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1.
Sadovskii Yu. S. Solomoichenko T. N. Kas'yan A. O. Golodaeva E. A. Anikanova S. V. Kas'yan L. I. Savelova V. A. 《Russian Journal of Organic Chemistry》2004,40(1):50-56
The nucleophilic reactivity of amines of the norbornane, norbornene, and adamantane series toward ptoluenesulfonyl chloride and diphenyl chlorophosphate in acetonitrile at 25°C is determined mainly by the steric factor. Parameters characterizing spatial accessibility of the reaction center in the amine molecule have been determined. Cage-like substituents show no appreciable effect on the amine reactivity, as compared to common alkyl groups. 相似文献
2.
T. N. Solomoichenko Yu. S. Sadovskii T. M. Prokop’eva E. A. Karpichev I. V. Kapitanov Zh. P. Piskunova V. A. Savelova A. F. Popov 《Theoretical and Experimental Chemistry》2006,42(6):364-370
We have studied the nucleophilicity of the hydroperoxide anion relative to 4-nitrophenyl diethyl phosphonate (NPDEPS) in the
presence of cetyltrimethylammonium bromide (water, 25 °C) while varying the acidity of the medium and the hydroperoxide anion
concentration over a broad range. The increase in the reaction rate when the reaction is transferred to a micellar pseudophase
is as high as ∼10-fold, which is explained by concentration effects. In CTAB micelles, as in water, the hydroperoxide ion
is one of the most effective α-nucleophiles, and the size of the α-effect, characterized by the ratio of the second-order rate constants for reactions of HOO− and OH− anions with NPDEPS, remains practically constant and reaches a value of ∼50-fold.
__________
Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 42, No. 6, pp. 357–363, November–December, 2006. 相似文献
3.
Popov A. F. Lobanova O. V. Savelova V. A. Sadovskii Yu. S. Solomoichenko T. N. Piskunova Zh. P. 《Russian Journal of Organic Chemistry》2002,38(11):1624-1628
For amides belonging to series RCONH2 (I), RCONHMe (II), RCONHPh (III), and RCONMe2 (IV) rate constants k1 (l mol-1 s-1) were determined (in acetonitrile at 25°C) specifying the nucleophilic reactivity of the oxygen atom in amides toward benzoyl chloride and diphenyl chlorophosphate. The lack of substrate selectivity in the reactions in question was established. For equal values of inductive constants * of the R substituents the reactivity sequence of amides with respect to both substrates is the same (I >>
IV >
II, and III >
II), and it does not follow the corresponding sequence of basicities. A conclusion was drawn that both groups of reactions proceed through cyclic transition states resembling reagents: six-membered with amides I and III, and five-membered with amides II and IV. 相似文献
4.
R. R. Akhmerov M. I. Kamenskii A. S. Potapov A. E. Rodkina B. N. Sadovskii 《Journal of Mathematical Sciences》1984,24(6):674-719
In the paper we present a survey of the investigations on the theory of equations of neutral type, i.e., equations for which the value of the derivative at the present moment depends explicitly on the prehistory of the behavior of the derivative. The paper consists of eleven sections.Translated from Itogi Nauki i Tekhniki, Seriya Matematicheskii Analiz, Vol. 19, pp. 55–126, 1982. 相似文献
5.
S. V. Verkhovskii Yu. I. Zhdanov A. M. Bogdanovitch K. N. Mikhalyov B. A. Aleksashin V. V. Serikov V. V. Lavrentjev M. V. Sadovskii 《Applied magnetic resonance》1992,3(3-4):649-663
NMR line shifts and spin-lattice relaxation rates of89Y and63Cu in YBa2Cu3O6.9 were measured in disordered samples irradiated by fast neutrons with a fluence of: ?=5·1018 cm?2 (T c ons =70 K), ?=1.2·1019 cm?2 (T c ons =20 K), in order to investigate the evolution of spin susceptibility χS under irradiation. According to the data obtained, χS decreases markedly as structural disorder accumulates in the samples. The variation of χS is related closely to that observed in oxygen-depleted YBa2Cu3O7?δ compounds with nearly the sameT c value. The data for yttrium display some features that are absent in oxygen-depleted samples. The different temperature dependence of the89Y and63Cu Knight shifts and the increase of the89Y spin-lattice relaxation rate in irradiated samples are discussed in terms of the electron localization effects arising in the CuO2 planes due to the radiation-induced structural disorder. 相似文献
6.
7.
The self-consistent theory of electron localization in a random system in the form proposed by Vollhardt and Wölfle is generalized for the analysis of localization in the Anderson model. We derive the general equations appropriate for the system with rather general form of the electronic spectrum. Explicit calculations are restricted to the lattices of cubic symmetry and use the effective mass approximation to obtain the final results. Anderson's critical ratio for the localization of all the electronic states in the tight-binding band is evaluated and found to be in surprisingly good agreement with the results of numerical analysis of localization in the Anderson model. 相似文献
8.
9.
We generalize the dynamical-mean field theory (DMFT) by including into the DMFT equations dependence on the correlation length of the pseudogap fluctuations via the additional (momentum dependent) self-energy Σk. This self-energy describes nonlocal dynamical correlations induced by short-ranged collective SDW-like antiferromagnetic spin (or CDW-like charge) fluctuations. At high enough temperatures, these fluctuations can be viewed as a quenched Gaussian random field with finite correlation length. This generalized DMFT + Σk approach is used for the numerical solution of the weakly doped one-band Hubbard model with repulsive Coulomb interaction on a square lattice with nearest and next nearest neighbor hopping. The effective single impurity problem is solved by using a numerical renormalization group (NRG). Both types of strongly correlated metals, namely, (i) doped Mott insulator and (ii) the case of the bandwidth W ? U (U-value of local Coulomb interaction) are considered. By calculating profiles of the spectral densities for different parameters of the model, we demonstrate the qualitative picture of Fermi surface destruction and formation of Fermi arcs due to pseudogap fluctuations in qualitative agreement with the ARPES experiments. Blurring of the Fermi surface is enhanced with the growth of the Coulomb interaction. 相似文献
10.
N. A. Kuleeva E. Z. Kuchinskii M. V. Sadovskii 《Journal of Experimental and Theoretical Physics》2004,99(6):1264-1278
We analyze the peculiarities of the superconducting state (s- and d-wave paring) in the model of the pseudogap state induced by Heisenberg antiferromagnetic short-range order spin fluctuations. The model is based on the pattern of strong scattering near hot spots at the Fermi surface. The analysis is based on the microscopic derivation of the Ginzburg-Landau expansion with the inclusion of all Feynman diagrams of perturbation theory for the interaction of an electron with short-range order fluctuations and in the ladder approximation for the scattering by normal (nonmagnetic) impurities. We determine the dependence of the critical superconducting transition temperature and other superconductor characteristics on the pseudogap parameters and the degree of impurity scattering. We show that the characteristic shape of the phase diagram for high-temperature superconductors can be explained in terms of the model under consideration. 相似文献