bluuebunny/crossref_metadata_2025 huggingface dataset:
Sinthesis and Properties of Hard Carbon Materials Made of Molybdenum-Doped Viscose Fiber for Negative Electrodes of Sodium-Ion Batteries
Authors: Zheleznov V. V. , Saenko N. S. , Maiorov V. Yu. , Ustinov A. Yu. , Sokol’nitskaya T. A. , Kuryavyi V. G. , Shlik D. Kh. , Sokolov A. A. , Opra D. P.
Published: April 2024

Herein, a method for the preparation of hard carbon via carbonization of chemically modified (molybdenum-doped) commercially available viscose fiber was developed. The effects of a molybdenum dopant on carbonization conditions were studied. The carbonization products retained the fibrous structure and flexibility. The structural features of the synthesized hard carbon materials were investigated, and their relationships to the carbonization temperature and the amount of the molybdenum dopant were analyzed. The texture of materials was studied, and correlations between the specific surface area and porosity, on the one hand, and the synthesis conditions, on the other, were discovered. The usefulness of the products as anode materials for sodium-ion batteries was evaluated. The electrochemical tests, together the extant relevant data, indicate that molybdenum induces the structural rearrangement of the carbon framework upon annealing, accompanied by the growth and ordering of graphite-like nanoclusters. The material prepared at 1050°C exhibited the best electrochemical performances among the synthesized products and the stable cyclability with a capacity of 290 (mA h)/g at a current density of 25 mA/g.
Influence of Fe3O4 on Physicochemical and Photocatalytic Properties of Nanosized Barium Titanate
Authors: Ivanov K. V. , Plotvina A. V. , Agafonov A. V.
Published: April 2024

A procedure has been proposed for the synthesis of a nanocomposite based on barium titanate modified by adding nanodispersed magnetite using the sol–gel method in an acetic acid medium followed by annealing at 800°C. The physicochemical analysis of the products has shown that the matrix phase after annealing is barium titanate with an admixture of barium carbonate, and, in addition to magnetite, there are minor inclusions of hematite and wustite. The elemental composition of nanosized samples has been determined using energy-dispersive X-ray spectroscopy. It has been demonstrated that the concentration of introduced Fe3O4 affects the morphological and phase composition of the composites. The specific surface area and type of porosity of calcined samples have been determined by the low-temperature nitrogen adsorption/desorption method. The effect of BaTiO3, BaTiO3/Fe3O4-1%, and BaTiO3/Fe3O4-10% powders on the adsorption capacity and photocatalytic activity in the process of decolorization of the dye rhodamine B from an aqueous solution in the dark and under the action of ultraviolet light has been studied. The kinetics of adsorption in the dark and photocatalytic decomposition of rhodamine B under the action of ultraviolet radiation in an aqueous suspension of the obtained composites have been analyzed using pseudo-first and pseudo-second order kinetic models.
Iron(III) Complexation with Barbituric and 2-Thiobarbituric Acids in Aqueous Solution
Authors: Lakeev A. P. , Korotchenko N. M. , Kurzina I. A.
Published: April 2024

Complexation in systems containing iron(III) chloride and barbituric (H2BA) or 2-thiobarbituric (H2TBA) acid has been studied by spectrophotometry and pH-metry in the pH range of 1.3–3.3 (I = 0.1 (NaCl), t = 20°C). The presence of 1 : 1 complexes with mono- and deprotonated forms of the ligand has been established, and their stability constants (in log units) have been determined: 1[FeHBA]2+ (3.49 ± 0.15), [FeHTBA]2+ (2.69 ± 0.07), [FeBA]+ (12.22 ± 0.13), and [FeTBA]+ (11.05 ± 0.08). It has been shown that the higher thermodynamic stability of barbiturate complexes compared to 2-thiobarbiturate ones is due to the greater basicity of the barbiturate anion. Based on the stability constants obtained, it has been proposed to use orthophosphate, fluoride, and ethylenediaminetetraacetate ions to eliminate the interfering effect of iron(III) in the determination of malondialdehyde by the thiobarbiturate method. Orthophosphoric acid is the most convenient for practical applications, as it makes it possible to mask iron(III) and to create a strongly acidic medium necessary for the formation of a colored malondialdehyde–H2TBA adduct.
Phase Equilibria in the Sodium Perchlorate—Ethoxylated Alkylamine—Water System in the Temperature Range of 58–90°C
Authors: Elokhov A. M.
Published: April 2024

The scheme of topological transformation of the phase diagram for systems composed of a water–ethoxylated surfactant binary system with a lower critical solution temperature and an inorganic salt possessing salting-in–salting-out effect upon temperature variation was experimentally proved in relation to the alkylamine ethoxylate (ethomeen C/15)–sodium perchlorate–water system. Two phase separation regions were detected in the system in the temperature range between 58 and 82°C.
Influence of Formation Conditions on Physicochemical Properties of CsxV2O5·nH2O
Authors: Podval’naya N. V. , Zakharova G. S.
Published: April 2024

Cesium-containing compounds of hydrated vanadium(V) oxide of general formula СsxV2O5·nH2O, where 0.1 ≤ x ≤ 0.6 and 0.8 ≤ n ≤ 1.2, were prepared by hydrothermal, hydrolytic, and sol–gel processes. The preparation conditions were found to determine the intercalated cation (Cs+) homogeneity range and the vanadium(IV) percentage in the samples. The prepared compounds were characterized by a set of physicochemical methods, namely, IR spectroscopy, X-ray powder diffraction, thermogravimetric analysis, scanning electron microscopy, and low-temperature nitrogen adsorption. The СsxV2O5·nH2O compounds prepared by the hydrolytic and hydrothermal methods had the highest specific surface area, equal to 34.0 and 16.5 m2/g, respectively. The temperature-dependent electrical conductivities of СsxV2O5·nH2O samples were measured to estimate the activation energy of conduction in compounds having various vanadium(IV) percentages. It is only in the high-temperature range that the activation energy of conduction depended on the V4+ percentage in the sample; the least value was found in the hydrothermally prepared Сs0.6V2O5·H2O samples.
High-Temperature Electrically Conductive Polymer Composites with Single-Walled Carbon Nanotubes
Authors: Kuznetsov V. A. , Fedorov A. A. , Kholkhoev B. Ch. , Tkachev E. N. , Buinov A. S. , Burdukovskii V. F.
Published: April 2024

