排序方式: 共有86条查询结果,搜索用时 17 毫秒
1.
V. R. Khabibulin A. V. Kulik I. V. Oshanina L. G. Bruk O. N. Temkin V. M. Nosova Yu. A. Ustynyuk V. K. Bel’skii A. I. Stash K. A. Lysenko M. Yu. Antipin 《Kinetics and Catalysis》2007,48(2):228-244
The formation mechanism of the active catalyst in the oxidative carbonylation of terminal alkynes at the ≡C-H bond has been investigated for the catalytic system Pd(OAc)2-PPh3-p-benzoquinone (Q)-MeOH. It has been demonstrated by NMR spectroscopy, X-ray crystallography, and kinetic measurements that the catalytically active palladium is in the oxidation state 0 and is bound into complexes stabilized by p-benzoquinone (PdL2Q, where L = PPh3). A mechanism is suggested for the catalytic process, which includes the formation of the complex PdL2Q, the oxidative addition of the alkyne to this complex at the ≡C-H bond, the insertion of CO into the Pd-C bond, and steps in which hydride hydrogen is intramolecularly transferred to the p-quinone. 相似文献
2.
O. V. Firsova T. S. Dolgushina V. A. Polukeev E. M. Ioannisyan V. E. Zavodnik A. I. Stash V. K. Bel’skii V. A. Galishev 《Russian Journal of Organic Chemistry》2005,41(5):762-768
Reactions of thiazoline-2-thione with C,N-disubstituted nitrile imines were investigated. The reaction products are substituted 2-(1,3,4-thiadiazol-2-ylideneamino)ethanethiols and bis[2-(1,3,4-thiadiazol-2-ylideneamino)ethyl] disulfides. The reaction of thiazoline-2-thione with a double excess of nitrile imine did not considerably change the process route. The structure of compounds obtained was proved by X-ray diffraction analysis. A presumable scheme is given describing the formation of compounds obtained.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 5, 2005, pp. 776–782.Original Russian Text Copyright © 2005 by Firsova, Dolgushina, Polukeev, Ioannisyan, Zavodnik, Stash, Bel’skii, Galishev. 相似文献
3.
Brel VK Belsky VK Stash AI Zavodnik VE Stang PJ 《Organic & biomolecular chemistry》2003,1(23):4220-4226
Reaction of 1-chloro-4-(diethoxyphosphonyl)alka-2,3-dienes 14,15 with purine and pyrimidine heterocyclic bases in the presence of cesium carbonate afforded new acyclic analogues of nucleotides containing a 1,2-alkadienic skeleton 18-23. Dealkylation of 18-23 furnished phosphonic acids 2a-f. In contrast, alkylation reaction with 1-chloro-4-(diethoxyphosphonyl)octa-2,3-diene 16 led to Z- and E-1,3-alkadienic phosphonates 25a,b and 26a,b. A similar reaction with 1-chloro-4-(diethoxyphosphonyl)-2-methylbuta-2,3-diene 17 led to the elimination of hydrochloride and formation of 4-(diethylphosphonyl)-2-methylbut-1-en-3-yne 24. Molecular structures of new acyclic nucleotides 18 and 2f are determined by X-ray crystallographic analysis. 相似文献
4.
Tsirelson Vladimir Abramov Yury Zavodnik Valery Stash Adam Belokoneva Elena Stahn Jochen Pietsch Ullrich Feil Dirk 《Structural chemistry》1998,9(4):249-254
The critical points in the model electron density distributions of LiF, NaF, NaCl, and MgO crystals, constructed from accurate X-ray diffraction data, are determined. For LiF and MgO they are compared with those obtained from a Hartree–Fock electron density calculation. Both experiment and theory show the same type of critical points on the bond lines. The topological features in areas between structural units, where the electron density is low and near-uniform, turn out to be model dependent and cannot be established well with the data available. Topological analysis of procrystals (hypothetical systems consisting of spherical atoms or ions placed on the same sites as atoms in real crystal) show that (3, –1) critical points, usually connected with bonding interaction, are observed on interatomic lines in these nonbonded systems as well. 相似文献
5.
RADIATION-INDUCED CHANGES IN THE STRUCTURE AND FERROELECTRIC PROPERTIES OF Pb5Ge3O11 SINGLE CRYSTALS
Stash A. I. Ivanov S. A. Boiko V. M. Ermakov V. S. Stefanovich S. Yu. Mosunov A. V. 《Journal of Structural Chemistry》2021,62(12):1880-1895
Journal of Structural Chemistry - Perfect stoichiometric Pb5Ge3O11 single crystals are irradiated with 60Co γ-rays (1·106 Rad) and high-energy electrons (0.13 e/cm2, 0.89 e/cm2,... 相似文献
6.
Crystallography Reports - Perfect stoichiometric Pb5Ge3O11 single crystals have been synthesized by the flux method. Their cationic and anionic stoichiometry is confirmed by chemical analysis. The... 相似文献
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Patrick J. Fricke Jenna L. Stasko Dylan T. Robbins Alexander C. Gardner Jacqueline Stash Mark J. Ferraro Michael W. Fennie 《Tetrahedron letters》2017,58(48):4510-4513
Propargyl imidates derived from aromatic and aliphatic nitriles cyclize at room temperature in high yields when treated with a catalytic amount of copper (I) iodide. This 5-exo-dig process affords dihydrooxazoles which do not aromatize under the reaction conditions, and which are isolated without chromatography. Investigations of the reaction scope, subsequent functionalization of the reaction products, and preliminary mechanistic data are presented. 相似文献
9.
O. V. Kovalchukova A. I. Stash S. B. Strashnova E. P. Romashkina B. E. Za?tsev 《Crystallography Reports》2010,55(3):428-431
The complex compounds (H3
L · Cl)[CoCl4] (I) and H2
L[CuBr4] (II), where L is 2,4,6-tri(N,N-dimethylamino)methylphenol, were isolated in the crystalline state and studied by X-ray diffraction. The organic cations
were found to be outer-sphere ligands. All three nitrogen atoms of the tertiary amino groups are protonated. In compound I, the H3
L
3+ cation exists as the cis tautomer. In compound II, the H2
L
2+ dication exists as the trans isomer. In the crystal structure, the dications are arranged in layers via hydrogen bonds. 相似文献
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