...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Density Functional Theory Study of the Platinum-Catalyzed Cyclopropanation Reaction with Olefin
【24h】

Density Functional Theory Study of the Platinum-Catalyzed Cyclopropanation Reaction with Olefin

机译：铂催化烯烃的环丙烷化反应的密度泛函理论研究

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

A computational study of the platinum-catalyzed cyclopropanation reaction with olefin is presented.The model system is formed by an ethylene molecule and the active catalytic species,which forms from a CH2 fragment and the C12Pt(PH3)2 complex.The results show that the active catalytic species is not a metal-carbene of the type(PH3)2C12Pt=CH2 but two carbenoid complexes which can exist in almost two degenerate forms,namely(PH3)2Pt(CH2Cl)Cl(carbenoid A)and(PH3)Pt(CH2PH3)Cl2(carbenoid B).The reaction proceeds through three pathways:methylene transfer,carbometalation for carbenoid A,and the reaction of a monophosphinic species for carbenoids(A and B).The most favored reaction channel is methylene transfer pathway for(PH3)Pt(CH2PH3)Cl2(carbenoid B)species with a barrier of 31.32 kcal/mol in gas phase.The effects of dichloromethane,THF,and benzene solvent are investigated with PCM method.For carbenoid A,both methylene transfer and carbometalation pathway barriers to reaction become remarkably lower with the increasing polarity of solvent(from 43.25 and 52.50 kcal/mol for no solvent to 25.36 and 38.53 kcal/mol in the presence of the dichloromethane).In contrast,the reaction barriers for carbenoid B via the methylene transfer path hoist 6.30 kcal/mol,whereas the barriers do not change significantly for the reaction path of a monophosphinic species for carbenoids(A and B).
机译：进行了铂与烯烃的环丙烷化反应的计算研究。模型系统由乙烯分子和由CH2片段和C12Pt（PH3）2配合物形成的活性催化物种组成。活性催化物质不是（PH3）2C12Pt = CH2类型的金属碳烯，而是两种可能以几乎两种简并形式存在的类胡萝卜素络合物，即（PH3）2Pt（CH2Cl）Cl（类胡萝卜素A）和（PH3）Pt（ CH2PH3）Cl2（类胡萝卜素B）。反应通过三个途径进行：亚甲基转移，类胡萝卜素A的碳金属化以及单膦类物质对类胡萝卜素（A和B）的反应。最优选的反应通道是（PH3）的亚甲基转移途径气相中阻隔率为31.32 kcal / mol的Pt（CH2PH3）Cl2（类胡萝卜素B）物种。采用PCM方法研究了二氯甲烷，THF和苯溶剂的影响。对于类胡萝卜素A，亚甲基转移和碳金属化途径的障碍使反应变得引人注目y随着溶剂极性的增加而降低（从无溶剂时的43.25和52.50 kcal / mol降低到二氯甲烷存在下的25.36和38.53 kcal / mol）。与此相反，类胡萝卜素B通过亚甲基转移路径提升器的反应势垒为6.30 kcal / mol，而对于类膦酸酯类化合物（A和B）的反应路径，势垒没有明显改变。

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