bluuebunny/crossref_metadata_2025 huggingface dataset:
New 5-n-C4H9-C2B9-Carborane Ligand and Its Ruthenium Complexes
Authors: Zimina A. M. , Kolpakova T. V. , Anufriev S. A. , Zueva E. I. , Somov N. V. , Sivaev I. B. , Grishin I. D.
Published: April 2024

The reaction of 9-iodo-ortho-carborane with n-butylmagnesium bromide affords 9-n-butyl-ortho-carborane. The reaction of the latter with alkali in boiling ethanol gives new nido-carborane [5-Bu-7,8-C2B9H11]– (I) containing the n-butyl substituent at the lower rim of the basket. The reaction of compound I with RuCl2(PPh3)(Ph2P(CH2)4PPh2) results in the formation of the corresponding ruthenium(IV) closo complex 3,3-(Ph2P(CH2)4PPh2)-3-H-3-Cl-9-Bu-closo-3,1,2-RuC2B9H10 (II) characterized by 2D NMR spectroscopy. On heating compound II can react with carbon tetrachloride to form the 17-electron complex 3,3-(Ph2P(CH2)4PPh2)-3-Cl-9-Bu-closo-3,1,2-RuC2B9H10 (III). The structure of complex III is solved by X-ray diffraction (XRD) (CIF file CCDC no. 2180761). The electrochemical studies show that complex III undergoes the reversible transition Ru(II) → Ru(III) similarly to the earlier studied ruthenacarboranes.
Synthesis, Structure, and Study of the Cytotoxic Activity of Zinc(II) Complex with 5-Benzyltetrazole and 1,10-Phenanthroline
Authors: Ermakova E. A. , Golubeva Yu. A. , Smirnova K. S. , Klyushova L. S. , El’tsov I. V. , Lider E. V.
Published: April 2024

The complex [Zn(Phen)(H2O)L2] (I), where HL is 5-benzyltetrazole, Phen is 1,10-phenanthroline,was synthesized. The compound was characterized by standard physicochemical methods (elementalanalysis, powder X-ray diffraction, IR spectroscopy). According to X-ray diffraction data (CCDC no.2220597), zinc coordination environment in the crystal structure of I corresponds to a distorted trigonalbipyramid. The ligand HL is monodentate and is coordinated via tetrazolate ring nitrogen. The stability ofcomplex I was studied by NMR spectroscopy in DMSO. The cytotoxic properties of the compound wereassessed against HepG-2 (hepatocellular carcinoma) and MRC-5 (noncancerous human fibroblasts) cells.Complex I exhibits weak cytotoxic properties in the studied concentration range (1–100 μM).
Complexes of Cu(II), Co(II), and Zn(II) Terephthalates with Hydroxyalkylamines
Authors: Zav’yalova D. A. , Kondratenko Yu. A. , Zolotarev A. A. , Ugolkov V. L. , Kochina T. A.
Published: April 2024

The reactions of Cu(II), Co(II), and Zn(II) terephthalates with hydroxyalkylamines (tris(2-hydroxyethyl)amine, bis(2-hydroxyethyl)amine, tris(hydroxymethyl)aminomethane, and bis(2-hydroxyethyl)aminotris(hydroxymethyl)methane) are studied for the first time. The structures and properties of the synthesized complexes are studied by IR spectroscopy, electronic absorption spectroscopy, mass spectrometry, and elemental and thermal analyses. The structure of the binuclear heteroligand [Cu2(TEA)2(Tph)]n·H2O complex is studied by single-crystal X-ray diffraction (XRD) (CIF file CCDC no. 2224437).
Trimethylplatinum(IV) Complexes for MOCVD Applications: A Physicochemical Study
Authors: Dorovskikh S. I. , Kuratieva N. V. , Korolkov I. V. , Basova T. V. , Ilyin I. Yu.
Published: April 2024

The structure of trimethylplatinum(IV) iodide [(CH3)3PtI]4 (I) (CIF file CCDC no. 22330007) is refined. The structure of the synthesized for the first time trimethylplatinum(IV) complex with tridentate N,N,O-iminoketonate [(CH3)3Pt(C9H17N2O)] (II) is determined by X-ray diffraction (XRD) (CIF file CCDC no. 22330008). The purity of the isolated phases is confirmed by elemental analysis and IR and NMR spectroscopy. The thermal behavior of complex II is studied by thermogravimetry. The energies of ionization and fragmentation of the molecules of complex II leading to the formation of the most stable fragment [(CH3)3Pt]+ are estimated by quantum-chemical calculations. Complex II is tested in the MOCVD processes. The Pt films with the pronounced (111) texture and particle sizes about 100 nm are prepared on Si plates in the presence of oxygen.
Coordination Compounds in Devices of Molecular Spintronics
Authors: Zlobin I. S. , Novikov V. V. , Nelyubina Yu. V.
Published: April 2024

Spintronics, being one of the youngest fields of microelectronics, is applied already for several decades to enhance the efficiency of components of computer equipment and to develop units of quantum computer and other electronic devices. The use of molecular material layers in a spintronic device makes it possible to substantially deepen the understanding of the spin transport mechanisms and to form foundation for a new trend at the nexus of physics and chemistry: molecular spintronics. Since the appearance of this trend, various coordination compounds, including semiconductors, single-molecule magnets, complexes with spin transitions, and metal-organic frameworks, are considered as molecular materials of spintronic devices with diverse unusual characteristics imparted by these materials. Specific features of using the earlier described representatives of the listed classes of compounds or their analogs, which are still “kept on the shelves” in chemical laboratories, for manufacturing polyfunctional devices of molecular spintronics are briefly reviewed.
Study of the Reduction of Cobalt(III) Complexes by In Situ NMR Spectroscopy
Authors: Nikovskii I. A. , Babakina D. A. , Denisov G. L. , Nelyubina Yu. V. , Khakina E. A.
Published: April 2024