High-temperature composite materials comprising single-walled carbon nanotubes embedded in a polybenzimidazole (PBI) polymer matrix with a weight percentage of nanotubes from 1 to 5% were prepared and characterized. Film composite samples were prepared by flow-coating from dispersions of nanotubes in 2% PBI solution in N-methyl-2-pyrrolidone. The temperature dependences of electrical resistance of the composites were studied in the range from room temperature to 300°C in a high vacuum at a pressure less than 1 × 10–3 Pa. The first heating cycle to 300°C gave rise to an increase in room-temperature electrical resistance of the samples due to the desorption of oxygen from the nanotubes. For the composites containing 5 and 1% nanotubes, the change was about 1.4 and 500 times, respectively. This increase was reversible: when the samples were transferred to the ambient air, the electrical resistance relaxed to its initial value. The thermal stability of the composites was proved by the repeatability of the subsequent heating cycles and by thermogravimetric analysis.
Effect of Synthesis Conditions on the Thermoluminescence of LiMgPO4
Authors: Gyrdasova O. I. , Kalinkin M. O. , Akulov D. A. , Abashev R. M. , Surdo A. I. , Kellerman D. G.
Published: April 2024

Lithium magnesium phosphate LiMgPO4 is one of the most promising materials for luminescence dosimetry. In this paper, we consider methods for the synthesis or additional processing of this material, such as microwave, hydrothermal, and flux techniques, as well as melting followed by quenching, which makes it possible to enhance its thermoluminescence by increasing the crystallinity of the samples and improving grain contacts. The best properties are shown by the LiMgPO4–Na2B4O7 composite.
Microwave-Assisted Hydrothermal Synthesis of Ceric-Ammonium Phosphates (NH4)2Ce(PO4)2⋅H2O and NH4Ce2(PO4)3
Authors: Tronev I. V. , Sheichenko E. D. , Razvorotneva L. S. , Trufanova E. A. , Minakova P. V. , Kozlova T. O. , Baranchikov A. E. , Ivanov V. K.
Published: April 2024

The possibility of preparation of crystalline double cerium(IV) phosphates (NH4)2Ce(PO4)2⋅H2O and NH4Ce2(PO4)3 under the conditions of microwave-assisted hydrothermal synthesis has been analyzed. It has been shown that these phosphates in a single-phase state can be obtained in the temperature range of 130–190°С with a synthesis duration of ≥5 min, while the phase composition of the synthesis products is determined by the molar ratio of ammonia and phosphoric acid in the reaction mixture. Short-term (5 min) low-temperature (130°С) hydrothermal synthesis under microwave heating leads to the preparation of (NH4)2Ce(PO4)2⋅H2O and NH4Ce2(PO4)3 with a particle size of ~70 and ~200 nm, respectively. At higher temperatures and treatment times (190°C and 24 h), the particle size of these phases increases to ~200 and ~500 nm, respectively. For the first time, the value of the optical band gap for (NH4)2Ce(PO4)2⋅H2O was determined to be 2.8 and 3.1 eV for indirect and direct transitions, respectively.
NaCl–NaVO3–Na2ЭO4 (E = Mo or W) Three-Component Systems
Authors: Gubanova T. V. , Kravets N. S. , Garkushin I. K.
Published: April 2024

Phase equilibria in the NaVO3–Na2WO4 two-component system and in the NaCl–NaVO3–Na2EO4 (E = Mo or W) three-component system were studied. The phase assemblages of the NaCl–NaVO3–Na2EO4 (E = Mo or W) three-component systems were analyzed. Differential thermal analysis (DTA) showed that the binary system is a eutectic system and the three-component systems are partitioned by the compound Na3ClEO4 into two secondary triangles, in each of which eutectics were found. The percentages of the components in the ternary eutectics and their melting points were determined. Phase equilibria were described for all elements of the phase diagrams studied in this work. The Na2WO4 crystallization field is represented by α, β, and γ phases, and the Na2MoO4 crystallization field, by δ, γ, and β phases. The smallest crystallization field in the ternary systems belongs to low-melting NaVO3.
Hydrothermal Synthesis of Silver Sulfide
Authors: Sadovnikov S. I.
Published: April 2024

Silver sulfide powders with submicro- and micrometer particle sizes have been synthesized by the hydrothermal method at temperatures from 373 to 453 K in aqueous and alcoholic solutions of silver nitrate, sodium sulfide and citrate, sulfur, and thiocarbamide. The crystal structures of the synthesized powders, morphology, composition, and particle size of silver sulfide have been analyzed by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, and gas adsorption. The powder particles have a similar morphology in the form of rectangular parallelepipeds and cubes with smoothed edges; the size of the powder particles depends on the synthesis conditions and ranges from ~500 to 2000 nm.
Phase Assemblage of the Li+,Na+,K+||F–,Cl–,Br– Five-Component Reciprocal System and Its LiF–KCl–KBr–NaBr–NaCl Stable Pentatope
Authors: Burchakov A. V. , Garkushin I. K. , Emel’yanova U. A.
Published: April 2024

The phase assemblage of the Li+,Na+,K+||F–,Cl–,Br– five-component reciprocal system was studied for the first time. The phase tree obtained by partition of the phase assemblage into stable elements is linear. It consists of the following stable elements: the LiF–NaF–KF–KBr–KCl pentatope, LiF–NaBr–NaCl–KCl–KBr–NaF hexatope, and NaCl–KCl–KBr–LiBr–LiCl–LiF–NaBr heptatope, linked by the LiF–NaF–KCl–KBr stable tetrahedron and the LiF–KBr–NaBr–NaCl–KCl square pyramid (pentatope). Phase equilibria in the LiF–KCl–KBr–NaBr–NaCl stable pentatope were studied by differential thermal analysis (DTA). Monovariant phase equilibrium L ⇄ LiF + NaClxBr1 – x + KClyBr1 – y occurs in the pentatope, where NaClxBr1 – x and KClyBr1 – y are continuous solid solutions (css) between NaCl and NaBr, KCl and KBr salt pairs, respectively. The composition of the mixture at point Min◻ 591 and the lowest monovariant equilibrium temperature were determined. A 3D computer model was designed as a projection of the phase assemblage on the LiF–KCl–KBr–NaBr–NaCl pentatope in KOMPAS-3D software. The volumes of crystallizing equilibrium phases were outlined.
Phase Formation in the Calcium Hexaboride–Iridium System
Authors: Lozanov V. V. , Gavrilova T. A. , Baklanova N. I.
Published: April 2024

