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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kovel E. S., Sachkova A. S., Vnukova N. G., Churilov G. N., Knyazeva E. M., Kudryasheva N. S.
Заглавие : Antioxidant Activity and Toxicity of Fullerenols via Bioluminescence Signaling: Role of Oxygen Substituents
Место публикации : Int. J. Mol. Sci. - 2019. - Vol. 20, Is. 9. - Ст.2324. - ISSN 14220067 (ISSN) , DOI 10.3390/ijms20092324
Примечания : Cited References: 74. - This work was supported by PRAN-32, Program: 'Nanostructures: physics, chemistry, biology, technological basis'; RFBR 18-29-19003; RFBR-Krasnoyarsk Regional Foundation 18-44-240004, Tomsk Polytechnic University CE Program.
Аннотация: Fullerenols are nanosized water-soluble polyhydroxylated derivatives of fullerenes, a specific allotropic form of carbon, bioactive compounds, and perspective basis for drug development. Our paper analyzes the antioxidant activity and toxicity of a series of fullerenols with different number of oxygen substituents. Two groups of fullerenols were under investigation: (1) C60Oy(OH)(x), C60,70Oy(OH)(x), where x+y = 24-28 and (2) C60,70Oy(OH)(x), Fe0,5C60Oy(OH)(x), Gd@C82Oy(OH)(x), where x+y = 40-42. Bioluminescent cellular and enzymatic assays (luminous marine bacteria and their enzymatic reactions, respectively) were applied to monitor toxicity in the model fullerenol solutions and bioluminescence was applied as a signaling physiological parameter. The inhibiting concentrations of the fullerenols were determined, revealing the fullerenols' toxic effects. Antioxidant fullerenol' ability was studied in solutions of model oxidizer, 1,4-benzoquinone, and detoxification coefficients of general and oxidative types (D-GT and D-OxT) were calculated. All fullerenols produced toxic effect at high concentrations (0.01 g L-1), while their antioxidant activity was demonstrated at low and ultralow concentrations (0.001 g L-1). Quantitative toxic and antioxidant characteristics of the fullerenols (effective concentrations, concentration ranges, D-GT, and D-OxT) were found to depend on the number of oxygen substituents. Lower toxicity and higher antioxidant activity were determined in solutions of fullerenols with fewer oxygen substituents (x+y ⋍ 24-28). The differences in fullerenol properties were attributed to their catalytic activity due to reversible electron acceptance, radical trapping, and balance of reactive oxygen species in aqueous solutions. The results provide pharmaceutical sciences with a basis for selection of carbon nanoparticles with appropriate toxic and antioxidant characteristics. Based on the results, we recommend, to reduce the toxicity of prospective endohedral gadolinium-fullerenol preparations Gd@C82Oy(OH)(x), decreasing the number of oxygen groups to x+y ⋍ 24-28. The potential of bioluminescence methods to compare toxic and antioxidant characteristics of carbon nanostructures were demonstrated.
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2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Solovyov L. A., Golovnev N. N., Molokeev M. S., Lesnikov M. K.
Заглавие : Bis(μ3-barbiturato−O,O,O′)-(μ2-aqua)- aqua-barium(II): crystal structure, spectroscopic and thermal properties
Место публикации : J. Coord. Chem.: Taylor & Francis, 2017. - Vol. 70, Is. 12. - P.1984-1993. - ISSN 00958972 (ISSN), DOI 10.1080/00958972.2017.1319943
Примечания : Cited References: 21
Ключевые слова (''Своб.индексиров.''): barbituric acid--barium--coordination compound--x-ray diffraction--infrared spectroscopy--thermal analysis
Аннотация: A polymeric coordination compound, [Ba(H2O) 2(Hba)2] (1) (H2ba – barbituric acid, C4H4N2O3), was obtained. The structure of 1 was solved using powder X-ray diffraction methods. The Ba2+ ion in 1 formed a three-capped trigonal prism. The BaO9 polyhedra, connected with each other by the edges and faces, formed a chain. Several 4- and 12-membered cycles due to the bridging μ2-H2O and bridging μ3-Hba– also formed implementing a 3-D polymer structure. The structures of 1 and other thiobarbiturate complexes were compared. The replacement of a S atom by an O atom in the heterocyclic ligand Htba− (thiobarbiturate ion) of the compound Ba(H2O)2(Htba)2 resulted in changes of the coordination number Ba(II) and supramolecular structure. The intermolecular hydrogen bonds O–H⋯O and N–H⋯O formed a 3-D net where pronounced 2-D layers of Hba– ions could be found. A new topological net in 1 was observed. The IR and thermal stability were investigated.