An approach for monitoring the redox activation of drug delivery in cobalt(III) complexes by in situ NMR spectroscopy is proposed. The reduction of the heteroleptic cobalt(III) complexes containing the 6,7-dihydroxycoumarin molecule applied as a model drug is studied using the proposed approach. The replacement of the bipyridine ligand in the cobalt(III) complex by phenanthroline considerably increases the redox-activated release rate of the drug.
Tetrapyridineplatinum(II) Carboxylates: Synthesis and Crystal Structure
Authors: Yakushev I. A. , Nesterenko M. Yu. , Dorovatovskii P. V. , Kornev A. B. , Maksimova A. D. , Popova A. S. , Cherkashina N. V. , Churakov A. V. , Vargaftik M. N.
Published: April 2024

A series of mono- and bimetallic cation-anionic complexes based on the [PtPy4]2+ cation with different single-charge anions of carboxylic acids (RCOO–) is synthesized and structurally characterized. A synthetic approach to the preparation of tetrapyridineplatinum complexes [PtPy4]2+ soluble in polar solvents from available reagents is developed. The reaction of tetrapyridineplatinum dichloride [PtPy4](Cl)2 with silver acetate or trifluoroacetate affords compounds [PtPy4](OOCMe)2·6H2O (I) and [PtPy4](OOCCF3)2· 2H2O (II) in the form of crystalline hydrates (CIF files CCDC nos. 2161100 and 2161101, respectively) in high yields. Other carboxylates can be prepared by the treatment of compound I with an excess of a stronger acid, for example, trifluoroacetic acid, with the formation of the corresponding complex trifluoroacetate [PtPy4](OOCCF3)2·4CF3COOH (IIa) (CIF file CCDC no. 2161102). Another method consists of the displacement of acetic acid with an excess of a lowly volatile acid, for example, pivalic acid, when [PtPy4](Piv)2· 5HPiv (III) is formed from the acid melt, and solvatomorph [PtPy4](Piv)2·4HPiv·3C6H12 (IIIa) (CIF files CCDC nos. 2161103 and 2161104, respectively) is formed in a cyclohexane medium. Heteroanionic heterometallic complex [PtPy4](OOCFc)(OOCMe) (IV) (CIF file CCDC no. 2161105) is shown to be formed by the reaction of complex I with ferrocenecarboxylic acid under mild conditions.
Rhenium(V) Tris(pyrazolyl)borate Complexes as Ligands in Square Planar Palladium and Platinum Complexes
Authors: Skabitskii I. V. , Il’ina Yu. Ya. , Shapovalov S. S.
Published: April 2024

The reactions of TpReO(SnC3H7)2 (Tp = tris(pyrazolyl)borate anion) with acetonitrile complexes PdCl2(MeCN)2 and PtI2(MeCN)2 in toluene solutions resulted in the formation of new heterometallic rhenium complexes TpReO(µ-SnC3H7)2MX2 (MX2 = PdCl2 (I), MX2 = PtI2 (II)). A similar complex TpReO(µ-SnC3H7)2PdI2 (III) was formed either on treatment of I with NaI in dichloromethane or in the reaction of TpReO(SnC3H7)2 with a suspension of PdI2 in toluene. Complexes I–III were characterized by IR and NMR spectroscopy and by X-ray diffraction (CCDC nos. 2172225–2172227).
Complex Formation in the Modified Xerogel Phase: Study and Application in Analysis
Authors: Morosanova E. I.
Published: April 2024

The review summarizes the author’s results concerning the complex formation in the phase of modified xerogels synthesized by the sol–gel process for application as sensor materials. The results of studying the complex formation (pH ranges of reactions, light absorption maxima and compositions of complexes, and equilibrium constants) are presented and discussed for 87 systems of two types, that is, immobilized ligand (organic analytical reagent)–metal ion and immobilized metal ion–organic or inorganic compound. The approach proposed by the author to describe the complex formation in the modified xerogel phase is presented. The results of applications of modified xerogels as sensor materials are considered, including their use for determining metal ions; organic compounds; hydrogen peroxide; chloride, fluoride, and oxalate ions in food and hygienic products, pharmaceuticals, biological fluids, and environmental media.
Species of Gold(III) Binding by Binuclear Zinc Dipropyldithiocarbamate: Supramolecular Self-Organization and Thermal Behavior of Ionic Complexes [Au(S2CNPr2)2]2[ZnCl4] and [Au(S2CNPr2)2]2[AuCl4][AuCl2]
Authors: Loseva O. V. , Rodina T. A. , Gerasimenko A. V. , Ivanov A. V.
Published: April 2024

The reaction of binuclear zinc dipropyldithiocarbamate [Zn2{S2CN(C3H7)2}4] with an AuCl3/2 М HCl solution is studied. The double ionic complex [Au{S2CN(C3H7)2}2]2[ZnCl4] (I) is identified as the main species of gold(III) binding in the heterogeneous system under study and is characterized by 13С and 15N CP-MAS NMR spectroscopy. Single crystals of heterovalent compound [Au{S2CN(C3H7)2}2]2[AuCl4][AuCl2] (II) are sampled as a by-product. The crystal and supramolecular structures of complexes I and II are determined by the direct XRD method (CIF files CCDC nos. 2159171 and 2159170, respectively). The self-organization of the complex pseudopolymeric structures of compounds I and II are shown to be due to the binding of ionic structural units by secondary nonvalent interactions Au⋅⋅⋅S and S⋅⋅⋅Cl and hydrogen bonds C–H⋅⋅⋅Cl. The thermal behavior of the complexes is studied by simultaneous thermal analysis (STA), and the quantitative regeneration of bound gold (I and II) with the partial transformation of released ZnCl2 to ZnS (I) is found.
New Binuclear Copper(II) Complex Based on 1,2-Bis(2-(4,4,4-trifluoro-1,3-dioxobutyl)phenoxyethane: Synthesis and Structure
Authors: Patrina A. N. , Veretennikova E. A. , Khamidullina L. A. , Puzyrev I. S. , Slepukhin P. A. , Pestov A. V.
Published: April 2024

