• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Theoretical and X-ray crystallographic evidence of a fluorine-imine gauche effect: An addendum to dunathan's stereoelectronic hypothesis
【24h】

Theoretical and X-ray crystallographic evidence of a fluorine-imine gauche effect: An addendum to dunathan's stereoelectronic hypothesis

机译：氟亚胺薄纱效应的理论和X射线晶体学证据：杜纳森（Dunathan）立体电子假说的附录

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The preference of β-fluoroimines to adopt a gauche conformation has been studied by single-crystal X-ray diffraction analysis and DFT methods. Empirical and theoretical evidence for a preferential gauche arrangement around the NCCF torsion angle (φ) is presented ((E)-2-fluoro-N-(4-nitrobenzylidene) ethanamine: φ_(NCCF)=70.0°). In the context of this study, the analysis of a pyridoxal-derived β-fluoroaldimine was performed, a species that is implicated in the inhibition of pyridoxal phosphate (PLP)-dependent enzymes by β-fluoroamine derivatives. The gauche preference of the internal aldimine (=NCH_2CH_2F) that can be rationalized by stereoelectronic arguments does not hold for the corresponding external system (N=CHCH_2F) (Emin when φ_(NCCF)=120°). Moreover, the C-F bond is lengthened by more than 0.02 ? at φ_(NCCF)=±90°, when it is exactly antiperiplanar to the conjugated imine. This activation of the C-F σ bond by an adjacent π system constitutes an addendum to Dunathan's stereoelectronic hypothesis.
机译：通过单晶X射线衍射分析和DFT方法研究了β-氟亚胺选择gauche构象的倾向。提出了围绕NCCF扭转角（φ）的优先纱布排列的经验和理论证据（（E）-2-氟-N-（4-硝基苄叉）乙胺：φ_（NCCF）= 70.0°）。在本研究的背景下，进行了对吡ido醛衍生的β-氟代醛亚胺的分析，该物种与β-氟胺衍生物对吡ido醛磷酸酯（PLP）依赖性酶的抑制有关。可以通过立体电子学参数合理化的内部醛亚胺（= NCH_2CH_2F）的树突偏好对于相应的外部系统（N = CHCH_2F）不成立（当φ_（NCCF）= 120°时为Emin）。而且，C-F键延长了0.02≤α。当φ_（NCCF）=±90°时，恰好与共轭亚胺成反平面。相邻π系统对C-Fσ键的激活构成了Dunathan立体电子假设的附录。

著录项

相似文献

  • 外文文献
  • 中文文献
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号