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71.
72.
Effect of copper(I) on the conformation of the thiacalixarene platform in azide-alkyne cycloaddition
V. A. Burilov R. R. Ibragimova R. I. Nugmanov R. R. Sitdikov D. R. Islamov O. N. Kataeva S. E. Solov’eva I. S. Antipin 《Russian Chemical Bulletin》2015,64(9):2114-2124
New lower-rim tetrasubstituted p-tert-butylthiacalix[4]arene derivatives bearing alkyl, propargyl, or triazole-containing substituents were synthesized. The structures of these compounds were determined by 1D and 2D NMR spectroscopy in solution and by X-ray diffraction in the solid phase. The copper-catalyzed azide-alkyne cycloaddition (CuAAC) of azides to a mixture of 1,3-alternate–partial cone stereoisomers of dipropargyl derivatives of thiacalix[4]arene affords triazole-containing products exclusively in the 1,3-alternate conformation. 相似文献
73.
T. I. Madzhidov A. V. Bodrov T. R. Gimadiev R. I. Nugmanov I. S. Antipin A. A. Varnek 《Journal of Structural Chemistry》2015,56(7):1227-1234
By means of a structural representation of the chemical reactivity as a condensed graph a model predicting rate constants of the bimolecular elimination reaction is derived for the first time. The model developed enables the prediction of rate constants of reactions proceeding in different solvents or water-organic mixtures at different temperatures. It demonstrates a good predictive performance: a mean square deviation of predicted values from experimental ones is less than 0.7 logarithmic units. An outlier analysis shows that prediction errors are mainly due to the imperfection of the training data containing unique reactions. The model is available for users at arsole.u-strasbg.fr. 相似文献
74.
Yushkova EA Stoikov II Puplampu JB Antipin IS Konovalov AI 《Langmuir : the ACS journal of surfaces and colloids》2011,27(23):14053-14064
In this work, the formation of two- and three-component supramolecular systems based on cone, partial cone, 1,3-alternate stereoisomers of heteroditopic "hosts": p-tert-butylthiacalix[4]arene containing 4-amidopyridine fragments with silver(I) cations and dicarboxylic acids in liquid and solid phases were studied by UV spectroscopy, dynamic light scattering, and atomic force microscopy methods. It has been shown that these macrocycles are coreceptors, capable of simultaneously binding silver(I) cations, dicarboxylic acids (oxalic, malonic, succinic, maleic, fumaric acids), and hydroxyl acids (glycol, tartaric acids). For the first time, by the dynamic light scattering method, it has been shown that the conformation of p-tert-butyl thiacalix[4]arenes significantly affects the type of three-component system formed: cone is characterized by the formation of cascade systems; for partial cone, intermediate systems; and for the 1,3-alternate stereoisomers, three types of three-component systems (cascade, intermediate, and commutative) were observed. 相似文献
75.
Alexander S. Romanov Tatiana V. Timofeeva Mikhail Yu. Antipin 《Journal of organometallic chemistry》2011,696(23):3822-3825
Novel radial tetra(ferrocenyl)- and tetra(cymantrenyl)cyclobutadienecobalt complexes were prepared by metal carbonyls free protocol of [2 + 2] cycloaddition reaction of 1,2-diferrocenyl- or 1,2-dicymantrenylethynes with chlorotris(triphenylphospine)cobalt(I) and carboethoxycyclopentadienide sodium with good yields. The molecular structure of these products was confirmed with X-ray analysis, and their electrochemical behavior was studied. 相似文献
76.
Gennady A. Evtugyn Rezeda V. Shamagsumova Ruzal R. Sitdikov Ivan I. Stoikov Igor S. Antipin Marina V. Ageeva Tibor Hianik 《Electroanalysis》2011,23(10):2281-2289
A sensitive electrochemical sensor based on a composite containing silver nanoparticles and a redox active thiacalixarene with catechol fragments in the substituents at the lower rim has been developed and used for dopamine detection. The electrochemical investigation of thiacalixarene in homogeneous solution and on the electrode interface showed the reversible character of the redox conversion of catechol fragments and its involvement in the chemical reduction of silver which resulted in formation of uniform nanoparticles of 4–6 nm in diameter. The use of such a material for electrode modification made it possible to record a high amplitude cathodic signal at ?700 mV that was proportional to the dopamine concentration within 1 nM–1 µM. (limit of detection 0.5 nM). 相似文献
77.
