Vol 61, No 5 (2016)

A new method of synthesis of volatile complex, tin trifluoroacetylacetonate [Sn(C₅H₄O₂F₃)₂], was proposed. The prepared compound was identified by IR spectroscopy, CH analysis, X-ray powder diffraction, and DTA/TGA, the composition was confirmed by MALDI-TOF mass spectrometry, crystal structure was established. Thin films of tin dioxide on silicon were obtained by atmospheric pressure chemical vapor deposition using [Sn(C₅H₄O₂F₃)₂] as a precursor. The morphology and composition of the films were studied by scanning electron microscopy, EDX elemental analysis, and X-ray powder diffraction. Surface resistance and light transmission in visible and near IR region were studied.

The efficiency of various methods for the preparation of titania-based nanocomposites, Fe₂Ti₂O₇ and Fe₂TiO₅, starting from colloid solutions of hydroxy iron species and the products of titanium tetraisopropoxide hydrolysis was evaluated. The effect of the conditions of synthesis (Fe³⁺/Ti⁴⁺ concentration ratios of 1 and 2, pH of the reaction medium, temperature, and sonication) on the composition, structure, and properties of the nanocomposites formed was elucidated; the effect of the phase composition on the photocatalytic activity of materials formed during the liquid-phase synthesis was established. The resulting materials were studied by electron microscopy, low-temperature adsorption, IR spectroscopy, and powder X-ray diffraction.

Sodium triuranate Na₂(UO₂)₃O₃(OH)₂ was synthesized by the reaction between aqueous uranyl acetate solution and aqueous sodium nitrate solution under hydrothermal conditions at 200°C. The composition and structure of the synthesized compound were determined, and its dehydration and thermal decomposition were studied, by chemical analysis, X-ray diffraction, IR spectroscopy, and thermal analysis.

Ligand system derived from pyrazolone-5 and N-aminoquinazolinone was prepared, its structure was studied. Metal chelates ML₂ were prepared by reaction of the obtained ligand with copper(II), nickel(II), and cobalt(II) acetates. The complexes were studied by IR, electronic, and ESR spectroscopy, magnetochemistry, X-ray diffraction. Copper(II) complex was shown to have pseudo-tetrahedral structure, nickel(II) and cobalt(II) complexes are octahedral.

On the basis of X-ray crystallographic data on molecular copper complexes with 1,3-bis(3-(pyrimidin-2-yl)-1H-1,2,4-triazol-5-yl)propane, quantum-chemical optimization of their equilibrium structure has been performed by the density functional theory method with subsequent analysis of the electron density distribution by Bader’s atoms in molecules method and g-factor anisotropy calculation. The topological parameters of electron density at the Cu–N bond critical points have been considered, and the bond energies have been estimated using the Espinosa equation. A phenomenon of variable coordination of nitrate ions with Cu(II) ions in the inner coordination sphere of the mononuclear copper complex with 1,3-bis(3-(pyrimidin-2-yl)-1H-1,2,4-triazol-5-yl)propane has been revealed. The contributions of different components to the gfactor anisotropy have been analyzed in the framework of the gauge-independent atomic orbital method. The largest contribution to the g-factor is made by the orbital (Zeeman) and spin–orbit components accounting for very high averaged g-factor values of 2.1413 and 2.5636 for the doublet state of the mononuclear complex and the triplet state of the binuclear complex, respectively.

We predicted elpasolites having the composition A₂BCHal₆ (A and C stand for different monovalent metals; B stands for trivalent metals; and Hal for F, Cl, or Br) that have not been obtained yet. Prediction was based on the data on properties of elements and simple halides only. The computations were carried out using specialized software for computer-assisted data analysis relying on the precedent-based pattern recognition method.

The geometric parameters of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II) (5656)macrotetracyclic complexes with the NNNN-coordination of the donor cites of the chelant, which can be formed upon template processes in M(II)–ethanedithioamide–methanimine–hydrogen cyanide quaternary systems, have been calculated using the density functional (DFT) hybrid method in the OPBE/TZVP approximation with the use of the Gaussian09 program package. It is shown that no one of the 5-membered chelate rings is planar, and these rings are not identical in the complexes studied. The 6-membered chelate rings are likewise not identical: one has a prominent noncoplanarity, and the other is almost planar. In all metal complexes, the nitrile nitrogen atom in one 6-membered ring noticeably departs from the plane of the ring, and in the other 6-membered ring, the respective nitrogen atom lies virtually in the plane of the ring.

The NaFeZr(PO₄)₂SO₄ and Pb_2/3FeZr(PO₄)_7/3(SO₄)_2/3 sulfate phosphates with the NaZr₂(PO₄)₃ (NZP) structure were synthesized and studied using X-ray diffraction, electron microprobe analysis, IR spectroscopy, and simultaneous differential thermal and thermogravimetric analysis. The phase formation and thermal stability of the compounds were studied by powder X-ray diffraction and DTA–TG. The Pb_2/3FeZr(PO₄)_7/3(SO₄)_2/3 structure was refined by full-profile analysis. The structure framework is composed of randomly occupied (Fe,Zr)O₆ octahedra and (P,S)O₄ tetrahedra; the Pb²⁺ ions occupy extra-framework sites. The thermal expansion of Pb_2/3FeZr(PO₄)_7/3(SO₄)_2/3 in the temperature range from–120 to 200°C was studied by temperature X-ray diffraction. In terms of the average linear coefficient of thermal expansion (α_av = 1.7 × 10^–6°C^–1), this compound can be classified as having low expansion. The combination of different tetrahedral anions (a phosphorus and a smaller sulfur one) in the NZP resulted in a decrease in the framework size and cavities and enabled the preparation of low-expansion sulfate phosphate with a smaller extra-framework cation (cheap Pb) instead of larger cations (Cs, Ba, Sr) used most often in the monoanionic phosphates.

Phase equilibria in the stable tetrahedron LiF–LiBr–Li₂CrO₄–KBr of the quaternary reciprocal system Li,KǁF,Br,CrO₄ were studied by differential thermal analysis. The composition (equiv %) and melting point of a quaternary eutectic were found as (2% LiF, 60% LiBr, 3% Li₂CrO₄, 35% KBr, 315°C).

Solubility at the invariant points of the Na,СаǁSO₄,СО₃–H₂O system at 0°C was studied, and a solubility diagram at this temperature constructed.

Complexation in the Co(II)‒Ni(II)‒aminoethanoic acid (HGly)‒EDTA (H₄Edta) system was studied at different molar ratios of components by absorption spectrophotometry. The mathematical modeling of A = f(pH) curves was used to establish that bi-, tri-, and tetranuclear heteroligand complexes like [(CoGly)Edta(NiGly)]^2‒, [(CoGly₂)Edta(NiGly₂)]^4‒, [(CoGly₂)Edta(NiGly₂)₂]^4‒, [(CoGly₂)₂Edta(NiGly₂)]^4‒, and [(CoGly₂)₂Edta(NiGly₂)₂]^4‒, whose accumulation fraction attained 80‒100% at optimal pH values, were formed depending on the ratio of reagents and the acidity of a medium. The formation equilibrium and total stability constants of these complexes were calculated, and a hypothesis about their structure was made.