• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Comparative Investigation of Ruthenium-Based Metathesis Catalysts Bearing N-Heterocyclic Carbene (NHC) Ligands
【24h】

Comparative Investigation of Ruthenium-Based Metathesis Catalysts Bearing N-Heterocyclic Carbene (NHC) Ligands

机译：N-杂环碳烯（NHC）配体的钌基复分解催化剂的比较研究

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

Exchange of one PCy_3 unit of the classical Grubbs catalyst 1 by N-het-erocyclic carbene (NHC) ligands leads to "second-generation" metathesis cata-lysts of superior reactivity and increased stability .Several complexes of this type have been prepared and fully character-ized ,six of them by X-ray crystallogra-phy.These include the unique chelate complexes 13 and 14 in which the NHC-and the Ru=CR entities are tethered to form a metallacycle.A particularly favorable design feature is that the reac-tivity of catalysts can be easily adjusted by changing the electronic and steric propertise of the NHC ligands The catalytic activity also strongly de-pends on the solvent used;NMR inves-tigations provide a tentative explanation of this effect.Applications of the "sec-ond-generation" catalysts to ring closing alkene metathesis and intramolecular enyne cycloisomerization reactions pro-vide insights into their catalytic perform-ance.From these comparative studies it is deduced that no single catalyst is optimal for different types of applica-tions .The search for the most reactive catalyst for a specific transformation is facilitated by IR thermography allowing a rapid and semi -quantitative ranking among a given set of catalysts.
机译：N-杂环碳烯（NHC）配体交换经典Grubbs催化剂1中的一个PCy_3单元会导致“第二代”复分解催化剂具有更高的反应性和更高的稳定性。已经制备了几种这类配合物并充分利用了这些配合物通过X射线晶体学对其中的六个进行了表征，其中包括独特的螯合配合物13和14，其中NHC-和Ru = CR实体被束缚形成金属环。可以通过改变NHC配体的电子和空间特性来轻松调节催化剂的反应性。催化活性也强烈依赖于所用的溶剂; NMR研究提供了对该效应的初步解释。闭环烯烃复分解和分子内烯炔环异构化反应的“第二代”催化剂提供了有关其催化性能的见解。从这些比较研究中可以推断出，没有单一的催化剂红外热成像技术可以在给定的一组催化剂之间进行快速和半定量的排名，从而为特定的转化寻找最具反应性的催化剂。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
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