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901.
V. P. Borovik I. Yu. Bagryanskaya Yu. V. Gatilov O. P. Shkurko 《Journal of Structural Chemistry》2003,44(4):650-654
The crystal structures of 2-amino-4-phenyl-9H-pyrimido[4,5-b]indole and its nitrate were determined by XRD analysis. 13C NMR, XRD, and quantum-chemical data indicate that the acid proton is predominantly localized at the N(3) atom of the pyrimidine ring in both isolated nitrate molecules and in molecules in crystal and solution. 相似文献
902.
M. G. Koroleva O. V. Dyablo A. F. Pozharskii Z. A. Starikova 《Chemistry of Heterocyclic Compounds》2003,39(9):1161-1171
The previously unknown 1-amino- and 3-aminonaphtho[1,2-d]imidazoles, 1-aminonaphtho[2,3-d]imidazole, 1-aminophenanthro[9,10-d]imidazole and the N-amino-N'-methylimidazolium picrates corresponding to them have been obtained by direct amination of a series of condensed imidazoles with O-picrylhydroxylamine. An X-ray structural investigation of 1-amino-3-methylnaphtho[1,2-d]imidazolium picrate showed that, in difference to 1-aminobenzimidazolium salts, a conformation exists in it in which the hydrogen atoms of the N-NH2 group are directed to the side of the meso carbon atom. 相似文献
903.
Krylov I. O. Lugovskaya I. G. Anufrieva S. I. Krylova A. V. 《Russian Journal of Applied Chemistry》2003,76(8):1234-1237
The chemical composition, specific surface area, and pore structure of a schungite sorbent were studied as influenced by the conditions of thermal treatment. 相似文献
904.
L. M. Babkov O. V. Gorshkova G. A. Puchkovskaya I. N. Khakimov 《Journal of Structural Chemistry》1998,39(1):44-48
The polymorphism, conformation mobility and structure of 4-cyano-4′-pentalkoxybiphenyl (5OCB) in different physical states
are studied by IR spectroscopy. The spectra were measured in the frequency range 400–4000 cm−1 at temperatures from 300 to 350 K. The IR spectra of 5OCB are modeled using the concept of conformational mobility of these
molecules. An analysis of the experimental and theoretical spectra reveals absorption bands whose spectroscopic parameters
are sensitive to variations of temperature (experiment) and conformation (theory); a relationship between these changes is
established. It is concluded that the polymorphism of 5OCB is of conformation type. In the solid crystalline state, 5OCB molecules
have conformations with a planar biphenyl fragment; the angle of orientation of the plane of the carbon framework of the alkyl
radical relative to the biphenyl fragment decreases as the temperature increases from 35° in the solid crystalline state to
10° in the liquid crystalline and isotropic liquid states. In both of these states the biphenyl fragment becomes nonplanar.
The angle between the phenyl rings is up to 30°.
Saratov State University. Institute of Physics, Ukrainian Academy of Sciences. Samarkand State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 1, pp. 55–60, January–February, 1998.
This work was supported by RFFR grant No. 97-03-32175a. 相似文献
905.
I. S. Belostotskaya V. B. Vol'eva N. L. Komissarova M. O. Dekaprilevich V. N. Khrustalev A. Yu. Karmilov V. V. Ershov 《Russian Chemical Bulletin》1997,46(7):1272-1280
Oxidative transformations of 2-dialkylaminomethyl-4,6-di-tert-butylphenols depend on the nature of the oxidant, the character of the substituents at the nitrogen atom, and the medium.
A mechanism of the oxidation of these compounds is suggested. The molecular structure of the compound obtained as a result
of oxidative trimerization of 2-dimethylaminomethyl-4,6-di-tert-butylphenol was established by X-ray structural analysis.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1328–1335, July, 1997. 相似文献
906.
A. González Arias C. Torres C. de
Francisco J. M. Muñoz P. Hernández
Gómez O. Alejos O. Montero J. I. Iñiguez 《Journal of Thermal Analysis and Calorimetry》2006,86(1):195-198
The article discusses theory and experiment about the measurement of
defect concentration in Ti-substituted yttrium iron garnet by means of thermogravimetry
techniques. The two possible cases arising from oxygen interchange with atmosphere,
oxygen vacancies and interstitial cations, may be analyzed quantitatively
from the derived expressions. The possibility of another type of defects being
present in the samples, not associated to oxygen evolution, is not excluded.
Measurements were carried out in air and CO2 for different
Ti contents. The substitution tends to increase slightly the defect parameter
θ in YIG, while a CO2 reducing atmosphere is
much more effective than the Ti substitution for increasing θ. Calculations
for a given single-phased sample sintered in air show two possibilities: a
deficit of one oxygen atom for every 2.5 unit cells of 96 atoms, or one excess
cation for every 3.5 cells. Other samples show very similar results. The accuracy
involved in the measurements is about 2–3%. 相似文献
907.
I. A. Zyryanova L. V. Baikalova O. A. Tarasova A. V. Afonin V. A. Kukhareva M. A. Maksimova B. A. Trofimov 《Russian Journal of General Chemistry》2005,75(8):1283-1289
With respect to Co2+, Ni2+, Zn2+,Cd2+, Cu2+, Pd2+, and Sn4+ salts, 1-isopropenyl-substituted imidazole, 2-methylimidazole, and pyrazole behave as monodentate ligands with only one coordination center on the N1 and N2 atoms, respectively; 1-isopropenylpyrazole under complex-formation conditions is dealkylated to form pyrazole complexes. The reaction with HCl leaves the unsaturated substituent in 1-isopropenylimidazole intact and yields corresponding hydrochlorides by the N3 atom of the heterocycle. The least basic 1-isopropenylpyrazole takes up HCl also by the double bond of the alkenyl group. 相似文献
908.
Betaines are formed in good yields in the reaction of N-heteroaromatic compounds with 2-dicyanomethyleneindane-1,3-dione oxide and its 4- and 5-halo derivatives in dioxane. The corresponding oxides were obtained by oxidation of 2-dicyanomethyleneindane-1,3-dione and its 4- and 5-substituted derivatives with hydrogen peroxide in dioxane. Data from the IR spectra of the compounds are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 889–892, July, 1978. 相似文献
909.
910.
Russian Chemical Bulletin - 相似文献