全文获取类型
收费全文 | 58篇 |
免费 | 0篇 |
专业分类
化学 | 57篇 |
物理学 | 1篇 |
出版年
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2013年 | 2篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 2篇 |
2009年 | 4篇 |
2008年 | 2篇 |
2007年 | 3篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1998年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1965年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有58条查询结果,搜索用时 328 毫秒
1.
2.
3.
V. F. Starichenko L. A. Shundrin L. N. Shchegoleva V. D. Shteingarts 《Journal of Structural Chemistry》2002,43(2):206-217
According to the data of UHF/INDO calculations of the model conformations of fluorinated nitrobenzene radical anions, rotation of the nitro group relative to the plane of the benzene ring is accompanied by a pyramidal distortion of the group, which is of pseudo-Jahn–Teller nature. The degree of structural distortions depends on the position of the fluorine atoms in the benzene ring and on the solvent, increasing from DMF to DMF–water mixtures. The values of isotropic hyperfine interaction constants are interpreted in the series of fluorinated nitrobenzene radical anions, and the effects of water content in binary mixtures of solvents are discussed. 相似文献
4.
Russian Journal of Organic Chemistry - 相似文献
5.
Galina A. Selivanova Leonid M. Pokrovskii Vitaliy D. Shteingarts 《Journal of fluorine chemistry》2004,125(12):1829-1834
Chlorine-containing polyfluorinated anilines and meta-phenylenediamines undergo selective hydrodechlorination easily upon reduction by zinc in aqueous ammonia. A new approach is thus provided to synthetically valuable, partially fluorinated arylamines based on utilizing polyfluorochloroarenes, which are available as intermediates of perfluoroarene production from perchloroarenes. When chlorine atoms are present in positions both ortho and para to the amino group, para chlorine is initially eliminated. Based on this reaction, a one-pot synthesis of partially fluorinated 4-aminopyridines from 3,5-dichlorotrifluoro- and 3-chlorotetrafluoropyridine has been realized. 相似文献
6.
When dissolved in SbF5, polyfluorinated trifluoromethylbenzenes produce polyfluorinated α,α-difluorobenzyl ions. The 19F chemicals shifts and spin-spin coupling constants J(FF) have been analysed in terms of the resonance structures which contribute to the overall positive charge distribution. The influence of halogen atoms situated at position 4 on the downfield signal shift of α-fluorines follows the sequence F > Cl > Br which is opposite to that observed for 4-XC6H4CF2+ ions. 相似文献
7.
Conclusion Cyclic polarometfy and ESR spectrometry were used to show that the introduction of fluorine atom into the meta position of benzonitrile leads to stabilization of the corresponding radical-anions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2794–2796, December, 1986. 相似文献
8.
9.
Synthetic and mechanistic aspects of the developed approach to the activation of aromatic nitriles are considered. The approach
is based on the transformation of aromatic nitriles into stable anionic reduced forms. The latter, as shown for the reactions
with alkyl halides and cyanoarenes, are promising reactants for the reactions with carbon-centered electrophiles.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 754–765, April, 2008. 相似文献
10.
L. I. Goryunov N. M. Romanova G. S. Zhilovskii V. D. Shteingarts 《Russian Journal of Organic Chemistry》2007,43(12):1765-1772
Reactions of fluoro-and chloromesitylene π-complexes [(η6-1-Hlg-2,4,6-Me3C6H2)(η5-C5EtMe4)Rh]-(BF4)2 (Hlg = F, Cl) with diethyl malonate anion in THF or acetone-d 6 at 20°C initially (within the first 5–30 min) involve nucleophile addition at unsubstituted carbon atom in the arene ligand with formation of π-cyclohexadienyl complexes {[η5-1-(EtOCO)2CH-1-H-3-Hlg-2,4,6-Me3C6H2](η5-C5EtMe4)Rh}(BF4). The subsequent replacement of the halogen atom yields {[η6-1-(EtOCO)2CH-2,4,6-Me3C6H2](η5-C5EtMe4)Rh}(BF4)2, where the arene ligand is readily withdrawn from π-coordination by the action of chloride ion or the solvent. Dimethyl mesitylmalonate was isolated in 76% yield. Likewise, the reactions with anions derived from malononitrile and ethyl cyanoacetate gave 25–38% of the corresponding derivatives 1-R-2,4,6-Me3C6H2 where R = (NC)2CH or EtOCO(NC)CH. 相似文献