The processes occurring in the Ca–Ir–B system were studied. The elemental and phase compositions and morphology of the products formed in the reaction of iridium metal with calcium hexaboride in the 700–1600°C temperature range were investigated. The signs of the onset of the reaction are already visible at 700°C. The first reaction products are iridium borides IrB0.9 and IrB1.1, where IrB0.9 is formed as a low-temperature and metastable high-temperature polymorphs. An increase in the treatment temperature in the 1000–1600°C range leads to the formation of three ternary compounds, presumably, Ca3Ir8B6, CaIr4B4, and CaIr2B2; the first two of these phases were previously unknown. The unit cell parameters of the new compounds, Ca3Ir8B6 (based on Sr3Rh8B6) and CaIr4B4 (based on LaIr4B4), were determined. The results attest to the complexity of the processes occurring in the Ca–Ir–B system and the diversity of ternary boride phases. The ternary boride phases can be of interest by themselves for high-temperature materials science.
Magnetic Carbon Nanocomposites: Preparation from Cellulose via Chemical Activation with FeCl3 and Characterization
Authors: Prusov A. N. , Prusova S. M. , Radugin M. V.
Published: April 2024

We have studied the preparation of magnetic graphitic carbon composites, which combine the adsorption properties of activated carbon with magnetic properties and properties intrinsic to graphite. The preparation method is efficient; it comprises modifying flax shive cellulose with citric acid to enhance the chelating ability of the flax shive cellulose matrix, impregnating the modified cellulose with iron chloride, and pyrolysis in an inert atmosphere to control the composition, morphology, specific surface, and porosity of hybrid carbon materials. The scenario of cellulose matrix pyrolysis was suggested using thermogravimetry. X-ray structural analysis was used to characterize the graphitic composites. The citric acid modification of cellulose helps to prepare a high-graphite (74%) carbon composite where the graphitization level of the graphite structure approaches the graphitization level of commercially available graphite at 700°С. Low-temperature N2 adsorption–desorption and ζ-potential measurements helped to suggest the adsorption mechanism for environmentally hazardous dyes. The greatest equilibrium adsorption of Methylene Blue (MB) and Methyl Orange (MO) dyes was 127.4 and 23.7 mg/g, respectively. The prepared composites can be used as adsorbents and fillers in polymer composite materials.
Thermodynamic Modeling and Experimental Implementation of the Synthesis of Vanadium Oxide Films
Authors: Shestakov V. A. , Seleznev V. A. , Mutilin S. V. , Kichay V. N. , Yakovkina L. V.
Published: April 2024

The paper describes the thermodynamic modeling and experimental study of the synthesis of vanadium oxide films at various temperatures from the tetrakis(ethylmethylaminovanadium) V[NC3H8]4 precursor in the presence of oxygen in an argon atmosphere. The thermodynamic modeling was carried out using the calculation of chemical equilibria based on the minimization of the Gibbs energy of the system. In the experimental part of the paper, the films were synthesized by the atomic layer deposition procedure. The thermodynamic modeling and experimental results agree with each other and can be used to develop procedures for the synthesis of film coatings based on vanadium oxides.
Preparation and Reduction of Graphene Oxide/Zinc Borate Composites as Candidate Flame-Retardant Materials
Authors: Ivannikova A. S. , Ioni Yu. V. , Sapkov I. V. , Kozlova L. O. , Kozerozhets I. V.
Published: April 2024

A new method for manufacturing composites comprising graphene oxide (GO) and zinc borate nanopowders is described. The method comprises ultrasonic stirring of precursor slurries followed by removal of water. Exposure to supercritical isopropanol provides a composite comprising reduced graphene oxide (RGO) and zinc borate nanopowder due to removal of oxygen functions from the graphene oxide structure, thereby providing a uniform distribution of zinc borate particles over the surface of reduced graphene oxide.
Ce0.9(Mg,Ni)0.1O2: Composite or Solid Solution
Authors: Smirnova M. N. , Nipan G. D. , Kop’eva M. A. , Nikiforova G. E. , Buzanov G. A. , Kozhukhova E. I. , Kozerozhets I. V. , Yapryntsev A. D. , Arkhipenko A. A. , Doronina M. S.
Published: April 2024

Samples of the composition Ce0.9(Mg1 – xNix)0.1O2 (0 ≤ x ≤ 1, step x = 0.1) have been obtained by gel combustion followed by hydrothermal treatment. X-ray powder diffraction data have showed that after gel combustion and annealing at 1100°C, composite CeO2 (fluorite structure)/solid solution Mg1 – xNixO (halite structure) is formed, and additional hydrothermal treatment followed by annealing promotes the formation of limited solid solution Ce0.9(Mg1 – xNix)0.1O2. According to the results of IR spectroscopy, the CeO2/Mg1 – xNixO composite does not adsorb CO2 even in the presence of water vapor, which is also confirmed by diffuse reflectance spectra in the UV-visible region. On the contrary, the Ce0.9(Mg1 – xNix)0.1O2 solid solution absorbs CO2, as evidenced by the results of IR spectroscopy and thermogravimetric analysis.
Interaction of SiC with Al2O3−(t + m)ZrO2(Y2O3) Oxide Composition
Authors: Ivannikov A. Yu. , Mel’nikov M. D. , Kargin Yu. F. , Frolova M. G. , Lysenkov A. S. , Perevislov S. N. , Petrakova N. V. , Kim K. A. , Sevost’yanov M. A.
Published: April 2024

