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Showing papers in "Russian Chemical Bulletin in 2018"


Journal ArticleDOI
TL;DR: In this article, the authors present current data on the methods of synthesis and biological activity of purine-isosteric azolo-annulated 1,2,4-triazines and pyrimidines with a bridgehead nitrogen atom.
Abstract: The review presents current data on the methods of synthesis and biological activity of purine-isosteric azolo-annulated 1,2,4-triazines and pyrimidines with a bridgehead nitrogen atom, which are among the most promising classes of biologically active compounds

69 citations


Journal ArticleDOI
TL;DR: In this article, three metal-organic coordination polymers were obtained, [Mn3(chdc)3-(NMP)2(DMF)2] (1, chdc2) is trans-1,4-cyclohexanedicarboxylate, NMP is N-methylpyrrolidone, DMF is N,N-dimethylformamide), [Zn3 (chdc),3(NMP),2.5]•DMF (3, ur is the urotropine bridging molecules
Abstract: Three new metal-organic coordination polymers were obtained namely, [Mn3(chdc)3-(NMP)2(DMF)2] (1, chdc2– is trans-1,4-cyclohexanedicarboxylate, NMP is N-methylpyrrolidone, DMF is N,N-dimethylformamide), [Zn3(chdc)3(NMP)2]•2NMP (2), and [Zn3(chdc)3(ur)-(DMF)0.5]•DMF (3, ur is the urotropine). The crystal structures of polymers 1, 2, and 3 were determined by single-crystal X-ray crystallography. All three compounds were found to contain a trinuclear secondary building unit {M3(OOC)6}. Coordination polymers 1 and 2 have a layered structure, while polymer 3 has a three-dimensional coordination framework with isolated pores formed due to the presence of urotropine bridging molecules. Compounds 1 and 3 were characterized by IR spectroscopy, thermogravimetric and elemental analysis data, powder X-ray diffraction. Compound 3 was also characterized by UV-Vis diffuse reflectance spectrum.

26 citations


Journal ArticleDOI
TL;DR: Selenium and silver nanobiocomposites were synthesized based on potentially metabolizable for microbes polysaccharides arabinogalactan and starch, as well as based on humic compounds obtained from peloids (therapeutic muds) and brown coals of Mongolia as mentioned in this paper.
Abstract: Selenium and silver nanobiocomposites were synthesized based on potentially metabolizable for microbes polysaccharides arabinogalactan and starch, as well as based on humic compounds obtained from peloids (therapeutic muds) and brown coals of Mongolia. Their influence on the phytopathogenic bacterium Clavibacter michiganensis subsp. sepedonicus was studied. The absence of a negative effect of nanocomposite precursors (arabinogalactan, starch, and humic compounds) on the bacterial growth was demonstrated. All the nanocomposites studied were found to reduce the bacterial growth. Vital dyes were used to reveal that after 24 h of incubation, the examined nanobiocomposites caused changes in the morphology of the cells: the bacteria grew shorter and thicker, which led to their death. The nanoselenium composite in starch and the nanosilver composite in humic substances possessed the greatest effects. The results obtained indicate the presence of bacteriostatic and bactericidal effects in a number of nanocomposites studied.

25 citations


Journal ArticleDOI
TL;DR: In this paper, a model for microporous carbon adsorbents with slit-shaped pores of different widths was developed using numerical and analytical methods, and the isobaric adsorption curves had a maximum the position of which depends on both the structural-energy characteristics of the adsorbent and thermodynamic conditions chosen to operate the adsoreption system.
Abstract: Using numerical and analytical methods, a model for microporous carbon adsorbents with slit-shaped pores of different widths was developed. Such pores are formed during activation procedure by the removal of the hexagonal carbon layers burnt out in a graphite-like crystallites. Dubinin’s theory of volume filling of micropores was used to calculate methane adsorption equilibria on these model adsorbents. Isobaric dependences of methane adsorption on pore width, specific micropore volumes, and the specific surface were plotted in the range of pressures from 1 to 10 MPa. It was found that the isobaric adsorption curves had a maximum the position of which depends on both the structural-energy characteristics of the adsorbent and thermodynamic conditions chosen to operate the adsorption system. As pressure increased, the maximum of adsorption shifts to the porous systems with wider pores and larger micropore volume.

