bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of the Structure of Taurine N-Derivatives on Their Complexing Properties
Authors: Zharkov G. P. , Bueva E. I. , Filimonova O. V. , Petrova Yu. S. , Chirtulova E. A. , Zemlyakova E. O. , Pestov A. V. , Neudachina L. K.
Published: April 2024

The paper presents data on the synthesis and study of the acid–base and complexing properties of N-hydroxyalkyl taurine derivatives. The ammonium group dissociation constants of the reagents were determined. The complex formation of taurine derivatives with transition and alkaline-earth metal ions was studied. Trends in the influence of the structure of ligands on the stability constants of their transition and alkaline-earth metal complexes were elucidated. In most cases, the studied ligands form most stable complexes with copper(II) ions. The decrease in amino group basicity in response to the incorporation of additional hydroxyl and/or sulfoethyl groups into a derivative leads to the differentiation of the ligand properties toward the studied ions. The data of this work can help expand the application range of the studied ligands, which can potentially be used as components of buffer solutions where there is the need to avoid or minimize complex formation in solution.
Revisiting the Thermodynamic Characteristics of Titanium Fluorides
Authors: Nikitin M. I. , Osina E. L. , Alikhanyan A. S.
Published: April 2024

New values for the standard enthalpies of formation of titanium fluorides at 0 K have been obtained by revisiting data on homogeneous and heterogeneous equilibria with their participation (kJ/mol): –1403.2 ± 2.7 for TiF3(c), –1144.2 ± 3.3 for TiF3, –2349.4 ± 6.3 for Ti2F5(c); –933.7 ± 6.8 for TiF2(c), and –650.4 ± 2.4 TiF2. The thermodynamic metastability of TiF2(c) has been shown.
Synthesis and Structure of Trisubstituted closo-Decaborane [B10H7(1-IPh)(6(7),10-NHOCCH3)]: Specifics of Interaction between the [2-B10H9NH=C(OH)CH3]– Ion and PhI(OAc)2
Authors: Voinova V. V. , Selivanov N. A. , Bykov A. Yu. , Kubasov A. S. , Zhdanov A. P. , Zhizhin K. Yu. , Kuznetsov N. T.
Published: April 2024

The preparation of trisubstituted closo-decaboranes by reacting 1,2-boroxazoles with PhI(OAc)2 was studied. The process could be implemented in a one-pot variant proceeding from borylated iminol. The reaction products were characterized by 1H, 11B, and 13C NMR spectroscopy. The XRD structure of the compound [B10H7(1-IPh)(6,10-NHOCCH3)] was determined.
Study of Crystal Structures of the [B10Cl10]2– Anion with Imidazolium Cations
Authors: Golubev A. V. , Kubasov A. S. , Bykov A. Yu. , Matveev E. Yu. , Sarkisov N. A. , Novikov I. V. , Starodubets P. S. , Romanov N. A. , Zhizhin K. Yu. , Kuznetsov N. T.
Published: April 2024

A new method for the synthesis of imidazolium salts of the perchlorinated closo-decaborate anion (RMIM)2[B10Cl10] (R = H, n-Et, n-Bu, n-C8H17) has been proposed. The synthesis of these compounds can be carried out by simple metathesis reactions between the potassium salt of the decachloro-closo-decaborate anion K2[B10Cl10] and chlorides of imidazolium derivatives. The crystal packings and intermolecular interactions in compounds (EMIM)2[B10Cl10] and (BMIM)2[B10Cl10] have been studied using X-ray diffraction and Hirshfeld surface analysis. The [B10Cl10]2– anions in the crystal lattice of these compounds are linked by a network of weak Cl···Cl interactions with a distance between chlorine atoms of 2.246–3.623 Å.
A New Approach to Prepare LuFeMgO4
Authors: Smirnova M. N. , Kondrat’eva О. N. , Nikiforova G. E. , Khoroshilov A. V.
Published: April 2024

A new method for the production of LuFeMgO4 based on the combustion reaction of a gel-like precursor prepared from metal nitrates and fossil fuels has been proposed. The possibility to prepare this oxide from stoichiometric compositions of metal nitrates with polyvinyl alcohol (PVA) and glycine has been studied. The adiabatic combustion temperatures Tad have been estimated for the systems under consideration. The combustion products of PVA-nitrate and glycine-nitrate compositions before and after their heat treatment have been studied using X-ray diffraction analysis and IR spectroscopy. It has been established that the combustion reaction products of the PVA-nitrate composition are an X-ray amorphous powder, while those of the glycine-nitrate composition are a mixture of nanocrystalline oxides containing 52.5 wt % LuFeMgO4. According to X-ray diffraction and SEM data, 4-h annealing of this mixture at 1300°C leads to the formation of a single-phase LuFeMgO4 powder with a layered microstructure and a grain size of about 1–2 μm.
Spin Crossover in Iron(II) Complexes with Polynitrogen Heterocyclic Ligands and Outer-Sphere Boron Cluster Anions (Review)
Authors: Lavrenova L. G. , Shakirova O. G.
Published: April 2024

The results of synthesis and study of magnetically-active iron(II) complexes with polynitrogen heterocyclic ligands and outer-sphere boron cluster anions have been considered. Derivatives of 1,2,4-triazole, tris(pyrazol-1-yl)methane, and 2,6-bis(imidazol-2-yl)pyridine have been used as ligands, decahydro-closo-decaborate, dodecahydro-closo-dodecaborate, decachloro-closo-decaborate, and 1,5,6,10-tetra(R)-7,8-dicarba-nido-undecaborates (R = H, Cl, Br) have been studied as outer-sphere anions. A number of iron(II) complexes showing spin crossover accompanied by thermochromism in the majority of cases has been obtained. Effect of ligand nature and cluster anion on temperature (Tc) and spin transition character has been considered. In particular, it has been shown that introduction of substituent increasing electron density over the system of conjugated three-centered two-electron bonds in cluster anion leads to increase in the field strength of ligand bound to anion via network of hydrogen bonds.
Synthesis and Electronic Structure of Bimetallic AuFe Nanocomposites
Authors: Vasil’kov A. Yu. , Voronova A. A. , Naumkin A. V. , Butenko I. E. , Zubavichus Ya. V.
Published: April 2024

