Vol 70, No 7 (2025)

New double cerium(IV)-rubidium phosphates, RbCe₂(PO₄)₃ and Rb₂Ce(PO₄)₂ · хH₂O, have been obtained under hydrothermal conditions. Using the crystallographic parameters of isostructural compounds, the unit cell parameters of RbCe₂(PO₄)₃ and Rb₂Ce(PO₄)₂ · хH₂O were calculated from X-ray powder diffraction data. The following values were obtained: for RbCe₂(PO₄)₃, a = 17.494(1) A, b = 6.7759(5) A, c = 7.9831(5) A, β = 102.875(4)°, V = 922.51(10), A3, Z = 4 (space group C2/c); for Rb₂Ce(PO₄)₂ · хH₂O, a = b = 6.8663(1) A, c = 17.6562(5) A, V = 832.42(3) A3, Z = 4 (space group I41/amd). Thermal behavior analysis of the synthesized compounds was performed, including phase composition determination of the thermolysis products. The results demonstrate that the initial structures exhibit relative thermal stability, with decomposition onset temperatures of approximately 500°C. At higher temperatures, progressive thermolysis leads to the formation of CePO₄ alongside RbPO₃ or Rb₄P₂O₇, depending on conditions.

Under hydrothermal conditions in the Bi₂O₃-Al₂O₃–Fe₂O₃–P₂O₅–H₂O system, variable-composition compounds Bi(Al_1–xFe_x)₃(PO₄)₂(OH)₆ with an alunite-like structure were obtained. Based on experimental data on the miscibility limits of components in the (1–x)BiAl₃(PO₄)₂(OH)₆–xBiFe₃(PO₄)₂(OH)₆ system, the parameters of the subregular solution model (Q₁ = 6.395, Q₂ = 8.987 kJ/mol) were determined, and spinodal and binodal decomposition curves of solid solutions with an alunite-like structure were calculated. Thermodynamic calculations showed that individual BiAl₃(PO₄)₂(OH)₆ and BiFe₃(PO₄)₂(OH)₆ can form at temperatures above 122 and 170°C, respectively, which is consistent with the experimental data obtained in this study, indicating the absence of compounds with alunite-like structure at 160°C in the range 0.8 < x ≤ 1.

The low temperature hydrothermal synthesis of copper nanowires in the presence of oleylamine and ascorbic acid has been investigated. It was found that ascorbic acid can be effectively used as a “soft” reducing agent in the preparation of one-dimensional copper nanostructures, and by varying the synthesis conditions their microstructural properties can be modified, as indicated by the change in position of the characteristic absorption band using spectrophotometry in the visible region. The formation of nanowires with the desired crystal structure and the average size of the coherent scattering region, ranging from 25.7 to 28.8 nm, was confirmed by X-ray diffraction analysis. The microstructural features of the obtained materials were studied by scanning and transmission electron microscopy along with atomic force microscopy. In particular, it was found that reducing the synthesis temperature from 110 to 90°C and increasing the content of oleic acid in the reaction system allows to obtain copper nanowires with an average diameter of about 70.2 nm and an aspect ratio of about 285.

Molybdenum(V) porphyrin complexes, O=Mo(X)P (P is a substituted porphine, X is a single-charged anionic ligand), show affinity to practically significant organic bases, give an accessible for registration spectral response in the UV-visible region and therefore have prospects as active components of sensor devices. In order to achieve high values of the sensory parameters, the present work analyzes the influence of the composition of the O=Mo(X)P coordination sphere on them by varying the axial ligand X and the substituent in the composition of the equatorial macrocyclic ligand. For this purpose, a complete kinetic description of the reaction with pyridine (Py), a classical example of highly volatile organic compounds (VOCs), proceeding as two consecutive two-way reactions, identification and characterization of the intermediate and final products by UV-visible, ¹H NMR, IR spectroscopy and mass spectrometry, and sensing activity parameters — time and numerical value of the spectral response to the presence of Py and the lower limit of determination of the latter is presented using oxo(5,10,15,20-tetraphenylporphinato)(ethoxy)molybdenum(V) (O=Mo(OEt)TРР) as an example. Using similar data for O=Mo(OH)TPP, O=Mo(OEt)TTP and O=Mo(OEt)T^tBuPP (TTP and T^tBuPP are dianions of tetra-4-methyl- and tetra-4-tert-butyl-substituted TPP, respectively), it is shown that the directed formation of the coordination sphere is a means for fine-tuning the sensory properties and that the complex O=Mo(OEt)TPP is the most effective in this capacity.