23 citations


Journal ArticleDOI
TL;DR: The review summarizes information on cyclopropane as an independent pharmacophore group and as a fragment for modification of pharmacological activity level of medicines used in practice.
Abstract: The review summarizes information on cyclopropane as an independent pharmacophore group and as a fragment for modification of pharmacological activity level of medicines used in practice. The advantages of a cyclopropane fragment over its bioisosteres are that, on the one hand, this fragment imposes conformational rigidity on the molecules of physiologically active compounds and, on the other hand, the replacement of acyclic terminal and “linker” groups with a cyclopropane fragment increases the metabolic stability of the target structures and extends the scope of their therapeutic action.

22 citations


Journal ArticleDOI
TL;DR: In this paper, a review summarizes the research and development data concerning the design and application of hypergolic rocket propellants involving hydrogen peroxide, starting from the 1930s and up to now.
Abstract: The research towards the development of new propellants aims to ensure not only their high performance, but also high environmental compatibility and low toxicity. Considerable attention is paid to the development of hypergolic propellant compositions, the use of which markedly simplifies the engine design and rocket system operation and provides the possibility of their repeated use. Hydrogen peroxide is a promising and nontoxic oxidant. The review summarizes the research and development data concerning the design and application of hypergolic rocket propellants involving hydrogen peroxide, starting from the 1930s and up to now. The data presented in the review could be useful for specialists engaged in the development of prospective high-performance green fuels.

21 citations


Journal ArticleDOI
TL;DR: The palladium complexes of the Pd-PEPPSI type with N-heterocyclic carbenes of the 1,2,4-triazole series were synthesized in 76-99% yields by the reactions of PdCl2 with 1, 4-di- alkyl-1, 2, 4, 4 triazolium salts in pyridine in the presence of KBr or KI as sources of halide ions and tetrabutylammonium salts as phase transfer catalysts as discussed by the authors.
Abstract: The palladium complexes of the Pd-PEPPSI type with N-heterocyclic carbenes of the 1,2,4-triazole series were synthesized in 76—99% yields by the reactions of PdCl2 with 1,4-di- alkyl-1,2,4-triazolium salts in pyridine in the presence of KBr or KI as sources of halide ions and tetrabutylammonium salts as phase-transfer catalysts. The obtained complexes can be used as efficient catalysts for the Suzuki—Miyaura cross-coupling and are not inferior to the commercially available Pd-PEPPSI catalysts in activity.

19 citations


Journal ArticleDOI
TL;DR: In this paper, surface activity, micelle formation, and solubilization ability towards hydrophobic compounds were estimated for the series of new cationic surfactants belonging to the type of 1-alkyl-1-(2-hydroxyethyl)pyrrolidinium bromides.
Abstract: The surface activity, micelle formation, and solubilization ability towards hydrophobic compounds were estimated for the series of new cationic surfactants belonging to the type of 1-alkyl-1-(2-hydroxyethyl)pyrrolidinium bromides. The presence of 2-hydroxyethyl group in these surfactants leads to the twofold increase in their micelle-forming ability as compared to unsubstituted analogs. The critical micelle concentration for the investigated series of pyrrolidinium surfactants is lower at the same hydrophobicity than that for the analogs belonging to the alkylpyridinium, alkylimidazolium, and alkylmorpholinium types. The data acquired for the studied surfactants on their solubilization ability, antimicrobial activity, and hemolytic efficiency indicate their prospective applications to encapsulate hydrophobic biologically active molecules and as the promising bactericidal agents.

18 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present the analysis and state-of-the-art of research in this area, with or without changes in the chemical composition, and without formation of solid products.
Abstract: The review addresses the special case of mechanical activation of solid-state chemical reactions when the stress field, strain, and defects in crystals are induced by the chemical reaction itself rather than by the external mechanical impact (chemo-mechanochemical (CMC) effect). This review presents the analysis and state-of-the-art of research activities in this area. Different cases of the CMC effect in homogeneous and heterogeneous systems are considered: with or without changes in the chemical composition, with or without formation of solid products, etc.