Au, Fe, and AuFe nanoparticles were obtained by metal vapor synthesis using acetone as the dispersion medium. The composition and electronic structure of the particles were studied by TEM, SEM, XPS, XANES, and EXAFS. The Au and Fe particles with average diameters of 5.3 and 1.8 nm, respectively, were obtained. According to X-ray diagnostic methods, gold was in the main Au0 state, and the Au+ and Au3+ states are present in small amounts while iron existed as mixture of non-stoichiometric oxides with states close to Fe2+ and Fe3+. Bimetallic nanoparticles were solid solutions with a disordered structure and Au–Fe–O and Au–O–Fe bonds. A carbon-containing shell was detected for all types of metal particles. The obtained materials may be promising for the development of improved antimicrobial agents and new methods for treating cancer diseases.
Synthesis of Boron Nitride by Reduction of Boron Oxide with Aluminum in Nitrogen
Authors: Tkachev D. A. , Ziatdinov M. Kh. , Zhukov I. A. , Litvinova V. A. , Belchikov I. A. , Kravtsov N. G.
Published: April 2024

The paper presents the results of studies of the self-propagating high temperature synthesis (SHS) of boron nitride via chemical reduction of boron oxide with aluminum in a nitrogen medium. The phase composition of the powder reaction products depending on the nitrogen pressure during the synthesis was studied by X-ray diffraction. It was found that SHS in the B2O3–Al system gives the BN–Al2O3 powder material containing 20–28 wt % hexagonal boron nitride depending on the nitrogen pressure. Microstructure examination showed that the obtained powder materials contains separate hexagonal BN particles with 3 μm size. The differences in the density and morphology of BN and Al2O3 determine the possibility of BN isolation from the obtained powder mixture by the pneumatic powder separation methods.
Study of Component Solubility Polytherm in the System Ca(ClO3)2–[21% ClCH2CH2PO(OH)2⋅NH3 + 11% ClCH2CH2PO(OH)2⋅2NH3 + 12% NH4H2PO4 + 56% H2O]–H2O
Authors: Yakubov Sh. Sh. , Obidzhonov D. O. , Adilova M. Sh. , Kim R. N. , Kucharov B. Kh. , Zakirov B. S.
Published: April 2024

Mutual effect of components in complex aqueous system comprising calcium chlorate, ammonium dihydrogen phosphate, and ammonium chloroethylphosphonates has been studied. Polythermal diagram of system solubility has been built in the temperature range from –40.3 to 68.0°C. Phase diagram of system solubility demarcates crystallization fields for ice, calcium chlorate hexa-, tetra-, and dihydrate, and compound of composition NH4ClO3·ClCH2CH2HPO3NH4. The compound has been isolated from supposed crystallization field and has been identified by chemical and physicochemical analysis. To provide foundation for the process of preparation of efficient stimulant and mild defoliant based on calcium chlorate and Nazhot preparation, rheological properties of components in the system Ca(ClO3)2–[21% ClCH2CH2PO(OH)2⋅NH3 + 11% ClCH2CH2PO(OH)2⋅2NH3 + 12% NH4H2PO4 + 56% H2O]–H2O have been studied. Composition–property diagram has been built for the system.
NaLn(IO3)4 Iodates (Ln = Pr, Tb): New Representatives of Nonlinear Optical Crystals with the NaY(IO3)4 Structure
Authors: Grigorieva O. P. , Stefanovich S. Yu. , Charkin D. O. , Dolgikh V. A. , Lysenko K. A.
Published: April 2024

Interaction of rare-earth oxides (Pr, Tb, Er) with periodic acid or sodium iodate under hydrothermal conditions in the presence of Na2HPO4⋅12H2O leads to formation of complex NaLn(IO3)4 iodates. The compounds of Pr and Tb are reported for the first time. Single-crystal studies reveal that they are isostructural to the previously reported analogs of other rare-earths and adopt the non-centrosymmetric space group Сс. Polycrystalline samples generate a strong SHG signal above that of the potassium dihydrogen phosphate reference standard. They also exhibit wide optical transparency areas and high thermal stability.
Zinc(II) Chelate Complexes with Redox-Active o-Indophenols: Synthesis and Structure
Authors: Ivakhnenko E. P. , Vitkovskaya Yu. G. , Lysenko K. A. , Kislitsyn S. E. , Starikov A. G. , Knyazev P. A. , Tereshchenko A. A. , Minkin V. I.
Published: April 2024

Zinc(II) complexes 2, 3, and 5 with redox-amphoteric o-indophenol ligands were prepared. The molecular structures of tetracoordinate complex 2 and hexacoordinate complex 3 were determined by single-crystal X-ray diffraction. The antioxidant properties of indophenols and their complexes were studied by cyclic voltammetry (CVA) and EPR spectroscopy. Complexation of indophenols increases the oxidation potentials by more than 0.84 V and leads to the formation of stable metal-containing radicals.
Synthesis, Chemical Structure, and Ground- and Excited-State Spectral Characteristics of (Porphyrinato)(chloro)indium(III) and Its Complexes with C60 and Pyridyl-Substituted Fullero[60]pyrrolidine
Authors: Ovchenkova E. N. , Bichan N. G. , Lomova T. N.
Published: April 2024

New complexes of [5,10,15,20-tetra-(4-methoxyphenyl)porphinato](chloro)indium(III) ((Cl)InTPP(p-OCH3)4) with unsubstituted C60 and 1-methyl-2-(pyridin-4'-yl)-3,4- fullero[60]pyrrolidine (PyC60) were synthesized in toluene. The stability constants of 1 : 1 complexes (dyads) were determined using UV-vis and fluorescence spectroscopy. The dyads were characterized by IR and 1H NMR spectroscopy data. It was established that fluorescence of (Cl)InTPP(p-OCH3)4 is quenched upon gradual addition of fullerenes. The numerical values of the Stern–Volmer quenching constants (KSV) were determined. The most important charge transfer characteristics of dyads (the lifetime of charge-separated states and charge separation and recombination constants), needed for further consideration of dyads based on indium(III) porphyrins as photoinduced electron transfer systems, were determined using femtosecond laser spectroscopy.
Enthalpy of Formation of Gaseous Nitryl Fluoride FNO2
Authors: Nikitin M. I. , Smorchkov K. G. , Alikhanyan A. S.
Published: April 2024

