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91.
A. B. Mirgorodskaya R. A. Kushnazarova A. Yu. Shcherbakov S. S. Lukashenko N. A. Zhukova V. A. Mamedov L. Ya. Zakharova O. G. Sinyashin 《Russian Chemical Bulletin》2018,67(11):1992-1996
Mixed micelles are formed in the binary compositions based on the cationic surfactant functionalized by the butyl carbamate fragment and nonionic surfactant Tween 80 in aqueous solutions. The aggregation parameters of the formed micelles (critical micelle concentration, size, and surface potential) depend on the component ratio in the system. The solubilization effect of individual and mixed micelles on the drugs of the heterocyclic series, indomethacin and 1-[5-(4-chlorophenyl)-3-phenylpyrrol-2-yl)]benzimidazol-2(3H)-one, was quantitatively characterized. 相似文献
92.
T. N. Pashirova E. P. Zhil´tsova S. S. Lukashenko E. M. Gibadullina A. R. Burilov L. Ya. Zakharova A. I. Konovalov 《Russian Chemical Bulletin》2016,65(5):1272-1277
The aggregation of octa-2-hydroxyethylated calix[4]resorcines (CR) with different alkyl chain length (R = Et, n-C5H11, n-C11H23), hydrophobically modified polyethyleneimine (HPEI) and their mixed systems was investigated by the tensiometry and dynamic light scattering in water and water-organic solvents at different temperatures. The critical aggregation concentration (CAC) and the size of aggregates were determined. It was established that the temperature affects significantly the surface and aggregation properties of the CR. The hydrolysis of 4-nitrophenyl-О-butylchloromethyl phosphonate was investigated in the presence of CR, HPEI, and their mixed systems by spectrophotometry. The parameters of the reaction (rate constant in the micellar phase, binding constant of the substrate with aggregates, and CAC) testify that the catalytic activity of the HPEI system in the presence of СR with undecyl radicals is the highest. 相似文献
93.
A. V. Lukashenko D. V. Osipov V. A. Osyanin Yu. N. Klimochkin 《Russian Journal of Organic Chemistry》2016,52(12):1817-1821
The reaction of o-(chloromethyl)phenols with enamino ketones afforded a series of 3-acyl- and 3-formyl-4H-chromenes as a result of cascade transformation including [4 + 2]-cycloaddition of enamino ketone to o-quinone methide generated in situ and subsequent elimination of secondary amine. 相似文献
94.
E. P. Zhiltsova T. N. Pashirova R. R. Kashapov N. K. Gaisin O. I. Gnezdilov S. S. Lukashenko A. D. Voloshina N. V. Kulik V. V. Zobov L. Ya. Zakharova A. I. Konovalov 《Russian Chemical Bulletin》2012,61(1):113-120
Aggregation of 1-hexadecyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide in the presence of diethyl 4-nitrophenyl phosphate was studied using 1H NMR spectroscopy. The quantitative characteristics of the aggregation were determined. The data obtained were used to explain the catalytic effect of micelles on the hydrolysis of the phosphate. It was found that the aggregation properties and biological activity of alkylated mono- and dicationic 1,4-diazabicyclo-[2.2.2]octanes are correlated. 相似文献
95.
A. K. Kadashchuk N. I. Ostapenko N. A. Davidenko N. G. Kuvshinskii N. V. Lukashenko 《Physics of the Solid State》1997,39(7):1047-1051
This paper reports an investigation into the features of geminate recombination of long-lived electron-hole pairs in films
of poly(N-epoxypropylcarbazole) (PEPC) containing intramolecular charge transfer compounds as centers of photogeneration of charge
carriers carried out by measuring the attenuation kinetics of isothermal recombination luminescence over a wide range of temperatures
(4.2–300 K) for times t>1 s, along with the kinetics of photoinduced EPR signals. A study is made of how the presence of a potential barrier to the
reverse transition of carriers to the recombination center and the initial triplet state of the charged pairs affects the
geminate recombination. It is established that the kinetics of isothermal recombintation luminescence attenuation follow the
law I(t)∝t
−m
for the times under study, where m takes values from 0.65 to 1.05. The first observations of a nonmonotonic change in m with temperature are reported (m passes through a minimum at a certain temperature), and a mechanism is proposed for recombination of charged pairs in PEPC
containing intramolecular charge-transfer compounds as an explanation for this phenomenon.
Fiz. Tverd. Tela (St. Petersburg) 39, 1183–1187 (July 1997) 相似文献
96.