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3.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kov V. V., Zlotnikov A. O.
Заглавие : Coexistence of superconductivity and antiferromagnetism in heavy-fermion intermetallic compound CeRhIn5
Место публикации : J. Supercond. Nov. Magn. - 2013. - Vol. 26, Is. 9. - P.2885-2886. - ISSN 1557-1939, DOI 10.1007/s10948-013-2222-4
Ключевые слова (''Своб.индексиров.''): coexistence superconductivity antiferromagnetism--heavy-fermion systems--periodic anderson model
Аннотация: An interference of heavy-fermion superconductivity (SC) and antiferromagnetism (AFM) has been studied in the framework of the periodic Anderson model with the superexchange interaction between localized electrons. It has been shown that pressure-induced energy change of the localized states leads to modifying antiferromagnetic and superconducting order parameters. Conditions have been found for the coexistence of SC and AFM in the model. Theoretical results of the pressure effects on the ground state character of the heavy-fermion systems are in good agreement with experimental data for a rare-earth intermetallic compound CeRhIn5. The divergence of the effective electron mass produced by suppressing the long-range antiferromagnetic order has also been analyzed in the same framework. В© 2013 Springer Science+Business Media New York.
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Boehm M., Roessli B., Schefer J., Ouladdiaf B., Kulda J., Petrakovskii G. A.
Заглавие : Coexisting 1D and 3D magnetic interactions in the insulating copper-oxygen compound CuB2O4
Разночтения заглавия :авие SCOPUS: Coexisting 1D and 3D magnetic interactions in the insulating copper-oxygen compound CuB2 O4
Место публикации : Physica B: ELSEVIER SCIENCE BV, 2006. - Vol. 378-80: International Conference on Strongly Correlated Electron Systems (SECES 05) (JUL 26-30, 2005, Vienna, AUSTRIA). - P1128-1129. - ISSN 0921-4526, DOI 10.1016/j.physb.2006.01.540
Примечания : Cited References: 8
Предметные рубрики: SPIN-WAVE SPECTRUM
PHASE 10 K
METABORATE
Ключевые слова (''Своб.индексиров.''): cuprates--magnetic soliton lattice--heisenberg exchange--low-dimensional excitations--cuprates--heisenberg exchange--low-dimensional excitations--magnetic soliton lattice--dispersions--insulating materials--magnetic properties--neutron scattering--positive ions--cuprates--heisenberg exchange--low-dimensional excitations--magnetic soliton lattice--copper compounds
Аннотация: We performed inelastic neutron scattering measurements on CuB2O4 with a magnetic field applied in the tetragonal basal plane. The spin dynamics in this cuprate is determined by the interplay of two magnetic Cu2+ subsystems, the magnetic cage with predominant 3d Heisenberg exchange and quasi Id zig-zag chains. The comparison of the dispersion spectra along the chain direction in zero field and under applied field suggests a decoupling of the two magnetic sublattices under field. (c) 2006 Elsevier B.V. All rights reserved.
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Klauss H. H., Luetkens H., Klingeler R., Hess C., Litterst F. J., Kraken M., Korshunov M. M., Eremin I., Drechsler S. L., Khasanov R., Amato A., Hamann-Borrero J. E., Leps N., Kondrat A., Behr G., Werner J., Buchner B.
