bluuebunny/crossref_metadata_2025 huggingface dataset:
Monitor Calibrator as an Alternative to Spectrofluorimeter: Determination of Quinine in Beverages and Medicinal Preparations
Authors: Gorbunova M. V. , Terentev T. A. , Apyari V. V. , Dmitrienko S. G. , Zolotov Yu. A.
Published: April 2024

A possibility of using a monitor calibrator for the determination of luminescent compounds is shown on an example of quinine. The determination is based on the irradiation of a sample with broadband radiation in the visible and near UV spectral regions from a built-in source exciting phosphor molecules and the simultaneous registration of the radiation incident on the detector. Measurement conditions are selected. Quinine can be determined in the range of 60−750 µM, the limit of detection is 20 µM. The determination is not affected by common inorganic ions, as well as sweeteners and acidity regulators present in many beverages. The developed method of determination is applicable to the analysis of carbonated drinks and drugs. Compared to a traditional spectrofluorimeter, monitor calibrator is characterized by compactness, mobility, ability of detecting luminescence in cuvettes of various sizes and shapes, and lower cost.
Chemical Oxidation and Characterization of Carbon Nanotubes of Different Types for Improving the Efficiency of REE Preconcentration for Their Subsequent Determination in Geological Samples
Authors: Ognev V. E. , Khludneva A. O. , Zakharchenko E. A. , Zhilkina A. V. , Dogadkin D. N. , Kazin V. I. , Tyurin D. A. , Gromyak I. N. , Kolotov V. P.
Published: April 2024

Various methods for the oxidation of different types of carbon nanotubes (CNTs) in nitric acid and a mixture of nitric and sulfuric acids at various temperatures and durations of exposure are studied. Oxidation conditions that provide the high sorption activity of sorbents with respect to REE are found. Oxidized CNTs are characterized by acid-base titration and scanning electron microscopy, and the electrokinetic (ζ) potential of nanotube suspensions is determined as a function of pH. The elemental composition of CNTs is determined by ICP MS/AES methods. The sorption capacity of the oxidized CNTs with respect to a wide range of elements is determined. Their unique selectivity with respect to REE is revealed. A possibility of using oxidized CNTs for the efficient sorption preconcentration of REE with the aim to determine their ultralow concentrations in rocks is proved.
Novel Adsorbents for the Determination of Amino Acids in Soil Extracts by Hydrophilic Interaction Liquid Chromatography with Mass Spectrometric Detection
Authors: Chikurova N. Yu. , Gorbovskaia A. V, , Stavrianidi A. N. , Fedorova E. S. , Shemyakina A. O. , Buryak A. K. , Uzhel A. S. , Chernobrovkina A. V. , Shpigun O. A.
Published: April 2024

Adsorbents based on various substrates—silica and a copolymer of styrene with divinylbenzene—are developed for the determination of amino acids by hydrophilic interaction liquid chromatography—mass spectrometry. The optimal version of the structure of the functional layer in two series of the obtained stationary phases was chosen, which provides the best hydrophilization for each substrate. Retention mechanisms were studied and the conditions for the mass-spectrometric detection, separation, and determination of 16 amino acids were chosen. The applicability of the obtained adsorbents and a method for determining amino acids for the analysis of soil extracts were estimated.
Biohybrid Technology for the Detection of Ultralow Concentrations of Trinitrotoluene in Air
Authors: Kiroy V. N. , Kosenko P. O. , Shepelev I. E. , Shcherban I. V. , Smolikov A. B. , Arsenyev F. V. , Zaborovsky A. V. , Aksenov V. A. , Tivileva M. I. , Gruznov V. M. , Zasypkina I. I.
Published: April 2024

The technology is based on recording the focal activity (FA) of the olfactory bulb (OB) of rats upon the exposure rats to trinitrotoluene (TNT) vapors in the concentration 4.7 × 10–15 g/cm3, separately and in a mixture with saturated vapors of a complex interference composed of spices. The focal activity of the rat olfactory bulb was recorded using an array of 16 special electrodes implanted in the dorsal part of the rat olfactory bulb. The setup contained a box with a rat, sources of vapors (odorants), a multichannel digital system for recording electrical signals from an electrode array, and software performing algorithms for recognizing and classifying odorants presented to the rat. One source of TNT vapors was a device for batch volumetric preparation with a concentration of about 10–15 g/cm3, and another source was a source with a concentration of 4.7 × 10–15 g/cm3 in an air flow presented to rats. Data from 25 tests showed a 100% probability of detecting TNT vapors of the specified concentrations in pure air and also in the presence of a complex odor interference in the form of vapors from a mixture of red pepper, coriander, tobacco, etc., which, as a rule, mask the smell of TNT for animals.The technology is based on recording the focal activity (FA) of the olfactory bulb (OB) of rats upon the exposure rats to trinitrotoluene (TNT) vapors in the concentration 4.7 × 10–15 g/cm3, separately and in a mixture with saturated vapors of a complex interference composed of spices. The focal activity of the rat olfactory bulb was recorded using an array of 16 special electrodes implanted in the dorsal part of the rat olfactory bulb. The setup contained a box with a rat, sources of vapors (odorants), a multichannel digital system for recording electrical signals from an electrode array, and software performing algorithms for recognizing and classifying odorants presented to the rat. One source of TNT vapors was a device for batch volumetric preparation with a concentration of about 10–15 g/cm3, and another source was a source with a concentration of 4.7 × 10–15 g/cm3 in an air flow presented to rats. Data from 25 tests showed a 100% probability of detecting TNT vapors of the specified concentrations in pure air and also in the presence of a complex odor interference in the form of vapors from a mixture of red pepper, coriander, tobacco, etc., which, as a rule, mask the smell of TNT for animals.
Adaptive Calibration in Electrothermal Atomic Absorption Spectrometry
Authors: Sadagov Yu. M. , Sadagov A. Yu.
Published: April 2024