Contradictory literature data on thermal stability, some methods of synthesis, and thermodynamic characteristics of nitryl fluoride have been considered and analyzed. Reliable estimates of reaction enthalpies have been obtained: 2FNO2 = 2FNO + O2, ΔrH°(0) ≥ 173.5, NO2 + 2CoF3(c) = FNO2 + Co2F5(c), ΔrH°(0) = –7.4; 3/2N2O4 + NaF(c) = FNO2 + NO + NaNO3(c), ΔrH°(0) = 11.3 kJ/mol. A new value of the enthalpy of formation of nitryl fluoride ΔfH°(FNO2(g), 0) = –161 ± 15 kJ/mol has been recommended. For the interaction of FNO2 with V2O5(c) as an example, the impossibility of formation of crystalline vanadium pentafluoride has been demonstrated.
Transformations of Cerium Tetrafluoride Hydrate under Hydrothermal Conditions: A New Cerium Fluoride Hydrate Се3F10 ⋅ 3Н2О
Authors: Il’in E. G. , Parshakov A. S. , Iskhakova L. D. , Kottsov S. Yu. , Filippova A. D. , Goeva L. V. , Simonenko N. P. , Baranchikov A. E. , Ivanov V. K.
Published: April 2024

The behavior of cerium tetrafluoride hydrate was studied in water at a temperature of 80°C and under hydrothermal treatment at 100, 130, and 220°C for a day. The product of the hydrothermal treatment of CeF4·H2O at 100°C was investigated by chemical, thermogravimetric, IR spectroscopic, and X-ray powder diffraction analyses, which identified a new cerium fluoride with the composition, presumably, Ce3F10⋅3H2O or, most likely, (H3O)Ce3F10⋅2H2O. New compound crystallizes in the space groupwith a unit cell parameter of 11.66 Å. Hydrothermal treatment of cerium tetrafluoride hydrate at temperatures above 130°C leads to hydrolysis and reduction of cerium(IV) fluoride compounds to form CeO2 and CeF3.
Supramolecular Hybrid Complexes Based on Octahedral Molybdenum(II) Iodide Cluster and Zinc(II) Porphyrin
Authors: Volostnykh M. V. , Loboda P. A. , Sinelshchikova A. A. , Dorovatovskii P. V , Kirakosyan G. A. , Mikhaylov M. A. , Sokolov M. N. , Gorbunova Yu. G.
Published: April 2024

The possibility of the formation of supramolecular hybrids based on two photosensitizers, an octahedral molybdenum(II) iodide cluster with six terminal isonicotinate ligands (Bu4N)2[{Mo6I8}(OOC–C5H4N)6] (PyMoC, C) and A4-type zinc(II) porphyrin (ZnTPP, P), has been demonstrated. Spectrophotometric and NMR titration methods have shown that the formation of CPn complexes (n = 1–6) occurs in solutions of noncoordinating chlorinated solvents due to the formation of metal–N-ligand coordination bonds between the components. The use of an octahedral cluster as a hexatopic N-ligand and the lability of the Zn···NPy bonds together lead to the formation of a series of CPn complexes (n = 1–6), which are in dynamic equilibrium in solution. Nevertheless, conditions have been selected to isolate single crystals of individual forms CP4 + 2 and CP6 + 2, and their structures have been determined by X-ray diffraction analysis. The PyMoC cluster turns out to coordinate four or six ZnTPP molecules, respectively, while both structures contain two “extramolecules” of zinc(II) porphyrin bound to the cluster via hydrogen bonds involving the oxygen atoms of the isonicotinate groups and protons of water axially coordinated to the porphyrin metal center.
Hydrothermal Synthesis of Calcium Silicates on the Recovery of Phosphorus from Phosphorite
Authors: Skachkov V. M. , Pasechnik L. A. , Medyankina I. S.
Published: April 2024

Calcium silicates with nanosized needle-like structure have been obtained from phosphorite by hydrothermal synthesis. Phosphorus is recovered from phosphorite as sodium phosphate solution under conditions of autoclave treatment of phosphorite with alkaline solution in the presence of silicon dioxide at 250°C. This approach enables involvement of low-phosphorus raw materials into non-waste processing owing to the synthesis of calcium silicates suitable in many branches of industry. Thus prepared phosphate solutions are applicable in agriculture and, after appropriate purification, in food industry. Hydrothermal synthesis conditions have been determined: temperature of 250–300°C, leaching time of 3 h, and NaOH concentration of 150 kg/m3.
Copper(II) Catecholate Complexes with Polypyridyl Ligands
Authors: Trofimova O. Yu. , Pashanova K. I. , Ershova I. V. , Arseniev M. V. , Yakushev I. A. , Dorovatovsky P. V. , Aisin R. R. , Piskunov A. V.
Published: April 2024

Copper(II) catecholate complexes based on 3,6-di-tert-butyl-o-benzoquinone with N-donor ligands of the phenanthroline series have been synthesized: (3,6-Cat)Cu(Phen) (I), (3,6-Cat)Cu(DPQ) (II), and (3,6-Cat)Cu(DPPZ) (III), where 3,6-Cat is the 3,6-di-tert-butyl-o-benzoquinone dianion, Phen is phenanthroline, DPQ is dipyrido[3,2-d:2',3'-f]quinoxaline, and DPPZ is dipyrido[3,2-a:2',3'-c]phenazine. The synthesized copper(II) complexes demonstrate intramolecular ligand-to-ligand charge transfer responsible for their intense violet color. The electronic structure of the synthesized chromophores was studied by electronic spectroscopy, cyclic voltammetry, and quantum-chemical calculations. The molecular and crystal structures of the synthesized compounds were determined by X-ray diffraction analysis (CIF files CCDC 2 250 975 (I⋅THF), 2 250 976 ([(II⋅THF)(II)]⋅3THF), 2250977 (II)).
Evaluation of the Standard Entropy of Crystalline Alkali Metal Borates
Authors: Tupitsin A. A. , Yas’ko S. V, , Bychinskii V. A. , Koroleva O. N. , Fomichev S. V.
Published: April 2024