Заглавие : Commensurate spin density wave in LaFeAsO: A local probe study
Место публикации : Phys. Rev. Lett.: AMER PHYSICAL SOC, 2008. - Vol. 101, Is. 7. - Ст.77005. - ISSN 0031-9007, DOI 10.1103/PhysRevLett.101.077005
Примечания : Cited References: 28
Предметные рубрики: LAYERED QUATERNARY COMPOUND
SUPERCONDUCTIVITY
Ключевые слова (''Своб.индексиров.''): arsenic compounds--chlorine compounds--ferromagnetism--magnetic materials--magnetic properties--magnetization--magnets--molybdenum--phase transitions--spin density waves--commensurate spin density wave--external fields--magnetic orders--muon spin relaxations--order parameter--ordered moments--probe measurements--ssbauer spectroscopy--structural phase transition--sublattice magnetizations--temperature dependences--spin dynamics
Аннотация: We present a detailed study on the magnetic order in the undoped mother compound LaFeAsO of the recently discovered Fe-based superconductor LaFeAsO(1-x)F(x). In particular, we present local probe measurements of the magnetic properties of LaFeAsO by means of (57)Fe Mossbauer spectroscopy and muon-spin relaxation in zero external field along with magnetization and resistivity studies. These experiments prove a commensurate static magnetic order with a strongly reduced ordered moment of 0.25(5)mu(B) at the iron site below T(N)=138 K, well separated from a structural phase transition at T(S)=156 K. The temperature dependence of the sublattice magnetization is determined and compared to theory. Using a four-band spin density wave model both, the size of the order parameter and the quick saturation below T(N) are reproduced.
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Vasilovskaya V. G., Tsifrinovich V. I.
Заглавие : Compound echo produced by an incoherent sequence of paired pulses
Место публикации : Fiz. Tverd. Tela. - 1992. - Vol. 34, Is. 7. - P.2200-2203. - ISSN 0367-3294
Примечания : Cited References: 7
Предметные рубрики: SUPERPOSITION
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7.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kirenskii L. V., Pynko V. G., Obrastsova L. M.
Заглавие : Domain structure of double layer single crystal films of iron
Место публикации : Czech. J. Phys. - 1971. - Vol. B21, no. 4-5. - P.513-515. - ISSN 0011-4626
Предметные рубрики: SPIN-PEIERLS TRANSITION
COMPOUND CUGEO3
SYSTEM CUGEO3
STATE
Аннотация: The magnetostriction of CuGcO(3) single crystals has been measured in the temperature range from 5 to 16 K in magnetic fields up to 12 T. Giant values of the magnetostrictive strains along the b-axis is observed near the phase transition from the dimerized phase to the high field magnetic phase. The field induced magnetostriction in the antiferromagnetic phase is considerably smaller than in the dimerized phase.
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8.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Wu, Po-Chang, Chen, Hsin-Li, Rudakova, Natalya V., Timofeev I. V., Zyryanov V. Ya., Lee, Wei
Заглавие : Electro-optical and dielectric properties of polymer-stabilized blue phase liquid crystal impregnated with a fluorine-containing compound
Коллективы : Ministry of Science and Technology, Taiwan [104-2112-M-009-008-MY3, 106-2923-M-009-002-MY3]; Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Region Science and Technology Support Fund [16-42-240704, 17-42-240464]
Место публикации : J. Mol. Liq. - 2018. - Vol. 267. - P.138-143. - ISSN 0167-7322, DOI 10.1016/j.molliq.2017.12.062. - ISSN 1873-3166(eISSN)
Примечания : Cited References: 47. - The authors are indebted to Prof. Mon-Juan Lee of Chang-Jung Christian University for valuable discussions on photopolymerization. This work was financially supported by the Ministry of Science and Technology, Taiwan, through Grant Nos. 104-2112-M-009-008-MY3 and 106-2923-M-009-002-MY3, and by the Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Region Science and Technology Support Fund to the research projects 16-42-240704 and 17-42-240464.
Предметные рубрики: HYSTERESIS
TEMPERATURE
MONOMERS
Ключевые слова (''Своб.индексиров.''): polymer-stabilized blue phase--liquid crystal--fluorine-containing--compound--operating voltage--ionic effect
Аннотация: The effects of a fluorine-containing compound (4,4′-difluorobenzophenone; DF) on the electro-optical and dielectric properties of polymer-stabilized blue phase (PSBP) liquid crystals were investigated. When a PSBP cell was driven by an in-plane electric field, the addition of DF up to 2.7 wt% effectively reduced the operation voltage by ~ 30%. Further inspection by dielectric spectroscopy indicated that the ionic concentration in PSBP decreased with increasing loading of DF. This finding can be ascribed to the complexation of impurity ions near the ketone group and carbon–fluorine bonds of the DF compound that restrained the ion transport after photopolymerization. As a result, the DF compound can be regarded as a superior ion-suppressor, enabling the reduction in the ionic effect and, in turn, the promotion of the electro-optical response of a PSBP.
