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61.
62.
A theory of electron tunneling through a single-center bridge redox group that has two electronic levels participating in the electron transfer process is presented. The temperature is presumed to be low enough to ignore activation redox conversions of the bridge group. Salient features of this system are due both to the presence of two electroactive states of the bridge group and to relaxation processes along the reaction coordinate. The processes in question make the tunneling current time-dependent at fixed potentials and can bring about hysteresis in current-voltage curves when cycling the bias potential. Effects of inelastic tunneling with excitation of vibrations of a local quantum degree of freedom are considered. 相似文献
63.
We have investigated the dependence of the electronic factor in electron-transfer rate constants on the energy gap and temperature by minimizing the electronic energy with respect to the instantaneous non-equilibrium solvent polarization. The electronic charge billows out and shrinks in the “normal” and strongly exothermic free energy region, respectively, but the effect is only comparable to the variation of the nuclear factor for low temperatures and strongly exothermic processes. 相似文献
64.
Y. E. Kuznetsov N. L. Sukhov F. V. Pichugin B. G. Ershov 《Russian Chemical Bulletin》1996,45(12):2816-2819
Reactions ofmyo-inositiol hexa-O-nitrate with ammonia and primary amines yield tetrahydroxy-1,4-benzoquinone derivatives,viz., its tetraammonium salt and its diimines, respectively. Reactions with secondary and tertiary amines give salts of rhodizonic acid, which are converted into salts of croconic acid under certain conditions. The reactions with secondary amines involve intermediate formation of radical species, which were dectected by ESR spectroscopy. A scheme for the chemical transformations ofmyo-inositol hexa-O-nitrate under the action of amines was proposed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2962–2967, December, 1996. 相似文献
65.
66.
Oriňák Andrej Vering Guido Arlinghaus Heinrich F. Andersson Jan T. Halas Ladislav Oriňáková Renáta Turčániová Ľudmila 《平面色谱法杂志一现代薄层色谱法》2005,18(1):44-50
JPC – Journal of Planar Chromatography – Modern TLC - A new hyphenated technique that enables coupling of thin-layer chromatography (TLC) with time-of-flight secondary-ion mass... 相似文献
67.
Shcherbakova I. V. Potemkhina N. N. Dorofeenko G. N. Kuznetsov E. V. 《Chemistry of Heterocyclic Compounds》1977,13(7):810-810
Chemistry of Heterocyclic Compounds - 相似文献
68.
Sevastyanov V. G. Sevastyanov D. V. Peresypkina E. V. Blatov V. A. Kuznetsov N. T. 《Russian Journal of Coordination Chemistry》2004,30(10):679-684
The structure-thermochemical approach to analysis and prediction of vaporization parameters of volatile organometallic compounds was modified and software-implemented on the basis of the concept of Voronoi–Dirichlet molecular polyhedra. The TOPOS program package was employed to analyze the intermolecular contacts and to calculate the vaporization enthalpies for 570 organotitanium molecular complexes selected from the Cambridge Structural Database. In the case of titanium hydrocarbon complexes, the results of semiempirical calculation are in satisfactory agreement with experimental data. In other cases, the quantitative thermochemical parameters obtained allow one to estimate the unknown cooperative contributions for various functional groups. 相似文献
69.
Tsykoza L. T. Ismagilov Z. R. Ushakov V. A. Kuznetsov V. V. Ovsyannikova I. A. 《Kinetics and Catalysis》2003,44(6):806-812
The phase composition of supported Mn–Al–O catalysts and their activity in the reaction of methane oxidation were studied depending on the composition of aluminum oxide supports (-Al2O3 with different -Al2O3 contents modified with individual Mg, La, and Ce oxides or Mg + La and Mg + Ce oxide mixtures) and calcination temperatures (500, 900, and 1300°C). It was found that the Mn–Al–O catalysts based on -alumina containing -Al2O3 and modified with Mg, La, or Ce additives are more active and thermally stable (up to 1300°C) than the samples based on pure -Al2O3. A conclusion was drawn that a higher degree of disorder of the structure of -Al2O3, compared to that of -Al2O3, is favorable for a deeper interaction of manganese and modifying additives with the support at the early stages of the synthesis and for the formation of Mn–Al compounds with complex composition (solid solutions and/or hexaaluminates) at 1300°C. These compounds are responsible for the stability and high activity of the catalysts in methane oxidation. 相似文献
70.
V. V. Kuznetsov 《Chemistry of Heterocyclic Compounds》2002,38(8):1008-1011
Gas-liquid chromatography was used to establish that the reactivity of the cis isomer in the reaction of 5-isopropyl-4-methyl-1,3-dioxane with the diisobutyl ester of isobutylboric acid leading to the corresponding 1,3,2-dioxaborinane is greater than for the trans isomer. An AM1 calculation for the energy of the intermediate ions in this reaction with model derivatives of boric acids: dioxyborane and the dimethyl ester of methylboric acid showed that one of the probable reasons for the observed behavior is the lower barrier for conversion of the intermediate bipolar structure of the cis derivative in the step involving formation of the endocyclic B-O bond. 相似文献