We employed contact alloying in the range 1000–1860°С to study the reaction specifics between SiC and Al2O3−(t + m)ZrO2(Y2O3) oxide composition. Real-time experiments with photographic recording of the changing size and shape of the Al2O3−(t + m)ZrO2(Y2O3) sample on a SiC ceramic substrate showed that Al2O3−(t + m)ZrO2(Y2O3) compositions react with the silicon carbide substrate in the range 1720–1860°С to melt and penetrate into (impregnate) the substrate. X-ray powder diffraction patterns were measured for samples taken from the contact area of the oxide composition with SiC directly on the substrate and in a chipped-off 1-mm-deep near-surface layer. ZrС, Al2Y4O9, and Al3.21Si0.47 were formed in the contact area via redox reactions involving oxide melt, in addition to 6H-SiC, Si and Al2O3, t-ZrO2 phases, which are the initial components of the substrate and oxide composition, respectively.
Synthesis of Conjugates of Cationic meso-Arylporphyrins with Substituted closo-Decaborate Anion Derivative [B10H9NH=C(CH3)CH2C≡CH]–
Authors: Bortnevskaya Yu. S. , Zakharov N. S. , Zhdanov A. P. , Grigoriev M. S. , Zhdanova K. A. , Bragina N. A. , Zhizhin K. Yu.
Published: April 2024

A click reaction-based approach to the synthesis of water-soluble conjugates of cationic meso-arylporphyrins of A3B type and closo-decaborate anion derivatives [B10H9NH=C(CH3)NHCH2C≡CH]– is presented. The structure of the conjugates was established by advanced methods of analysis. Their main absorption and luminescence characteristics were investigated.
6Ag2Se + Ag8GeTe6 ↔ 6Ag2Te + Ag8GeSe6 Reciprocal System
Authors: Amiraslanova A. J. , Mammadova A. T. , Imamaliyeva S. Z. , Alverdiyev I. J. , Yusibov Yu. A. , Babanly M. B.
Published: April 2024

Here, we present the results of DTA and XRD studies of phase equilibria in the 6Ag2Se + Ag8GeTe6 ↔ 6Ag2Te + Ag8GeSe6 reciprocal system (system A). A Т–х diagram of the Ag8GeSe6–Ag8GeTe6 boundary system, several inner polythermal sections, isothermal sections at 300 and 1000 K, and the liquidus surface projection were plotted. The Ag8GeSe6–Ag8GeTe6 system is a partially quasi-binary system; it features continuous substitutional solid solutions between Ag8GeTe6 and the high-temperature cubic Ag8GeSe6 phase (the δ phase). Once solid solutions are formed, the polymorphic transition temperature in Ag8GeSe6 decreases, thereby stabilizing the ion-conducting cubic phase in the range of ≥40 mol % Ag8GeTe6 compositions at room temperature and below it. System A is shown to be a reversible reciprocal system; its liquidus surface is comprised of three fields, which relate to the primary crystallization of the solid solutions between the high-temperature Ag2Se and Ag2Te (α phase) phases, IT-Ag2Te-base solid solutions (β phase), and the δ phase. The subsolidus portion of system A features complex interactions related to polymorphism in the terminal compounds and in phases based on them
Reaction of Highly Dispersed Nickel Metal Powders with Pd(II) Aqueous Solutions under Hydrothermal Conditions
Authors: Borisov R. V. , Belousov O. V. , Likhatski M. N. , Zhizhaev A. M.
Published: April 2024

The processes of contact reaction of nickel metal powders with aggregated particle sizes of 300–400 nm with aqueous solutions of palladium(II) in autoclaves at elevated temperatures in acidic and alkaline media have been studied. It has been found that when metallic nickel contacts with aqueous solutions of palladium(II) chloride in 0.01 M hydrochloric acid at temperatures of 100 and 130°C for 15 min, the concentration of divalent palladium ions decreases to zero. The process is accompanied by a partial transition of nickel into solution. The precipitates are a mixture of metallic particles of nickel and palladium of variable compositions. In the case of contact of metallic nickel with solutions of tetraammine palladium(II) chloride at temperatures of 160 and 170°C in a medium of 0.1 M potassium hydroxide, metal palladium particles 5–25 nm in size are formed on the surface of larger nickel particles. The structure of bimetallic particles has been determined by X-ray photoelectron microscopy.
Effect of F Substituents in Thiophenol on the Structure and Properties of µ2-S-(Difluorothiolate)tetranitrosyl Iron Binuclear Complexes
Authors: Sanina N. A. , Konyukhova A. S. , Korchagin D. V. , Ovanesyan N. S. , Kulikov A. V. , Mumyatova V. A. , Terent’ev A. A. , Aldoshin S. M.
Published: April 2024

Two new neutral binuclear tetranitrosyl iron complexes of general formula [Fe2R2(NO)4] with R = 2,4-difluorothiophenyl (complex 1) and 3,4-difluorothiophenyl (complex 2), donors of nitrogen monoxide (NO), were prepared. The complexes were characterized by single-crystal X-ray diffraction, IR, Mössbauer, EPR spectroscopy, and elemental analysis. The antibacterial activity and cytotoxicity of complex 1, complex 2, and previously synthesized [(NO)4] with R'= 2,4-dichlorothiophenyl (complex 3) were studied for the first time. The “amount of NO–biological activity” correlations were analyzed depending on the nature and position of the substituent in the thiophenyl ligand. Complex 2 was found to have antibacterial activity that was four times as high as that of the known antibiotic kanamycin. The anti-biofilm activity of complex 2 was studied; it inhibited 46% of biofilm formation and destroyed 32% of M. Luteus biofilms, surpassing the effects of the reference drugs kanamycin and ampicillin.
Synthesis and Functionalization of Unsymmetrical Terbium(III) Bis-Phthalocyaninates, Promising Components of Hybrid Magnetic Materials
Authors: Yagodin A. V. , Kormshchikov I. D. , Martynov A. G. , Gorbunova Yu. G. , Tsivadze A. Yu.
Published: April 2024