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Voronov V. N., Petrakovskaya E. A., Alexandrovskaya A. V.
Заглавие : EPR Study of Solid Solutions Based on the Compound ScF3
Место публикации : Functional Materials. - 2010. - Vol. 17, Is. 3. - С. 324-328
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10.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Voronov V.N., Petrakovskaya E.A., Alexandrovskaya A.V.
Заглавие : EPR study of solid solutions, based on the compound ScF3
Коллективы : "Functional Materials", International Conference
Место публикации : International Conference "Functional Materials" (ICFM-09): book of abstracts : october 5-10, Ukraine, Crimea, Partenit. - 2009. - С. 61
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aplesnin S. S.
Заглавие : Existence of massive singlet excitations in an antiferromagnetic alternating chain with S=1/2
Место публикации : Phys. Rev. B: AMERICAN PHYSICAL SOC, 2000. - Vol. 61, Is. 10. - P6780-6784. - ISSN 1098-0121, DOI 10.1103/PhysRevB.61.6780
Примечания : Cited References: 26
Предметные рубрики: PEIERLS COMPOUND CUGEO3
SPIN SYSTEMS
TRANSITION
Аннотация: The one-dimensional Heisenberg model with alternating antiferromagnetic bond and spin-1/2 has been studied by the Monte Carlo method. The thermodynamic characteristics, spin-spin, and four spin-correlation function have been calculated. From several maxima of the correlation radius of the four spin-correlation function and sharp slopes of the dimer order parameter, a longitudinal component of the total spin square as a function of temperature and magnetic field, the existence of two mass singlet excitation branches with Delta S-z=0 and one triplet with Delta S-z=1 is suggested. Critical temperatures and fields related to singlet filled bands have been estimated. From these results low-temperature (TT-SP) properties of spin-Peierls (SP) compounds CuGeO3 and NaV2O5 have been explained.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Matsumoto Y., Sakai S., Entani S., Naramoto H., Avramov P., Takagi Y., Nakagawa T., Yokoyama T.
Заглавие : Ferromagnetic interlayer coupling in C60-Co compound/Ni bilayer structure
Место публикации : Chemical Physics Letters. - 2011. - Т. 511, № 1-3. - P.68-72. - ISSN 0009-2614, DOI 10.1016/j.cplett.2011.05.038. - ISSN 1873-4448(eissn)
РИНЦ
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Golovnev N. N., Molokeev M. S., Lesnikov M. K., Atuchin V. V.
Заглавие : First outer-sphere 1,3-diethyl-2-thiobarbituric compounds [M(H2O)6](1,3-diethyl-2-thiobarbiturate)2·2H2O (M = Co2+, Ni2+): Crystal structure, spectroscopic and thermal properties
Место публикации : Chem. Phys. Lett.: Elsevier, 2016. - Vol. 653. - P.54-59. - ISSN 00092614 (ISSN), DOI 10.1016/j.cplett.2016.04.059
Примечания : Cited References: 50. - The study was carried out within the public task of the Ministry of Education and Science of the Russian Federation for research engineering of the Siberian Federal University in 2015-2016. V.V. A. is grateful to the Ministry of Education and Science of the Russian Federation for the financial support of the investigation. X-ray data were obtained with use the analytical equipment of Krasnoyarsk Center of collective use of SB RAS.
