排序方式: 共有73条查询结果,搜索用时 15 毫秒
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Svetlana V. Amosova Vladimir A. Shagun Natalia A. Makhaeva Konstantin A. Lysenko 《Journal of organometallic chemistry》2007,692(16):3307-3315
The structure of 2,4-dibromo-2-dibromomethyl-3,3-dimethyl-1-selena-3-silacyclopentene-4, formed by regioselective electrophilic addition of SeBr4 to dimethyl diethynyl silane, has been determined using X-ray analysis technique. Quantum chemistry methods were used to study elementary stages of the reaction. It was found that the first stage consisted of SeBr4 conversion into bimolecular complex Br2?SeBr2, initiated by dimethyl diethynyl silane. Possible formation of five-membered and six-membered heterocycles involves different cyclization mechanisms. The formation of only five-membered heterocycle is explained by kinetically preferable ring closure through four-center transition state. The conclusions obtained by calculations were confirmed by monitoring of the reaction using 1H NMR method. 相似文献
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Core-shell nanostructures from single poly(N-vinylcaprolactam) macromolecules: stabilization and visualization 总被引:1,自引:0,他引:1
Bronstein LM Kostylev M Tsvetkova I Tomaszewski J Stein B Makhaeva EE Okhapkin I Khokhlov AR 《Langmuir : the ACS journal of surfaces and colloids》2005,21(7):2652-2655
Formation of core-shell poly(N-vinylcaprolactam) (PVCL) single-molecule nanostructures due to interaction of PVCL with metal ions was studied using transmission electron microscopy, 13C NMR, and light scattering. This study demonstrates that addition of CoCl2 to PVCL in its globular conformation yields unimolecular core-shell polymer particles with the core decorated with Co(II) ions. The crucial condition for formation of well-defined unimolecular nanostructures is the presence of stable globular aggregates in aqueous solution. Moreover, the metal ions should have a sufficiently high coordination number (higher than 2) to provide a cross-linking and stabilization of the core. 相似文献
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Alexei R. Khokhlov Elena Yu. Kramarenko Elena E. Makhaeva Sergei G. Starodubtzev 《Macromolecular theory and simulations》1992,1(3):105-118
A very simple theory of swelling and collapse of weakly charged polyelectrolyte networks in the solution of an oppositely charged surfactant has been developed. The following contributions to the free energy were taken into account: free energy of volume interaction and of elastic deformation of the network chains, free energy connected with micelle formation and free energy of translational motion of all mobile ions in the system (translational entropy). Both the cases of a solution of charged surfactant and that of a mixed solution of charged and neutral surfactant components have been taken into account. It has been shown that the behaviour of the network depends on the total surfactant concentration in the system and corresponds to one of the three following regimes: At low concentration, micelles inside the network are not formed and the behaviour of the polymer network is similar to that of a network swelling in the solution of a lowmolecular-weight salt (regime 1). In the second regime, surfactant concentration inside the network exceeds the critical micelle concentration and micelles are formed; in this regime the network collapses because surfactant molecules, aggregated in micelles, cease to create “exerting” osmotic pressure in the network sample. In the third regime, at very high surfactant concentration, formation of additional micelles inside the network ceases, and the network dimensions coincide with those of the corresponding neutral network. 相似文献
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The effect of the different kinds of ionogenic groups of copolymers of N-isopropylacrylamide with sodium methacrylate, sodium vinylsulfonate, and diallyldimethylammonium chloride on the temperature-induced
conformation transition from a swollen gel to a collapsed gel is studied. The presence of different kinds of ionogenic groups
in a thermosensitive copolymer is shown to affect the temperature, collapse amplitude, and reversibility of the transition
between the swollen gel and the collapsed gel. 相似文献
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V.?B.?SokolovEmail author G.?F.?Makhaeva A.?Yu.?Aksinenko V.?V.?Grigoriev E.?F.?Shevtsova S.?O.?Bachurin 《Russian Chemical Bulletin》2017,66(10):1821-1831
Synthetic approaches to the design of new multitarget agents for the treatment of neurodegenerative diseases are surveyed. These approaches are based on the conjugation of the pharmacophoric indole, phenothiazine, and aminoadamantane moieties via 1-oxopropylene and 2-hydroxypropylene spacers using reactions of acrylate- and epoxide-containing pharmacophores with tetrahydro-γ-carbolines, cycloalkaneindoles, carbazoles, and aminoadamantanes. The review considers data on biological activity of the compounds assessed within a complex screening system. This system includes neurotransmitter targets associated with cognitive compensation, such as cholinesterases and glutamate receptors, mitochondria, the influence on which can provide neuroprotective effects, and microtubules, the stabilization of which leads to the improvement of axonal transport. The ability of the compounds to act as free-radical scavengers was evaluated. Types of polypharmacophoric compounds promising for further development are proposed. 相似文献
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A. Yu. Aksinenko V. B. Sokolov T. V. Goreva G. F. Makhaeva 《Russian Chemical Bulletin》2011,60(8):1769-1771
A number of fluorine-containing ??-amino phosphonates of the general formula (RO)2P(O)C(CF3)(COOC2H5)NHSO2Ph were obtained and found to irreversibly inhibit four serine hydrolases: acetyl- and butyrylcholinesterases, neuropathy target esterase, and carboxylesterase. 相似文献
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Ivan?M.?Okhapkin Elena?E.?Makhaeva Alexei?R.?KhokhlovEmail author 《Colloid and polymer science》2005,284(2):117-123
A classification of amphiphilic monomers based on the interfacial and partitioning properties has been proposed. Monomers partitioned at equilibrium between two immiscible phases were ascribed with a pair of parameters: standard free energy of adsorption at the interface and standard free energy of partition between the two phases. These two parameters are represented in a form of two-dimensional diagram (both of them being normalized by kT factor). Comparison of the parameters in question gives information on energetic preferences of the molecules to be located at the interface or in the bulk phases. Four monomers of synthetic water-soluble polymers, namely, N-isopropylacrylamide, 1-vinylimidazole, N-vinylpyrrolidone and N-vinylcaprolactam have been classified according to the above method at various temperatures. The possibility to extend the classification to arbitrary chemicals is discussed.An erratum to this article can be found at 相似文献
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G. F. Makhaeva A. N. Proshin N. P. Boltneva E. V. Rudakova N. V. Kovaleva O. G. Serebryakova I. V. Serkov S. O. Bachurin 《Russian Chemical Bulletin》2016,65(6):1586-1591
Detailed studies of properties of new 3-substituted 5-anilino-1,2,4-thiadiazoles containing different substituents at position 3 of the thiadiazole ring were carried out, in particular, their esterase profile and antioxidant properties. It was found that the presence in the molecule of 2-aminopropyl fragment determines an efficient and selective inhibition of butyrylcholinesterase as compared to acetylcholinesterase and carboxylesterase, with radical-scavenging activity being weak. The compounds containing a 2-aminopropenyl fragment possess a high radicalscavenging activity, weakly inhibit cholinesterases, and exhibit anticarboxylesterase activity. A wide spectrum of activity of 3-substituted 5-anilino-1,2,4-thiadiazoles as inhibitors of cholinesterases and highly efficient scavengers of free radicals gives a basis for the optimization of structure and development in this series of original agents for therapy of neurodegenerative diseases. 相似文献