A method is developed for determining concentrations in Zeeman electrothermal atomic absorption spectrometry based on the conversion of the transformation function of an atomic absorption spectrometer into a calibration dependence adapted to the matrix of the analyzed sample. The transformation function is expressed as a one-parameter saturation function, which is an integral optical characteristic of the spectrometer, independent of the composition of the analyzed sample. The algorithm of the method includes measurement of the analytical signals of an analyzed sample and a same sample with a known additive of the analyte and calculation of the matrix coefficient and the desired concentration of the analyte in the analyzed sample from these signals. The adaptive calibration method is tested for As, Au, Cd, Cu, Mo, Pd, Pb, Mo, Pd, Pb, Ti, V. The relative systematic error in determining the concentration of an element in the range of measuring the absorbance of atomic vapor does not exceed 10%. The analytical ranges for the elements exceed three orders of magnitude.
Effect of Organic Additives on the Intensity of Metal Lines in the Emission Spectrum of a Drop-Spark Discharge upon Sample Introduction into an Electrolyte Anode
Authors: Yagov V. V. , Zhirkov A. A. , Mal’chenkova A. A.
Published: April 2024

The effect of the nature and concentration of organic medium modifiers on the intensity of lines of some heavy metals (Ag, Cd, Hg, Pb, Tl, Zn) in the spectrum of a drop-spark discharge upon sample introduction into an electrolyte anode is studied. It is shown that additives of 0.1–6 wt % of polar organic compounds greatly increase the intensity of Pb, Tl, and Zn lines and reduce the intensity of Ag lines. The greatest effect, a twenty-fold enhancement of zinc lines, is observed upon the introduction of methanol into dilute acids. The cadmium signal is insensitive to organic impurities in dilute acids, but is enhanced in concentrated salt solutions.
Nanocomposites Based on Multi-Walled Carbon Nanotubes, Magnetite Nanoparticles, and Core–Shell Molecularly Imprinted Polymers in Piezoelectric Sensors for the Determination of Macrolide Antibiotics
Authors: Bizina E. V. , Efrosinina A. V. , Farafonova O. V. , Zolotareva N. I. , Grazhulene S. S. , Ermolaeva T. N.
Published: April 2024

A piezoelectric sensor with a recognition layer based on magnetic carbon nanocomposites, including multi-walled carbon nanotubes, magnetic Fe3O4 nanoparticles, and polymer nanospheres with molecular imprints of erythromycin and azithromycin, obtained by the “core–shell” method, is developed. Silicon dioxide particles are used as cores, on the surface of which a shell molecularly imprinted with macrolides is synthesized by free radical polymerization or the sol–gel method. SiO2 particles are obtained by the Stober method by varying the ratio of reagents during the synthesis. The size of the cores and nanoparticles of molecularly imprinted polymers (MIP) is determined by atomic force microscopy, and the density and uniformity of the layer on the surface of magnetic carbon nanocomposites (MCNC) are determined by the piezoelectric quartz crystal microbalance method. The optimal ratio of the reagents (template : functional monomer : cross-monomer) is established by a spectrophotometric method during the synthesis of “core–shell” nanostructures by free radical polymerization. A thin shell of SiO2 with imprints of an antibiotic based on organosilicon compounds used in the synthesis of the core is formed by the sol–gel method on the surface of the silicon dioxide core. The sensor recognition layer is formed under the action of an external magnetic field. The dependence of the analytical signal of the sensor based on MIP@SiO2/MCNC on concentration is linear in the range 5–160 µg/mL for azithromycin and 10–160 µg/mL for erythromycin, and with a recognition layer based on SiO2@SiO2/MCNC, in the concentration range 20–400 µg/mL for erythromycin.
Voltammetric Determination of 7-Ethylthio-3-Nitro-1,2,4-Triazolo[5,1-c]-1,2,4-Triazin-4-One Dihydrate Sodium Salt as a Potential Antiviral Drug
Authors: Mozharovskaia P. N. , Ivoilova A. V. , Dem’yanovich (Selyanina) T. V. , Balin I. A. , Malakhova N. A. , Ivanova A. V. , Kozitsina A. N. , Matern A. I. , Rusinov V. L.
Published: April 2024

The sodium salt of 7-ethylthio-3-nitro-1,2,4-triazolo[5,1-c]-1,2,4-triazin-4-one dihydrate (1) is one of promising antiviral compounds that have shown a pronounced biological activity against influenza virus subtype H5N1, West Nile, and SARS (severe acute respiratory syndrome). Using cyclic voltammetry, it was shown that the electrochemical activity of compound 1 in a Britton–Robinson buffer solution (BRB) of pH 2.0 on a glassy carbon electrode is due to the electrochemical reduction of the nitro group conjugated with the heterocyclic system. A method was developed for the determination of compound 1 by direct cathodic square-wave voltammetry. The linearity region of the calibration curve in a BRB solution of pH 7.0 is 10–300 mg/L (R2 = 0.999), the limit of detection is 1.5 mg/L, and the limit of quantification is 4.5 mg/L. The accuracy of the developed procedure is close to 100%, the relative standard deviation is 3.6%.
Chromatographic Determination of Drotaverine and Mathematical Modeling of Its Biodegradation in Soil
Authors: Vikhareva E. V. , Selyaninov A. A. , Tyumina E. A.
Published: April 2024

The regularities of the biodegradation of drotaverine hydrochloride in soil by actinobacteria of the genus Rhodococcus in the presence of native microflora were studied. A method based on liquid–liquid extraction with chloroform followed by analysis using reverse-phase HPLC was proposed for determining the pharmaceutical pollutant in soil. A decrease in the ecotoxicant concentration by a factor of 100 in the course of its biodegradation was forecasted with a given probability of 95%.
Problems in Imaging the Decomposition of Liquid and Solid Solutions in the Ag–Cu–Ni and Ag–Cu–Pb Systems
Authors: Vorob’eva V. P. , Lutsyk V. I. , Parfenova M. D.
Published: April 2024