A composition–property relationship has been developed that makes it possible to select the optimal values of the standard entropy of alkali metal borates, for which available experimental and reference data vary in wide ranges. This relationship allows one to estimate the standard entropy of unstudied alkali metal borates with sufficient validity. To ensure the reliability of the relationship, a critical analysis of the initial data borrowed from reference books and original experimental works has been carried out. Experimental measurements of low-temperature heat capacity were processed to verify the reliability of the standard entropy values of alkali metal borates presented in the literature.
Synthesis of New Iminium Derivatives of Sulphonio-сloso-Decaborate Anion (Bu4N)[2-B10H9SC(NH2)R] (R = –CH3, –CH2CH3, –CH(CH3)2, –Ph, –PhCH3)
Authors: Golubev A. V. , Kubasov A. S. , Lukoshkova A. A. , Sarkisov N. A. , Novikov I. V. , Starodubets P. A. , Bykov A. Yu. , Zhdanov A. P. , Zhizhin K. Yu. , Kuznetsov N. T.
Published: April 2024

New iminium derivatives of the sulfonio-closo-decaborate anion have been obtained in the form of tetrabutylammonium salts (Bu4N)[2-B10H9SC(NH2)R] (R = –CH3, –CH2CH3, –CH(CH3)2, –Ph, –PhCH3), in which the iminium group acts as a protective group and allows further modification of the boron cluster anion without acting the sulfonium group. The compounds have been studied by elemental analysis, IR and 11B, 1H, 13C NMR spectroscopies. The structure of compounds (Bu4N)[2-B10H9SC(NH2)CH3] and (Bu4N)[2-B10H9SC(NH2)Ph] has been confirmed by X-ray diffraction analysis. The yield of final compounds is 80%.
Behavioral island syndrome and its ecological drivers in the Mednyi Island Arctic fox
Authors: Goltsman M. E. , Kruchenkova E. P. , Doronina L. O.
Published: April 2024

Reptiles, birds, and mammals inhabiting oceanic islands tend to change many ecological, behavioral, and genetic characteristics. These changes are referred to as the “island syndrome”. The behavioral components of these changes have been little studied so far. Based on a 40-year study of the biology of the Arctic fox (Vulpes lagopus) on the Mednyi Island, we show that the island Arctic foxes changed many behavioral characteristics compared to mainland foxes. They use smaller home ranges, travel shorter daily distances, and their dispersal distance from the natal territory is much smaller. An increase in the family size of the island Arctic foxes, together with a decrease in litter size, leads to an increase in parental and kin investment and increased cooperation between family members. At the same time, the island foxes, to a large extent, lost their fear of humans. These features are consistent with those found in other island populations. On the other hand, in contrast to other island populations, Mednyi Arctic foxes have increased territoriality, apparently in response to an increased risk of infanticide. Furthermore, Mednyi Arctic foxes expose sex-biased dispersal and maternal inheritance of home range, which are absent in the mainland foxes. The sex-biased dispersal can be considered a mechanism for avoiding inbreeding. Comparison with island fox (Urocyon littoralis) populations in the Channel Islands (Southern California) suggests that these traits have evolved under the influence of specific environmental drivers of the Mednyi Island: patchy and highly predictable resource distribution. The particular resource distribution led to the increased importance of another driver, social landscape, and a new behavioral metatrait of the Mednyi fox – increased conservatism in spatial, reproductive, and foraging behavior.
Evolution of viruses in immunized populations of vertebrates
Authors: Panchenko P. L.
Published: April 2024

Scientists have described thousands of species of viruses, many of which are pathogens of vertebrates. Given that vertebrates have their highly sophisticated adaptive immune systems capable of memorizing pathogens, interaction with such systems should theoretically be one of the most important factors influencing the evolution of viruses. The review focuses on how acquired immunity (infection-induced and vaccine-induced) affects the most important medical characteristics of viral pathogens – transmissibility, infectivity, and virulence. Both known real examples of the evolution of viruses in immunized populations, as well as theoretical articles and the results of mathematical modeling, are considered. Special attention is paid to the SARS-CoV-2 pandemic. Methodological recommendations are given for creating vaccines and conducting vaccination campaigns in the light of the raised evolutionary issues.
Thirteen years of monitoring a coenopopulation of Eritrichium caucasicum: Stochastic growth rate under reproductive uncertainty
Authors: Logofet D. O. , Golubyatnikov L. L. , Kazantseva E. S. , Ulanova N. G. , Khomutovsky M. I. , Tekeev D. K.
Published: April 2024

Eritrichium caucasicum is an alpine short-lived perennial species endemic for the Caucasus. The stage structure of a local population has been observed on permanent plots in the alpine belt of the Northwestern Caucasus annually for 13 years (2009–2021), accumulating data of the “identified individuals from unknown parents” type. The latter circumstance has predetermined what is called reproductive uncertainty in the terminology of matrix models for discrete-structured population dynamics and means that the annual recruitment rates inherent in the groups of generative plants and final flowering generative plants cannot be calibrated in a uniquely way. As a result, instead of the annual values of the asymptotic growth rate, the model gives only certain ranges of their values that vary from year to year, corresponding to the data. This introduces both technical difficulties and uncertainty in the viability forecast based on the asymptotic growth rates. A well-known alternative approach is to estimate the stochastic growth rate λS, but only artificial modes of randomness involved in the calculation of λS have been proposed in the literature. Our realistic model of randomness is related to variations in weather and microclimatic conditions of the habitat. It is reconstructed from a fairly long (60 years) time series of the weather indicator. Using this realistic model in Monte Carlo calculations of λS, we have obtained a more reliable and accurate estimate of the stochastic growth rate.
The role of human serum albumin in prevention and treatment of Alzheimer’s disease
Authors: Shevelyova M. P. , Deryusheva E. I. , Nemashkalova E. L. , Machulin A. V. , Litus E. A.
Published: April 2024