New binuclear complex 1,2-bis[2-(4,4,4-trifluoro-1-hydroxy-3-oxobut-1-enyl)phenoxy]ethanedi(dimethylformamide)dicopper(II) is synthesized, and its structure is studied by X-ray diffraction (XRD) (CIF file CCDC no. 2179252). A crystal of the complex is formed by centrosymmetric Cu2L2(DMF)2 molecules in which the coordination environment of each metallocenter is a distorted square pyramid, and the whole molecule is a metallomacrocycle containing the calixarene-like cavity. Its size is determined the distance between the Cu…Cu metallocenters (7.699 Å) and the distance between the planes of the opposite phenyl radicals in the cis position (8.200–8.323 Å). The cavity is a parallelogram. The carcass-type binuclear structure is formed due to an increase in the denticity of the ligand via the formation of the bis(triketone)-like structure that weakens the donor character of both functional groups of the β-diketone fragment.
Trimethylammonium dichloro-hexachlorotellurate(IV): crystal structure and features of non-covalent interactions of Cl···Cl
Authors: Usoltsev A. N. , Sonina A. A. , Korobeinikov N. A. , Adonin S. A.
Published: April 2024

By the reaction of tellurium(IV) oxide with trimethylammonium chloride in the presence of chlorine gas in concentrated hydrochloric acid, supramolecular dichloro-hexachlorotellurate (Me3NH)2{[TeCl6](Cl2)} (I) was obtained, the structure of which was determined by X-ray diffraction. Based on elemental and X-ray phase analysis data, a conclusion was made about the limited stability of the resulting compound. The features of non-covalent Cl···Cl interactions in the crystal structure of this compound were studied by Raman spectroscopy (Raman).
Interaction of Cobalt Tetrasulfophthalocyanine with ORF8 Accessory Protein of SARS-CoV-2
Authors: Koifman O. I. , Maizlish V. E. , Lebedeva N. Sh. , Yurina E. S. , Guseinov S. S. , Guriev E. L. , Gubarev Yu. A.
Published: April 2024

The interaction of cobalt(II) tetrasulfophthalocyanine (CoPc) with the ORF8 accessory protein of SARS-CoV-2 was studied by spectroscopy and calorimetry. The protein was found to shift the aggregation equilibrium in cobalt tetrasulfophthalocyanine solutions towards dimerization. Most probably, the CoPc dimer binds to ORF8 on the greater β-sheet side, thus causing fluorescence quenching. The protein affinity constant to CoPc dimer is 1.5 × 105. Differential scanning calorimetry data indicate that ORF8 undergoes thermally induced denaturation in the temperature range of 38–67°C. Melting of ORF8 includes two stages, which partly overlap. The complex formation of ORF8 with CoPc leads to thermal stabilization of the protein, thus preventing the second stage of protein unfolding. Denaturation of the complex proceeds between 40 and 77°C as two temperature-separated stages. According to gel electrophoresis and immunoblotting data, visible light photoirradiation of the ORF8 complex with CoPc does not induce photooxidation of the protein. It was shown that water-soluble cobalt sulfo-substituted phthalocyanine can be considered as a potential drug inhibiting the ORF8 accessory protein.
Nitro-Substituted Pyridinimine Complexes of Pd(II): Synthesis and Inhibition of MAO-B ex vivo
Authors: Denisov M. S. , Beloglazova Yu. A.
Published: April 2024

The first ever synthesis of complexes [PdLCl2] (I) and [PdLBr2] (II) was successfully achieved,where L = 2,6-dimethyl-4-nitro-N-(pyridin-2-ylmethylildene)aniline, a ligand with a purported ability toinhibit monoamine oxidase B (MAO-B). To gain insight into the molecular structure of complexes Iand II, as well as the ligand precursor 2,6-dimethyl-4-nitroaniline L4 (CIF files CCDC nos. 2255106 (I),2255105 (II), 2255103 (L), 2255104 (L4)), X-ray diffraction analysis was utilized. Complex I underwent furthercharacterization to determine its stability, solubility, and lipophilicity. Cytotoxicity studies of substancesL, I, and II on human embryonic kidney cell line HEK-293 showed no evidence of cytotoxic activity. To evaluatethe inhibitory activity of new substances L, I, and II as well as established substances III−IX, selegiline,and rasagiline, ex vivo studies were conducted, establishing a structure/activity relationship.
SOLVOTHERMAL SYNTHESIS, STRUCTURE, AND PROPERTIES OF CADMIUM(II)-ORGANIC COORDINATION POLYMER CONTAINING CARBOXYL GROUPS
Authors: Xu B. , Yao W. , Yu S. , Samsonenko D. G. , Fedin V. P. , Gao E.
Published: April 2024

Under the conditions of solvothermal synthesis, a new metal-organic coordination polymer of the composition Cd[H2L] (I, H4L = 4,4'-([2,2'-bipyridine]-6,6'-diylbis(oxy))diphthalic acid). According to X-ray diffraction analysis, each Cd(II) cation binds four organic ligands: one via the coordination of the chelate bipyridyl fragment, two via the bidentate coordination of deprotonated COO groups, and one more via the monodentate coordination of the protonated carboxylate group. The obtained three-dimensional metal-organic framework does not contain free space capable of including guest molecules. Compound I was characterized by powder X-ray diffraction, IR spectroscopy, elemental (C, H, N) and thermogravimetric analyses, and luminescence spectra were recorded for it.
Copper(II) and Zinc(II) Complexes with Heterocyclic Acid Anions and 3,5-Dimethylpyrazole: Synthesis, Structure, and Biological Properties
Authors: Uvarova M. A. , Novikova M. V. , Eliseenkova V. A. , Baravikov D. E. , Dolgushin F. M. , Bekker O. B. , Fatushina E. V. , Kiskin M. A. , Eremenko I. L. , Lutsenko I. A.
Published: April 2024