Three-dimensional (3D) computer models of Ag–Cu–Ni and Ag–Cu–Pb isobaric phase diagrams, designed based on 23 and 31 base points, respectively, assembled from 14 and 32 surfaces, 9 and 15 phase fields, respectively, and intended to digitize information on these diagrams, are used to verify the adequacy of interpretation of published isothermal and polythermal sections, both calculated and experimentally studied ones. The geometric features of the phase diagram regions that relate to liquid–liquid miscibility gaps and solid solution decomposition are refined in the 3D models. Mistakes arising from an incorrect imaging of the decay of copper–nickel solid solutions and from discrepancies in the values of the Ag–Cu–Pb ternary eutectic temperature are shown on polythermal sections.
Effects of the Preparation Method on the Dielectric Properties of Ni–Al Layered Double Hydroxides
Authors: Agafonov A. V. , Shibaeva V. D. , Kraev A. S. , Sirotkin N. A. , Titov V. A. , Khlyustova A. V.
Published: April 2024

Ni–Al layered double hydroxides (LDHs) are of interest as functional materials. The effects of preparation methods on the dielectric properties of Ni–Al layered double hydroxides were studied on samples prepared from solution (by coprecipitation and a hydrothermal process) and by plasma technology. The prepared layered structures were characterized by advanced analytical methods. The high ζ potentials of the particles prepared in suspensions evidence their high aggregation stability. X-ray powder diffraction and IR spectroscopy were used to determine the phase composition of samples and to identify the interlayer anion. The plasma between Al and Ni electrodes in distilled bulk water gives rise to the formation of Ni–Al LDHs with hydroxide ion as the interlayer anion. Thermal properties of the structures prepared were studied by thermal analysis. The results of dielectric measurements are presented.
PRODUCTION OF FUNCTIONALLY GRADIENT MATERIALS BASED ON SILICON CARBIDE AND HIGH-ALLOY STEEL USING SPARK PLASMA SINTERING TECHNOLOGY
Authors: CHUKLINOV S. V. , SERGIENKO V. I. , PAPYNOV E. K. , SHICHALIN O. O. , BELOV A. A. , MARCHUKOV E. Yu. , MUKHIN A. N.
Published: April 2024

An important scientific task of practical materials science is the production of metal-ceramic composites in the form of functional gradient materials (FGM) for special-purpose products. In this regard, a study was conducted on the application of spark plasma sintering (IPS) technology for the effective diffusion connection of SiC ceramics and high-alloy steel (grade X18R15) to obtain a combined FGM composite. In a comprehensive experimental study, the dynamics of consolidation and changes in the phase composition of dispersed SiC under conditions of different temperatures and heating rates, pressing pressure, and holding time were studied. As a result, the IPS conditions were optimized for obtaining SiC ceramics of high relative density (82%) and microhardness (500 HV) of stable phase composition. The physicochemical foundations of the formation of a strong compound of a two-component SiC-ceramic and steel system under IPS conditions without additives and using a mixture of additives in the form of a binder, a reaction binder and a damper (Ti–Ag, Ti–TiH2, Ti–Ag–TiH2 and Ti–Ag/Mo additive systems) have been studied. The structure, composition of ceramics and intermediate (binding and damping) layers, as well as the diffusion of elements at the boundary of the formed compounds in FGM composites, were studied using XRF, SEM and EMF methods. It was found that the Ti–Ag/Mo additive in the ratio of 30 wt. % Ti–70 wt. % Ag and a dense layer of Mo (thickness ~ 2 mm), acting as a damper to compensate for the temperature coefficient of linear expansion, ensure the formation of a connected FGM composite of an integral shape. The presented studies have been implemented for the first time, are promising and require further development in order to gain scientific knowledge of the manufacture of composite products for special purposes.
Indium Oxide–Graphene Composites Prepared by the Sol–Gel Process and Single-Electrode Gas Sensors on Their Base
Authors: Haiduk Yu. S. , Usenka A. E. , Rutkovskaya L. S. , Golodok R. P. , Timonenkova A. S. , Pankov V. V.
Published: April 2024

Indium oxide–graphene composites (containing 0–6.0 wt % graphene) were manufactured by the sol–gel process. The phase composition, microstructure, and gas-sensitive properties of the prepared materials were studied. The composites consist of isolated In2O3 and graphene phases, where graphene is predominantly adsorbed on the surfaces of indium oxide grains (the indium oxide grain sizes are 8–11 nm). The nanocomposites are distinguished by an enhanced sensitivity to both reducing gases (CH4, acetone) and oxidative gases (NO2). A far greater enhancement is in the sensory response to oxidative gases. Presumably, the major factors influencing the sensory properties of the composite are the high defectiveness of In2O3 and graphene phases, higher specific surface areas of composites compared to those of individual In2O3, and the likely formation of p–n junctions in the indium oxide and graphene contact zone. Graphene additives to indium oxide can improve the main performances (sensory response, response time, and recovery time) of single-electrode semiconductor sensors.
Synthesis, Structure, and Thermal Properties of Scandium(III) and Iron(III) Complexes with 3-Methyl-2,4-Pentanedione as Precursors for Chemical Gas-Phase Processes
Authors: Makarenko A. M. , Kuratieva N. V. , Pishchur D. P. , Zherikova K. V.
Published: April 2024

Complexes Sc(Meacac)3 and Fe(Meacac)3 (Meacac is 3-methyl-2,4-pentanedionate anion) have been synthesized, and their crystal structures have been first determined by X-ray diffraction. The volatility and thermal stability of the obtained compounds have been studied. The temperature, enthalpy, and entropy of melting of the complexes have been determined by differential scanning calorimetry. The flow method has been used to obtain the temperature dependence of the saturated vapor pressure of Sc(Meacac)3 in the range 414–472 K, from which the thermodynamic characteristics of the sublimation process have been calculated at an average temperature (= 132.8 ± 1.8 kJ/mol,= 226.1 ± 4.6 J/(K mol)) and at 298.15 K (= 143.9 ± 2.6 kJ/mol,= 256.5 ± 6.4 J/(K mol)). The compounds studied can be used as precursors in chemical vapor deposition, and the set of obtained thermodynamic data can be used to select the optimal deposition conditions.
Thermodynamic Characterization of Volatile Alkylamine Boranes as Precursors for the Formation of BCxNy Films
Authors: Sysoev S. V. , Sulyaeva V. S. , Kosinova M. L.
Published: April 2024