Alzheimer’s disease (AD) has been and remains the main cause of dementia in aging patients. This neurodegenerative disease belongs to the progressive and socially significant ones. There are several hypotheses for the development of AD: the tau hypothesis, the amyloid cause, the cholinergic cause, the cause of oxidative stress and inflammation. The lack of a generally accepted understanding of the etiology and pathogenesis of AD hinders the development of new effective mechanisms for its treatment and prevention. In 2021, for the first time, a drug for pathogenetic therapy of AD (aducanumab) was approved, which helps to reduce the content of amyloid-β peptide (Aβ) in the brain of patients. Another promising approach to the treatment of AD, aimed at removing Aβ from the patient’s central nervous system, is the impact on human serum albumin (HSA), which carries 90% of Aβ in the blood serum and 40–90% of Aβ in the cerebrospinal fluid. In clinical practice, plasmapheresis has already been tested and shown to be effective with the replacement of one’s own HSA with a purified therapeutic albumin preparation. Another variant of this approach is to enhance the interaction of HSA with Aβ through the action of exogenous and endogenous HSA ligands, such as serotonin, ibuprofen and some unsaturated fatty acids. In vivo studies confirm the association of this group of ligands with the pathogenesis of AD. These substances are well-studied natural metabolites or drugs, which greatly simplifies the development of new methods of therapy and prevention of AD with their use. In general, a new direction of scientific research devoted to the study of HSA as a carrier and depot of Aβ in the blood and cerebrospinal fluid will expand our understanding of Aβ metabolism and its role in the pathogenesis of AD.
Ecological-parasitological method in studies of population biology of beaked redfish Sebastes mentella (Scorpaeniformes: Sebastidae) in the Irminger Sea
Authors: Bakay Y. I. , Melnikov S. P. , Glubokov A. I.
Published: April 2024

The results of the analysis of the data set obtained in course of long-term studies of the population biology of beaked redfish Sebastes mentella are used as an interdisciplinary approach in the study of its geographical, biotopic, ontogenetic and phylogenetic features, population structure in the pelagic zone of the Irminger Sea and the adjacent bathyal zone of Greenland and Iceland. The approach is based on the ecological-parasitological method, which involves the use of data on the composition of parasite communities and the occurrence of their individual species as biomarkers for understanding the features of the hydrobionts ecology. The results obtained, which include information on the spatial distribution, functional subdivision of the area, ontogenetic migrations, maturation and growth rate, underwater marking, phenetic, genetic and other features of beaked redfish, made it possible to identify the conditions for divergent formation and significant isolation of its pelagic and benthic groupings, constituting the North Atlantic population. The colonization by this species of great depths of the oceanic pelagial and the near-bottom layer of the bathyal, accompanied with an increase in the rate of sexual maturation and migratory activity in the pelagial, characterizes the direction of the current stage of its phylogenesis. The unity of the pelagic grouping of beaked redfish in the vast water area and throughout the depth of its distribution in the Irminger and Labrador seas is substantiated. It is shown that significant differences in infestation rate between males and females of beaked redfish, stable in time and space, with the only species-specific parasite (the copepod Sphyrion lumpi), serve as a phene of the pelagic grouping of the North Atlantic population of the host.
Size-morphological structure and ecological strategies of prokaryotoplankton in a large mountain lake Sevan (Armenia)
Authors: Kuznetsova E. V. , Kosolapov D. B. , Kosolapova N. G. , Skopina M. Yu.
Published: April 2024

The dynamics of the size-morphological groups of heterotrophic prokaryotoplankton of the largest freshwater reservoir in the Caucasus, Lake Sevan (Armenia) has been studied, which makes it possible to explain its spatio-temporal organization and succession. The lake is characterized by an alternation of stable and unstable periods of existence of hydrobionts due to abrupt changes in environmental conditions, mainly caused by anthropogenic impacts. In the community of planktonic prokaryotes of the lake, the following size-morphological groups were distinguished: small cocci and coccobacilli, small rods and vibrios, medium-sized cocci and coccobacilli, large rods and vibrios, filaments, as well as cells associated with detrital particles. The main contribution (on average 55.5%) to the formation of the prokaryotoplankton biomass of the lake was made by small rods and vibrios. The biomass of each of the groups fluctuated in time and space within relatively narrow limits, and the development of the groups occurred in close relationship with each other. Apparently, different size-morphological groups of prokaryotes are adapted to exist within similar ecological and phylogenetic niches, and jointly and consistently perform common functions in the mineralization of organic matter and trophic interactions in the lake. At the same time, these groups implement various ecological strategies that can be successful at different periods of the ecosystem’s existence.
Synthesis, structure and non-covalent interactions of 5-methyl-2,3-dihydrothiazolo[2,3-b]thiazolium halides
Authors: Tarasova N. M , Yushina I. D , Kim D. G , Sharutin V. V
Published: April 2024

2,3-Dihydrothiazolo[2,3- b ]thiazolium iodides and bromide were obtained for the first time by the cyclization of corresponding metallyl- and propinylsulfanyl derivatives of 1,3-thiazole with iodine and bromine in dichloromethane without heating and the use of strong acids. The structure of the obtained compounds was studied by 1H, 13C{1H} NMR spectroscopy. Structure of the 3-iodomethyl-3,5-dimethyl-2,3-dihydrothiazolo[2,3- b ][1,3]thiazolium heterocyclic system is characterized by the X-ray analysis. The bonding in the heterocyclic system and non-covalent cation-anion interactions are analyzed on the basis of quantum chemical calculations with periodic boundary conditions; I···S chalcogen bond is discussed.
Synthesis of 2-heteroylidene triterpenoids: complex formation with palladium and cytotoxic activity in vitro
Authors: Denisov M. S
Published: April 2024

Triterpenoids with a pyridinylmethylidene substituent in the C2 position were prepared via the reaction of betulonic acid with pyridine-2-carbaldehyde, pyridine-3-carbaldehyde, pyridine-4-carbaldehyde or quinoline-2-carbaldehyde. The products were tested as ligands for palladium(II). Two ligands and one complex were prepared for the first time. The structures of new compounds were confirmed by 1D and 2D NMR spectra, as well as by electrospray ionization mass spectra. The E -isomerism of pyridinylmethylidene substituent in the C2 position of triterpenoid was proved. Cytotoxic activity of the complexes with respect to A549 (adenocarcinomic human alveolar basal epithelial cells) cell line was estimated.
Nucleophilic Addition of Thiol to Peripheral C=C Bonds of Tetraaryltetracyanoporphyrazine Macrocycle
Authors: Lyubova T. S , Lermontova S. A , Klapshina L. G , Ladilina E. Yu.
Published: April 2024