16 citations


Journal ArticleDOI
TL;DR: In this paper, the diversity of nickel complexes with pincer ligands, as well as the existing methods for their preparation and practical application, are discussed, and a detailed review of the methods and applications of these complexes is presented.
Abstract: Over the past decades, the pincer ligands have attracted an increasing interest due to the unique properties of the coordination compounds they form. These monoanionic tridentate ligands are of great importance in organometallic and coordination chemistry. Their complexes with transition metals are used as homogeneous catalysts for various processes and also as functional materials with specified properties. The metal complexes formed by the pincer ligands provide an efficient alternative to the existing catalysts based on noble metals and, hence, the use of these complexes is a promising task of the modern chemical science. Therefore, nickel as the most accessible and inexpensive analog of palladium and platinum is of great practical interest. In this review, we consider the diversity of nickel complexes with pincer ligands, as well as the existing methods for their preparation and practical application.

15 citations


Journal ArticleDOI
TL;DR: In this paper, an efficient mediated electrosynthesis of nanocomposite Au@р(MVCA8+-co-St) (~6 nm), in which ultrasmall Au nanoparticles (Au-NP) were bound in nanocapsules of water-soluble nanoparticles of tetraviologen calix[4]resorcinol with styrene (St), was accomplished by the reduction of AuI in aqueous medium.
Abstract: Efficient mediated electrosynthesis of nanocomposite Au@р(MVCA8+-co-St) (~6 nm), in which ultrasmall Au nanoparticles (Au-NP) were bound in nanocapsules of water-soluble nanoparticles of соpolymer р(MVCA8+-co-St) of tetraviologen calix[4]resorcinol (MVCA8+) with styrene (St), was accomplished by the reduction of AuI in aqueous medium. The quanti- tative reduction of AuI was carried out using the theoretically necessary amount of electricity and was not accompanied by the deposition of metal on the electrode. Radical cations of viologen units MV•+ of the molecule р(MVCA4•+-co-St) adsorbed on the electrode and π-dimers MV•+···MV•+ of π-polymers [р(MVCA4•+-co-St)] n deposited on the electrode act- ed as the reducing agents with respect to AuI. During electrolysis, the nanoparticles agglo- merated to 37—50 nm. The nanocomposite particles dispersed in ethanol had sizes of 72±16 nm and also contained Au-NP with sizes of 51±8 and 19±3 nm. The catalytic activity of the nanocomposite in the reduction of p-nitrophenol with sodium borohydride was demon- strated. A similar reduction of AgCl nanoparticles (~250 nm) led to the formation of silver nanoparticles with crystallite sizes in the range of 7—11 nm, the process was inefficient, however, even when using 250% of electricity, an incomplete reduction of AgCl was still observed.

Journal ArticleDOI
TL;DR: The localization of the pentaamino acid fullerene derivatives in the region of polar heads and fatty acid chains of the membrane phospholipids was established on the basis of estimation of the equilibrium constants in the WPDF—probe complexes.
Abstract: Regularities of interaction of water-soluble pentaamino acid derivatives of fullerenes (WPDFs) with the lipid bilayer of phosphatidylcholine liposomes were studied using the fluorescent probe method. The studied WPDFs act as quenchers of fluorescence of the hydrophilic probe 2,7-dibromoproflavine in aqueous solutions and in the membranes of phsophatidylcholine liposomes, as well as of the hydrophobic probe pyrene in the phospholipid membrane. The singlet state of the probes is deactivated due to the formation of the long-lived WPDF—probe complex rather than their dynamic interaction. The WPDFs stud- ied were revealed to penetrate into the bilayer membrane of phosphatidylcholine liposomes. The localization of the pentaamino acid fullerene derivatives in the region of polar heads and fatty acid chains of the membrane phospholipids was established on the basis of estimation of the equilibrium constants in the WPDF—probe complexes.

Journal ArticleDOI
TL;DR: In this paper, pyrazines were synthesized by direct transition metal-free C-H functionalization in the pyrazine ring and their photophysical and sensory properties with respect to nitrobenzene and 2,4-dinitrotoluene vapors were studied using a Nitroscan portable detector of nitro-explosive substances.
Abstract: 5-(9-Ethyl-9H-carbazol-3-yl)-substituted 6-(het)aryl[1,2,5]oxadiazolo[3,4-b]pyrazines were synthesized by direct transition metal-free C—H functionalization in the pyrazine ring. Their photophysical and sensory properties with respect to nitrobenzene and 2,4-dinitrotoluene vapors were studied using a Nitroscan portable detector of nitro-explosive substances (Ekaterinburg, Russia).