Предметные рубрики: Thiobarbituric acid complexes
Transition-metal-complexes; 2-thiobarbituric acid; hydrogen-bond
2-thiobarbituric acid
Hydrogen-bond
Chemistry
Transformation
Diffraction
Ligand
Series
Copper
Ключевые слова (''Своб.индексиров.''): 1,3-diethyl-2-thiobarbituric acid--nickel(ii)--cobalt(ii)--coordination compound--x-ray diffraction--infrared spectroscopy--thermal analysis
Аннотация: Two new d-element compounds, [Co(H2O)6](Detba)2·2H2O (1) and [Ni(H2O)6](Detba)2·2H2O (2) (HDetba - 1,3-diethyl-2-thiobarbituric acid) were synthesized and characterized by single-crystal and powder X-ray diffraction analysis, TG-DSC and FT-IR. Structural analysis revealed that (1) and (2) are discrete structures, in which M2+ ion (M = Co, Ni) is six-coordinated by water molecules and it forms an octahedron. The outer-sphere Detba- ions and H2O molecules participate in O-H?(O/S) intermolecular hydrogen bonds which form the 2D layer. Thermal decomposition includes the stage of dehydration and the following stage of oxidation of Detba- with a release of CO2, SO2, H2O, NH3 and isocyanate gases. © 2016 Elsevier B.V. All rights reserved.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bykova L. E., Zharkov S. M., Myagkov V. G., Balashov Yu. Yu., Patrin G. S.
Заглавие : Formation of Cu6Sn5 intermetallic in Cu/Sn thin films
Место публикации : Phys. Solid State. - 2022. - Vol. 64, Is. 14. - P.2414-2418. - ISSN 10637834 (ISSN), DOI 10.21883/PSS.2022.14.54350.139. - ISSN 10906460 (eISSN)
Примечания : Cited References: 16. - This research was supported financially by the Russian Foundation for Basic Research (grant No. 19-43-240003). Electron microscopic studies were carried out at the Krasnoyarsk Regional Research Equipment Sharing Center of the Federal Research Center Krasnoyarsk Scientific Center of the Siberian Branch of the Russian Academy of Sciences and the Electron Microscopy Laboratory of the Research Equipment Sharing Center of the Siberian Federal University, supported under the state assignment of the Ministry of Science and Higher Education of the Russian Federation (scientific topic code FSRZ-2020-0011)
Аннотация: The study of the formation of the Cu6Sn5 intermetallic compound in Sn(55 nm)/Cu(30 nm) thin bilayer films was carried out directly in the column of a transmission electron microscope (electron diffraction mode) by heating the film sample from room temperature to 300oC and recording the electron diffraction patterns. The thin films formed as a result of a solid state reaction were monophase and consisted of the η-Cu6Sn5 hexagonal phase. The temperature range for the formation of the η-Cu6Sn5 phase was determined. The estimate of the effective interdiffusion coefficient of the reaction suggests that the main mechanism for the formation of the Cu6Sn5 intermetallic is diffusion along the grain boundaries and dislocations.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gladczuk L., Szymczak R., Nabialck A., Krynetskii I., Petrakovskii G. A., Sablina K. A., Vorotynov A. M., Szymczak H.
Заглавие : Giant magnetostriction of CuGeO3
Коллективы : International Conference on Low Temperature Physics
Место публикации : Czech. J. Phys. - 1996. - Vol. 46. - P.1969-1970. - ISSN 0011-4626, DOI 10.1007/BF02570976
Примечания : Cited References: 10
Предметные рубрики: SPIN-PEIERLS TRANSITION
COMPOUND CUGEO3
SYSTEM CUGEO3
STATE
Аннотация: The magnetostriction of CuGcO(3) single crystals has been measured in the temperature range from 5 to 16 K in magnetic fields up to 12 T. Giant values of the magnetostrictive strains along the b-axis is observed near the phase transition from the dimerized phase to the high field magnetic phase. The field induced magnetostriction in the antiferromagnetic phase is considerably smaller than in the dimerized phase.
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16.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Gorev M.V., Flerov I.N., Kartashev A.V.
Заглавие : Guillemet-Fritsch S. Thermal expansion study of CaCu3Ti4012 compound in temperature range 150-200 К
Коллективы : European Meeting on Ferroelectricity
Место публикации : 12th European Meeting on Ferroelectricity: Abstracts. - 2011. - Ст.P9-1
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gorev M. V., Flerov I. N., Bondarev V. S., Sciau P., Lehmann A. G.