An irreversible addition reaction of benzylmercaptan to the macrocycle of the cyanoarylporphyrazine family (Ar = p -MeOPh and Nph) was established for the first time. The reaction proceeds along the polarized peripheral semi-isolated double bonds of the macrocycle and takes place under mild conditions. Mass spectrometry and 1H NMR spectroscopy confirm the composition and structure of the products.
Silver metal-nanocomposites based on 1-vinyl-1,2,4-triazole copolymer with methacrylic acid
Authors: Sargsyan A. S , Sargsyan S. H , Khizantsyan K. M , Aghajanyan I. G , Sargsyan T. S , Margaryan K. S
Published: April 2024

Silver nanocomposites in the matrix of a copolymer of 1-vinyl-1,2,4-triazole with methacrylic acid were synthesized by the electrochemical method by combining the process of electrochemical polymerization with cathodic precipitation of metals on metal electrodes. Structure and composition of the obtained nanocomposites and nanocoatings were recorded using UV, IR, atomic absorption and X-ray spectroscopy, thermogravimetric and elemental analyses. Transmission electron microscopy data show that the synthesized nanocomposites consist of particles with a diameter of 1 to 12 nm, predominantly spherical.
Comparative characteristics of the nearest environment structural parameters of metal ions in water and acetonitrile
Authors: Smirnov P. R
Published: April 2024

The literature data of various research methods on the structural characteristics of the nearest environment of some monatomic inorganic cations in aqueous solutions and in acetonitrile under ambient conditions are summarized. A quantitative comparison of the cations first solvation shell structures in these solvents has been carried out. It is suggested that for these systems, the structure of solvation shells of cations do not depend on the solvent, but is determined only by the physicochemical nature of the ions.
Quantum-chemical study of the structure of amidinyltetramethoxycarbonylcyclopentadiene and its Hg(II) and Tl(I) complexes
Authors: Dushenko G. A , Mikhailov I. E , Mikhailova O. I , Minyaev R. M , Minkin V. I
Published: April 2024

DFT CAM-B3LYP/6-311++G(d,p) and CAM-B3LYP/6-311++G(d,p)/SDD calculations showed that the polydentate amidinyltetramethoxycarbonylcyclopentadienyl ligand and its Hg(II) and Tl(I) complexes are the most stable in the form of ylide isomers, in which the hydrogen or metal atom is bonded to the terminal nitrogen atom of the amidinium fragment and in the case of metal complexes, it is additionally coordinated by the π -system of the cyclopentadiene ring. Alternative isomers in which hydrogen or metal atoms are bonded to carbon atoms of the cyclopentadiene ring or to carbonyl oxygen atoms of methoxycarbonyl substituents are energetically less stable at Δ E ZPE = 4.1-15.1 kcal/mol.
Development of a reproducible and scalable method for the synthesis of biologically active pyrazolo[1,5-a]pyrimidine derivatives
Authors: Novikova D. S , Darwish F. , Grigoreva T. A , Tribulovich V. G
Published: April 2024

A reproducible and scalable method for the synthesis was developed, and a series of 3,6-substituted pyrazolo[1,5- a ]pyrimidines, which are the basis for the rational design of selective inhibitors of AMP-activated protein kinase, was obtained and characterized. In the course of the formation of new types of carbon skeleton, the possibility of applying Suzuki-Miyaura cross-coupling with Buchwald ligands to form C-C bond in the sterically hindered position 6 of 5,7-dimethyl-substituted pyrazolo[1,5- a ]pyrimidine was shown.
Kinetic stability and glass-forming ability of phenacetin by fast scanning calorimetry
Authors: Lapuk S. E , Gerasimov A. V
Published: April 2024

In the present work, an amorphous active pharmaceutical ingredient, phenacetin, was obtained by fast scanning calorimetry. The critical cooling rate and kinetic fragility of its supercooled melt were determined. The process of cold crystallization of phenacetin was studied by methods of isothermal and non-isothermal kinetics. It was found that the best correspondence between the two kinetic approaches is observed in the case of using the Nakamura crystallization model. The results obtained can find their application in the development of approaches to obtaining amorphous forms of drugs prone to crystallization.
Bromination of 1(9)H-2,3-dihydroimidazo[1,2-a]benzimidazole and its N-derivatives
Authors: Sochnev V. S , Koshchienko Yu. V. , Kuz'menko T. A , Kolodina A. A , Borodkin G. S , Morkovnik A. S
Published: April 2024

2,3-Dihydro-1 H -imidazo[1,2- a ]benzimidazole in acetic acid, and its N 1-Me derivative in CHCl3, are brominated at position 6 with bromine. Less nucleophilic N 9-R derivatives do not enter into the reaction under these conditions, but, like their N 1-R isomers, they are quite effectively brominated by the KBrO3-HBr system, but at position 7, probably due to the transition of the reaction to the mode of bromination of protonated forms of substrates. N 1- and N 9-alkyl-6(7)-Br-2,3-dihydroimidazo[1,2- a ]benzimidazoles can also be obtained by N -alkylation of 6(7)-Br-2,3-dihydroimidazo[1,2- a ]benzimidazoles under neutral or basic conditions.
Synthesis and phosphonylation of S-methylthiouracil and its derivatives
Authors: Skrylkova A. S , Nosova N. A , Egorov D. M , Khalikova M. D , Rozikov U. A , Safarov S. Sh.
Published: April 2024

A series of S -methylated derivatives of 2-thiouracil were prepared and then phosphonylated with diethyl chlorophosphate. The reaction conditions were optimized, the structure of the obtained compounds was determined by 1Н, 13С, 31Р NMR spectroscopy methods.
Mannich reaction involving 6-amino-4-methyl2-(thio)oxo-1,2-dihydropyridine-3,5-dicarbonitriles
Authors: Panaetov A. O , Strelkov V. D , Dotsenko V. V , Aksenov N. A , Aksenova I. V , Chausov F. F , Lomova N. V , Kazantseva I. S , Isupov N. Yu.
Published: April 2024