A new unsymmetrical terbium bis-Phthalocyaninate Tb(A7B) with one terminal aliphatic OH group was obtained by template cross-condensation of diethoxyphthalonitrile (A) and phthalonitrile (B) functionalized with diethylene glycol moiety. The subsequent functionalization of the complex included the successive replacement of this OH group by the iodide and thioacetate substituents. The synthesized complexes can act as components of hybrid materials upon immobilization on surfaces of various nature.
Spatial Computer Model of the UCl3–NaCl–MgCl2–PuCl3 Isobaric Phase Diagram
Authors: Vorob’eva V. P. , Zelenaya A. E. , Lutsyk V. I. , Lamueva M. V.
Published: April 2024

A four-dimensional (4D, in concentration–temperature coordinates) computer model of the isobaric phase diagram of uranium, sodium, magnesium, and plutonium chlorides, as well as four three-dimensional (3D) computer models of the phase diagrams of the ternary systems forming it, has been constructed. The technology of assembling a 4D model of 46 hypersurfaces and 17 phase regions was used in the design. The obtained 4D model of the UCl3–NaCl–MgCl2–PuCl3 phase diagram makes it possible to visualize a four-dimensional object as a whole (with all its hypersurfaces and phase regions) by any arbitrarily given 2D and 3D sections, as well as it is able to reproduce published (experimental or thermodynamically calculated) 2D sections. The scope of application of the results of the work is the development of materials for fuel components of fourth-generation molten salt reactors and pyrochemical recycling of spent fuel rods. For the first time, a comprehensive, complete description of phase diagrams composed of uranium, plutonium, sodium, and magnesium chlorides has been obtained.
Spin Selectivity of the Conductivity of Gold Nanotubes according to the Cylindrical Wave Method Data
Authors: D’yachkov P. N. , D’yachkov E. P
Published: April 2024

The band structures of two series of chiral single-walled gold nanotubes (5, n2) and (10, n2) have been calculated using the cylindrical wave method with inclusion of spin–orbit coupling. Compounds with high spin polarizability of the electronic structure and spin selectivity of conductivity have been revealed. They can be used as materials for design of molecular spintronics elements.
Nucleophilic Addition of Aliphatic Diamines NH2(CH2)nNH2 (n = 6, 9) to Nitrilium Derivatives of the closo-Decaborate Anion [2-B10H9NCR]– (R = CH3, C2H5, nC3H7)
Authors: Voinova V. V. , Selivanov N. A. , Bykov A. Yu. , Klyukin I. N. , Zhdanov A. P. , Zhizhin K. Yu. , Kuznetsov N. T.
Published: April 2024

The reaction of a number of nitrilium derivatives of the closo-decaborate anion with hexamethylene- and nonamethylenediamine has been studied. It has been shown that the process proceeds with the functionalization of both amino groups of the nucleophile to form amidines of the type (Bu4N)2[B10H9NH=C(R)NH (CH2)nNH(R)C=NHB10H9] (R = CH3, C2H5, nC3H7; n = 6, 9). Target compounds have been characterized by high resolution multinuclear NMR and ESI mass spectrometry.
Study of Hydrophilic/Hydrophobic Properties of Borylated Iminols [BnHn – 1NHC(OH)R]– (n = 10, 12)
Authors: Ryabchikova M. N. , Nelyubin A. V. , Klyukin I. N. , Zhdanov A. P. , Zhizhin K. Yu. , Kuznetsov N. T.
Published: April 2024

The behavior of borylated iminols based on the closo-decaborate and closo-dodecaborate anions in the dichloromethane–water system has been studied as a function of the pH of the aqueous phase. The distribution coefficients of compounds in the n-octanol–water system have been determined: for (Bu4N)[B12H11NHC(OH)CH3], log Kow = –0.46; for (Bu4N)[2-B10H9NHC(OH)CH3], log Kow = –0.51. These compounds show hydrophilic properties similar to those of formic and acetic acids. It has been shown that this method can be used to purify target compounds from hydrolysis products in the preparation of various derivatives as a result of nucleophilic addition of the closo-borate anions to nitrilium derivatives.
Structure and Unusual Magnetic Properties of Mg-Containing Solid Solutions Based on Y2FeTaO7
Authors: Ellert O. G. , Popova E. F. , Kirdyankin D. I. , Imshennik V. K. , Kulikova E. S. , Egorysheva A. V.
Published: April 2024

Mg-containing solid solutions based on Y2FeTaO7 and formed by various mechanisms of heterovalent substitution were synthesized and had the following compositions: Y2Fe0.55Mg0.3Ta1.15O7, Y2Fe0.625Mg0.3Ta1.075O7, Y2Fe0.7Mg0.3TaO7, Y2Fe0.7Mg0.2Ta1.1O7, Y2Fe0.85Mg0.15TaO7, Y1.85Mg0.15Fe0.925Ta1.075O7, and Y1.85Mg0.15FeTaO7. It was shown that all synthesized solid solutions have a pyrochlore-like layered structure (space group P3121), in which Fe3+ ions are distributed over three structural positions. The magnetic properties of these solid solutions are due to the presence of a small ferromagnetic component in a predominantly antiferromagnetic system and characterize a ferrimagnet or a canted antiferromagnet with the Néel transition at the Néel temperature TN above room temperature. According to the data of magnetic measurements, two magnetic phase transitions to the ordered phase occur in all the studied samples. Along with the TN transition, in weak magnetic fields and below TN, there is a second transition, which is most likely due to a spin reorientation of the Morin type. The existence of magnetic ordering at room temperature in one magnetic sublattice or an internal magnetic field (Hin) was confirmed by Mössbauer spectroscopy.
Synthesis and High-Temperature Heat Capacity of LaMgAl11O19 and SmMgAl11O19 Hexaaluminates
Authors: Gagarin P. G. , Guskov A. V. , Guskov V. N. , Khoroshilov A. V. , Ryumin M. A. , Gavrichev K. S.
Published: April 2024

The processes occurring during heating of a stoichiometric mixture of lanthanum, samarium, magnesium, and aluminum hydroxides synthesized by the reverse precipitation method have been studied by DTA/TG and X-ray powder diffraction methods. The conditions for the synthesis of single-phase LaMgAl11O19 and SmMgAl11O19 samples of the magnetoplumbite structure type have been determined, and the isobaric heat capacity has been measured in the temperature range 317–1817 K, showing the absence of structural transformations in this range.
Derivation of a Force Field for Computer Simulations of Multi-Walled Nanotubes Using Genetic Algorithm. I. Tungsten Disulfide
Authors: Bandura A. V. , Lukyanov S. I. , Domnin A. V. , Kuruch D. D. , Evarestov R. A.
Published: April 2024