The reaction of copper(II) and zinc(II) acetates with 3-furancarboxylic (HFur) and 2-thiophenecarboxylic (HTph) acids with subsequent addition of 3,5-dimethylpyrazole (HDmpz) gave mononuclear complexes [M(L)2(HDmpz)2] (M = Cu(II), L = Fur– (I), Tph– (II); Zn(II), L = Fur– (III)). The structures of compounds I–III were determined by X-ray diffraction. According to X-ray diffraction data, I and II are isostructural: the central Cu(II) atom occurs in a square planar environment formed by two oxygen atoms of carboxylate anions and HDmpz nitrogen atoms; in III, the Zn atom is in the tetrahedral environment of two furoate anions and HDmpz molecules, thus forming the {MO2N2} groups. The complexes are additionally stabilized in the crystal by inter- (I and II) and intramolecular (III) hydrogen bonds. The biological activity of I–III was determined in relation to the non-pathogenic Mycolicibacterium smegmatis.
Copper(II) Furancarboxylate Complexes with 5-Nitro-1,10-Phenanthroline as Promising Biological Agents
Authors: Koshenskova K. A. , Baravikov D. E. , Nelyubina Yu. V. , Primakov P. V. , Shender V. O. , Maljants I. K. , Bekker O. B. , Aliev T. M. , Borodin E. A. , Kotel’nikov D. D. , Leusova N. Yu. , Mantrov S. N. , Kiskin M. A. , Eremenko I. L. , Lutsenko I. A.
Published: April 2024

The reaction of copper(II) acetate with 2-furancarboxylic (HFur)/5-nitro-2-furancarboxylic (HNfur) acids and 5-nitro-1,10-phenanthroline (Nphen) in methanol resulted in the formation of the binuclear coordination compounds [Cu2(L)4(Nphen)2]·X (L = Fur (I), Nfur (II); X = H2O (I)), which were structurally studied by direct X-ray diffraction (CCDC no. 2244205 (I) and 2244206 (II)). According to X-ray diffraction data, the coordination environment of the central metal ion in I and II is composed of two nitrogen atoms of Nphen and three oxygen atoms of the acid anions, which thus form the {CuN2O3} tetragonal pyramid in which the copper coordination number is five. Intermolecular hydrogen bonds and stacking interactions between the Nphen aromatic rings provide supramolecular stabilization of I and II. A characteristic feature of supramolecular organization of II is the presence of a coordination bond between the Cu2+ cation and oxygen of the Nphen NO2- group of parallel chains. A biological activity assay for complexes I and II concerning the cytotoxic properties against a human ovarian adenocarcinoma cell line (SKOV3) and the mycobacterial strain Mycolicibacterium smegmatis showed an efficient suppression of cell viability. The results of mathematical modeling of the probability of Cu2+ binding to amino acid residues of M. smegmatis proteins suggested the affinity of the Cu(II) ion to a number of amino acids in polypeptide sites. It was shown that metal ion binding in mycobacterial proteins is more characteristic of histidine- and glutamic acid-containing moieties.
Synthesis and Structure of the (µ2-OP(O)Ph2)-Linked Dimeric Amide Lanthanum Complex {[
CP(O)Ph2]La[N(SiMe3)2](µ2-OP(O)Ph2)}2 Bearing the Tridentate Heteroscorpionate Ligand. Investigation of the Catalytic Activity in rac-Lactide and ε-Caprolactone Polymerization
Authors: Rad’kova N. Yu. , Cherkasov A. V. , Trifonov A. A.
Published: April 2024

The dimeric amide lanthanum complex {[CP(O)Ph2]La[N(SiMe3)2](µ2-OP(O)Ph2)}2 (PzlMe2 is 3,5-dimethylpyrazole) bearing the N,N,O-tridentate heteroscorpionate ligand is synthesized. As found by X-ray diffraction (XRD) (CIF file CCDC no. 2212274), the complex is binuclear and its lanthanum ions are linked by two bridging monoanionic diphenyl phosphinate ligands. The synthesized lanthanum complex demonstrates a high catalytic activity in the polymerization with ring opening of rac-lactide and ε-caprolactone providing the quantitative conversion of 500 equivalents of the monomer to the polymer at room temperature within 360–720 min for rac-lactide and 10–30 min for ε-caprolactone. The formed polylactides are characterized by the atactic microstructure (Pr = 0.54–0.56) and polydispersity indices (PDI) of 1.6–2.5, whereas for polycaprolactone PDI = 2.1–2.8.
Binuclear Vanadium(V) Complex with the Ligand Based on Isonicotinic Acid Hydrazide and 1-Phenyl-1,3-Butanedione: Synthesis and Crystal Structure
Authors: Bourosh P. , Cocu M. , Danilescu O. , Bulhac I.
Published: April 2024

A new molecular binuclear vanadium(V) complex [VO(L)(OCH3)]2 (I) is synthesized in which ligand H2L is prepared by the reaction of isonicotinic acid hydrazide (INAH, isoniazide) with 1-phenyl-1,3-butanedione. Ligand H2L and complex I are studied by elemental analysis, IR spectroscopy, mass spectrometry, and X-ray diffraction (XRD) (CIF files CCDC nos. 2172124 and 2172125, respectively). The composition and structure of the ligand in the free state is additionally studied by NMR spectroscopy. The bideprotonated organic ligand L2– coordinates to the metal atom via the tridentate mode through a set of donor atoms ONO to form two conjugated metallocycles. Different tautomeric forms are stabilized in H2L and in the corresponding coordinated ligand.
Structure of Copper(II) N-Methylbenzoylhydroxamate in the Crystalline State and in Solution
Authors: Rotov A. V. , Yakushev I. A. , Zhilov V. I. , Kornev A. B. , Ugolkova E. A. , Breslavskaya N. N. , Timokhina E. N. , Efimov N. N. , Minin V. V.
Published: April 2024

The geometrical structure of CuL2 (I), where L = R1N(O)–(O)CR2, R1 = Me, R2 = Ph, was studied by X-ray diffraction in the crystalline state and by stationary ESR spectroscopy in solution. In the crystalline state, I is a chain polynuclear complex. According to ESR data, in frozen solutions, complex I exists as three species, two being mononuclear and one being binuclear. The magnetic resonance parameters and concentrations of the species in frozen solutions were determined. The electronic structure of the complex with full geometry optimization of all systems was calculated in terms of the unrestricted density functional theory (DFT) method.
Coordination Polymers of Lithium Based on 1,2-Bis[(2,6-diisopropyl-4-diethylmalonophenyl)imino]acenaphthene
Authors: Bazyakina N. L. , Sokolov V. G. , Moskalev M. V. , Baranov E. V. , Fedushkin I. L.
Published: April 2024

