Vol 62, No 11 (2017)

It was studied how the conditions of heat treatment of a [Zn(H₂O)(O₂C₅H₇)₂] solution in isoamyl alcohol at 120–140°C for 2–60 min affect the precursor decomposition mechanism and the characteristics of the obtained nanocrystalline zinc oxide. In all the cases, the product was a crystalline substance with the wurtzite structure and a size of crystallites of 14–18 nm, which was independent of the synthesis conditions. The thermal behavior and microstructure of the separated and dried nanostructured ZnO powder were investigated. It was determined how the duration and temperature of the heat treatment of the precursor solution affects the microstructure of ZnO coatings dip-coated onto glass substrates using dispersions produced at 120 and 140°C. The nanosized ZnO application procedure was shown to be promising for creating a gas-sensing layer of chemical gas sensors for detecting 1% H₂ (\(R_0 /R_{H_2 } \) was 58 ± 2 at an operating temperature of 300°C) and 4 ppm NO₂ (\(R_{NO_2 } /R_0\) were 15 ± 1 and 1.9 ± 0.1 at operating temperatures of 200 and 300°C, respectively).

How the specific surface area and the amorphous-to-crystalline titania phase ratio in TiO₂–SiO₂ (14 mol % TiO₂) xerogels change during the fivefold repeated cycles comprising the hydrogen peroxide treatment of the xerogel followed by drying and calcining of the binary material, was traced by the BET method, X-ray powder diffraction, and IR spectroscopy.

Tris(3-fluorophenyl)antimony dicarboxylates (3-FC₆H₄)₃Sb[OC(O)R]₂, R = CH₂Cl (I), Ph (II), CH₂C₆H₄NO₂-4 (III), C₁₀H₁₅ (IV)) have been synthesized with a high yield by the reaction between tris(3-fluorophenyl)antimony and carboxylic acids in ether in the presence of tert-butyl hydroperoxide. The Sb atoms in complexes I–IV have a distorted trigonal bipyramidal coordination with carboxylate ligands in axial positions. The OSbO angles are 176.61(11)° (I), 177.8(2)°, 175.9(3)° (II), 173.25(16)° (III), and 177.84(14)° (IV). The Sb–O and Sb–C_eqv bond lengths are 2.111(3), 2.131(3) and 2.102(5)–2.117(4) Å (I); 2.101(1)–2.547(6) and 2.103(8)–2.132(7) Å (II); 2.035(7), 2.144(6) and 2.116(9)–2.130(10) Å (III); 2.131(5), 2.156(4) and 2.103(2)–2.153(5) Å (IV). The carboxylate ligands show anisobidentate properties, and the Sb⋯О=С distances are 2.804(4), 2.923(4) Å (I), 2.541(8)–2.747(9) Å (II), 2.967(9), 3.007(9) Å (III), and 2.561(9), 2.617(9) Å (IV). The structural organization in crystals is based on weak intermolecular hydrogen bonds H⋯F (2.48–2.64 Å) and H⋯O(=C) (2.55–2.71 Å).

The work is devoted to the theoretical study of sensor activity of nanosystems based on a carbon nanotube modified with a functional amino group, with respect to certain metal atoms and ions. The calculations were performed within the molecular cluster model using the semiempirical MNDO scheme and density functional theory DFT. The mechanism of attachment of an amino group to the open edge of zigzag single-walled carbon nanotubes possessing cylindrical symmetry was studied to design a chemically active sensor based on them. The key geometric and electron-energy characteristics of the constructed systems have been determined. The interaction of the sensors thus constructed with atoms and ions of some metals—potassium, sodium, and lithium—has been studied. The scanning of arbitrary surfaces containing selected atoms or ions has been modeled; from the interaction energies, and the activity of the single-walled carbon nanotube + amino group probe system has been determined with respect to the selected elements to be initialized. Analysis of the charge state of the system has established that the sensor action mechanism is realized, as a result of which the number of charge carriers in the resulting nanotubular system serving as a sensor probe changes, which provides the appearance of conductivity in the system. The presence of metallic atoms can be experimentally detected by the change in the potential in a probe system based on a nanotube with a functional group. The theoretical studies have proved the possibility of creating highly sensitive sensors based on the most promising nanomaterial— carbon nanotubes functionalized with active chemical groups, including the amino group NH₂.

The solution state of palladium cationic–anionic complexes (AmH_n)_k[PdCl₄] prepared for the first time, where Am is morpholine, methylmorpholine, aminoethylmorpholine, 5-aminovaleric acid, L-1-phenyl-2-methylaminopropanol, and m-xylilenediamine, has been studied by electronic absorption spectroscopy, NMR, and pH measurements. The agreement of obtained results for the state of the complexes in water and NaCl solutions with IR and X-ray diffraction data for these complexes has allowed us to substantiate the principle for designing patent formulation (C₅H₁₂NO)₂[PdCl₄], a new type of palladium complexes, palladium(II) cationic–anionic complexes showing high antitumor and antimetastatic activity. Crystallographic data for six obtained complexes have been presented.