Tensimetric studies were carried out to determine temperature-dependent saturated vapor pressures and calculate thermodynamic characteristics of vaporization for R3N·BH3 (R = Me or Et) alkylamine boranes. These compounds have sufficient volatility and thermal stability to be used as precursors in vapor deposition processes to produce films based on phases of the B–C–N system. Triethylamine borane (TEAB) was used to synthesize boron carbonitride films at 773 and 873 K. The resulting layers were characterized by ellipsometry, atomic force and scanning electron microscopy, FTIR, Raman, and energy dispersive spectroscopies. The conditions for the production of continuous homogeneous films consisting of nanoparticles 20–60 nm in size aggregated into larger pseudohexagonal particles were determined. The surfaces of the films have an average and root mean square roughness, equal to 0.8 and 1.0 nm, respectively.
Stability of Colloidal Silver Sulfide Solutions
Authors: Sadovnikov S. I.
Published: April 2024

Stable colloidal solutions of silver sulfide Ag2S quantum dots of various sizes were prepared by hydrochemical bath deposition from low-concentration aqueous solutions of silver nitrate, sodium sulfide, and sodium citrate. The Ag2S quantum dot sizes determined by dynamic light scattering (DLS) were 2–3 to 28–30 nm. The great negative values of the measured ζ-potentials of the colloidal solutions and the small changes in ζ-potential and quantum dot sizes upon the long-term storage of the solutions indicate their stability across time.
Effect of Substituent Position on Saturated Vapor Pressure of Tetrafluorosubstituted Zinc Phthalocyanines
Authors: Bonegardt D. V. , Trubin S. V. , Sukhikh A. S. , Klyamer D. D. , Basova T. V.
Published: April 2024

This work is devoted to the study of the effect of the position of fluorine substituents in the molecules of tetrafluorosubstituted zinc phthalocyanines on their saturated vapor pressure. For this purpose, the temperature dependence of the saturated vapor pressure of zinc phthalocyanines with fluorine substituents in the peripheral (ZnPcF4-p) and non-peripheral (ZnPcF4-np) positions of the phthalocyanine ring has been studied by the Knudsen method with mass spectrometric recording of the composition of the gas phase and the thermodynamic parameters of vaporization were calculated. The data obtained for ZnPcF4-p and ZnPcF4-np with unsubstituted and hexadecafluorosubstituted zinc phthalocyanines are compared in terms of analysis of intermolecular interactions in the crystals of these compounds. It has been shown that tetrafluorosubstituted phthalocyanines have a higher vapor pressure than their unsubstituted (ZnPc) and hexadecafluorosubstituted (ZnPcF16) derivatives. In this case, the enthalpy of sublimation increases in the series ZnPcF4-p ZnPcF4-np ZnPc ZnPcF16.
Density, Thermal Expansion, Enthalpy, Heat Capacity, and Thermal Conductivity of Calcium in the Temperature Range 720–1290 K
Authors: Abdullaev R. N. , Khairulin R. A. , Agazhanov A. Sh. , Khairulin A. R. , Kozlovskii Yu. M. , Samoshkin D. A.
Published: April 2024

Thermophysical properties of solid and liquid calcium (99.75 wt % pure) were experimentally studied with high accuracy in the temperature range 720–1290 K using dilatometer measurements, gamma-ray attenuation measurements (the gamma-ray method), high-temperature drop calorimetry, and the laser flash method. The behaviors of the density, enthalpy, and thermal conductivity of calcium in the fusion–crystallization region were studied. The enthalpy of fusion was measured as 8075 J/mol, the relative density change upon fusion as 3.3%, and the relative change in thermal conductivity upon fusion as 26%. The results were compared to the respective values in the related literature. The measurements at temperatures above 720 K either significantly amend the available literature data, or are currently unique. The constancy of the heat capacity of liquid calcium in the temperature range 1115–1290 K was verified. Fitting equations were derived, and recommended values of the investigated properties of calcium were tabulated for 720–1290 K, the temperature range where calcium is in the condensed state.
Preparation of MgAl2O4 Spinel Activated with Manganese Ions by Self-Propagating High-Temperature Synthesis
Authors: Tomilin O. B. , Muryumin E. E. , Fadin M. V.
Published: April 2024

A self-propagating high-temperature synthesis of samples of the MgAl2O4 : Mn2+ luminophor has been carried out using the thermal effect of the reaction between aluminum and sodium perchlorate. Using energy dispersive analysis, the qualitative and quantitative composition of the luminophor has been established. To determine the degree of oxidation of manganese ions, the EPR spectra of the luminophor have been studied. The phase composition of the synthesis products has been established by X-ray diffraction, and the luminescent properties have been characterized by the excitation and emission spectra. The influence of the manganese content, as well as the Al : Al2O3 ratio in the charge, on the luminescent characteristics of the synthesized product has been studied.
A New Structural Type of Bismuth(III) Dithiocarbamato-Chlorido Complexes: Preparation, Structural Organization, and Thermal Behavior of Binuclear Compounds [Bi2{S2CN(CH2)6}4(μ2-Cl)2] and [Bi2{S2CN(CH2)6}4(μ2-Cl)2]·2CH2Cl2
Authors: Novikova E. V. , Isakovskaya K. L. , Ivanov A. V.
Published: April 2024

