No 4 (2025)

The Gly–GaF₃·3H₂O–H₂O(HF) system was studied by vibrational spectroscopy methods. A number of complex gallium(III) fluorides were obtained: (GlyH)₃[GaF₆], (GlyH)(Gly···GlyH)[GaF₅(H₂O)]·H₂O, (GlyH)₆[GaF₅–F–GaF₅]·F and (GlyH)[GaF₄(H₂O)₂·0,5H₂O.The vibrational (IR, Raman) spectra of the obtained compounds were analyzed, and band assignments were made. A distorted octahedral structure of the anions was established in the structures of all the obtained compounds, with the outer-sphere glycine cations being in the protonated state, with the outer-sphere glycine cations being in the protonated state.

Film composites Ti/TiO₂–SiO₂–Bi were formed by the method of one-stage pulsed plasma electrolytic oxidation (PEO). The obtained samples were studied by the methods of X-ray phase analysis, energy-dispersive analysis, electron microscopy, diffuse reflectance and impedance spectroscopy. X-ray phase analysis showed that all PEO coatings contain metallic bismuth and titanium oxide in the modifications of rutile and anatase. It is shown that a change in the pulse duration has a significant effect on the morphology, elemental composition and optical properties of the coatings. Analysis of the Mott–Schottky diagrams showed that all the obtained composites are n-type semiconductors. For all bismuth-modified samples, a shift in the potentials of flat bands to the cathode region is observed compared to the unmodified sample, which indicates the formation of a Schottky barrier at the metal-semiconductor interface. The number of charge carriers (N_d) increases with increasing PEO pulse duration, but in all cases it is lower compared to the Ti/TiO₂sample.It was found that modification of titanium dioxide films with bismuth leads to an improvement in their optical properties and the emergence of stable photocurrents under the action of visible light.

The mechanism of electrochemical formation of a nanocomposite based on polymethylolacrylamide with inclusion of gold and platinum nanoparticles was studied using chronoamperometry and impedance spectroscopy. It was found that the process is complex and includes electrochemical (formation of radicals, synthesis of AuNPs and PtNPs nanoparticles, electrodeposition of a Zn sublayer) and chemical (initiation of polymerization and formation of a polymer layer, inclusion of nanoparticles into the polymer matrix) stages occurring simultaneously for 5–10 minutes. It was found that as a result of these processes, the electrode capacitance passes through a maximum, and the resistance increases, which is associated with both the deposition of a new crystalline phase on the cathode and the insulating effect of the polymer. The inclusion of metal nanoparticles in the film increases the electrical conductivity of the nanocomposite.

New glasses have been synthesized in the CdNbOF₅–BaF₂–хErF₃(х = 0−5.0 mol. %) system. The glasses are two-phase. The ratio of amorphous phases, depending on the erbium trifluoride content in the glass, affects the thermal, crystallization, structural and optical characteristics of the glasses. When the ErF₃content in the glass is 3 mol. %, rearrangements in the glass structure occur, leading to an increase in the connectivity of oxyfluoroniobate networks. Glasses in the CdNbOF₅–BaF₂–ErF₃system are characterized by green luminescence of Er³⁺, corresponding to the transitions:⁴S_3/2→⁴I_15/2(544 nm),²Н_11/2→⁴I1_5/2(551 nm). The luminescence intensity increases with an increase in the ErF₃content to 2 mol. %. A further increase in the content of erbium trifluoride in the glass composition leads to a gradual decrease in the luminescence intensity, caused by concentration quenching and changes in the structure and phase composition at given dopant concentrations.

This article demonstrates two fast methods for synthesizing complex oxides in air high-voltage pulsed discharge plasma. In one of them, a powder containing CuO/Cu₂O/Y₂O₃/Y₂BaCuO/YBa₂Cu₃O_6,32was synthesized, from which CuO/YBa₂Cu₃O_6,91composite was obtained by calcination, including a superconducting phase below 87 K. In the other variant, Cr₂NiO₄/NiO/Ni composite was synthesized. The magnetic properties of the obtained substances were studied. The methods can be used for the rapid synthesis of high-temperature superconductors with a variety of oxide compositions and other complex oxides in order to search for new functional materials.

The paper presents the research results on integrative processing of datolite ore using the fluorite concentrate and ammonium sulphate. It is shown that fluorination can be carried out without expensive ammonium bifluoride, using chemical interactions fluorite concentrate and ammonium sulphate. The products are easily separated to obtain complex fluorammonium salts of boron, silicon and calcium sulphate in the gypsum form.

The review examines the prospects for involvement in the processing of gold-bearing and rare earthmetal ores that are considered to bestrategic mineralresources.Itprovides information about the mineral resource base of goldand describes themineral formations and associations of gold intheseores.The article also provides informationon the state of the mineral resource baseforrare earth metals,includingscandium,based ondatafrom published sources such asthe journals “Mining Industry” and “Gold and Technology”. Due to the complexnatureoftheseores andtheirlow content of valuable components,obtainingaccurate analytical datacan be challenging. However, thereviewdiscussesmodern analytical methods thatcan helpaccurately determine theconcentrationof strategic metals intheseore objects. The method of instrumental neutron activation analysis(INAA), which belongs to the group of non-destructive methods, provides the analysis of representative samples and is characterized by high accuracy (correctness) of definitions, is considered in detail. The article presents the nuclear physical characteristics of the elements often determined by this method. Examples of the determination of Au, Sc, andrare earth elements (REE)in ore samples andwaste materials usingthe INAAtechniquewith a Californium neutron sourceare given.

The article provides information on the methods for studying the mechanisms of depolymerization and thermal destruction of polytetrafluoroethylene (PTFE) and its low-molecular-weight fractions. It is shown that pyrolysis gas chromatograph mass spectrometry (Pi-GC/MS) is the most widely used method for analyzing the consist and properties of high-molecular-weight and low-molecular-weight polytetrafluoroethylenes, but this method does not allow good separation of the peaks of saturated and unsaturated fluorocarbons and identification is possible only by characteristic ions. It is possible to use the Pi-GC/MS option, where the mass spectrometer operates in the negative chemical ionization mode with methane and isobutane reagent gases. The separation does not become better, but good mass spectra are recorded, where molecular ions are present. Only multidimensional gas chromatography allows complete separation of the peaks of saturated and unsaturated fluorocarbons.

The development of new functionalized organic compounds capable of efficiently coordinating metal ions remains a pressing challenge in the design of chemical sensors for environmental monitoring. In this work, a significant reduction in the detection limit of Cd²⁺ ions was achieved by using a 6-formyl-substituted spiro[indoline-benzopyran]. Derivative containing a benzoxazole fragment at the 8´position of the benzopyran moiety. Incorporation of spiropyran molecules into a siloxane-acrylate latex matrix and their association with a tetraphenylborate ion, acting as a spacer to prevent π-stacking and self-quenching of luminescence, led to a notable enhancement in sensor sensitivity. The use of transparent, ion-permeable latex films modified with SP·TFB complexes enabled a five orders of magnitude decrease in the detection limit of Cd²⁺, reaching 1.66 nM.

March 1, 2025 marked the 110^thanniversary of the birth of Yuri Vladimirovich Gagarinsky, a surprisingly modest, bright and talented man, Doctor of Sciences in Chemistry, Professor, Corresponding Member of USSR Academy of Sciences, Director of the Institute of Chemistry, FEB RAS.The article presents the biography of Yuri Gagarinsky and his scientific legacy: the main scientific directions and people who stood at the origins of the Institute of Chemistry and continued the work of their Teacher.