1,2-Bis[(2,6-diisopropyl-4-diethylmalonophenyl)imino]acenaphthene (Dem-Bian) with zinc chloride forms complex [(Dem-Bian)ZnCl2] (I). The reaction of complex I with n-BuLi proceeds with the deprotonation of the malonate fragments and gives 1D coordination polymer [ZnCl2(Dem-Bian)Li(DME)2]n (II). The reaction of [(Dem-Bian)CuCl] with n-BuLi affords 1D polymer [(Dem-Bian)Li2(DME)2]n (III). Compounds I–III are characterized by elemental analysis and IR spectroscopy. Derivatives I and II are characterized by 1Н NMR spectroscopy. The crystal structures of compounds II and III are determined by X-ray diffraction (XRD). Their thermal stability is studied by thermogravimetric analysis.
Molecular Switches of the LD-CISSS Type Based on Ni(II) Azomethine Bis-Chelate Complexes. Quantum Chemical Modeling
Authors: Kharabayev N. N. , Starikov A. G. , Minkin V. I.
Published: April 2024

(DFT/B3LYP/6-311++G(d,p)) calculations were performed to study Ni(II) azomethine bis-chelates with photoactive moieties (imidazole and benzimidazole derivatives of azo compounds, azomethines, and stilbenes) exhibiting the behavior of molecular magnetic switches by the light-driven coordination-induced spin state switching (LD-CISSS) mechanism. The structural and energy characteristics of the complexes favorable to or restricting the applicability of these complexes as molecular switches were determined.
Biologically Active Palladium(II), Zinc(II), and Copper(II) Complexes with Terpene Ligands as Potential Pharmaceutical Drugs
Authors: Gur’eva Ya. A. , Zalevskaya O. A. , Kuchin A. V.
Published: April 2024

A final review of the results of studies of versatile biological activities (in vitro) of chiral metal complexes with benzylamine and ethylenediamine derivatives of terpenes is presented. The cytotoxic profiles of palladacycles containing a Pd–C bond and palladium and zinc chelate complexes were determined. For a number of compounds, the possible mechanisms of potential anticancer action were analyzed, such as modulation of mitochondrial functioning and effect on the parameters of glycolytic function of tumor cells. The antibacterial and antifungal activities of palladium complexes of different types and copper chelate complexes were investigated. A correlation between high antimicrobial activity and antioxidant properties was found for a number of copper complexes. The material is supplemented by an extended analysis of publications in relevant subjects.
Possibilities of Determining Quantitative and Qualitative Characteristics of Mixed Forest Stands Using Sentinel-1 Imagery
Authors: Sidorenkov V. M. , Kositsyn V. N. , Badak L. A. , Astapov D. O. , Achikolova I. S.
Published: April 2024

The paper presents studies on using Sentinel-1 imagery data to determine attributes of mixed forest stands. The fieldwork was carried out on the territory of the Kostroma, Vologda, Arkhangelsk regions, the Udmurt Republic. The study revealed that quantitative and qualitative forest characteristics correlate with radar survey parameters; the value of this correlation was identified. The obtained results enabled to make study area zoning the according to the standing volume and forest density.
Analysis of Anthropogenic Influence on Desertification Processes in the Northern Caspian Region According to Satellite Data
Authors: Shinkarenko S. S. , Vypritskiy A. A. , Vasilchenko A. A. , Berdengalieva A. N.
Published: April 2024

Pasture loads are one of the key anthropogenic factors in the dynamics of the state of vegetation and soil cover of arid landscapes. The purpose of this study is to establish the spatial distribution of pasture loads in the Black Lands region using remote sensing data from space, geoinformation technologies and statistical data. In this work, mapping of livestock farms, sheepfolds and other places of concentration of livestock for 1984–1986 and 2020 was carried out. Both periods are characterized by a surge in desertification processes and a sharp increase in the areas of open sands and deflated lands. The areas of pastures with different loads during cattle grazing are established, the patterns of spatial distribution of mobile sands depending on the soil-forming rocks and distance from livestock farms are also determined. In recent years, compared with 1984–1986, the density of farms on sandy soils has increased, which led to overgrazing, destruction of vegetation and activation of Aeolian processes. Approximately 80% of pastures exceeded the permissible grazing standards, and 90% of pastures are located in a 3 km zone around the places of concentration of livestock. The results obtained can be used to regulate pasture loads in the region to prevent desertification of landscapes.
Manifestations of Upwellings in the Black Sea in Multisensor Remote Sensing Data
Authors: Khlebnikov D. V. , Ivanov A. Yu. , Evdoshenko M. A. , Klimenko S. K.
Published: April 2024

The paper presents the results of a study of upwelling in the Black Sea in three marine areas: in the northeastern part of the sea, near the Tendrovskaya Spit and the Western Crimea, and off the coast of Turkey. They are based on the use of multi-sensor remote sensing data, namely ocean color scanners (MODIS, VIIRS, OLCI-a and OLCI-b), infrared radiometers (TIRS and AVHRR), as well as synthetic aperture radar (SAR) images acquired by spaceborne SARs. An integrated approach using practically only remote sensing data makes it possible to quite fully characterize the observed upwellings in the sea. In the active phase, upwelling, in addition to sea surface temperature (SST), is usually displayed both in the phytoplankton chlorophyll-a concentration (chlor-a) and in the sea surface roughness on the SAR images. In the analyzed cases, the duration of upwellings varied from 6 to 10 days, the SST differences in the upwelling zone were up to 8°С, and the concentrations of chlor-a were 5–6 times higher than the background values of 0.5–0.7 mg/m3. The maximum SST anomalies, which are about 8°C, were observed off the Turkish coast. As a result of the analysis, a dynamic relationship was revealed between the areas of low SST in the upwelling zone (compared to the sea waters surrounding this zone), sea surface roughness and chlor-a concentration. It is shown that in the case of using the full set of available remote sensing data, the observation, monitoring and study of upwelling does not present any fundamental difficulties.
Response of the Ionosphere to Strong Tropospheric Disturbances
Authors: Shalimov S. L. , Zakharov V. I. , Solov’eva M. S. , Bulatova N. R. , Korkina G. M. , Sigachev P. K.
Published: April 2024