A technique for constructing force fields based on the use of genetic algorithms is proposed, which is aimed at parameterization of potentials intended for computer simulation of polyatomic nanosystems. To illustrate the proposed approach, a force field has been developed for modeling layered modifications of WS2, including multi-walled nanotubes, the dimensions of which are beyond the capabilities of ab initio methods. When determining the potential parameters, layered polytypes of bulk crystals, monolayers, bilayers, and nanotubes of small diameters were used as calibration systems. The parameterization found was successfully tested on double-walled nanotubes, the structure of which was determined using density functional calculations. The obtained force field was used for the first time to model the structure and stability of achiral multi-walled nanotubes based on WS2. The interwall distances obtained from the simulation are in good agreement with the results of recent measurements of these parameters for existing nanotubes.
Catalytic Oxidation of CO over LaNi1/3Sb5/3O6 Synthesized by Different Methods
Authors: Egorysheva A. V. , Golodukhina S. V. , Plukchi K. R. , Liberman E. Yu. , Ellert O. G. , Naumkin A. V. , Chistyakov A. V. , Kolesnik I. V. , Arapova O. V.
Published: April 2024

Methods for the synthesis of LaNi1/3Sb5/3O6 with a rosiaite structure have been developed using citrate method and coprecipitation followed by annealing. The influence of synthesis conditions on the morphology of the samples has been demonstrated. A comparative analysis of the catalytic properties of LaNi1/3Sb5/3O6 synthesized by various methods, in the reaction of CO oxidation has been carried out. The catalyst synthesized by the citrate method demonstrated the greatest efficiency and stability (the temperature of 90% CO conversion was T90 = 336°C). The LaNi1/3Sb5/3O6 surface was studied before and after catalysis by in situ diffuse reflectance IR spectroscopy, X-ray photoelectron spectroscopy, and temperature-programmed O2 desorption. It has been shown that the catalytic oxidation of CO on the LaNi1/3Sb5/3O6 surface proceeds according to the Mars–van Krevelen mechanism and is accompanied by redox Sb3+ ↔ Sb5+ processes. It has been established that no contamination of the sample surface occurs during the catalysis process.
Low-Temperature Synthesis of Highly Dispersed Strontium Aluminate
Authors: Kozlova L. O. , Ioni Yu. V. , Son A. G. , Buzanov G. A. , Murav’eva G. P. , Kozerozhets I. V.
Published: April 2024

A new method for producing highly dispersed strontium aluminate with specified properties (low bulk density, particle size and shape) is described. The essence of the method is the sequential multi-stage heat treatment of a concentrated water-carbohydrate solution of Al(NO3)3, Sr(NO3)2, and D-glucose. The final product has a molar ratio of SrO : Al2O3 = 1 : 1. The main stages of the synthesis have been characterized by X-ray powder diffraction, SEM, and TEM methods. The initial stages of crystallization of SrAl2O4 upon heating at 1400°C have been revealed.
Phase Equilibria in the NaF–Na3ClMoO4–Na3ClWO4 Stable Triangle of the NaF–NaCl–Na2MoO4–Na2WO4 Four-Component System
Authors: Garkushin I. K. , Matveev A. A. , Sukharenko M. A.
Published: April 2024

Theoretical and experimental studies of the NaF–Na3ClMoO4–Na3ClWO4 stable secant triangle of the NaF–NaCl–Na2MoO4–Na2WO4 four-component system have been carried out. The review of the literature concerned with the boundary elements of the title system has shown two options for the numbers and compositions of crystallizing phase: in case the solid solutions are stable, two solid phases would be formed, and in case of their decay, three solid phases would. The experimental tools used to study the NaF–Na3ClMoO4–Na3ClWO4 system were differential thermal analysis (DTA) and X-ray powder diffraction (XRD). The melting point and composition of the mixture that correspond to point d, which lies on monovariant curve e1e2 connecting binary eutectics, have been determined. X-ray powder diffraction showed two solid phases, namely, NaF and Na3ClMoxW1 – xO4 continuous solid solutions (CSS), in an alloy of point d composition. The nonexistence of invariant points in the title system has been shown. The CSS based on Na3ClMoO4 and Na3ClWO4 are stable. The projection of the phase assemblage of the system on the composition triangle is represented by two crystallization fields of the terminal components: a sodium fluoride field, which is the dominant one, and a Na3ClMoxW1 – xO4 CSS field.
The role of cultural traditions in ecological niche partitioning in cetaceans
Authors: Filatova O. A.
Published: April 2024

Ecological niche partitioning is a process that allows organisms to achieve differences in resource use to reduce competition. Niche partitioning is traditionally viewed as a result of modification of genetically inherited traits through the process of adaptive evolution. However, in social animals with developed cognitive abilities, a significant portion of behavioral patterns is transmitted not genetically, but through social learning. Complex sets of behavioral patterns transmitted through social learning are called cultural traditions. The partitioning of ecological niches in cetaceans is most often considered in the context of morphological adaptations: changes in size, skull shape, and the structure of the filtering apparatus. The role of cultural traditions in niche partitioning is still poorly understood, but it is an important and promising area of research, as it provides a novel approach to the ability of animals to change their behavior in order to exploit the environment more efficiently. The main advantage of traditions over genetically inherited behavioral patterns is the ability to change quickly and spread rapidly in a population. Estimating the role of cultural traditions in ecological niche partitioning would highlight the significance of behavior plasticity and social learning in the evolution of animal intelligence. Ecological niche partitioning through the rapidly changing and rapidly spreading behavioral adaptations in the population, allowing to adapt quickly to changes in the environment, could provide a significant evolutionary advantage, which could lead to the development of a relatively high level of intelligence in cetaceans.
The phenomenon of marine bioprospecting
Authors: Rusyaev S. M. , Orlov A. M.
Published: April 2024