The reaction of (1-ethoxyethylidene)malononitrile with cyanoacetamide or cyanothioacetamide yielded 6-amino4-methyl-2-(thio)oxo-1,2-dihydropyridine-3,5-dicarbonitriles. The resulting pyridine derivatives enter into an aminomethylation reaction with an excess of formaldehyde and primary amines with the formation of previously unknown 8-methyl-6-oxo-3-R-1,3,4,6-tetrahydro-2 H -pyrido[1,2- a ][ 1,3,5]triazine-7,9-dicarbonitriles. Further treatment of 6-amino-4-methyl-2-thioxo-1,2-dihydropyridine-3,5-dicarbonitrile and its oxygen analogue with excess formaldehyde leads to the formation of 3,10-dimethyl-1,8-dithioxo-5,6,12,13-tetrahydro-1 H ,8 H -dipyrido[1,2- a :1’,2’- e ][1,3,5,7]tetrazocin-2,4,9,11-tetracarbonitrile and 6,6’-[methylenedi(imino)]bis(4-methyl-2-oxo-1,2-dihydropyridine-3,5-dicarbonitrile), respectively. These compounds show a pronounced antidote effect against the herbicide 2,4-D (2,4-dichlorophenoxyacetic acid) in laboratory and field experiments on sunflower seedlings. Also, 6-amino-4-methyl-2-oxo-1,2-dihydropyridine-3,5-dicarbonitrile exhibits pronounced anticorrosion properties and is an adsorption-type corrosion inhibitor. The mechanism of anti-corrosion action was studied in detail using X-ray photoelectron spectroscopy.
Effect of n-acetylcysteine on cu2+(fe2+)/h2o2-mediated free radical fragmentation of glycerophosphate in the presence of biologically active compounds
Authors: Ovsyannikova E. M , Soloninkina I. O , Yurkova I. L
Published: April 2024

The effect of N -acetylcysteine on homolytic fragmentation of β-glycerophosphate with cleavage of phosphoester bond was studied. It was shown that, N -acetylcysteine activates the fragmentation induced by Cu2+(Fe2+)-H2O2, and inhibits the radiation-induced process. The stimulated effect of N -acetylcysteine on Cu2+/H2O2-mediated fragmentation in the presence of compounds affecting on HO• level, the Cu2+/Cu+ ratio, or interacting with thiol is either enhanced (Trolox, Ubiquinone Q0) or switched to a prоtective one (NaN3, Met, ascorbate). In the presence of Fe2+ Trolox unlike Q0 reduces the promoter effect of N -acetylcysteine.
Mn(II)-cu(I) hybrid complex based on 1,3,5-tris(diphenylphosphinyl)benzene
Authors: Davydova M. P , Bagryanskaya I. Yu. , Sadykov E. Kh. , Brel V. K
Published: April 2024

The reaction of 1,3,5-tris(diphenylphosphinyl)benzene (L) with MnI2 in the presence of CuI (wet MeCN, 25°C, 30 min) leads to the formation of a complex [MnL4(H2O)2][Cu5I7(CH3CN)]·7MeCN with yield of 72%. The Mn2+ ion of this complex has a distorted Mn@O6 octahedral environment formed by four L ligands and two coordinated water molecules. The [Cu5I7(CH3CN)]2- anion has an unprecedented structure of the {Cu5I7} backbone, which includes five copper atoms bound by bridging iodide ions (µ2, µ3, µ4), as well as four short Cu···Cu contacts (
Charge transfer complexes of nitroderivatives of 9,10-phenanthreqinone with 9-methyl-9H-carbazole: quantum chemical simulation, x-ray diffraction study
Authors: Linko R. V , Ryabov M. A , Davydov V. V , Khrustalev V. N
Published: April 2024

Within the framework of the density functional theory approximation, quantum-chemical calculations were performed and data on the structure and properties of charge-transfer complexes of 9,10-phenanthrenquinone nitro derivatives with 9-methyl-9 H -carbazole were obtained. The formation energies of complexes, the average distances between the donor and acceptor planes, and the values of charge transfer from the donor to the acceptor have been calculated. The crystal and molecular structure of the complex of 2,4,7-trinitro-9,10-phenanthrenquinone with 9-methyl-9 H -carbazole (C14H5N3O8·C13H11N) was determined by X-ray diffraction analysis. In the crystal of the complex, the donor and acceptor molecules form parallel stacks of the {-D-A-D-A-}∞ mixed type with average interplanar distances of 3.29 and 3.35 Å. Each acceptor molecule forms intermolecular hydrogen bonds C-H···O 2.42-2.69 Å.
2,3,5,6-tetramethyl-1H,4h-3a,6a-diaza-1,4-diphosphapentalene and its 1,4-dichloro derivative: specifics of synthetic approaches
Authors: Sushev V. V , Khristolyubova A. V , Zolotareva N. V , Grishin M. D , Panova Yu. S. , Rumyantcev R. V , Fukin G. K , Kornev A. N
Published: April 2024

Reaction of azine-2-butanone with PCl3 in THF or methylene chloride gives a mixture of isomeric diazadiphosphapentalene dichlorides. Carrying out the reaction without solvent leads to 1,4-dichloro-2,5,3,6-tetramethyl-1 H ,4 H -3a,6a-diaza-1,4-diphosphapentalene (DDPCl2) (32%) and the cleavage product of the heteropentalene backbone - 4,5-dimethyl-2 H -1,2,3-diazaphospholium chloride (29%), while in acetonitrile the only reaction product is dichloride DDPCl2 (60%). The reduction of the latter with manganese powder in tetrahydrofuran leads to 2,5,3,6-tetramethyl-1 H ,4 H -3a,6a-diaza-1,4-diphosphapentalene in 57% yield. The products were investigated by X-ray diffraction analysis and cyclic voltammetry method.
Terpyridine-containing 5-(2-pyridylmethylene)-2-thioimidazolones and their coordination compounds with copper(II) chloride: synthesis and cytotoxicity
Authors: Salimova I. O , Berezina A. V , Moiseeva A. A , Skvortsov D. A , Sukonnikov M. A , Zyk N. V , Beloglazkina E. K
Published: April 2024