A. B. Mirgorodskaya L. A. Kudryavtseva V. A. Pankratov S. S. Lukashenko L. Z. Rizvanova A. I. Konovalov 《Russian Journal of General Chemistry》2006,76(10):1625-1631
Geminal alkylammonium surfactants containing a hexamethylene spacer show a specific behavior, namely, a catalytic effect at low concentrations of the detergent in the system. The critical micellization concentrations of these surfactants are by an order of magnitude lower than those of the related surfactants with one hydrophobic fragment. The effect exerted on the hydrolysis of carboxylic acid esters by micellar structural rearrangements induced by addition of a supporting electrolyte is determined. 相似文献
97.
G. A. Gainanova E. P. Zhiltsova L. A. Kudryavtseva S. S. Lukashenko I. R. Knyazeva A. R. Burilov V. I. Kovalenko L. V. Avvakumova A. I. Konovalov 《Russian Journal of General Chemistry》2007,77(1):40-46
Kinetics of the reaction of alkylated polyethylene imines with 4-nitrophenyl bis(chloromethyl)-phosphinate in chloroform in the absence and in the presence of substituted calix[4]resorcinarenes were studied by UV spectrophotometry. It was shown that calixarenes forming mixed aggregates with polyethylene imines have a catalytic effect on the polymer phosphorylation process. The catalytic effect depends on the structure of polyethylene imine and the component ratio in the system. 相似文献
98.
Yu. I. Sal’nikov G. A. Boos I. S. Ryzhkina S. S. Lukashenko D. N. Manzhukova 《Colloid Journal》2006,68(5):607-612
Aggregation and protolytic properties of bis(dimethylaminomethyl)phenols containing methyl (HA) and nonyl (HL) substituents at the benzene ring are studied in aqueous solutions of isopropanol and various surfactants with potentiometric titration, tensiometry, and mathematical modeling of equilibria. Monomers, dimers, and tetramers of HA and HL are found. It is shown that the degree of compound aggregation depends on the solution concentration and pH. Sodium dodecyl sulfate and HA form associates, whereas SDS and HL form mixed micelles at the CMC-1 and CMC-2 critical micellization concentrations. In micellar solutions of Triton X-100 and cetyltrimethylammonium bromide, the mixed micelles are not found via tensiometry. Protonated species of tetramer, dimer, and monomer of investigated compounds are revealed, depending on the acidity of the medium. Phenolate forms of HA and HL do not exist under experimental conditions. Apparent protonation constants are determined and it is shown that, for the HA compound that does not form micelles, the protonation constants of the same-type species increase in the presence of the three surfactants used as compared to the water-isopropanol solution. Decreasing constants of analogous HL forms in the solutions of CTAB, nonionic surfactant (C Tx = 10 mM), and SDS (pH > 7) are attributed to the formation of associates or mixed micelles of this compound and surfactants under experimental conditions. 相似文献
99.
Sal'nikov Yu. I. Boos G. A. Ryzhkina I. S. Ganieva E. R. Lukashenko S. S. 《Russian Journal of Coordination Chemistry》2004,30(6):430-434
The acid-basic and complexing properties of N,N-dimethyl-N-(2-hydroxybenzyl)ethylenediamine (HL) in aqueous propan-2-ol were characterized by spectrophotometry, pH-metry, and mathematical simulation of equilibria in solutions (T = 25 ± 0.1°C, = 0.1 M KNO3). Dimer H2L2 was found to predominate in solution at c
HL = 0.01 mol/l. Three protonated dimeric (H3L2
+, H4L2
2+, and H5L2
3+), diprotonated monomeric (H3L2+), and triprotonated tetrameric forms (H7L4
3+) were detected in the system, depending on pH. At lower ligand concentrations (c
HL = 0.0015 mol/l), the solution contains both dimers and monomers of this compound. The higher dentate number of HL compared to 2-alkylaminomethylphenols allows it to form more number of both mono- and binuclear complexes ([Cu(HL)]2+, [Cu(HL)2]2+, [CuL2], [CuL2OH]–, [Cu2(HL)2]4+, and [Cu2(HL)2L2]2+), making them more stable. 相似文献
100.
A method for approximation of functions of two variables by a linear combination of nonnegative piecewise linear functions
with a compact support is presented. The crucial idea of this method consists in an “integral” calculation method for the
coefficients. The accuracy of the approximation in the spaces of continuous and integrable functions is proved to have the
same order as the best approximation by piecewise linear functions. 相似文献