Journal ArticleDOI
TL;DR: In this paper, the preparation and study of electrochemical properties of a graphite screen-printed electrode (SPE) modified with the GO/Fe3O4@SiO2 (GO is graphene oxide) nanocomposites are described.
Abstract: The preparation and study of electrochemical properties of a graphite screen-printed electrode (SPE) modified with the GO/Fe3O4@SiO2 (GO is graphene oxide) nanocomposites are described. The morphologies of the GO/Fe3O4@SiO2 nanocomposites were examined by scanning electron microscopy. The electrochemical oxidation of vitamin B6 (pyridoxine) on SPE modified with the GO/Fe3O4@SiO2 nanocomposite was investigated by cyclic voltammetry, differential pulse voltammetry, and chronoamperometry. Under optimum conditions (pH 7.0), the vitamin B6 oxidation at the surface of the modified SPE occurs at a potential about 190 mV less positive than that at the unmodified SPE. A linear voltammetric response for vitamin B6 was obtained in the concentration range 1.0•10 6—9.0•10 4 mol L–1 with a detection limit of 5.2•10 7 mol L–1 using differential pulse voltammetry. The developed sensor was also successfully applied for determination of trace level of vitamin B6 in both the standard vitamin B6 sample and biological samples (urine).

Journal ArticleDOI
TL;DR: In this article, the conditions and degree of disaggregation in the presence of solubilizing additives of nonionic surfactants (Tween 80) and biocompatible polymers (polyethylene glycol and polyvinylpyrrolidone) were also investigated.
Abstract: Electronic absorption spectroscopy and fluorescence spectroscopy were used to study conditions for the formation of associates of amphiphilic phorbins and chlorins in an ethanol–water system. The conditions and degree of disaggregation in the presence of solubilizing additives of nonionic surfactants (Tween 80) and biocompatible polymers (polyethylene glycol and polyvinylpyrrolidone) were also investigated. The propensity of the macroheterocycles based on chlorophyll a to association in water-alcoholic solutions decreases on going from covalently bound dimeric structures to monomeric ones, on going from phorbins to chlorins and on accumulating hydrophilic glycol or positively charged alkylammonium fragments in the molecule. Among the considered solubilizers, the nonionic surfactant Tween 80 emerged as the most efficient means for destroying chlorin associates in water–alcohol solutions with a high content of water.

Journal ArticleDOI
TL;DR: In this article, a norbornene type monomer bearing reactive triethoxysilyl group was synthesized, and its addition homo-and copolymerization with 3-trimethylsilyltricyclononon-7-ene was studied.
Abstract: New norbornene type monomer bearing reactive triethoxysilyl group was synthesized, and its addition homo- and copolymerization with 3-trimethylsilyltricyclonon-7-ene was studied. The target monomer was obtained using regio- and stereospecific [2σ+2σ+2π] cyclo-addition of quadricyclane with vinyltrichlorosilane followed by the reaction of the formed cycloadduct with ethanol in the presence of triethylamine. Addition polymerization was investigated over the three-component Pd-containing catalytic system (Pd complex, Na+[B(3,5-(CF3)2C6H3)4]–(cocatalyst) and tricyclohexylphosphine). The N-heterocyclic carbene Pd complex (SIPrPd(cinn)Cl) with high activity and tolerance to the Si—O—C moieties was used as a catalyst. The yields of the homo- and copolymers were 24—68% depending on the monomer (comonomer): Pd: B: PCy3 ratio. The obtained addition polymers are high-molecular-weight amorphous products, the glass transition temperature of which exceeds 300 °C. The presence of reactive Si(OC2H5)3 groups in the homo- and copolymers made it possible to carry out a hard-to-realize cross-linking involving side substituents and followed by the formation of insoluble polymers.