Heteroleptic compounds of bismuth(III) adopting a new binuclear structural type: hexamethylenedithiocarbamato(HmDtc)-chloride of [Bi2(S2CNHm)4(μ2-Cl)2] (I) and its solvated form [Bi2(S2CNHm)4(μ2-Cl)2]·2CH2Cl2 (II) have been isolated and studied by X-ray diffraction, IR spectroscopy, and simultaneous thermal analysis. Despite the identical chemical composition, the structure of binuclear molecules in I and II differs significantly. In the first case, the noncentrosymmetric molecule includes two nonequivalent moieties of [Bi(S2CNHm)2Cl], which are combined by μ2-Cl ligands to form the [Bi–(μ2-Cl)2–Bi] metallocycle in the butterfly conformation: Bi(1)–Bi(2) 4.0785(5) Å, Cl(1)–Cl(2) 3.936(2) Å. On the contrary, in the solvated form II, the complex is centrosymmetric and four-membered [Bi2Cl2] ring is stabilized in a rhombic configuration: Bi(1)–Bi(1)a 3.9592(9) Å and Cl(1)–Cl(1)a 4.540(4) Å. According to the microprobe method, the main residual substance after the thermolysis of the complexes is microcrystalline Bi2S3 with inclusions of metallic bismuth particles.
A Microstructural Study of the InSb〈Ni, Mn〉 alloy
Authors: Sanygin V. P. , Pashkova O. N.
Published: April 2024

The InSb + 1 at % Ni + 1 at % Mn alloy was studied by optical microscopy and scanning electron microscopy. A Heusler phase based on NiMnSb in the form of microinclusions on InSb dislocations was detected. The chemical composition of the microinclusions on dislocation pile-ups ranges from Ni1.1MnSb to Ni1.2MnSb, and that on individual dislocations is close to Ni1.1MnSb. However, the synthesis gives rise to bulk structural defects in the form of micropores and to elastic deformations around them, which are the main obstacles to the creation of a coherent material with unhindered movement of polarized electrons throughout the volume.
Synthesis of Magnesium- and Aluminum-Based Mixed Oxide Systems by Low and High Supersaturation Methods
Authors: Fadeev V. V. , Tronov A. P. , Tolchev A. V. , Galimov D. M. , Zhivulin V. E. , Morozov R. S. , Avdin V. V.
Published: April 2024

Magnesium–aluminum layered double hydroxides and mixed oxides based on them were obtained by high and low supersaturation methods and analyzed. It was shown that the phase composition and formation of nano-sized particles with a large surface area is significantly affected by the rate of introduction of magnesium–aluminum systems into the medium of the precipitated material. All of the obtained samples were studied by thermogravimetric analysis with mass-spectrometric detection, X-ray diffractometry, scanning electron microscopy, energy dispersive X-ray spectroscopy, and infrared spectroscopy.
Protolytic and Complexing Properties of Isomeric N-(Pyridylethyl)taurines
Authors: Zharkov G. P. , Filimonova O. V. , Petrova Yu. S. , Zemlyakova E. O. , Pestov A. V. , Neudachina L. K.
Published: April 2024

New N-derivatives of taurine, N-[2-(2-pyridyl)ethyl]taurine (HL1) and N-[2-(4-pyridyl)ethyl]taurine (HL2) have been synthesized. Using the method of alkalimetric titration of aqueous solutions with pH potentiometric indication at I = 0.1 mol/L (KCl/KNO3) and T = 25 ± 1°C, the acid dissociation constants of functional groups in the composition of reagents have been determined (HL1: pKa0 = 3.80 ± 0.03, pKa1 = 8.67 ± 0.02, HL2: pKa0 = 4.80 ± 0.05, pKa1 = 8.18 ± 0.04). It has been found that reagent HL1 is more resistant to the degradation process. The complexation of transition and alkaline earth metal ions with НL1 has been studied. It has been shown that the introduction of a 2-(2-pyridyl)ethyl substituent into the structure of taurine leads to a significant increase in the stability (Δ log β ≥ 1) of copper(II), cobalt(II), nickel(II), zinc(II), cadmium(II) and silver(I) complexes with НL1. Calcium(II), magnesium(II), strontium(II), and barium(II) complexes with HL1 are characterized by a slight increase in stability (Δ lg β 1) compared to taurine. Based on the data obtained, the structure of the studied complexes have been assumed.
Mechanochemical Synthesis of closo-Decaborate Anion Derivatives with Pendant Functional Groups
Authors: Matveev E. Yu. , Kubasov A. S. , Nichugovskii A. I. , Avdeeva V. V. , Zhizhin K. Yu. , Kuznetsov N. T.
Published: April 2024

A new method for the preparation of derivatives of the closo-decaborate anion with pendant functional groups has been developed, which includes the reaction of 1,4-dioxane, tetrahydropyran, and tetrahydrofuran derivatives of the [B10H10]2– anion with C-, O-, S-, and F-nucleophilic reagents (potassium cyanide, potassium hydroxide, sodium acetate, potassium hydrosulfide, potassium thiocyanate, sodium thiosulfate, and potassium fluoride) under mechanochemical conditions. It has been shown that these reactions proceed through the opening of exopolyhedral substituents of the oxonium type and lead to the formation of closo-decaborates with the corresponding С-, O-, S-, and Hal-functional groups. The developed method makes it possible to synthesize derivatives of the [B10H10]2– anion with pendant groups of various structures in a short time and without using aprotic polar solvents, which greatly facilitates the process of product isolation. The resulting closo-decaborates due to the presence of donor centers of various types can be used as polydentate ligands to obtain complex compounds of d-elements. In addition, the synthesized compounds can be used as a platform for further functionalization due to the reactivity of the attached pendant groups. The obtained derivatives of the [B10H10]2– anion have been studied by elemental analysis, IR, 11B, 13C, 1H NMR spectroscopy, and ESI mass spectrometry. The structure of Cs2[B10H9O(CH2)2O(CH2)2SCN] compound has been determined using X-ray diffraction.
Polymorphism in the Mg3BPO7–Ni3BPO7 System
Authors: Smirnova M. N. , Kop’eva M. A. , Nipan G. D. , Nikiforova G. E. , Yapryntsev A. D. , Arkhipenko A. A. , Doronina M. S.
Published: April 2024