The response of the lower and upper ionosphere to the passage of several powerful typhoons during 2014–2016 years was studied using regional network of VLF radio stations and measurements of electron density disturbances by satellites of the SWARM mission in the Russian Far East. It was found that the disturbances of the amplitude and phase of the VLF signal, as well as the electron density during the active stage of typhoons, correspond to the passage of atmospheric internal gravity waves and their dissipation. A mechanism for the action of internal gravity waves upon the ionosphere is proposed, which allows to interpret the observed variations in the phase of the VLF signal and variations in the electron density in the upper ionosphere.
Features of data processing of the study experiment of proton-proton correlations in the d + 1H → n + p + p reaction
Authors: Mitcuk V. V. , Afonin A. A. , Kasparov A. A. , Lebedev V. M. , Mordovskoy M. V. , Spassky A. V.
Published: April 2024

A method for determining the energy of a singlet quasibound pp-state in the d + 1H → n + p + p reaction is considered. Procedures for obtaining experimental data on the measurement of the pp-scattering length and extracting of the proton-proton state energy from the experimental data using the χ2 minimum method are presented.
Optical-terahertz solitons with tilted wave fronts of system of the Zakharov–Boussinesq type equations
Authors: Sazonov S. V. , Ustinov N. V.
Published: April 2024

The generation of terahertz radiation in a quadratically nonlinear medium by optical pulses with tilted wavefronts is investigated. A system of equations describing this process is derived. Solutions of this system in the form of optical-terahertz solitons are obtained. The possibility of the existence of a new type of solitons—dispersionless solitons is shown.
Interaction of solitary electromagnetic waves in a 2D graphene superlattice
Authors: Babina О. Yu. , Glazov S. Yu. , Fedulov I. N.
Published: April 2024

The mutual influence of solitons propagating along the axes of a two-dimensional graphene superlattice in mutually perpendicular directions has been studied. It is shown that due to the nonadditivity of the energy spectrum of the structure, the overlap region of solitons undergoes characteristic changes associated with the formation of pulses propagating along the fronts of interacting solitary waves.
Dispersion characteristics of oversized travelling wave tubes of the submillimeter wave range
Authors: Rodyakin V. E. , Pikunov V. M. , Aksenov V. N.
Published: April 2024

The possibilities of using oversized slow-wave structures in traveling wave tubes of the submillimeter wave range are investigated. A description of a linear theory developed to analyze the properties of such slow-wave structures is given. The results of the theoretical analysis of the hot dispersion characteristics of oversized diaphragm waveguides at frequencies of 315 and 800 GHz are presented.
Two-dimensional wave motion in a viscous homogeneous liquid
Authors: Ochirov A. A.
Published: April 2024

The propagation of two-dimensional periodic capillary-gravitational waves in a viscous homogeneous liquid with a free surface in the frequency range from \(5 \cdot {{10}^{{ - 2}}}\) to \(5 \cdot {{10}^{4}}\) Hz is investigated. Dispersion relations are obtained, as well as expressions for phase and group velocities for surface waves in physically observable variables. It is shown that there is another class of solutions that is not observed in the ideal fluid model.
Study of magnetic heterostructure MgO/CoFeB/Ta using the harmonic method
Authors: Trushin A. S. , Kichin G. A. , Zvezdin K. A.
Published: April 2024

The heavy metal/ferromagnet type MgO/CoFeB/Ta structure with in-plane magnetization and high spin polarization was studied. We use the adiabatic harmonic Hall voltage method to study the effective damping coefficient and to estimate the values of the effective fields that arise in such structures under the action of a spin-polarized current.
Evolution of magnetic tunnel junction’s modes for different directions of an external magnetic field
Authors: Shkanakina M. D. , Kichin G. A. , Skirdkov P. N. , Putrya M. G. , Zvezdin K. A.
Published: April 2024

We present the investigation of the behavior of magnetic tunnel junction’s (MTJ) modes for the different magnitude and the directions of the external magnetic field by the ST-FMR method. We have found an insensitive mode of MTJ to the direction of the external magnetic field. Using macrospin modeling, we show that the behavior of the uniform mode of a free layer of MTJ is like the insensitive mode.
Mathematical model of the global ionospheric electric field generated by thunderstorms
Authors: Denisenko V. V. , Rycroft M. J. , Harrison R. G.
Published: April 2024

A model is created for the thunderstorm-related ionospheric part of the global electric circuit in January. This current system consists of both mid-latitude currents and equatorial electrojets, day-time and night-time, westward and eastward, up to 120 A. Data on the atmospheric fair weather electric field obtained during Carnegie cruise VII are plotted as a two dimensional map in Universal Time and month coordinates to show both time and seasonal variations.
Spin transport in a volume of a Hall dielectric
Authors: Gorbunov A. V. , Larionov A. V. , Kulik L. V. , Timofeev V. B.
Published: April 2024

A high-aperture optical system is used to visualize the spatial spreading of a dense ensemble of spin cyclotron magnetoexcitons in a quantum Hall dielectric at a filling factor ν = 2 (a state of the integer quantum Hall effect). It has been found that the ability to propagate in a nondiffusive manner over macroscopic distances is inherent not only to excitons with a momentum on the order of the reciprocal magnetic length, which form a coherent magnetoexciton condensate, but also to excitons with momenta close to zero.
Low-temperature properties of a silicon-based sub-THz detector
Authors: Khisameeva A. R. , Shchepetilnikov A. V. , Fedotova Ya. V. , Dremin A. A. , Kukushkin I. V.
Published: April 2024

