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991.
G. I. Chipen R. P. Bokaldere V. Ya. Grinshtein 《Chemistry of Heterocyclic Compounds》1971,4(4):546-547
By the reaction of 5-amino-1, 2, 4-triazoles with benzoyl isothiocyanate we have synthesized 5-amino-1-(benzoylaminothioformyl)-1, 2, 4-triazoles, which form 5-amino-1-(aminothioformyl)-1, 2, 4-triazoles on alkaline hydrolysis. 相似文献
992.
Ya. Yu. Stepanskii N. P. Evmenenko G. S. Yablonskii V. I. Bykov 《Reaction Kinetics and Catalysis Letters》1980,14(3):335-339
Self-oscillation found experimentally in the cool-flame combustion of a model n-heptane-i-octane mixture has been studied in dependence on the composition of the reaction mixture. Calculations based on the CSTR model are in qualitative agreement with experimental data.
--. . .相似文献
993.
A. S. Shashkov V. I. Grishkovets A. E. Kondratenko V. Ya. Chirva 《Chemistry of Natural Compounds》1995,30(6):693-698
A new hederagenin pentaoside — glycoside L-6d — has been isolated from the leaves of common ivyHedera helix L., fam. Araliaceae, and its structure has been determined by using various NMR-spectroscopic methods. Glycoside L-6d is hederagenin 3-O-[O--L-rhamnopyranosyl-(14)-O--D-glucopyranosyl-(16)-O--D-glucopyranosyl-(14)-O--L-rhamnopyranosyl-(12)--L-arabinopyranoside.Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 746–752, November–December, 1994. 相似文献
994.
995.
T. V. Magdesieva A. V. Dolganov P. M. Polestchuk A. V. Yakimanskii M. Ya. Goikhman I. V. Podeshvo V. V. Kudryavtsev 《Russian Chemical Bulletin》2007,56(7):1380-1389
Structural reorganization of polyamide (PA) and low-molecular-weight CuI and CuII complexes with biquinolyl (biQ) ligands during their mutual redox transformations in solution was studied using the electrochemical
methods (cyclic voltammetry and preparative electrolysis) and quantum chemical DFT calculations. The influence of electronic
factors and geometry distortions in the complexes on the ionization energy on going from CuI to CuII was evaluated in comparison. The catalytically active form of the [CuI(PA)L2]BF4 complex can be synthesized in situ from the stable tetrahedral complex [CuI(PA)2]BF4 by the series of successive redox transitions CuI → CuII → CuI accompanied by the loss of one biQ-containing macroligand.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1331–1340, July, 2007. 相似文献
996.
Effect of epitaxial growth on the formation of the cobalt catalysts of the Fischer-Tropsch synthesis
Ya. V. Mikhailova S. A. Sviderskii M. N. Mikhailov I. V. Mishin V. Z. Mordkovich 《Russian Chemical Bulletin》2007,56(9):1922-1926
Mixed oxides CoxAlyO4 with different Al/Co ratios applied as supports for the catalysts of the Fischer-Tropsch synthesis were prepared using the
solid-state chemical reaction. The CoxAlyO4 supports were prepared by modifying gibbsite with various cobalt salts (acetate, nitrate, and basic carbonate). The use of
basic cobalt carbonate gives the Co(20%)/CoxAlyO4 catalyst, which provides an increased yield of hydrocarbons C5+ and a decreased methane content compared to the impregnation catalyst Co(30%)/Al2O3. The introduction of small amounts of rhenium additives makes it possible to enhance the yield of hydrocarbons C5+ (179 g m−3) and also to increase the selectivity with respect to the C5–C18 fraction. The introduction of basic cobalt carbonate into the support, most likely, creates favorable conditions for the
epitaxial growth of the precursor of the active phase.
Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1856–1860, September, 2007. 相似文献
997.
V. A. Mamedov N. A. Zhukova T. N. Beschastnova Ya. A. Levin A. T. Gubaidullin I. A. Litvinov 《Russian Chemical Bulletin》2007,56(11):2308-2314
The condensation of methyl phenylchloropyruvate with 1-phenyl-3-(2-pyridyl)thiourea and its 3-and 4-picolyl homologs affords
the corresponding 4-hydroxythiazolidines, which react with o-phenylenediamine to give one of two possible thiazolo[3,4-a]quinoxalines containing the pyridyl-or picolylimine substituents at position 1. 3a-Hydroxy-3-phenylimino-1-(2-pyridyl)thiazolo[3,4-a]quinoxalin-4-(3H,5H)-one, which is a covalent hydrate of the final product, was isolated as an intermediate in this reaction. 相似文献
998.
999.
The patterns of the Cu(2+) ion arrangements in the magnetic oxides A(2)Cu(PO(4))(2) (A = Ba, Sr), ACuP(2)O(7) (Ba, Ca, Sr, Pb), CaCuGe(2)O(6), and Cu(2)UO(2)(PO(4))(2) are quite different from the patterns of the strongly interacting spin exchange paths deduced from their magnetic properties. This apparently puzzling observation was explained by evaluating the strengths of the Cu-O-Cu superexchange and Cu-O...O-Cu supersuperexchange interactions of these oxides on the basis of qualitative spin dimer analysis. Supersuperexchange interactions are found to be crucial in determining the dimensionality of magnetic properties of these magnetic oxides. 相似文献
1000.
Kuepper K Falub MC Prince KC Galakhov VR Troyanchuk IO Chiuzbaian SG Matteucci M Wett D Szargan R Ovechkina NA Mukovskii YM Neumann M 《The journal of physical chemistry. B》2005,109(19):9354-9361
The electronic properties of a series of colossal magnetoresistance (CMR) compounds, namely LaMnO3, La(1-x)Ba(x)(MnO3 (0.2 < or = x < or = 0.55), La(0.76)Ba(0.24)Mn(0.84)Co(0.16)O3, and La(0.76)Ba(0.24)Mn(0.78)Ni(0.22)O3, have been investigated in a detailed spectroscopic study. A combination of X-ray photoelectron spectroscopy (XPS), X-ray emission spectroscopy (XES), X-ray absorption spectroscopy (XAS), and resonant inelastic X-ray scattering (RIXS) was used to reveal a detailed picture of the electronic structure in the presence of Ba, Co, and Ni doping in different concentrations. The results are compared with available theory. The valence band of La(1-x)()Ba(x)MnO3 (0 < or = x < or = 0.55) is dominated by La 5p, Mn 3d, and O 2p states, and strong hybridization between Mn 3d and O 2p states is present over the whole range of Ba concentrations. Co-doping at the Mn site leads to an increased occupancy of the e(g) states near the Fermi energy and an increase in the XPS valence band intensity between 0.5 and 5 eV, whereas the Ni-doped sample shows a lower density of occupied states near the Fermi energy. The Ni d states are located in a band spanning the energy range of 1.5-5 eV. XAS spectra indicate that the hole doping leads to mixed Mn 3d-O 2p states. Furthermore, RIXS at the Mn L edge has been used to probe d-d transitions and charge-transfer excitations in La(1-x)Ba(x)MnO3. 相似文献