Journal ArticleDOI
TL;DR: Theoretical estimation of the efficiency factors of solid composite propellants whose components are CHNO compounds designed from various combinations of four structural motifs, namely pyrazole and tetrazole rings, nitro group, and trinitromethyl moiety, was performed in this article.
Abstract: Theoretical estimation of the efficiency factors of solid propellants whose components are CHNO compounds designed from various combinations of four structural motifs, namely pyrazole and tetrazole rings, nitro group, and trinitromethyl moiety, was performed. The positional isomerism was shown to have effect on the properties of the compounds and the energy characteristics of solid composite propellants (SCPs) on their basis. The use of these components in metal-free SCP compositions can allow one to achieve a specific impulse of 258–263 s, neither toxic HCl nor condensed products being produced upon their combustion, i.e., they are superior in energy and environmental indices to SCP formulations based on ammonium perchlorate.

Journal ArticleDOI
TL;DR: The heteronuclear complex [Fe4Li2O)2(Piv)10(H2O2] as mentioned in this paper was obtained by refluxing FeIII pivalates with LiI Pivalates in toluene and isolated as the 1•PhCH3 solvate.
Abstract: The heteronuclear complex [Fe4Li2(O)2(Piv)10(H2O)2] (1, Piv is the pivalic acid anion) was obtained by refluxing FeIII pivalates with LiI pivalates in toluene and isolated as the 1•PhCH3 solvate with a toluene molecule. According to X-ray diffraction data, complex 1 contains the {Fe4Li2O2} core. The Mossbauer spectroscopy data indicate that the core comprises para magnetic FeIII ions in the high-spin state located in the symmetric octahedral environment of oxygen atoms. Thermolysis of 1 studied by simultaneous thermal analysis demonstrated thermal stability of the complex up to 225 °С. The main end product of thermolysis at 600 °С is the mixed oxide LiFe5O8.

Journal ArticleDOI
TL;DR: The data on the composition of ester products formed in the Baeyer-Villiger reaction in the liquid phase oxidation of organic compounds with molecular oxygen, on production channel of peroxy acids, as well as on the influence of a carbonyl compound structure on its reactivity in reactions with peroxy acid have been classified and considered as mentioned in this paper.
Abstract: The data on the composition of ester products formed in the Baeyer–Villiger reaction in the liquid-phase oxidation of organic compounds with molecular oxygen, on production channel of peroxy acids, as well as on the influence of a carbonyl compound structure on its reactivity in reactions with peroxy acids have been classified and considered. The Baeyer–Villiger reaction was shown to be the main source of accessory primary alcohol esters and lactones in industrial processes of aerobic oxidation of cyclohexane and paraffin hydrocarbons.

Journal ArticleDOI
TL;DR: In this article, the results of a number of studies on the synthesis and investigation of the homo- and heteroligand iron(II) complexes with tris(3,5-dimethylpyrazol-1-yl)methane derivatives (HC(pz)3) are considered.
Abstract: The studies concerning coordination compounds of various salts of iron(II) with tris(pyrazol-1-yl)methane derivatives (HC(pz)3) are discussed. The results of a number of studies on the synthesis and investigation of the homo- and heteroligand iron(II) complexes with tris(3,5- dimethylpyrazol-1-yl)methane (HC(3,5-Me2pz)3) are considered. The study of the temperature dependence μeff (T) showed that the spin crossover (SCO) 1A1↔5T2 observed in a series of the compounds discussed is accompanied by thermochromism (color change pink (purple) ↔ colorless). Specific features of the SCO and their dependence on the outer-sphere anion in the iron(II) complexes are discussed. The data of the recently published work devoted to the synthesis of the iron(II) complexes with three N-substituted HC(pz)3 derivatives (general formula xL, where x = H, CH2C6H5 (Bn) and p-SO3C6H4CH3 (Ts)) are considered.

Journal ArticleDOI
TL;DR: In this paper, the condensation reactions of β- and γ-amino alcohols containing phenyl or tricarbonylchromium substituent with formaldehyde, acetaldehyde, benzaldehyde, and (η6-benzaldehyde)tricarbony lchromium were studied.
Abstract: The condensation reactions of β- and γ-amino alcohols containing phenyl or (η6-arene) tricarbonylchromium substituent with formaldehyde, acetaldehyde, benzaldehyde, and (η6-benzaldehyde)tricarbonylchromium were studied. The resulting 1,3-oxazolidine and 1,3-oxazinane products were isolated in a pure form and identified by different physicochemical methods. The effect of (η6-arene)tricarbonylchromium moiety on the reaction process was demonstrated.

