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11.
Wieland Tyrra Harald Scherer Lesya A. Babadzhanova Natalya V. Kirij Yurii L. Yagupolskii Dieter Naumann Ingo Pantenburg 《Helvetica chimica acta》2008,91(1):97-110
A convenient synthesis of the 1,3‐dihydro‐1,3,3‐tris(perfluoroalkyl)isobenzofuran‐1‐ols 3a , b was elaborated starting from commercially available phthaloyl dichloride and trimethyl(perfluoroalkyl)silanes (Me3SiRf) 1a , b (Rf=CF3, C2F5) in the presence of a fluoride source (Schemes 1 and 3). In a reaction analogous to alkyl Grignard reagents, double chloride substitution by two perfluoroalkyl groups and subsequent addition of one perfluoroalkyl group with concomitant ring closure led to this new class of compounds (Scheme 2). The syntheses of the alcohols and some alcoholates, as well as of the corresponding trimethylsilyl ethers are described. A combination of special 1D and 2D NMR experiments allowed the assignment of all atoms of the new compounds. The solid‐state structure of 1,3‐dihydro‐1,3,3‐tris(trifluoromethyl)isobenzofuran‐1‐ol ( 3a ) was elucidated by X‐ray diffraction methods. 相似文献
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2-Trimethylsilylcorannulenyl trifluoromethanesulfonate, prepared from bromocorannulene, provides a means for generating of 1,2-didehydrocorannulene (corannulyne) under very mild conditions as demonstrated by the high-yield formation of its adducts with dienes. 相似文献
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We give a complete classification of stable vector bundles over a cuspidal cubic and calculate their cohomologies. The technique
of matrix problems is used, similar to [2, 3]. 相似文献
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Application of the synthetic methodology developed in our laboratory yields molecular clips and tweezers with corannulene pincers and cyclooctadiene or cyclooctatetraene tethers. These highly nonplanar systems possess a potential for binding guest molecules of various sizes. One of the clips, bis(benzocorannulene)[a,e]cyclooctadiene, exists in a ‘open’ chair conformation encapsulating solvating nitrobenzene in the solid state, while it is expected to prefer an internally π-π stacked twist-boat conformation in the gas phase. 相似文献
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Lesya Momot Tatyana Zheltonozhskaya Nataliya Permyakova Sergey Fedorchuk Vladimir Syromyatnikov 《Macromolecular Symposia》2005,222(1):209-218
The phenomenon of self-assembly of aggregates formed by relatively short chains of poly(vinyl alcohol) (PVA) on the long macromolecules of polyacrylamide (PAA) in aqueous medium are discussed. PVA and PAA form intermolecular polycomplexes (InterPC) of a constant composition independently on a ratio of polymer components. The complex formation between high-molecular-weight PAA and relatively low-molecular-weight poly(ethylene oxide) (PEO) are considered also. PEO with M ⩽ 4·104 g.mol−1 weakly interacts with PAA. The polymer-polymer interaction can be intensified when the part of amide groups (∼20 mol %) on PAA chain to transform into the carboxylic groups. InterPCs formed by PEO and initial or modified PAA have associative structure with friable packing of the polymer segments. They are stabilized by the hydrogen bond system. 相似文献
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Nataliya Permyakova Tatyana Zheltonozhskaya Valery Shilov Nina Zagdanskaya Lesya Momot Vladimir Syromyatnikov 《Macromolecular Symposia》2005,222(1):135-142
Thermal transitions in the bulk structure of triblock copolymers (PAA-b-PEO-b-PAA) based on polyacrylamide and poly(ethylene oxide) with varying molecular weight (length) of PEO block comparing with the structures of individual polymers and polymer mixtures were investigated. A lot of effects, such as the melting temperature depression, decreasing of the crystallinity degree of PEO and also appearance of the microphase separation in amorphous regions of the polymer mixtures and the triblock copolymers were found. Such investigations pointed to a strong intramolecular interaction of the polymer blocks in the triblock copolymers that is confirmed by the results of IR spectroscopy. It was shown that PEO and PAA blocks formed the system of H-bonds with participant of trans-multimers of amide groups. 相似文献
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A.E. Kobryn M.V. Tokarchuk Y.A. Humenyuk 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,13(3):579-583
The Enskog-Landau kinetic equation is considered to describe non-equilibrium processes of a mixture of charged hard spheres.
This equation has been obtained in our previous papers by means of the non-equilibrium statistical operator method. The normal
solution of this kinetic equation found in the first approximation using the standard Chapman-Enskog method is given. On the
basis of the found solution the flows and transport coefficients have been calculated. All transport coefficients for multicomponent
mixture of spherical Coulomb particles are presented analytically for the first time. Numerical calculations of thermal conductivity
and thermal diffusion coefficient are performed for some specific mixtures of noble gases of high density. We compare the
calculations with those ones for point-like neutral and charged particles.
Received 10 June 1999 and Received in final form 15 October 1999 相似文献
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Yakovenko Georgiy G. Saliyeva Lesya N. Rusanov Eduard B. Donchak Il’ya S. Vovk Mykhailo V. 《Chemistry of Heterocyclic Compounds》2021,57(11):1137-1145
Chemistry of Heterocyclic Compounds - N-Boc-4-aminopyrazole-5-carbaldehydes react with methyl 3,3-dimethoxypropanoate or β-keto esters in acetic acid under reflux to form methyl(ethyl)... 相似文献