Methods for the synthesis of new ditopic organic ligands containing coordinating fragments of two types, terpyridine and thiohydantoin, have been developed. The synthesized ligands were studied in complex formation reactions with copper(II) chloride. As a result, two types of coordination compounds were isolated and characterized by electron spectroscopy, elemental analysis, and cyclic voltammetry: bis-ligand tetranuclear mixed-valent complexes of copper(I, II) and a monoligand binuclear complex containing two copper(II) ions. The cytotoxic activity of the obtained coordination compounds with respect to the MCF7, A549, and HEK293 cell lines was studied.
Synthesis and spectral characteristics of quinoline derivatives of maleopimaric acid
Authors: Vafina G. F. , Akchurina O. V. , Lobov A. N.
Published: April 2024

The reaction of maleopimaric acid and its acid chloride with 3-, 6-, and 8-aminoquinolines afforded quinoline containing maleopimarimides and carboxamides, respectively. Structure of the synthesized compounds was determined by 1Н, 13С, 1H-13C HSQC, 1H-13C HMBC, COSY, NOESY, and 1Н-15N HMBC NMR spectroscopy methods.
Tris(2,6-dimethoxyphenyl)ethylstibonium iodide and nitrate: synthesis, structure, and some properties
Authors: Egorova I. V. , Zhidkov V. V. , Zubakina I. N. , Rodionova N. A. , Kuratieva N. V. , Pervukhina N. V.
Published: April 2024

Alkylation of tris(2,6-dimethoxyphenyl)stibine Ar3Sb, where Ar = 2,6-(MeO)2C6H3, with iodoethane in chloroform resulted in [Ar3EtSb]I, which further reacted with lead(II) nitrate to form [Ar3EtSb]NO3·0.75Н2О. The comparative characterization of the complexes was carried out by X-ray diffraction analysis, IR spectroscopy, and simultaneous thermal analysis. Antimony atoms in stibonium cations have a distorted tetrahedral coordination [CSbC 106.80(12)-115.22(12)° and 105.33(14)-115.33(14)°]. In a boiling aqueous solution, [Ar3EtSb]I, [Ar3EtSb]NO3·0.75Н2О decompose to tris(2,6-dimethoxyphenyl)stibine.
Deposition of iron, cobalt, and nickel phosphides on the surface of highly porous silica
Authors: Tarasyuk I. A. , Filippov D. V. , Vashurin A. S.
Published: April 2024

The sol-gel method was used to obtain materials with deposited cobalt and nickel phosphides of the general formula Me2P and iron phosphide on highly porous silica ( S sp 811 m2/g). The advantage of the methods for obtaining materials considered in the work is the absence of the need to use structure-forming substances, such as surfactants. The properties of materials obtained by different methods were compared. For all materials, it was found that the proportion of metal is 4.5-4.7 wt.% of the material.
Synthesis, properties, and pyrolysis of organoalumoxanes modified with refractory metals
Authors: Shcherbakova G. I. , Pokhorenko A. S. , Krivtsova N. S. , Varfolomeev M. S. , Apukhtina T. L. , Drachev A. I. , Ashmarin A. A. , Storozhenko P. A.
Published: April 2024

Organoalumoxane oligomers modified with refractory metals (zirconium, hafnium or chromium) were synthesized. Their physico-chemical and fiber-forming properties were studied. Models of the group and elemental composition of oligomeric molecules of organoalumoxanes containing zirconium, hafnium or chromium were proposed. Based on the results of X-ray elemental microanalysis (SEM) and X-ray diffraction, it was found that pyrolysis of metal-containing organoalumoxanes at 1500°C in air results in the microcrystalline ceramic powders of corundum composition, modified with refractory metal oxides.
Clustering of organoleptic quality evaluations of red and white wines by physicochemical parameters using statistica software
Authors: Bondarev N. V.
Published: April 2024

Organoleptic evaluations in a ten-point scale of wine experts and experimental physicochemical parameters of red (1599 samples) and white (4898 samples) wines of Portuguese manufacturers were analyzed using STATIS-TICA sofware. Methods of agglomerative and iterative ( k -means algorithm) clustering revealed the grouping of similar wine samples into three, four and six clusters depending on the Euclidean distance of association. The quantitative filling of clusters with samples of bad wines (grades 3 and 4), normal wines (grades 5 and 6) and good wines (grades 7, 8, 9) was established. Neural network (MLP) and discriminant analyzes (DA) were performed; algorithms of classification trees (CT), support vector machines (SVM), naive Bayesian classification (NBC) and nearest neighbors (kNN) were involved. The best performance was demonstrated by neural network models. Multilayer perceptorons classifiers were trained: for red wines - MLP 11-7-3, MLP 11-13-4, MLP 11-14-6; for white wines - MLP 11-9-3, MLP 11-5-4, MLP 11-9-6. The properties of wines, whose contribution to the separating power of classifiers is decisive, are revealed. The ranges of changes in physicochemical parameters in three clusters of red and white wines for bad, normal and good wines were given.
Complexation of lanthanide ions with citric acid in aqueous solutions
Authors: Guseva P. B. , Badikov A. R. , Kadygrob E. D. , Saitov Ya. E. , Bogachev N. A. , Skripkin M. Yu. , Pestova O. N. , Mereshchenko A. S.
Published: April 2024

The stability constants of triply charged lanthanide ions complexes with citric acid of 1:2 stoichiometry weremeasured by potentiometric titration in a wide pH range, and the relationship between the constants and the lanthanide type was analyzed. A mathematical model for the equilibrium in studied solutions was proposed.
On Cauchy Problems for Nonlinear Sobolev Equations in Ferroelectricity Theory
Authors: Korpusov M. O. , Shafir R. S.
Published: April 2024

Two Cauchy problems for the nonlinear Sobolev equations@ and @ are investigated. Conditions are found under which the Cauchy problems have weak generalized local-in-time solutions, and the blow-up conditions for weak solutions of these problems are determined.