Journal ArticleDOI
TL;DR: In this paper, N-(2-Azidoethyl)chitosan was synthesized from low-molecular-weight chitosans (molescular weight 37 000 and degree of deacetylation 0.74) in three steps: (1) reaction of CHI with chloroacetaldehyde to form a Schiffbase, (2) reduction of the Schiffbase with sodium borohydride, and (3) treatment of the reduction product with sodium azide.
Abstract: N-(2-Azidoethyl)chitosan was synthesized from low-molecular-weight chitosan (molecular weight 37 000 and degree of deacetylation 0.74) in three steps: (1) reaction of chitosan with chloroacetaldehyde to form a Schiffbase, (2) reduction of the Schiffbase with sodium borohydride, and (3) treatment of the reduction product with sodium azide. The course of the formation of the Schiffbase (this step is determining for the degree of substitution of the final product) was affected by the molar ratio of the reagents, the reaction time, and, primarily, the pH value of the medium. This method for selective to an amino group, does not require harsh conditions, and can be proposed for the azide pre-click modification of chitosan.

Journal ArticleDOI
TL;DR: In this article, the authors studied the hydrogenation of naphthalene and anthracene on Sibunit and active carbon, at a temperature of 280 °C and a pressure of 90 atm.
Abstract: Hydrogenation of naphthalene and anthracene deposited on Sibunit and active carbon was studied. The reactions were carried out at a temperature of 280 °C and a pressure of 90 atm. The directions for the complete hydrogenation of the investigated substrates were studied. Correlations between the structures of naphthalene and anthracene and their activity in hydrogen absorption are presented. The hydrogenation rates decrease as the substrate is saturated with hydrogen.

Journal ArticleDOI
TL;DR: A mixture of allylbromide and diphenylacetonitrile is reduced to afford 2,2-diphenylpentene-4-nitrile as a major product in the presence of catalytic amounts of the magnesium complex.
Abstract: A mixture of allylbromide and diphenylacetonitrile is reduced to afford 2,2-diphenylpentene-4-nitrile as a major product in the presence of catalytic amounts of the magnesium complex (dpp-bian)Mg(thf)3 (dpp-bian is 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene dianion). The overall conversion of nitrile is 71% within 3 h at 85 °С. 4,4-Diphenylbutene-1 and diphenylmethane are by-products in this process. Complexes (dpp-bian)Mg(thf)3 and (dpp-bian)Ca(thf)4 (in an amount of 0.5—5 mol.%) catalyze the intramolecular hydroamination of some aminopentenes and aminohexenes with the conversion from 67 to 99%.

Journal ArticleDOI
TL;DR: In this article, a one-pot synthesis of 2,1,3-benzothiadiazole 1-oxides by the reaction of o-nitroanilines with sulfur monochloride was developed.
Abstract: A convenient one-pot synthesis of nitro derivatives of 2,1,3-benzothiadiazole 1-oxides by the reaction of o-nitroanilines with sulfur monochloride was developed. The structural features of 4-nitrobenzothiadiazole and its N-oxide were considered. High in vitro release of nitric oxide (69%) was found for a 6-nitro-2,1,3-benzothiadiazole sample by the Griess assay, which indicated good prospects for this class of compounds.

Journal ArticleDOI
TL;DR: In this article, the mechanism assuming different routes of the hydride transfer in the key intermediates was proposed, and it was proved by using deuterated reactants that the hydroxide transfer can involve the allyl, norbornenyl, or formyl moieties.
Abstract: Allylation of norbornadiene with allyl formate in the presence of the palladium catalytic systems is characterized by several peculiarities associated with the new reaction route: hydroallylation (reductive allylation) occurs along with the traditional allylation (oxidative allylation). Both processes are considered from the single point of view, and the mechanism assuming different routes of the hydride transfer in the key intermediates was proposed. It was proved by using deuterated reactants that the hydride transfer can involve the allyl, norbornenyl, or formyl moieties. In all cases, the hydrogen atom bound to the carbon atom in the β-position relative to palladium is eliminated in this step.