Characteristics of the silicon-based sub-THz plasmon detector were studied in a wide temperature range, down to the temperature of the liquid nitrogen. Temperature dependences of the detector sensitivity were obtained, and its noise characteristics were studied. The frequency dependence of the sensitivity in the frequency range 70–120 GHz was measured at room temperature, with the maximum of 25 V/W reached at the frequency of 96 GHz. The noise equivalent power of the detector under study was estimated assuming that the main source of noise was of Nyquist nature and varied from a value of 2 · 10–10 W · Hz–1/2 at room temperature down to 2 · 10–11 W · Hz–1/2 at temperature of the liquid nitrogen. Additionally, the volt-ampere characteristics of the sub-THz detector were investigated. It was found that the feature in the differential resistance and sensitivity as a function of the applied DC voltage emerges at the temperature of the liquid nitrogen.
Sub-terahertz polarization converter based on a silicon lattice structure
Authors: Brovko A. M. , Dzhikirba K. R. , Muravev V. M. , Bahteev I. Sh. , Molchanov S. Yu.
Published: April 2024

A single-layer polarizer converting linear polarization into circular one is presented. The polarization converter consists of a lattice structure made of silicon. The polarizer is developed and optimized for the millimeter wave band, for the spectral ‘transmission window’ of 2 mm. The obtained results show that the measured values are in line with the simulation results.
Aptasensors based on track-etched membranes coated with nanostructured silver layer for influenza A and B virus detection
Authors: Kukushkin V. I. , Kristavchuk О. V. , Zhdanov G. А. , Keshek А. К. , Gambaryan А. S. , Andreev Ye. V. , Nechaev A. N. , Zavyalova Е. G.
Published: April 2024

A biosensor based on a polyethylene terephthalate track membrane coated with silver nanoparticles is proposed for the detection of influenza A and B viruses using aptamers for specific sorption of the viruses on the membrane surface, as well as for the introduction of a Raman-active or fluorescent label in the complex. The analytical signal was recorded using a Raman spectrometer, observing the effects of surface-enhancing of the intensity of optical responses from the labels.
Comparison of the low-frequency characteristics of the model solar wind spiral magnetic cloud with observed disturbances
Authors: Barkhatov N. А. , Revunov S. E. , Barkhatova O. M. , Revunova Е. А.
Published: April 2024

We presented the results of a comparison of the analytical study of the features of the radial distribution of MHD disturbances of the magnetic field components in the body of a model solar wind magnetic cloud with data on a real cloud recorded by a spacecraft. The analytical-numerical solution for perturbations is performed in a cylindrical coordinate system for a cloud represented by a force-free cylindrical tube with a helical magnetic field. The obtained general idea of the radial distribution of the magnetic field components in the MC body is consistent with the registered parameters of the magnetic field disturbances on the patrol spacecraft and is confirmed by an objective correlation analysis. Joint post-processing of the counting results and real data compared with them enhances the consistency, which indicates the adequacy of the applied MHD approach to the analysis of oscillations in the model body of the magnetic cloud.
Simulation of current sheet in the Jupiter’s near magnetotail
Authors: Setsko P. V.
Published: April 2024

We considered numerical modeling of the current sheet in the Jupiter’s near magnetotail to estimate the possible range of parameters of this layer depending on the presence of hot sulfur and oxygen ions. The characteristics of the obtained stationary configurations of the current sheet formed by counterflows of either protons alone, or oxygen ions alone, or sulfur ions alone, are in good agreement with the Juno’s data.
Growth of geomagnetic-induced currents during coronal mass ejection and corotating solar wind streams of geomagnetic storms in 2021
Authors: Belakhovsky V. B. , Pilipenko V. A. , Sakharov Ya. A. , Selivanov V. N.
Published: April 2024

We analyzed the growth of geomagnetically induced currents (GIC) recorded in power lines on the Kola Peninsula during two types of magnetic storms: caused by the arrival of a coronal mass ejection (CME) and caused by a high-speed corotating solar wind stream (CIR). The relative efficiency of the CIR of the storm (the ratio of the maximum values of the GIC and the |Dst| index) turned out to be almost 3 times greater than that of the CME of the storm. This is caused by the large contribution of Pi3 geomagnetic pulsations and associated medium-scale vortex current systems in the ionosphere.
Peculiarities of excitation of the Earth–ionosphere waveguide at frequencies above the frequency of the first transverse resonance
Authors: Larchenko A. V. , Lebed O. M. , Pilgaev S. V. , Sidorenko D. I. , Fedorenko Yu. V.
Published: April 2024

Experimental data on the registration of signals from tweek-atmospherics and an ionospheric source formed because of heating of the ionosphere at frequencies higher than the frequency of the first transverse resonance of the Earth–ionosphere waveguide (~1.8 kHz) are considered. It is shown that, far from the source, at frequencies near the resonance, almost complete circular left-hand polarization of the horizontal magnetic field is observed, and the angles of incidence are small and range from 10° to 35°. A joint analysis of observational data and simulation results showed that it is possible to calculate the effective reflection height from estimates of the incidence angle, which can be used to diagnose the lower ionosphere. But, in the case of an ionospheric source, it is important to take into account the inhomogeneity of its radiation pattern.
Model estimation of total electron content calculation error by the method of spaced reception of satellite signals
Authors: Cherniakov S. M.
Published: April 2024

The method for model estimation of the total electron content calculation error in the ionosphere from the data of spaced reception of signals from low Earth orbit satellites was proposed. To estimate the accuracy, a dynamic model of the electron density of the Earth’s ionosphere was used. Model estimations of the errors of the total electron content calculations from calculated model values were received.
Efficiencies of emission excitation and electron density formation in auroras
Authors: Ivanov V. E. , Dashkevich Zh. V. , Yagodkina O. I.
Published: April 2024

It is shown that the efficiencies of excitation of optical emissions λ = 391.4, 557.7, and 630.0 nm and the efficiency of formation of the total electron density weakly depend on the shape of the energy spectrum of precipitating electrons and are mainly determined by the values of the average energy of the electron flux.
Application of various influences to obtain isolated or oriented nanoparticles
Authors: Doludenko I. M. , Khairetdinova D. R. , Zagorsky D. L. , Rizvanova A. , Muslimov A. E. , Kanevsky V. M. , Panina L. V.
Published: April 2024