The Mg3 – nNinBPO7 (n = 0.0, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0) samples were prepared by solid-phase reactions at 980°C followed by inertial cooling, and then were characterized by X-ray powder diffraction, IR spectroscopy, diffusive reflectance and X-ray fluorescence spectrometry. It was for the first time that experiments yielded Ni3BPO7 crystals having the β-Zn3BPO7 non-centrosymmetrical hexagonal structure. The α-Mg3BPO7 and Ni3BPO7 coexistence range was determined. The diffuse reflectance spectra of an Mg1.5Ni1.5BPO7 sample featured a strong Ni2+ absorption band in the blue spectral range.
Boron-Containing Coumarins (Review)
Authors: Las’kova Yu. N. , Serdyukov A. A. , Sivaev I. B.
Published: April 2024

Synthesis methods, properties, and application fields of various boron-containing coumarin derivatives are summarized. Particular attention is paid to derivatives with various polyhedral boron clusters as substituents, such as carboranes, metallacarboranes, and the closo-dodecaborate anion. Derivatives of coumarin with simple organoboron compounds, boronic acids and their esters, are also considered.
Synthesis, Ionic, and Phase Compositions of Ferrogarnet Y2.5Ce0.5Fe2.5Ga2.5O12
Authors: Teterin Yu. A. , Smirnova M. N. , Maslakov K. I. , Teterin A. Yu. , Nikiforova G. E. , Glazkova Ya. S. , Sobolev A. N. , Presnyakov I. A. , Ketsko V. A.
Published: April 2024

X-ray powder diffraction, X-ray photoelectron, and Mössbauer spectroscopy are used to study the ionic and phase compositions of samples of powdered ferrogarnet Y2.5Ce0.5Fe2.5Ga2.5O12 obtained by gel combustion followed by crystallization in vacuum and additional annealing in air at 750°С. According to X-ray photoelectron and Mössbauer spectroscopy data, the iron and cerium cations in the homogeneous ferrogarnet structure are stabilized in the formal oxidation state Fe3+. At the same time, along with Ce3+, the surface of Y2.5Ce0.5Fe2.5Ga2.5O12 particles contains Ce4+ ions. The results obtained can be used to create functional materials for a new generation of magnetooptical devices.
Preparation of NASICON Silico Phosphates of Composition Na1 + xZr2SixP3 – xO12 by Pyrolysis of Solution in Melt
Authors: Grishchenko D. N. , Medkov M. A.
Published: April 2024

A new method for preparing Na1 + xZr2SixP3 – xO12 (0 x 3) based on pyrolysis of solution containing a mixture of organic components in rosin melt has been proposed. Effect of superstoichiometric amounts of sodium and phosphorus on the phase composition of synthesis products has been proved. It has been found that precursor for the sample of maximal purity of phase composition is prepared at molar ratio Na : Zr : Si : P = (1.15 + x) : 2 : x : (y – x), where y = 3 (1.20 + x)/(1 + x). Precursor calcination temperature is 1000°C. Different NASICON compositions without crystalline admixtures have been obtained in the range 1.5 ≤ x ≤ 2.12. The prepared samples have been studied by X-ray powder diffraction and scanning electron microscopy. The disclosed method of synthesis is promising for the preparation of NASICON as both bulk materials and thin layer coatings.
Effect of Bridging Group Nature on the Extraction Ability of Diphenylphosphorylketones toward Actinides and Lanthanides
Authors: Safiulina A. M. , Borisova N. E. , Lizunov A. V. , Golubev A. V. , Bodrin G. V. , Goryunov E. I. , Goryunova I. B. , Brel’ V. K. , Tananaev I. G.
Published: April 2024

Effect of structure of phosphorylketones containing flexible alkyl and conformationally rigid fragments in the linker on extraction ability toward actinides and lanthanides has been studied. It has been shown that the introduction of conformationally rigid cycloalkanediyl and alkenediyl fragments in the bridge between P=O and C=O groups in the structure of molecule decreases efficiency of extractants for both actinides and lanthanides. At the same time, the introduction of flexible alkyl groups in linker structure increases complexing and extraction ability. This dependence has been explained theoretically by modeling complexation (DFT, PBE, cc-pVDZ), monodentate coordination was observed for all studied phosphorylalkanones
Zirconium (Hafnium)-Containing Yttriumoxane Alumoxanes and Multicomponent Ceramics Based on Them
Authors: Shcherbakova G. I. , Pokhorenko A. S. , Krivtsova N. S. , Varfolomeev M. S. , Drachev A. I. , Lebed Yu. B. , Ashmarin A. A. , Apuhtina T. L. , Chernyshev A. E. , Storozhenko P. A.
Published: April 2024

Ceramic-forming zirconium (hafnium)-containing yttriumoxane alumoxanes, precursors of multicomponent ceramics based on alumina, yttria and zirconia/hafnia, were synthesized by co-condensation of chelated alkoxyalumoxanes, yttrium acetylacetonate hydrate (or organic yttriumoxane alumoxanes) and zirconium or hafnium acetylacetonate. The physicochemical properties of zirconium (hafnium)-containing yttriumoxane alumoxanes were studied. Computational models of the group and elemental composition of oligomeric Zr(Hf)-containing yttriumoxane alumoxane molecules were proposed. According to X-ray diffraction and scanning electron microscopy data, pyrolysis of the oligomers at 1500–1600°C results in multicomponent nano- or fine-crystalline ceramic powders, depending on the Al/Y and Al/Zr(Hf) molar ratios.
Revision of Data on the Thermochemistry of Scandium Fluorides
Authors: Nikitin M. I. , Kayumova D. B. , Alikhanyan A. S.
Published: April 2024

A critical analysis of the literature data on equilibria of gas-phase reactions involving scandium fluorides and calcium and barium monofluorides has been carried out. The most reliable values of ∆fH°(0) for gaseous ScF3 (–1251 ± 15 kJ/mol), ScF2 (–683 ± 10 kJ/mol), and ScF (–141 ± 6 kJ/mol) are recommended. These values and sequential Sc–F bond dissociation energies are in good agreement with the data of quantum mechanical calculations.
Synthesis and Physicochemical Properties of Yttrium Subgroup REE Lactates Ln(C3H5O3)3·2H2O (Ln = Y, Tb–Lu)
Authors: Golikova M. V. , Yapryntsev A. D. , Jia Ch. , Fatyushina E. V. , Baranchikov A. E. , Ivanov V. K.
Published: April 2024