V. Yu. Rad��kov G. G. Skvortsov G. K. Fukin K. A. Lyssenko M. Yu. Antipin A. A. Trifonov 《Russian Chemical Bulletin》2011,60(5):803-808
The reaction of lithium silylamide [??o-MeOC6H4N(SiMe3)}Li(OEt2)]2 with 2 equiv. of benzonitrile in THF at ??20 °C affords the lithium derivative of the new tridentate amidinate ligand [{o-MeOC6H4NC(Ph)N(SiMe3)}Li]2. The X-ray diffraction study showed that this complex has a dimeric structure due to the coordination of the N atoms and the ether group of one amidinate ligand to different Li atoms. The reaction of anhydrous YCl3 with the resulting complex in THF gives the monoamidinate complex [{o-MeOC6H4NC(Ph)N(SiMe3)}YCl2(THF)2]2 regardless of the reagent ratio. The latter has a dimeric structure in the crystalline state as a result of the presence of two ??2-bridging Cl atoms that link Y atoms. The ether groups of the amidinate ligands are not involved in the metal-ligand interaction. 相似文献
78.
N. B. Mel’nikova E. N. Kochetkov S. E. Solov’eva E. V. Popova I. S. Antipin A. E. Bol’shakova O. E. Zhil’tsova A. I. Konovalov 《Russian Chemical Bulletin》2011,60(9):1948-1955
The possibility of designing a model of sensor to antioxidants based on thiacalix[4]arene monolayers with immobilized cytochrome c was shown. The molecular surface area S 0 of thiacalix[4]arene in the monolayers and the surface pressure coefficient ?dπ/dS (elasticity) reflect changes in the redox state of cytochrome c in the presence of dihydroquercetin and ascorbic acid in the aqueous subphase. The absorption spectra in the visible and UV ranges of solutions of the subphase and transferred thiacalix[4]arene monolayers with immobilized cytochrome c confirm the oxidation of the antioxidants to quinones and formation of the reduced form of cytochrome c. 相似文献
79.
I. V. Ananyev Yu. V. Nelyubina A. A. Korlyukov P. Yu. Barzilovich M. Yu. Antipin S. M. Aldoshin K. A. Lyssenko 《Russian Chemical Bulletin》2011,60(11):2161-2174
The spatial and electronic structure studies of nitramide NH2NO2 suggest that the change in its molecular geometry upon transition from the gas phase to the condensed state is caused by an increase in the contribution of conjugation between functional groups. According to the analysis of the Bader atomic charges, the effects of such conjugation are to a considerable extent governed by intramolecular charge transfer from the amino to the nitro group. From estimation of the contribution of conjugation to the charge transfer it follows that conjugation remains in the isolated molecule. The influence of hydrogen bonding on the increase in the contribution of conjugation and the corresponding charge redistribution in the molecule was considered. Despite the presence of conjugation between functional groups, the planar configuration of the molecule in the crystal is not realized and the crystallographic twofold axis corresponds to superposition of two molecular configurations with C s symmetry. 相似文献
80.
We compute constrained equilibria satisfying an optimality condition. Important examples include convex programming, saddle
problems, noncooperative games, and variational inequalities. Under a monotonicity hypothesis we show that equilibrium solutions
can be found via iterative convex minimization. In the main algorithm each stage of computation requires two proximal steps,
possibly using Bregman functions. One step serves to predict the next point; the other helps to correct the new prediction.
To enhance practical applicability we tolerate numerical errors.
Research supported partly by the Norwegian Research Council, project: Quantec 111039/401. 相似文献