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91.
A. P. Polishchuk T. V. Timofeeva N. N. Makarova M. Yu. Antipin Yu. T. Struchkov 《Liquid crystals》2013,40(3):433-439
Abstract Previous structural investigations of mesogenic organosilicon compounds (1, 3-dihydroxytetraalkyldisiloxanes, [R2(OH)Si]2O, R = C n H2n+1) which form thermotropic phases are outlined. The crystal and molecular structure determination of a non-mesogenic member of this series [Me2(OH)Si]2O is described. It is inferred that the mesophases formed by this family of compounds belong to a new structural type with columnar stacks of the molecules laced together with hydrogen bonds. 相似文献
92.
The Michael condensation in the series of 5-aryl-3-arylidene-3H-pyrrol-2-ones and 5-aryl-3-arylidene-3H-furan-2-ones, containing
an activated C=C bond, with cyclohexanone was investigated. It was shown that the condensation products were 1,5-dicarbonyl
compounds containing a heterocyclic fragment. The enolization of one of the oxo groups, leading to the formation of hydroxypyrrole
or hydroxyfuran structures, was demonstrated by the spectral data.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 823–827, June, 2007. 相似文献
93.
Timofeeva M. N. Matrosova M. M. Maksimov G. M. Likholobov V. A. Golovin A. V. Maksimovskaya R. I. Paukshtis E. A. 《Kinetics and Catalysis》2001,42(6):791-795
The esterification reaction of n-butanol with acetic acid ([BuOH] : [HOAc] = 1 : 15 mol/mol; 55°C, 5% H2O) was studied in the presence of tungsten heteropoly acids of the Keggin (H3PW12O40, H4SiW12O40, H5PW11TiO40, H5PW11ZrO40, and H3PW11ThO39) and Dawson structure (-H6P2W18O62, H6P2W21O71(H2O)3, H6As2W21O69(H2O), and H21B3W39O132). The reaction orders with respect to H6P2W21O71(H2O)3, H3PW12O40, and H6P2W18O69are equal to 0.78, 1.00, and 0.97, respectively. It was found that the reaction rate depends on the acidity, as well as on the structure and composition of heteropoly acids. The H21B3W39O132heteropoly acid is most active, whereas the Keggin-structure heteropoly acids exhibit the lowest activities. Of the Keggin structure heteropoly acids, H5PW11ZrO40exhibits the highest activity because of the presence of a Lewis acid site in its structure. 相似文献
94.
Gainullina Yu. Yu. Gus’kov V. Yu. Timofeeva D. V. 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2019,93(12):2477-2481
Russian Journal of Physical Chemistry A - The affinity of surfaces of porous polymer Polysorb-1 samples modified with thymine (5-methyluracil) and 6-methyluracil toward sorbates capable of various... 相似文献
95.
96.
97.
n‐Dopants Based on Dimers of Benzimidazoline Radicals: Structures and Mechanism of Redox Reactions
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Evgheni V. Jucov Prof. Sean Parkin Eric G. B. Evans Glenn L. Millhauser Tatiana V. Timofeeva Dr. Chad Risko Prof. Jean‐Luc Brédas Prof. Zhenan Bao Dr. Stephen Barlow Prof. Seth R. Marder 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(30):10878-10885
Dimers of 2‐substituted N,N′‐dimethylbenzimidazoline radicals, (2‐Y‐DMBI)2 (Y=cyclohexyl (Cyc), ferrocenyl (Fc), ruthenocenyl (Rc)), have recently been reported as n‐dopants for organic semiconductors. Here their structural and energetic characteristics are reported, along with the mechanisms by which they react with acceptors, A (PCBM, TIPS‐pentacene), in solution. X‐ray data and DFT calculations both indicate a longer C?C bond for (2‐Cyc‐DMBI)2 than (2‐Fc‐DMBI)2, yet DFT and ESR data show that the latter dissociates more readily due to stabilization of the radical by Fc. Depending on the energetics of dimer (D2) dissociation and of D2‐to‐A electron transfer, D2 reacts with A to form D+ and A? by either of two mechanisms, differing in whether the first step is endergonic dissociation or endergonic electron transfer. However, the D+/0.5 D2 redox potentials—the effective reducing strengths of the dimers—vary little within the series (ca. ?1.9 V vs. FeCp2+/0) (Cp=cyclopentadienyl) due to cancelation of trends in the D+/0 potential and D2 dissociation energy. The implications of these findings for use of these dimers as n‐dopants, and for future dopant design, are discussed. 相似文献
98.
