated in both tetradentate and tridentate mode, while only tridentate coordination is typical for complex II. The coordination polyhedra of metal atoms are tetragonal bipyramids elongated due to the Jahn–Teller effect in complex I and octahedra in complex II. In both crystals, structural units are linked into 2D associates via hydrogen bonds.

Feasible structures of the SnCl₄ complex with pyridine-3-carboxylic acid chloride were calculated by the MP2/LANL2DZ method. The results of calculations were compared to experimental ³⁵Сl nuclear quadrupole resonance (NQR) data. The coordination site of the ligand was found to be the nitrogen atom and not the carbonyl oxygen atom. The partial negative charge of the electron-donating center and the positive charge of the electron-drawing center increase appreciably upon complex formation.

The radial distribution functions for aqueous solutions of samarium chloride over a broad concentration range under standard conditions, obtained previously by X-ray diffraction, were used to develop various physically substantiated models for structural organization of the systems. The optimal versions were identified by calculating the theoretical functions for each model and comparing their agreement with experimental functions. The quantitative characteristics of the local environment of Sm³⁺ and Cl^– ions such as coordination numbers, interparticle distances, and sorts of ion pairs were established. The average number of water molecules in the first coordination sphere of the cation was found to decrease from 9 to 6 with increasing concentration. The structure of the systems is determined by solvent-separated ion associates over the whole concentration range.

Reaction of tetrabutylammonium salts of [2-B₁₀H₉(N≡CR)]^– (R = CH₃, C₂H₅, C(CH₃)₃, or C₆H₅) anions with water results in N-borylated iminols (Bu₄N)[2-B₁₀H₉NH=C(OH)R], and in the presence of an alkali, corresponding N-substituted amides (Bu₄N)₂[2-B₁₀H₉NH-C(=O)R] are formed. The compounds obtained are identified by IR, ESI/MS, and ¹H, ¹¹B, and ¹³C NMR spectroscopy. The crystal structure of compound (Bu₄N)[2-B₁₀H₉(Z-{NHC(OH)C₂H₅})] is studied by X-ray diffraction.

An EPR spectroscopy study was made into the simultaneous effect of intense degradation factors (UV radiation, elevated temperature) on nanocluster porous polyoxomolybdate Mo₁₃₂ of the Keplerate type in the solid state and also into the behavior of film composites including water-soluble nonionogenic polymers (polyvinylpyrrolidone, polyethylene glycol) under the action of these factors. The effect of mutual stabilization of polyoxometalate and polymer components in the studied composites was detected.

The possibility of the synthesis of hydrogen-nonstoichiometric cubic titanium carbide ТiС_х of high purity from powdery nonstoichiometric cubic titanium carbohydride ТiС_хH_y or nonstoichiometric titanium carbide with admixture hydrogen by annealing in a continuously maintained vacuum of no worse than 1.33 × 10^–3 Pa at temperatures of 600–750°C for several hours has been shown. Similar annealing at higher temperatures (T ≥ 800°C) does not lead to the complete removal of hydrogen from a sample due to intensive sintering. In this case, it seems that pores between sintered particles are hydrogen traps, and the release of hydrogen through the surface of sintered particles is hindered.

The solubility was studied in the system NaCl–AlCl₃−SrCl₂–HCl–H₂O of the eutonic type at 25°C in the section 28 wt % HCl. It was determined that it is possible to derive equations of the solubility surface of crystallizing salts and to calculate the composition of the eutonic solution.

We report the results of our studies into the oxidation reactions of μ-carbido-dimeric iron(IV) octapropyltetraazaporphyrinate with organic peroxides. Kinetic parameters have been determined, and a possible scheme of the process suggested. The nature of peroxide has been shown to influence the rates of redox transformations. The reaction has been shown to generate the μ-carbido-dimeric iron(IV) octapropyltetraazaporphyrinate radical cation through the dissociation of the О–О bond in the peroxide coordinated to the iron atom. The reaction product enters an aggregated state over time, and readily recovers the initial form in the presence of a nitrogen-containing base.

Manifestations of ion association of lithium cation with BrO₃^- ion in the vibrational spectrum have been studied by IR spectroscopy. The microstructure of the bromate ion with lithium cation in a contact ion pair in an aprotic solvent has been determined by the density functional theory method in the B3LYP/cc-pVTZ approximation, and the vibrational spectrum of coordinated bromate ion has been calculated.