Within the framework of the cluster approach using the 6-31G* basis set and the hybrid density functional (B3LYP), was modeled successive abstraction of H₂ from the [ZnMg(BH₄)₄ 4NH₃] and [Zn₂Mg₂(BH₄)₈⋅8NH₃] complexes. It was found that to start the dehydrogenation process, it is necessary to overcome the energy barrier of ~1.25 eV, then the process proceeds with the release of energy until about 70% of the available H₂ is extracted, for a higher degree of conversion additional energy costs will be required. The cleavage of H₂ molecules occurs through a number of intermediate structures of varying complexity with the significant participation of metal cations and the formation of fragments of chains based on B-N bonds containing fragments of N-H and B-H, which can be detected by IR spectroscopy, when dehydrogenation is stopped.

Relativistic discrete variation calculations of the electronic structure and the X-ray photoelectron spectrum of the valence electrons of the LrO₈ were done. This cluster reflects the lattice fragment of lawrencium dioxides. A MO scheme of the valence molecular orbitals in the binding energy range 0 to ~50 eV was built. The Lr6d, 5f and O2p atomic orbitals were found to participate in the outer valence molecular orbitals (OVMO) formation, the Lr6p_3/2 and O2s — АО atomic orbitals were found to participate in the inner valence molecular orbitals (IVMO) formation. The MO scheme allows understanding the chemical bond nature and the valence XPS spectrum in the LrO₈ cluster. The relative contribution of the OVMO and IVMO electrons to the chemical bond covalence component was evaluated. A comparison with the valence XPS spectra of AnO₂ of other actinides was done.

Modified silica aerogels were obtained by co-gelation of tetramethoxysilane and acylated 3-aminopropyl-trimethoxysilane (with the general formula (MeO)₃–Si–(CH₂)₃–NHC(O)–R), followed by supercritical drying in CO₂. Methyl esters of acetic, valeric, pelargonic, and stearic acids were used as acylating agents. The resulting aerogels were characterized using low-temperature nitrogen adsorption, scanning electron microscopy (SEM), and infrared spectroscopy (IR). It was shown that the specific surface area of the aerogels significantly depends on the length of the alkyl substituent in the modified silane and can vary from 40 to 1375 m²/g. An increase in the length of the alkyl substituent also leads to increased hydrophobicity of the aerogel, up to the formation of superhydrophobic materials (contact angle is 163.7°).

Vanadyl and nickel alkoxoacetylacetonates were used to prepare vanadium pentaoxide films doped with 1, 3, and 10 mol % nickel oxide. All films crystallized in tetragonal β-V₂O₅. The materials are strongly textured along the (200) axis and formed from one-dimensional structures, however, at 3 and 10 mol % NiO content, nanoparticles of 30–50 nm size are also observed in addition to them. According to the results of Raman spectroscopy, the materials contain a noticeable amount of V⁴⁺, ions, but no traces of NiO phases were found. All obtained materials, in terms of electrochromic properties are cathodic, changing color during reduction to dark blue, and during oxidation — to more transparent yellow. At the same time, an increase in nickel content leads to a decrease in coloring efficiency and slowing down of electrochromic processes. The results of the study allow us to conclude that it is promising to use materials based onV₂O₅, doped with nickel, obtained with the use of metal alkoxoacetylacetonates as precursors, as components of electrochromic devices.