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61.
Vadim A. Dubskikh Anna A. Lysova Denis G. Samsonenko Alexander N. Lavrov Konstantin A. Kovalenko Danil N. Dybtsev Vladimir P. Fedin 《Molecules (Basel, Switzerland)》2021,26(5)
Three new 3D metal-organic porous frameworks based on Co(II) and 2,2′-bithiophen-5,5′-dicarboxylate (btdc2−) [Co3(btdc)3(bpy)2]·4DMF, 1; [Co3(btdc)3(pz)(dmf)2]·4DMF·1.5H2O, 2; [Co3(btdc)3(dmf)4]∙2DMF∙2H2O, 3 (bpy = 2,2′-bipyridyl, pz = pyrazine, dmf = N,N-dimethylformamide) were synthesized and structurally characterized. All compounds share the same trinuclear carboxylate building units {Co3(RCOO)6}, connected either by btdc2– ligands (1, 3) or by both btdc2– and pz bridging ligands (2). The permanent porosity of 1 was confirmed by N2, O2, CO, CO2, CH4 adsorption measurements at various temperatures (77 K, 273 K, 298 K), resulted in BET surface area 667 m2⋅g−1 and promising gas separation performance with selectivity factors up to 35.7 for CO2/N2, 45.4 for CO2/O2, 20.8 for CO2/CO, and 4.8 for CO2/CH4. The molar magnetic susceptibilities χp(T) were measured for 1 and 2 in the temperature range 1.77–330 K at magnetic fields up to 10 kOe. The room-temperature values of the effective magnetic moments for compounds 1 and 2 are μeff (300 K) ≈ 4.93 μB. The obtained results confirm the mainly paramagnetic nature of both compounds with some antiferromagnetic interactions at low-temperatures T < 20 K in 2 between the Co(II) cations separated by short pz linkers. Similar conclusions were also derived from the field-depending magnetization data of 1 and 2. 相似文献
62.
I. F. Makarevich S. N. Kovalenko T. D. Gusarova Yu. I. Gubin 《Chemistry of Natural Compounds》2009,45(1):40-44
Twelve compounds including secologanin, loganin, the aglycon of loganin, and a new iridoid called glucologanin were isolated
from fruit of common snowberry Symphoricarpos albus (L.) Blake. The structure of glucologanin was confirmed using PMR and mass spectroscopy and chemical transformations. 2′,3′,4′,6′,7-Penta-O-acetylloganin and 2′,3′,4′,6′-tetra-O-acetylloganin were synthesized.
Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 37–40, January–February, 2009. 相似文献
63.
64.
R. Stanoeva D. A. Artemenkov V. Bradnova S. Vokál L. A. Goncharova P. I. Zarubin I. G. Zarubina N. A. Kachalova A. D. Kovalenko D. O. Krivenkov A. I. Malakhov G. I. Orlova N. G. Peresadko N. G. Polukhina P. A. Rukoyatkin V. V. Rusakova M. Haiduc S. P. Kharlamov M. M. Chernyavsky T. V. Shchedrina 《Physics of Atomic Nuclei》2009,72(4):690-701
Experimental data on fragmentation channels in peripheral interactions of 8B nuclei in nuclear track emulsions are presented. A detailed analysis made it possible to justify selections of events of the electromagnetic-dissociation process 8B → 7Be + p and to estimate its cross section. Events of 10C peripheral dissociation that were observed in the same exposure are described. 相似文献
65.
S. S. Kovalenko 《Ukrainian Mathematical Journal》2012,63(10):1534-1542
We present the group classification of one class of (1 + 3)-dimensional nonlinear boundary-value problems of the Stefan type
that simulate the processes of melting and evaporation of metals. The results obtained are used for the construction of the
exact solution of one boundary-value problem from the class under study. 相似文献
66.
