Volume 69, Nº 10 (2024)

This work is devoted to the study of the nucleophilic addition reaction of isomers of iodo-aniline to the nitrile derivative of closo-decaborate anion. The structure of the products was established by multinuclear NMR spectroscopy, ESI-mass spectrometry, and IR spectroscopy. The structure of compound (NBu₄)[2-B₁₀H₉NHC(CH₃)HN(2-C₆H₄I)] was established by single crystal X-ray analysis.

The high-entropy niobate (Mg_0.2Cu_0.2Ni_0.2Co_0.2Zn_0.2)Nb₂O₆ with a columbite structure was synthesized for the first time. A modified method of combustion solutions followed by high-temperature sintering was used. According to the diffuse reflectance spectra, the band gap of the direct electronic transition is 3.36 eV. Mixed electronic-ionic conductivity was determined. The total conductivity of the sample is 2.5 · 10^–3 S/cm at 750°C and is comparable to Mg_0.8Cu_0.2Nb₂O₆.

For the first time, molecular solid solutions of yttrium and dysprosium lactates of [Y_1-xDy_x(C₃H₅O₃)₃(H₂O)₂] composition, where x = 0, 0.01, 0.1, 0.5, 0.8, and 1, have been obtained. These can be considered the first solid solutions of rare-earth hydrogen-bonded organic framework (M-HOF). The obtained compounds were analyzed using a set of instrumental methods, including X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX), infrared (IR), and Raman spectroscopy. It has been shown that the unit cell volume of the lactate solid solutions linearly depends on their cationic composition. It has been established that changes in the cationic composition of the solid solutions result in a monotonic shift of the lines in the Raman spectra corresponding to Ln–O vibrations (151–158 cm^–1). It has been demonstrated that the obtained compounds can be single-molecule magnets with an energy barrier of up to 108 K.

Coordination compounds of yttrium(III) nitrate with urea (Ur) and N,N-dimethylacetamide, [Y(H₂O)(Ur)₂(NO₃)₃] (I), [Y(Ur)₃(NO₃)₃] (II) and [Y(DMAA)₃(NO₃)₃] (III), were synthesized; their compositions, structural features and thermolysis were studied with the use of elemental analysis, IR spectroscopy, X-ray powder and single-crystal diffraction, thermal gravimetric analysis, differential scanning calorimetry. The coordination compounds can be used for the synthesis of nano-scale yttrium(III) oxide.

Isobaric heat capacity of magnesium-praseodymium hexaaluminate PrMgAl₁₁O₁₉ with magnetoplumbite structure was measured by three calorimetric methods in the temperature range 2–1865 K. Heat capacity values were docked and smoothed to calculate thermodynamic functions (entropy, enthalpy change and derived Gibbs energy) in the mentioned temperature region. A gentle anomaly of heat capacity with a maximum of about 8 K was found, its entropy and enthalpy were calculated. Magnetic properties of PrMgAl₁₁O₁₉ have been studied using the method of dynamic magnetic susceptibility in the temperature range 2–300 K. Based on the results of measurements of magnetic properties, an anomaly was found on the imaginary component of dynamic magnetic susceptibility, the temperature range of which is consistent with the area of the anomaly of heat capacity.

Using the method of topological modeling and basing on fragmentary experimental data on phase equilibria and transformations, P–T–x phase diagrams of binary systems Li–V, Li–O, V–O, as well as a complete isothermal concentration diagram of the Li–V–O system, which take into account the formation of limited solid solutions and the presence of saturated vapor, were constructed for the first time.

Processes involving gold(I) glutathionate complexes in aqueous solution at t = 25°C and I = 0.2 M (NaCl) in the pH range 7.20–6.06 (C_Au = (5–10 × 10^–4 M)) were studied. Using mass spectrometry, it was shown that at C_GS > C_Au, in addition to monomeric Au(GS)₂*, there can exist polymeric forms Au₄(GS)₄*, as well as Au_n(GS)_n+1*, where n ≤ 4, the symbol * means the sum of forms of different degrees of protonation. From UV spectroscopy it follows that in the entire region of 0.5 < C_GS/C_Au < 3, spectra of four forms, including Au(GS)₂*, are sufficient to describe all spectra within experimental errors in the form of a linear combination. As pH decreases, the proportion of Au(GS)₂* decreases. The equilibrium constant 0.25 Au₄(GSH)₄^4– + GSH₂^– = Au(GSH)₂^3– + H⁺ is equal to lgK = –4.4 ± 0.1 (I = 0.2 M, NaCl).

Hollow aluminosilicate microspheres (cenospheres) of stabilized composition (glass phase – 95.4 wt. %; (SiO₂/Al₂O₃)_glass – 3.1) isolated from fly ashes from coal combustion were used to prepare composite sorbents containing a sorption-active component based on zirconosilicates of framework structure. The synthesis products were characterized by XRD, SEM-EDS and low-temperature nitrogen adsorption methods, and their sorption properties towards Cs⁺ were studied. Zirconosilicate material demonstrates the high distribution coefficient in the process of Cs⁺ sorption from aqueous solutions (~10³–10⁴ ml/g) and stability of sorption capacity as a result of decationation. The possibility of application of SPS-synthesis technology to create high-density mineral-like ceramics for cesium immobilization based on the zirconosilicate sorbent has been investigated. The results of dilatometry, structure and porosity analyses were obtained for ceramics sintered at different temperatures (800–1000°C).

Microstructural features, phase composition, and eletrochromic properties of V₂O₅ film formed by spin-coating using vanadyl alkoxoacetylacetonate as a precursor have been studied. The obtained material possesses a significant amount of V⁴⁺ ions, which is indicated both by the presence of the corresponding modes on the Raman spectra and the presence of the V₇O₁₆ phase. As a result, the material exhibits anodic electrochromism – it colors upon oxidation, changing color from pale blue to a much less transparent orange-yellow. The optical contrast can reach 30% at a wavelength of 400 nm, and the coloration efficiency is 65.26 cm²/C. The results of the study clearly demonstrate the promising application of materials based on V₂O₅, obtained using heteroligand hydrolytically active vanadyl complexes, as functional components of devices that provide a change in optical properties when an electrical voltage is applied.