Vladislava Timofeeva José Miguel Léon Baeza Dr. Raphael Nougué Dr. Mikhail Syroeshkin Prof. Dr. Rene Segundo Rojas Guerrero Dr. Nathalie Saffon-Merceron Dr. Gül Altınbaş Özpınar Dr. Saskia Rathjen Prof. Dr. Thomas Müller Dr. Antoine Baceiredo Dr. Tsuyoshi Kato 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(44):e202201615
A stable (amino)plumbylene-substituted phosphaketene 3 was synthesized by the successive reactions of PbCl2 with two anionic reagents (lithium amidophosphine and NaPCO). Of particular interest, the thermal evolution of 3 , at 80 °C, leads to the transient formation of corresponding amino- and phosphanylidene-phosphaketenes ( 6 and 7 ), via a reductive elimination at the PbII center forming new N−P and P−P bonds. Further evolution of 6 gives a new cyclic (amino)phosphanylidene phosphorane 4 , which shows a unique reactivity as a phosphinidene. This result provides a new synthetic route to phosphinidenes, extending and facilitating further their access. 相似文献
99.
A. B. Shipovskaya G. N. Timofeeva A. Yu. Abramov S. Yu. Shchegolev V. P. Ryabukho 《Polymer Science Series A》2010,52(2):126-133
The phenomenon of spontaneous changes in the linear dimensions (elongation-contraction) is described for commercial and laboratory
samples of acetate yarns processed by wet spinning from high- molecular -mass cellulose diacetate in vapors of a mesophas
ogenic solvent (which is able to form a lyotropic LC phase with the polymer), nitromethane, and its mixtures with water. The
thermodeformational, elastic- plastic, physicomechanical, and surface characteristics of the yarns at different stages of
their spontaneous deformation are analyzed. When samples are treated with probe vapors, orientational processes in the polymer
matrix are activated, and this observation makes it possible to prepare yarns with improved physicomechanical characteristics
and with low linear density. A new phenomenon (to our knowledge) of cyclic three- stage deformation of acetate monofilaments
in nitromethane vapors is discovered. This evidence is interpreted from the standpoint of phase (amorphous glassy-liquid crystalline
state) and conformational transitions as well as by the mechanism of interaction between polymers and solvent vapors and related
development of the LC phase. 相似文献
100.
O. A. Mel’nik A. S. Shaplov E. I. Lozinskaya N. A. Popova M. V. Makarov I. L. Odinets K. A. Lysenko G. I. Timofeeva I. A. Malyshkina Ya. S. Vygodskii 《Polymer Science Series B》2010,52(5-6):316-326
A number of new ionic vinyl monomers composed of 1-vinylimidazolium cation with diethoxy- and dihydroxyphosphoryl groups and various anions—Br?, (CN)2N?, and (CF3SO2)2N?—are synthesized. The free-radical polymerization of the monomers in solutions of molecular and ionic solvents yields new polymer analogs of ionic liquids, and their molecular-mass characteristics, solubility, heat resistance, thermal stability, and electrical conductivity are estimated. It is shown that the incorporation of bulky phosphorylalkyl side substituents into the vinylimidazolium polycation causes a decrease in the glass-transition temperature and an increase in the ionic conductivity of polymer salts. The highest ionic conductivity (2.6 × 10?5 S/cm at 25°C) is exhibited by the polymer with the (CN)2N? anion. 相似文献