Heterostructural nanowires with alternating copper and nickel layers were obtained by matrix synthesis, then were cut into cylindrical magnetic nanoparticles of calibrated sizes. For their use in medicine, the tasks of their separation (overcoming agglomeration) and spatial orientation for targeted drug delivery and hyperthermia, respectively, were solved.
Magneto-optical spectroscopy of GaSb–MnSb composites
Authors: Ganshina E. A. , Pripechenkov I. M. , Perova N. N. , Kanazakova E. S. , Oveshnikov L. N. , Jaloliddinzoda M. , Ril’ A. I. , Granovsky A. B. , Aronzon B. A.
Published: April 2024

Polycrystalline samples of (GaSb)100 – x(MnSb)x composites with x = 69.2, 52.0 and 31.7 mol %, MnSb, Mn2Sb compounds were synthesized and their magneto-optical properties in the equatorial (transverse) Kerr effect geometry were studied. The difference of magneto-optical spectra for related compounds MnSb and Mn2Sb is shown. The anomalous temperature behavior of the magneto-optical signal in the composites and MnSb with decreasing temperature is associated with a redistribution of the population of d-states with the opposite spin index.
Investigation of the effect of temperature on the magneto-optical effect of changing the transparency of a magnetic emulsion
Authors: Belykh S. S. , Yerin C. V. , Fursova V. V.
Published: April 2024

The influence of temperature on the effect of changes in the transparency of magnetic emulsions with low interfacial tension in a magnetic field has been studied. A nonmonotonic dependence of the amplitude of the magneto-optical effect with a change in the temperature of the test sample is found.
Features of thermal expansion in substitution alloys based on heavy rare-earth metals \({\mathbf{R}}_{{{\mathbf{1}} - x}}^{{\mathbf{I}}}{\mathbf{R}}_{x}^{{{\mathbf{II}}}}{\mathbf{F}}{{{\mathbf{e}}}_{{\mathbf{2}}}}\)
Authors: Umkhaeva Z. S. , Tereshina I. S. , Pankratov N. Yu. , Aliev I. M. , Khomenko M. R.
Published: April 2024

We consider the features of the behavior of thermal expansion and magnetostriction in magnetically ordered substitutive alloys based on heavy rare earth metals, namely: TbFe2, Tb0.8Zr0.2Fe2, Tb0.8Sm0.2Fe2 and Gd0.8Sm0.2Fe2. It is found that the of thermal expansion anomalies observed in alloys are mainly due to the competition of exchange interactions. In TbFe2 and Tb0.8Zr0.2Fe2 alloys invar-type features are observed in a wide temperature range.
Dynamics of multiphase magnetic fluid systems in microchannels of different shapes in a nonhomogeneous magnetic field
Authors: Ryapolov P. A. , Sokolov E. A. , Shel’deshova E. V. , Kalyuzhnaya D. A. , Vasilyeva A. O.
Published: April 2024

We presented the results of a study of the dynamics of gas bubbles injected into a ferrofluid under the influence of an inhomogeneous magnetic field in microchannels of five configurations. The dependences of bubble sizes on the configuration of the magnetic field and the physical properties of the magnetic fluid are obtained. The results obtained can be used in gas meters and dispensers in microfluidics.
Materials based on RCo2 and RMnSi for solid-state magnetic cooling
Authors: Tereshina I. S. , Ovchenkova I. A. , Politova G. A. , Pankratov N. Yu.
Published: April 2024

The aim of the work was to create highly efficient materials for solid-state magnetic cooling at temperatures below room temperature (120–280 K). For this, new (R,R')(Co,T)2 and R(Mn,T)Si (T = Fe, Co, Al) compounds with a noticeable magnetocaloric effect (MCE) in the Curie temperature region were investigated. The main regularities of the behavior of the MCE depending on the composition are revealed.
Formation of skyrmions in thin CoPt films with an atomic force microscope probe
Authors: Temiryazev A. G. , Zdoroveishchev A. V. , Temiryazeva M. P.
Published: April 2024

Methods of magnetic force microscopy have been developed that make it possible to visualize the evolution of the domain structure when scanning a sample with a magnetic probe. These methods were used to study the processes of formation of skyrmions in thin CoPt films, a characteristic feature of which is the presence of the Dzyaloshinskii–Moriya interaction. A change in the position, shape, and size of skyrmions under the action of a spatially inhomogeneous magnetic field of the probe has been experimentally demonstrated.
The magnetostriction in garnet ferrite Y1.8Bi1.2Fe3.5Ga1.5O12 synthesizing by the modified method of gel combustion using ethylene glycol
Authors: Zelenov F. V. , Tarasenko T. N. , Kovalev O. E. , Kravchenko Z. F. , Burkhovetskii V. V. , Mikhaylov V. I. , Golovchan A. V.
Published: April 2024

The temperature dependence of the magnetostriction constant of yttrium–bismuth iron garnet with Fe3+ ions replaced by Ga3+ has been studied. The description of the improved technology for the synthesis of bulk samples, the results of X-ray diffraction analysis and the study of the microstructure are given. A change in the sign of the magnetostriction constant versus temperature, which is associated with a spin-orientation transition, is found.
Competitive effects of substitutions in La1 – xSrxMn0.9(MgyGez)0.1O3 + γ system
Authors: Badelin A. G. , Derzhavin I. M. , Karpasyuk V. K. , Estemirova S. Kh.
Published: April 2024

Structural, magnetic, and electrical characteristics of La1 – xSrxMn0.90(Mg0.5Ge0.5)0.10O3 + γ (0.15 x 0.30, γ = 0, γ 0) and La0.91Sr0.09Mn0.90Mg0.10O3, La0.71Sr0.29Mn0.90Ge0.10O3 manganites are investigated and compared. Comparison of the properties of manganites having identical summary concentrations of substituents for manganese and equivalent concentrations of Mn4+, Mn3+ ions revealed several competing effects caused by Sr2+(4p6), Mg2+(2p6), Ge4+(3d10) ions and oxygen.