To synthesize donor–acceptor complexes exhibiting biological activity, the reaction of (2,3,7,8,12,13,17,18-octaalkylporphinato)manganese(III) containing axial acetate and chloride ions with pyridine has been quantitatively studied. In all cases, equilibrium is established instantaneously to give 1 : 1 donor–acceptor complexes. The key spectral characteristics and stability parameters have been obtained for donor–acceptor dyads. Multiple functional substitution of the porphyrin macroheterocycle can be used to control the properties of porphyrins and dyads based on them.

The textural and structural characteristics of phosphorites from the Polpinsky deposit have been determined. These raw materials are shown to be of siliceous polymineral type and consist mostly of α-quartz, hydroxycarbonate apatite, montmorillonite, and bonschtedtite. The modification dynamics of chemical composition and the textural characteristics (specific surface, pore volume, and pore diameter) of the solid upon the acid decomposition of a phosphorite sample from Polpinsky deposit have been studied. The α-quartz in phosphorites is shown to not experience crystal-structural alterations upon acid decomposition; its pore size does not inhibit the extraction of acid-soluble components, including calcium and phosphorus, from the bulk.

The phase diagrams of binary systems of gallium sulfate with lithium or sodium sulfate were studied for the first time. The Li₂SO₄–Ga₂(SO₄)₃ system is of the eutectic type. The coordinates of the eutectic are (548°C, 30 mol % Ga₂(SO₄)₃). The region of a solid solution based on the high-temperature modification α-Li₂SO₄ is small. In the Na₂SO₄–Ga₂(SO₄)₃ system, compound Na₃Ga(SO₄)₃ forms, which melts incongruently at 585°C. The coordinates of the eutectic are (538°C, 17 mol % Ga₂(SO₄)₃). The region of a solid solution based on α-Na₂SO₄ reaches 8 ± 1 mol % Ga₂(SO₄)₃. The X-ray powder diffraction pattern of Na₃Ga(SO₄)₃ was indexed in a tetragonal unit cell with the parameters a = 9.451(3) Å and c = 7.097(3) Å; the unit cell parameters for an aluminum-containing analog, Na₃Al(SO₄)₃, are a = 9.424(5) Å and c = 7.053(3) Å.

Solubility in ternary aqueous systems including calcium chlorate and diethanolamine (triethanolamine) has been studied at 25°C. Solubility diagrams have been constructed. Solubility curves consist of three branches corresponding to the crystallization of calcium chlorate, diethanolamine (triethanolamine), and compound Ca(ClO₃)₂ · NH(C₂H₄OH)₂ or Ca(ClO₃)₂ · N(C₂H₄OH)₃. The compounds have been isolated and identified by chemical analysis, X-ray powder diffraction, and thermal analysis.

According to the compositions of the underground brines in the Sichuan Basin, solid-liquid equilibria in the quinary system NaCl–NaBr–Na₂SO₄–Na₂B₄O₇–H₂O and its quaternary subsystem NaCl–Na₂SO₄–Na₂B₄O₇–H₂O at 348 K were measured by isothermal solution saturation method. The solubilities of salts and the densities of saturated solutions in the systems listed above were determined. Using the experimental data, phase diagrams, water content diagrams and density-composition diagrams were constructed, respectively. The quaternary system NaCl–Na₂SO₄–Na₂B₄O₇–H₂O belongs to a simple type, which consists of three univariant curves, one invariant point and three crystallization regions of NaCl, Na₂B₄O₇ · 5H₂O and Na₂SO₄. The equilibrium phase diagram (saturated with Na₂SO₄) in the quinary system NaCl–NaBr–Na₂SO₄–Na₂B₄O₇–H₂O is a type of solid solution and has not invariant point. There are two crystallization regions (saturated with Na₂SO₄): Na₂B₄O₇ · 5H₂O and solid solution Na(Cl,Br), one univariant curve.

The complex formation of lithium with benzo-15-crown-5 (B15C5) was investigated. The complexes LiB15C5H₂OX, where X = Cl⁻ (1), I⁻ (2), (3), (5), and LiBF₄B15C5 (4) were synthesized and studied by IR spectroscopy. Complexes 1–4 were examined by X-ray diffraction. According to IR spectroscopy data, the crown ether conformation changes upon dissolution. The interaction of the extracted complex with the solvent was identified.