Заглавие : Heat capacity of the PbFe1/2Ta1/2O3 perovskite-like compound
Разночтения заглавия :авие SCOPUS: Heat Capacity of the PbFe1/2Ta1/2O3 Perovskite-Like Compound
Место публикации : Phys. Solid State: AMER INST PHYSICS, 2004. - Vol. 46, Is. 3. - P521-525. - ISSN 1063-7834, DOI 10.1134/1.1687872
Примечания : Cited References: 26
Предметные рубрики: SINGLE-CRYSTALS
PBFE0.5TA0.5O3
FERROELECTRICS
DIFFRACTION
NIOBATE
GROWTH
Аннотация: The heat capacity C-p(T) of the complex perovskite PbFe1/2Ta1/2O3 has been studied using adiabatic calorimetry in the temperature range 150-370 K. Three diffuse anomalies in C-p(T) are found to exist at temperatures T-d approximate to 350 K, T-m approximate to 250-300 K, and T-c approximate to 205 K. The anomalous and the lattice contribution to the heat capacity are separated, and the change in the entropy is determined. The results of the study are discussed jointly with the data on the structure and physical properties of the compound. (C) 2004 MAIK "Nauka / Interperiodica".
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Golovnev N. N., Molokeev M. S., Sterkhova, Irina V., Atuchin V. V., Sidorenko, Maxim Y.
Заглавие : Hydrates [Na2(H2O)x](2-thiobarbiturate)2 (x = 3, 4, 5): crystal structure, spectroscopic and thermal properties
Коллективы : Ministry of Education and Science of the Russian Federation [3049]
Место публикации : J. Coord. Chem.: Taylor & Francis, 2016. - Vol. 69, Is. 21. - P.3219-3230. - ISSN 0095-8972, DOI 10.1080/00958972.2016.1228914. - ISSN 1029-0389(eISSN)
Примечания : Cited References:33. - This work was supported by the the Ministry of Education and Science of the Russian Federation for research engineering of the Siberian Federal University [grant number 3049].
Предметные рубрики: 2-THIOBARBITURIC ACID
COMPLEXES
1,3-DIETHYL-2-THIOBARBITURATE
TRANSFORMATION
CESIUM
Na
Li
Ключевые слова (''Своб.индексиров.''): 2-thiobarbituric acid--sodium--coordination compound--x-ray diffraction--infrared spectroscopy--thermal analysis
Аннотация: The hydrates [Na2(H2O)3(Htba)2] (1) and [Na2(H2O)4(Htba)2] (2), where H2tba is 2-thiobarbituric acid, were obtained under different thermal conditions from aqueous solutions and were structurally characterized. The molecular and supramolecular structures were compared to the known structure of [Na2(H2O)5(Htba)2] (3). In polymeric 1–3, the Htba− ions are linked to Na+ through O and S forming octahedra. The decrease of the number of coordination water molecules led to an increase of the total number of bridge ligands (μ2-H2O, Htba−) and a change of the Htba− coordination. These factors induced higher distortion of the octahedra. It was assumed that hydrates, with a different number of coordinated water molecules, are more probable when the central metal has weaker bonds with O water molecules and with other ligands. The net topologies of 1–3 were compared. Thermal decomposition and IR spectra were analyzed for 1 and 2.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Wang X., Li J. -G., Molokeev M. S., Wang X., Liu W., Zhu Q., Tanaka H., Suzuta K., Kim B. -N., Sakka Y.
Заглавие : Hydrothermal crystallization of a Ln2(OH)4SO4·nH2O layered compound for a wide range of Ln (Ln = La-Dy), thermolysis, and facile transformation into oxysulfate and oxysulfide phosphors
Место публикации : RSC Adv.: Royal Society of Chemistry, 2017. - Vol. 7, Is. 22. - P.13331-13339. - ISSN 20462069 (ISSN), DOI 10.1039/c7ra00645d
Примечания : Cited References: 54. - This work was partly supported by the National Natural Science Foundation of China (Grants No. 51672039, 51172038, and 51302032), the Fundamental Research Fund for the Central Universities (Grant No. N140204002), the Grants-in-Aid for Scientific Research (KAKENHI No. 26420686), and the Russian Foundation for Basic Research (15-52-53080). Xuejiao Wang acknowledges the financial support received from the China Scholarship Council for her overseas Ph. D. study at the National Institute of Materials Science (Contract No. 201406080035).