T. N. Pashirova E. A. Burilova S. S. Lukashenko O. A. Lenina V. V. Zobov A. R. Khamatgalimov V. I. Kovalenko L. Ya. Zakharova O. G. Sinyashin 《Russian Journal of General Chemistry》2017,87(12):2832-2837
A new amphiphilic derivative–methoxy(polyethoxy)ethyl stearate has been synthesized with the goal of creating therefrom systems for delivery and enhancement of bioavailability of piperine. The aggregation and solubilizing properties of ω-methylpoly(oxyethylene) stearate have been studied by means of a set of physicochemical methods. 相似文献
67.
V. V. Fimushkin A. S. Belov A. D. Kovalenko L. V. Kutuzova Yu. V. Prokofichev S. S. Shimanskiy V. P. Vadeev 《The European physical journal. Special topics》2008,162(1):275-280
The proposed project assumes the development of a universal high-intensity source of polarized deuterons (protons) using a
charge-exchange plasma ionizer. The design output current of the source will be up to 10mA for ↑ D+(↑ H+) and polarization will be up to 90% of the maximal vector (±1) and tensor (+1,−2) polarization. The project is based on the
equipment which was supplied within the framework of an agreement between JINR and IUCF (Bloomington, USA). The project will
be realized in close cooperation with INR (Moscow, Russia). The source will be installed in the linac hall (LU-20) and polarization
of beams will be measured at the output of LU-20. The main purpose of the project is to increase the intensity of the accelerated
polarized beams at the JINR Accelerator Complex up to 1010 d/pulse. Calculations and first accelerator runs have shown that the depolarization resonances are absent for the deuteron
beam in the entire energy range of the NUCLOTRON. The source could be transformed into a source of polarized negative ions
if necessary. The period of reliable operation without participation of the personnel should be within 1000 hours. The project
should be implemented within two to two and a half years from the start of funding. 相似文献
68.
[reaction: see text] The Bergman cyclization of benzannelated enediynes is highly sensitive to ortho substitution. This finding opens possibilities for the rational design of conformer-specific and pH-dependent DNA-cleaving agents. 相似文献
69.
Popova N. A. Sosnin O. V. Ignatenko L. N. Konovalov S. V. Kovalenko V. V. Ivanov Yu. F. Gromov V. E. Koneva N. A. 《Russian Physics Journal》2002,45(3):319-328
The methods of transmission electron microscopy are used to investigate the structure and phase content of Fe–0.45C–17Mn–3Al steel subjected to multicyclic fatigue tests to failure after intermediate electrostimulation. It is demonstrated that electrostimulation does not change the mechanism of steel failure. An increase in the operating life time of samples after electrostimulation in the intermediate test stage is connected with the hindered -martensitic transformation, the relaxation of stress concentrators, and the reduction of the volume fraction of the critical dislocation (network) substructure in which -martensite is mainly developed. 相似文献
70.
The processes of the irreversible aggregation of chain molecules with various numbers of associating groups are studied by the Monte Carlo method using the Eden model. Three-dimensional lattice systems are considered. The model developed qualitatively reproduces the main structural (morphological) characteristics that are observed experimentally for the aggregates composed of macromolecules of ionic polymers under the conditions of strong segregation. It is established that the chains with one associating terminal group form tree-like coral-shaped aggregates; associating groups form the skeleton with a large number of branches at the periphery. It is shown that the chains with the number n
s 2 of associating groups form aggregates whose structures correspond to a three-dimensional network. Integral characteristics of a system are scale-invariant; molecular parameters, such as the chain length N and the number of associating groups n
s, enter into corresponding scaling dependences in the form of scaling multipliers N
and n
s
. Critical indices and , as well as main index determining the dependence of the mean aggregate sizes on the number n of constituting molecules, are estimated. It is established that an increase in the number of associating groups in a chain results in the formation of more compact aggregates with smaller characteristic size of a network cell. For the model considered, such an effective compression is explained by the intensification of branching, i.e., by the dispersal of growth points, rather than by the folding of chains (on the contrary, their substantial fraction is attached to the cluster in greatly extended conformations). The important role of intra- and interchain screening effects arising during the formation of local morphology of aggregates is demonstrated. As a result of such screening, the sizes of lattice nodes composed of associating groups seem to be the nonmonotonic function of the number of these groups in the chain. 相似文献