Bioprospecting (bioexploration or biosearch), which has taken shape since the end of the 90s of the last century, is developing rapidly. In recent decades, the dynamics of scientific publications on this topic has increased many times. Marine bioprospecting, as part of the general research direction, is characterized by an extremely wide range of studies, most of which are still in the phase of accumulating information about the genetic and biochemical diversity of biological material. In order to assess the potential of bioprospecting, a review of the results of the conducted studies was carried out. Within its framework, the periodization of the biosearch was carried out, the scale, the main factors, the problems, and the economic foundation of bioprospecting development are identified. The analysis and classification of methodological concepts is carried out. The role of information is revealed and the consequences of the development of bioprospecting are considered. The significant lag of the Russian marine bioprospecting requires taking serious steps toward the development of important and promising directions such as the creation of appropriate infrastructure and new forms of research organizations, the consolidation of the scientific community, the inclusion of business and government structures in the process.
Selective synthesis of some carboxylic acids esters
Authors: Sultanova R. M , Khusnutdinova N. S , Borisova Yu. G. , Raskildina G. Z , Meshcheryakova S. A , Samorodov A. V , Zlotsky S. S
Published: April 2024

The synthesis of esters of some carboxylic acids by the method of oxidative esterification was carried out. It was shown that the proposed method allows the selective esterification of carboxylic acids with hindered carboxyl groups. It was found that the synthesized esters have anti-aggregation activity at the level of acetylsalicylic acid.
Synthesis and some properties of 2-amino-4-aryl-6-hexyl7-hydroxy-4h-chromene-3-carbonitriles
Authors: Dotsenko V. V , Khalatyan K. V , Russkikh A. A , Varzieva E. A , Kramareva D. A , Vasilin V. K , Aksenov N. A , Aksenova I. V
Published: April 2024

Three-component condensation of aromatic aldehydes with malononitrile and 4-hexylresorcinol in toluene in the presence of a base leads to the formation of 2-amino-4-aryl-6-hexyl-7-hydroxy-4 H -chromene-3-carbonitriles in good yields (79-90%). Structure of the compounds was studied using the methods of two-dimensional NMR spectroscopy. Bioavailability parameters were predicted in silico , and possible protein targets were predicted by protein-ligand docking.
Reaction of c-alkyl-substituted 1,4,8,11-tetraazacyclotetradeca-4,11-dienes with carboxylic acid halides as a new method for the synthesis of c- and N-acyl-2,3,6,7-tetrahydro-1,4-diazepines
Authors: Anisimova N. A , Melkova D. A
Published: April 2024

The reactions of 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene with acetic and tetrafluorobenzoic acids halides produce C - and N -acyl-substituted 1,4-diazepines. Their structure was characterized by IR, 1H, and 13C NMR spectroscopy using two-dimensional experiments 1H-13C HMQC, HMBC, and 1H-1H COSY.
New reactions of acetylene generated in two-chamber reactor
Authors: Ledovskaya M. S , Voronin V. V , Valov N. R
Published: April 2024

For the first time reactions of acetylene generated in a two-chamber reactor with methyl diazoacetate, iodine and benzoyl chlorides were studied. Methyl 1 H -pyrazole-3-carboxylate, ( E )-1,2-diiodoethylene, ( E )-1,2-dideutero-1,2-diiodoethylene, (2 E )-1-aryl-3-chloroprop-2-en-1-ones, including D-labeled 3-chloro-2,3-dideutero1-phenylprop-2-en-1-one were synthesized.
Decyclization of substituted 2-[2-oxofuran-3(2h)-ylidene)furan-2-carbohydrazides by the action of alcohols and analgesic activity of the obtained compounds
Authors: Igidov S. N , Turyshev A. Yu. , Makhmudov R. R , Shipilovskikh D. A , Dmitriev M. V , Zvereva O. V , Silaichev P. S , Igidov N. M , Shipilovskikh S. A
Published: April 2024

A new series of substituted 4-oxo-2-[2-(furan-2-ylcarbonyl)hydrazinylidene]butanoic acids and 2-[2-oxofuran3(2 H )-ylidene]furan-2-carbohydrazides was synthesized. A methodology was developed for their decyclization under the action of primary and secondary alcohols with the formation of substituted alkyl 4-oxo-2-[2-(furan-2ylcarbonyl)hydrazinylidene]butanoates, which exist in the form of three isomeric forms. Among the synthesized compounds, substances with pronounced analgesic activity were found.
First Synthesis of N-Organyl-S-silylorganyl Derivatives of 2-Mercaptobenzothiazole
Authors: Yarosh N. O , Zhilitskaya L. V , Dorofeev I. A
Published: April 2024

The alkylation of 2-[dimethyl-(phenyl)/(phenylethynyl)silyl)methylthio]benzothiazoles with α-iodoketones of the aliphatic, aromatic and heteroaromatic series in the absence of basic media and solvents leads to formation of unknown salts based on 2-mercaptobenzothiazolium cations.
Complex of Mn(II) Perchlorate with (2-Methylenepropane-1,3-diyl)bis(diphenylphosphine Oxide): Synthesis, Structure, and Double Luminescence
Authors: Davydova M. P , Bagryanskaya I. Yu. , Rakhmanova M. I , Brel V. K
Published: April 2024

The reaction of Mn(ClO4)2·6H2O with (2-methylenepropan-1,3-diyl)bis(diphenylphosphine oxide) (L) in a methanol medium yielded a previously unknown complex [MnL2(MeOH)2](ClO4)2. According to X-ray diffraction data, its Mn2+ ion has a distorted octahedral environment formed by two chelate L ligands and two coordinated methanol molecules. At 298 K, this complex exhibits low-intensity dual luminescence, the low-energy component of which is attributed to Mn2+-centered phosphorescence, and the high-energy component is assigned to intraligand fluorescence.
Effect of Co-Doping on the Electrical Properties of Magnesium and Copper-Containing Bismuth Niobate with Pyrochlor-Type Structure
Authors: Piir I. V , Koroleva M. S , Maksimov V. S
Published: April 2024

