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21.
An earlier paper by the authors has undergone criticism by Jankowski and Rabczenko. The arguments presented are analysed in this paper and the criticism is rejected. 相似文献
22.
Magnesium-aluminum-iron layered hydroxides with hydrotalcite-like structure have been synthesized, and their chemical composition and crystal lattice parameters have been elucidated. Thermal decomposition of the iron-containing layered hydroxides has been studied by X-ray diffraction, thermogravimetry, and IR spectroscopy; the decomposition starts with loss of interlayer water, followed by dehydroxylation of metal hydroxide layers and decomposition of anions at higher temperature. Onset of the both decomposition stages has been shifted to lower temperature with increasing iron fraction in the sample. Magnesium-aluminum-iron hydroxides restore their structure after annealing and subsequent rehydration. 相似文献
23.
A. S. Vorontsova V. G. Kurbatov N. A. Zakharova E. A. Indeikin 《Russian Journal of Applied Chemistry》2018,91(7):1153-1159
Aqueous dispersions of doped polyaniline were synthesized in the presence of mixtures of a carboxylcontaining polymeric surfactant with low- and high-molecular-mass stabilizers. Polyaniline aqueous dispersions obtained using a mixture of carboxyl-containing polymeric and low-molecular-mass surfactants are characterized by high dispersity and narrow particle-size distribution but low sedimentation stability. The doping agent influences the stability of the dispersions prepared in the presence of polymeric and low-molecular-mass surfactants. The dispersions obtained using a mixture of macromolecular surfactants are characterized by larger particle size but higher sedimentation stability due to increased viscosity of the system. 相似文献
24.
The possibility of recyclizing oxazolium salts into 3-pyrrolin-2-ones by the action of base has been shown for the first time.Omsk State University, Omsk 644077. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 979–980, July, 1997. 相似文献
25.
M. M. Krayushkin D. V. Pashchenko B. V. Lichitsky B. V. Nabatov A. N. Komogortsev L. G. Vorontsova Z. A. Starikova 《Russian Chemical Bulletin》2008,57(10):2168-2174
The reactions of dithienyl-substituted furanones with hydrazines afford the corresponding pyridazinone-bridged dithienylethenes
with photochromic properties. The structure of 4,5-bis-(2,5-dimethyl-3-thienyl)-2,6-dimethyl-2H-pyridazin-3-one was established by X-ray diffraction. 相似文献
26.
M. M. Krayushkin L. G. Vorontsova V. N. Yarovenko I. V. Zavarzin V. N. Bulgakova Z. A. Starikova V. A. Barachevskii 《Russian Chemical Bulletin》2008,57(11):2402-2404
New 1,2-dihetarylethene containing two 6-acetyl-2-methylbenzo[b]thiophene moieties linked by the cyclopentene bridge was synthesized. In a toluene solution, this compound exhibits photochromic properties. The X-ray diffraction study showed that the crystal structure also has properties characteristic of photochromic compounds, viz., the anti-parallel conformation of the molecule and the distance between the reaction centers equal to 3.729 Å. 相似文献
27.
The elementary processes of crystal growth in the case of a low kink density on step edges have been studied by in situ atomic force microscopy. High-resolution images of the first turn of the polygonal dislocation spiral on the (101) face of monoclinic lysozyme crystals, which allow one to discern separate crystal cells, have been obtained. It has been shown that the dependence of the spiral segment velocity on its length is inconsistent with the Gibbs-Thomson law and is represented by several rectilinear sections. The results were explained by taking into account the features of the growth of crystals with a low kink density at low supersaturation. 相似文献
28.
M. M. Krayushkin M. A. Kalik D. L. Dzhavadov L. G. Vorontsova Z. A. Starikova A. Yu. Martynkin V. L. Ivanov B. M. Uzhinov 《Russian Chemical Bulletin》2000,49(10):1757-1762
A series of new photochromic compounds were obtained for the first time from 1,2-bis(2-ethylthio-3-thienyl)perfluorocyclopentene by substituting bromine atoms or carboxy, alkoxycarbonyl, and carbamoyl groups for hydrogen atoms in positions 4 and 4′. Introduction of these substituents causes a slight bathochromic shift (by 20–30 nm) of a long-wavelength absorption band for the cyclic form and significantly increases the quantum yields of photocyclization ФA→B and ring opening ФB→A. Depending on the nature of a substituent, ФA→B decreases in the order COOH>COOMe>CONHAr. The quantum yields are markedly reduced when the ethylthio groups in positions 5 and 5′ are replaced by ethylsulfonyl groups (a tenfold reduction in ФA→B and a four- to fivefold reduction in ФB→A) The most considerable bathochromic shift of a long-wavelength band and the highest quantum yields of forward and reverse photoreactions were observed for 1,2-bis(4-bromo-2-ethylthio-3-thienyl) perfluorocyclopentene. 1,2- Bis (2-ethyl-5-ethylthio-4-methoxycarbonyl-3-thienyl)perfluorocyclopentene was structurally characterized by X-ray diffraction analysis. 相似文献
29.
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