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化学学报
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化学学报 ›› 2006, Vol. 64 ›› Issue (14): 1474-1478. 上一篇    下一篇

研究论文

2D NMR研究对称四甲基六元瓜环与5,5'-二甲基-2,2'-联吡啶的相互作用

陶龙玲1，薛赛凤2，祝黔江2，陶朱2，余亦华*,1   

  1. (1华东师范大学教育部光谱学与波谱学重点实验室 上海 200062)
    (2贵州大学应用化学研究所 贵阳 550025)
  • 投稿日期:2005-11-04 修回日期:2006-03-16 发布日期:2006-07-28
  • 通讯作者: 余亦华

2D NMR Studies on the Interaction of Symmetrical Tetramethylcucurbit[6]uril with 5,5'-Bimethyl-2,2'-bipyridine

TAO Long-Ling1, XUE Sai-Feng2, ZHU Qian-Jiang2, TAO Zhu2, YU Yi-Hua*,1   

  1. (1 Key Laboratory of Optical and Magnetic Resonance Spectroscopy, East China Normal Univer-sity, Ministry of Education, Shanghai 200062)
    (2 Institute of Applied Chemis-try, Guizhou University, Guiyang 550025)
  • Received:2005-11-04 Revised:2006-03-16 Published:2006-07-28
  • Contact: YU Yi-Hua

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983

被引次数

11

运用二维NMR实验研究了作为主体的对称四甲基取代六元瓜环(TMeQ[6])与作为客体的5,5'-二甲基-2,2'-联吡啶(bmbpy)的相互作用. 2D ROESY谱上主客体分子间的NOE相关峰明确地给出了主客体的结合位置和结合物的空间结构: 客体的一个吡啶环进入了主体的内腔, 而另一个吡啶环则位于主体的一端端口外, 进入内腔的吡啶环平面位于主体的长截面上, 两个吡啶环之间为顺式构象. 2D EXSY谱呈现的客体两个吡啶上对应氢之间的交换峰表明: 高温下两个吡啶环交替进入主体的内腔, 分别结合于主体的两个端口, 形成了动态的平衡. 由2D EXSY的交换峰和对角线峰强度计算出了不同温度下的交换速率, 并由此得到了该交换过程的活化能为104.2 kJ/mol.

关键词: 对称四甲基取代六元瓜环, 5,5'-二甲基-2,2'-联吡啶, NOE, 动态平衡, 活化能

Complexation between symmetrical tetramethylcucurbit[6]uril (TMeQ[6]) and 5,5'-bimethyl- 2,2'-bipyridine (bmbpy) was studied by two dimensional nuclear magnetic resonance (2D NMR) as a host-guest interaction. Intermolecular NOE to appear in 2D ROESY (Rotating Frame Overhause Effect Spectroscopy) revealed a well-defined complex structure between them. One of pyridine rings in bmbpy intercalated the cavity of TMeQ[6] and the other was located outside one portal of TMeQ[6]. Two-dimensional exchange spectroscopy (2D EXSY) showed that the complex has undergone slow exchange at high temperature with two pyridine rings of bmbpy alternatively entering the cavity of TMeQ[6] and changing the combinative sites between the two portals of TMeQ[6]. The temperature dependence of the rate constants calculated from the exchange spectra yielded an activation energy of 104.2 kJ/mol for the exchange process.

Key words: symmetrical tetramethylcucurbit[6]uril, 5,5'-bimethyl-2,2'-bipyridine, NOE, dynamic equilibrium, activation energy