Journal ArticleDOI
TL;DR: Conjugate of Xymedon with l-ascorbic acid facilitates the decrease in the concentration of a lipid peroxidation product and the activity of superoxide dismutase in liver and serum of laboratory animals exposed to intoxication with a known hepatotropic toxin CCl4.
Abstract: Antiradical activity and antioxidant properties of a conjugate of Xymedon with l-ascorbic acid were studied. In contrast to Xymedon, a conjugate of Xymedon with l-ascorbic acid was found to react with free radicals. Pro-oxidant activity of the conjugate of Xymedon with l-ascorbic acid in a chemiluminescence system is weaker as compared to individual l-ascorbic acid. This is the evidence of the increase in the stability of ascorbic acid upon conjugation with a molecule of Xymedon. Conjugate of Xymedon with l-ascorbic acid facilitates the decrease in the concentration of a lipid peroxidation product (malondialdehyde) and the activity of superoxide dismutase in liver and serum of laboratory animals exposed to intoxication with a known hepatotropic toxin CCl4. This observation shows the contribution of the antioxidant action to the hepatoprotective effect of the studied Xymedon derivative.

Journal ArticleDOI
TL;DR: In this article, the physicochemical properties of nanosized low-temperature modifications of titanium(iv) oxide with the anatase and η-phase (TiO2-x•mH2O) structures were compared.
Abstract: Nanosized low-temperature modifications of titanium(iv) oxide with the anatase and η-phase (TiO2–x•mH2O) structures were prepared by the sulfate method (pH <3) and for the first time characterized by a complex of methods (X-ray diffractometry, scanning electron microscopy, IR spectroscopy, Raman spectroscopy, differential scanning calorimetry, low-temperature sorption capacity of samples to nitrogen, and differentiating dissolution). The physicochemical properties of the modifications were compared. Differences in compositions of the surface and volumes of the samples, compositions and structures of the phases (structure of η-phase is superstructure to anatase), and microstructure elements (sizes of crystallites, nanoparticles, and specific surface area; volume of nano- and ultrananopores) were revealed. The region of η-phase stability was found in the coordinates of temperature (T = 50–95 °C) and hydrolysis duration (τ = 10–80 min) and temperature (T≤200 °C) and annealing duration (τ <6 h). The distinctions in the thermal behavior of the nanosized anatase and η-phase were studied. The photocatalytic activity (PCA) is determined by the physicochemical characteristics of the samples and phases and also by the composition and structure of the decomposed substrate. In the case of difenoxazole, the PCA is affected by the compositions of the samples, phases, and surface (the presence of OH groups) and specific surface area, whereas the composition of the samples and specific surface area affect the PCA in the case of thiamethoxam.

Journal ArticleDOI
TL;DR: Khimicheskaya et al. as discussed by the authors published in Russian in Izvestiya Akademii Nauk, No. 1, pp. 0172-0175, January, 2018.
Abstract: Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 0172—0175, January, 2018.

Journal ArticleDOI
TL;DR: In this paper, the reaction of the hydride [(dpp-bian)Al(H)Cl] (1) containing the 1,2-bis[(2,6-diisopropylphenyl) imino]acenaphthene radical anion with MeLi affords the compound [dpp]-Al(Me)Me] (2).
Abstract: The reaction of the hydride [(dpp-bian)Al(H)Cl] (1) containing the 1,2-bis[(2,6-diisopropylphenyl) imino]acenaphthene (dpp-bian) radical anion with MeLi affords the compound [(dpp-bian)Al(H)Me] (2). The reaction of complex 1 with two equivalents of PhC≡CNa involves the replacement of chlorine along with oxidative substitution of hydrogen accompanied by the reduction of dpp-bian to the dianion to form the compound [(dpp-bian)Al(C≡CPh)2Na(Et2O)2] ({sn3}). This reaction gives the complex [{dpp-bian(H)}Al(C≡CPh)3Na(Et2O)2] (4) as the second product, which is apparently generated in the reaction of compound 3 with PhC≡CH. The reaction of compound 1 with Cp*Na (Cp* is pentamethylcyclopentadiene) in dimethoxyethane is also accompanied by the reduction of redox-active dpp-bian to the dianion, giving the complex [(dpp-bian)Al(H)Cl][Na(DME)3] (5). Diamagnetic derivatives 3–5 were characterized by 1H NMR spectroscopy; paramagnetic compound 2, by EPR spectroscopy. The molecular structures of compounds 2–5 were determined by X-ray diffraction.