A series of yttrium subgroup rare earth elements (REE) lactates of [Ln(C3H5O3)3(H2O)2] (Ln = Tb–Lu) composition isostructural to yttrium lactate has been prepared for the first time. Synthesis of crystalline REE lactates has been performed from solutions of REE nitrates in the presence of L-lactic acid and hexamethylenetetramine. The composition and structure of the obtained compounds have been confirmed by X-ray powder diffraction, thermal, and chemical (CHN) analysis. The coordination type of lactate anions to REE cations has been determined by IR spectroscopy. Thermal decomposition of REE lactates at 800°C leads to formation of nanocrystalline (20–40 nm) REE (Y, Tb–Lu) oxides.
Heat Capacity and Thermodynamic Functions of Ho2O3·2HfO2 Solid Solution
Authors: Guskov A. V. , Gagarin P. G. , Guskov V. N. , Khoroshilov A. V. , Gavrichev K. S.
Published: April 2024

Isobaric heat capacity measurements in the range 2.4–1807 K have been performed by relaxation calorimetry, adiabatic calorimetry, and differential scanning calorimetry on a Ho2O3‧2HfO2 solid solution sample prepared and characterized by X-ray powder diffraction, electron microscopy, and chemical analysis, and thermodynamic functions have been calculated. The Schottky anomaly contribution has been determined in the range 2.4–300 K.
Structure and Luminescent Properties of Tellurium(IV) Bromide Complex with p-Toluidinium (HPT)2TeBr6 · H2O
Authors: Bukvetskii B. V. , Sedakova T. V, , Mirochnik A. G.
Published: April 2024

A complex of tellurium(IV) bromide with p-toluidinium, (HPT)2TeBr6·H2O, was synthesized, its crystal structure was determined by X-ray diffraction, and its absorption and luminescent properties were studied. A comparative study of the luminescent properties at 77 K was performed for a number of tellurium(IV) bromide complexes with outer-sphere cations: cesium, rubidium, tetraethylammonium, and p-toluidinium. The electronic and geometric aspects determining the absorption and luminescent properties of the tellurium(IV) bromide complexes are considered. At 77 K, (HPT)2TeBr6·H2O is characterized by luminescence in the near-IR range; the luminescence band maximum is significantly red-shifted (50 nm) with respect to those of the analogues. The luminescence intensity of complex compounds is influenced by the geometric structure (type of anionic sublattice and the structure and degree of distortion of the coordination polyhedron of the s2-ion). The coordination polyhedron distortion and the presence of a dense system of hydrogen bonds account for the minimum luminescence intensity of the (HPT)2TeBr6·H2O complex among other tellurium(IV) bromide compounds.
Vanishing Superstructure: Crystal and Local Structures of Ni3 – xMTe2 (M = Sb, Sn)
Authors: Stroganova E. A. , Kazakov S. M. , Fabrichnii P. B. , Afanasov M. I. , Kuznetsov A. N.
Published: April 2024

Series of compounds Ni3 – xMTe2 (M = Sb, Sn; x = 0–1) were obtained by high-temperature sealed-tube synthesis and characterized by X-ray powder diffraction and 121Sb and 119Sn Mössbauer spectroscopy. For Ni3–xSnTe2, it was shown that, as х varies from 1 to 0, nickel is distributed over three possible sites, two of which give a total occupancy of 1 and have ordered vacancies. Meanwhile, for Ni3–xSbTe2 and х other than ~0.9–1.0, the vacancy ordering disappears. The temperature dependence of the presence or absence of vacancy ordering was established for Ni2SbTe2; the ordering disappears on heating above 600°C and appears again on cooling.
Effect of Torsional Deformations on the Spin States of Carbon Nanotubes with Metallic Conductivity
Authors: D’yachkov E. P. , Lomakin N. A. , D’yackov P. N.
Published: April 2024

The formation of spin levels upon torsional deformation of nonchiral (n, n) carbon nanotubes has been theoretically studied. In the absence of mechanical deformation, nanotubes have inversion symmetry and a metallic band structure with a spin-degenerate state near the Fermi level. The twisting deformation breaks the inversion symmetry, so that the tube becomes chiral. As a result, due to the Rashba effect, the degeneracy of the levels is completely lifted and spin gaps are formed between the bands of predominantly α and β types.
Bird population dynamics during the regenerative succession of mossy pine woodland in southwestern Belarus
Authors: Abramova I. V.
Published: April 2024

Disturbed forest ecosystems are characterized by significant spatial and temporal changes. As a part of the study on bird communities, changes in bird abundance during the secondary succession of a cleared mossy pine woodland in southwestern Belarus were investigated. The purpose of the work was to determine the inter-annual dynamics of bird species abundance and to assess the variability of individual species abundance during the secondary succession of the mossy pine woodland. The material was collected in 2000–2019. Line transects were set to conduct bird counts in ecosystems at different stages of succession. For the data processing, generally accepted methods of statistical analysis were used. The species diversity of birds was found to increase from 8 to 42 species, the overall abundance from 171.7 to 587.1 birds/km2 during the succession (6 stages, from 1 to 90 years in age). The abundance of species (birds/km2) and inter-annual variability during 11 seasons were determined. The coefficient of variation (CV) was the highest (71.00–82.50%) for species whose abundance did not exceed 1.0 birds/km2. The average abundance of species varied considerably, e.g., among passerines at the 80–90-year old stage from 1.1 birds/km2 (Little Flycatcher) to 153.7 birds/km2 (Chaffinch). Bird populations with high abundance turned out to be the most stable, for example at the last two successional stages the CV of the Chaffinch is 6.02 and 7.16%. For species with average abundance the variability is found to be low or medium (varies from 11.90 to 36.20%), for species with low abundance the CV varies from 17.68 to 82.50%. All six stages of succession were dominated by nesting migratory birds, which account for 75.0% of the species in the first stage of succession to 52.4% in the fifth and sixth stages. Near and distant migrants form the basis of the bird community at all stages. Populations of sedentary species and distant migrants are more stable than those of near migrants.
The pattern of natural variability of palynomorphological features with the example of some Nierembergia and Bouchetia species (Solanaceae) and natural system of bio-variety
Authors: Pozhidaev A. E. , Grigoryeva V. V. , Semyonov A. N.
Published: April 2024