Ruthenium-codoped bismuth niobate Bi1.5Cu0.375Mg0.375Nb1.45Ru0.05O7-δ with the pyrochlore structure was obtained by Pechini method. The distribution of Ru4+ over Nb5+ sites was established by structural analysis. According to the data of optical reflectance spectra, the optical band gap decreases from 2.40 to 2.27 eV for the sample doped with ruthenium. A small amount of ruthenium in the system was found to result in an increase in conductivity by 0.5 orders of magnitude compared to Cu-Mg-substituted bismuth niobate, due to an increase in the electronic component of the conductivity.
Formation of Hydrated Titanium Dioxide on the Surface of Aqueous Solution of Titanium(III, IV) Salt under the Action of Ammonia Gas
Authors: Gulina L. B , Skvortsova I. , Kuklo L. I
Published: April 2024

During the interaction at the phase boundary, the aqueous interface between the titanium salt solution and air (NH3) gives rise to TiO2 · n H2O films consisting of nanoparticles about 20 nm in size. The morphology of products synthesized on the surface of TiOSO4, TiCl3, Ti2(SO4)3 solutions was studied by optical and electron microscopy. Using X-ray spectral microanalysis and X-ray phase analysis, the composition and crystal structure of the synthesized compounds were established. The conditions for obtaining tubular TiO2 · n H2O structures with the morphology of microscrolls about 10 µm in diameter and 200 to 600 µm in length were found. Possible reactions for the formation of gradient films of hydrated titanium dioxide and a hypothesis to explain the reasons for their transformation into microscrolls are proposed.
Colloidal and nanosized catalysts in organic synthesis: XXV. Reductive alkylation of nitroarenes with alcohols in the presence of a supported copper nanocatalyst
Authors: Nebykov D. N , Razvalyaeva A. V , Panov A. O , Latyshova S. E , Mokhov V. M
Published: April 2024

Using a modified deposition-precipitation method followed by sodium borohydride reduction of the precursor deposited on γ-Al2O3, copper-containing catalysts were obtained, which allow the continuous process of reductive alkylation of nitroarenes with alkanols at 200-220°C and atmospheric pressure of hydrogen with mono- N -alkylated products selectivity up to 100% and complete conversion of nitroarenes.
Synthesis, some transformations and antibacterial activity of 5H-spiro[benzo[h][1,2,4]triazolo[3,4-b]quinazoline6,1′-cycloheptane]-7(11H)-ones
Authors: Markosyan A. I , Ayvazyan A. S , Gabrielyan S. H , Mamyan S. S , Ayvazyan A. A , Arakelyan H. H
Published: April 2024

Condensation of 2-thioxo-2,3-dihydro-1 H -spiro[benzo[ h ]quinazoline-5,1′-cycloheptane]-4(6 H )-one with hydrazine hydrate afforded 2-hydrazinyl-3 H -spiro[benzo[ h ]quinazoline-5,1′-cycloheptane]-4(6 H )-one. The reaction of the latter with orthoformic acid ethyl ester or carbon disulfide yielded 5 H -spiro[benzo[ h ][1,2,4]triazolo[3,4- b ]quinazoline-6,1′-cycloheptane]-7(11 H )-one and 9-mercapto-5 H -spiro[benzo[ h ][1,2,4]triazolo[3,4- b ] quinazoline-6,1 ‘-cycloheptane]-7(11 H )-one, respectively. Alkylation of the latter with methyl and ethyl iodides, allyl bromide, and benzyl chloride gave 9-sulfanyl-substituted 5 H -spiro[benzo[ h ][1,2,4]triazolo[3,4- b ]quinazoline-6,1′-cycloheptane]-7(11 H )-ones. The synthesized compounds exhibited antibacterial properties.
Reactions of 5-(1,2-dicarbadodecaboran-1-yl)-3-(2-pyridyl)1,2,4-triazines with dienophiles
Authors: Valieva M. I , Rammohan A. , Starnovskaya E. S , Kudryashova E. A , Krinochkin A. P , Kopchuk D. S , Zyryanov G. V , Chupakhin O. N
Published: April 2024

The reactions of 5-(1,2-dicarbadodecaboran-1-yl)-3-(2-pyridyl)-1,2,4-triazines with various dienophiles (2,5-norbornadiene, 1-morpholinocyclopentene, 1,2-dehydrobenzene, and 2-amino-4-phenyloxazole) were studied. It was shown that the presence of a carborane fragment in the 1,2,4-triazine ring causes an atypical reaction with dienophiles without the formation of the expected aza -Diels-Alder reaction products except for the reaction with 2,5-norbornadiene. The reaction of 5-(1,2-dicarbadodecaboran-1-yl)-3-(2-pyridyl)-1,2,4triazines with 2-amino-4-phenyloxazole unexpectedly led to the formation of the corresponding 4,5-dihydro1,2,4-triazines. One of the previously described procedures for the direct introduction of a carborane residue into the C5 position of 1,2,4-triazines was optimized.
Phosphonomethylated acetoxymethyl derivatives of acetylfurans and alkyl furoates with the remote location of substituents: synthesis and further transformations
Authors: Pevzner L. M , Ponyaev A. I
Published: April 2024

Methods of synthesis of phosphonomethylated acetoxymethyl derivatives of acetylfurans and alkyl furoates with the remote location of functional groups were developed. Investigation of methanolysis of these compounds in presence of sodium methylate showed that complete transesterification of acetates is achived when the equimolar amount of base is used. It takes place due to high acidity of furan alcohols. If acetoxymethyl group is located in the position 3 of the furan ring, and diethoxyphosphorylmethyl one - in the position 2, cleavage of P-C bond takes place. If phosphonomethyl group is located in the position 3, and acetoxymethyl one occupies position 2 or 4, transesterification of ester groups of phosphonate takes place, but P-C bond is not touched. The ester group of carbonic acid is transesterified in any case. The alcohols formed are oxidized according to Kollins to give the corresponding aldehydes. 2-Furylbenzo[ d ]thiazole having ester and diethoxyphosphorylmethyl groups in the furan ring was synthesized by reacting methyl 2-(diethoxyphosphorylmethyl)-5-formylfuran-3-carboxylate with 2-aminothiophenol.