Ключевые слова (''Своб.индексиров.''): dysprosium--hydrothermal synthesis--light emission--phase structure--phosphors--rare earth elements--acceleration voltages--chemical compositions--electron beam irradiation--hydrothermal conditions--hydrothermal crystallization--lanthanide contraction--photoluminescence properties--structure refinements--dysprosium compounds
Аннотация: The synthesis of a layered Ln2(OH)4SO4·nH2O material (Ln-241) with a smaller lanthanide ion (Dy3+) was successfully achieved through the optimization of the hydrothermal conditions, and the effect of lanthanide contraction on the chemical composition, phase structure, and crystallite/particle morphology of the products was investigated and discussed. Structure refinement showed that the lattice parameters (a, b, and c), cell volume, and axis angle across the series (Ln = La-Dy) monotonously decrease as the size of Ln3+ decreases. Comparative TG/DTA analysis in air indicated that the dehydroxylation temperature of Ln-241 tends to increase, whereas the dehydration and desulfurization temperatures decrease as the size of Ln3+ decreases, thus narrowing the stable temperature range for Ln2O2SO4. Taking advantage of the fact that Ln-241 has exactly the same Ln/S molar ratio as Ln2O2SO4 and Ln2O2S, the latter two groups of important compounds (excluding Ce) were facilely transformed from the former via the removal of water by calcination. The photoluminescence properties of Eu3+ and Tb3+, in terms of excitation, emission, fluorescence decay, quantum yield, and emission color, were investigated and compared for the two hosts Gd2O2S and Gd2O2SO4, and the (Gd0.99Tb0.01)2O2S phosphor was shown to be stable under electron beam irradiation in the studied range and exhibited an increasingly higher emission brightness as the acceleration voltage (up to 7 kV) or beam current (up to 50 μA) increased.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Golovnev N. N., Molokeev M. S., Samoilo A. S., Atuchin V. V.
Заглавие : Influence of alkyl substituents in 1,3-diethyl-2-thiobarbituric acid on the coordination environment in M(H2O)2(1,3-diethyl-2-thiobarbiturate)2 M = Ca2+, Sr2+
Место публикации : J. Coord. Chem.: Taylor & Francis, 2016. - Vol. 69, Is. 6. - P.957-965. - ISSN 00958972 (ISSN), DOI 10.1080/00958972.2016.1149168
Примечания : Cited References: 42. - The study was carried out within the public task of the Ministry of Education and Science of the Russian Federation for research engineering of the Siberian Federal University in 2015-2016. V.V.A. is grateful to the Ministry of Education and Science of the Russian Federation for the financial support of the investigation.
Предметные рубрики: CRYSTAL-STRUCTURE
2-THIOBARBITURIC ACID
STRUCTURAL-CHARACTERIZATION
THIOBARBITURIC ACID
THERMAL-PROPERTIES
HYDROGEN-BOND
COMPLEXES
DIFFRACTION
NETWORKS
POLYMERS
Ключевые слова (''Своб.индексиров.''): 1,3-diethyl-2-thiobarbituric acid--alkaline earth metals--coordination compound--x-ray diffraction--thermal analysis
Аннотация: Two new isostructural complexes, [Ca(H2O)2(μ2-Detba-O,O′)2]n (1) and [Sr(H2O)2(μ2-Detba-O,O′)2]n (2) (HDetba = 1,3-diethyl-2-thiobarbituric acid), were synthesized and characterized by single-crystal and powder X-ray diffraction analysis, TG-DSC, FT-IR, and emission spectroscopy. The single-crystal X-ray diffraction data revealed that 1 and 2 are polymeric where M2+ (M = Ca, Sr) is a six-coordinate octahedral binding four Detba− ions and two water molecules. The octahedra are linked through bridging Detba− ions forming a 2-D layer. Two intermolecular hydrogen bonds O–H…S in the crystal form a 3-D net. The comparison of M(Detba)2 and M(Htba)2 (H2tba = 2-thiobarbituric acid) structures showed that the coordination number of metals in M(Detba)2 does not exceed six and there are no π–π interactions, unlike compounds with Htba−; Detba− ions are only bridges in HDetba coordination compounds. Thermal decomposition of 1 and 2 includes dehydration, which mainly ends at 200 °C, and organic ligand oxidation at 300–350 °C with a release of CO2, SO2, H2O, NH3, and isocyanate. Upon excitation at 220 nm, 1 and 2 exhibit an intense emission maximum at 557 nm.
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