On the example of pollen morphological features of 8 species of Nierembergia and 2 species of Bouchetia (family Solanaceae), the properties of individual variability are described. Most of the studied characters (structure of apertures, ultrastructure of the sporoderm, surface sculpture, dimensions) do not have significant differences at the individual and intraspecific levels; taxonomically significant variability of morphological features of pollen is manifested at the level of the genus and suprageneric groups. The genera differ significantly in the sculpture of the pollen grain surface – striate in Nierembergia and tuberculate in Bouchetia. Pollen contained in one bud, anther or tetrad (fully completed gametophytic generation, where there is no death – all descendants of one ancestor without exception), is considered as an extreme model (maximum completeness with minimum complexity) to study the properties of natural morphological variability and the causes of its occurrence. It was found that pollen characters (sculpture, number and location of apertures) have the same pattern of variability (continuous and transitively ordered series), which embodied at different taxonomic levels in different characters. The natural variability of pollen morphological features is ordered not into a genealogical clade, but into a cline – continuous, geometrically ordered and transitive series (taxon-nonspecific and rank-independent). In this system of parallelisms, homological series are inseparable from non-homological ones, and typical forms, from deviations. The origin of typical and deviant forms cannot be explained separately (typical – genealogically, and deviant – as parallelism, convergence, chance or regularity). The individual variability of pollen forms is geometrically ordered and is not the result of random disturbances, failures of the hereditary program, or pathology. The typical form turns out to be a harmonious part of a geometrically ordered series of pure forms, free from functional and historical connotations. The similarity of pollen forms in these series is determined by their geometry and does not depend on affinity, homology, functionality (improvement, exercise, adaptation). The natural system of pollen forms is formed not by the structure of supposed affinity of supposed taxa (universalia, general concepts, the result of speculation that requires confirmation and admits refutation), but the structure of the observed parallelisms of the variability of individual living bodies. Evolutionary novelty (the current state, the observed variability) arises initially ordered in a pre-established form.
Synthesis of bis-α-hydroxyphosphine oxides based on salicyl aldehyde scaffold
Authors: Aleksandrova E. A , Ponomareva N. A , Rudakov A. S , Derkacheva O. Yu. , Serebryakov E. B , Trishin Yu. G.
Published: April 2024

By addition of secondary phosphine oxides to dicarbonyl compounds obtained by binding two salicylaldehyde molecules with ether-type spacers, previously unknown bis-α-hydroxyphosphine oxides were synthesized. The obtained compounds are of interest as potential biologically active substances, complexing agents and initial building blocks in the synthesis of macrocyclic compounds bearing pendant phosphorus-containing substituents.
Magnetic susceptibility La1-0.397xGd0.067xCa0.33xMnхAl1-хO3 solid solutions
Authors: Fedorova A. V , Chezhina N. V , Ponomareva E. A , Chuvilo Yu. D.
Published: April 2024

Solid solutions of lanthanum manganites with perovskite structure containing calcium and gadolinium atoms were studied by the method of magnetic dilution. The obtained magnetic characteristics and the character of their temperature changes point to a clustering of magnetic atoms in the perovskite structure. A comparison of the solid solutions under study with La1- y Gd y AlO3 testifies for gadolinium atoms taking part in the exchange interactions in the La1-0.397 х Gd0.067 х Ca0.33 х Mn х Al1- х O3 solid solutions.
1,2,3-Triazole-Containing 1,5,6,7-Tetrahydro-4h-indazol-4-ones and 6,7-Dihydrobenzo[d]isoxazol-4(5h)-ones: Synthesis and Biological Activity
Authors: Khlebnicova T. S , Zinovich V. G , Piven Yu. A. , Baranovsky A. V , Lakhvich F. A , Trifonov R. E , Golubeva Yu. A. , Klyushova L. S , Lider E. V
Published: April 2024

Triazole-containing 1,5,6,7-tetrahydro-4 H- indazol-4-ones and 6,7-dihydrobenzo[ d ]isoxazol-4(5 H )-ones were synthesized by cyclocondensation of 2-[(1 H -1,2,3-triazol-1-yl)acetyl]cyclohexane-1,3-diones with phenylhydrazine (4-fluorophenylhydrazine) or hydroxylamine, respectively. SStructure and composition of the obtained compounds were confirmed by 1H, 13C, 19F NMR spectroscopy methods and by data of elemental analysis. Cytotoxic and cytostatic activities of the series of obtained compounds were investigated in vitro against human hepatocellular carcinoma cells HepG2, mammary adenocarcinoma cells MCF-7 and laryngeal cancer cells Hep2.
Catalytic synthesis of 1,2-azole and pyridine derivatives of 1,8-dioxooctahydroxanthenes using FIBAN K-1 fibrous sulfonic cation exchanger
Authors: Akishina E. A , Dikusar E. A , Polikarpov A. P , Alekseeva K. A , Menshikova D. I , Kurman P. V , Potkin V. I
Published: April 2024

Arylmethylenebis(3-hydroxy-2-cyclohexen-1-ones) were obtained by condensation of 1,2-azole- and pyridine-substituted aromatic aldehydes of the vanillin series with 1,3-cyclohexanedione in methanol in the presence of trimethylamine. Catalytic cyclization using fibrous sulfocationite FIBAN K-1 gave corresponding 1,8-dioxooctahydroxanthenes.