Acta Scientiarum Naturalium Universitatis Pekinensis

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NMR Study on Cryptand (2,2) and Its Lanthanum Nitrate Cryptate

LI Yuejun, TIAN Feng, XU Zhenhua, XU Guangxian   

  1. College of Chemistry and Molecular Engineering, State Key Laboratory of Rare Earth Material Chemistry and Applications, Peking University, Beijing, 100871
  • Received:1996-03-27 Online:1996-07-20 Published:1996-07-20

穴醚(2,2)及其硝酸镧配合物的核磁共振研究

李月军,田丰,许振华,徐光宪   

  1. 北京大学化学与分子工程学院,稀土材料化学与应用国家重点实验室,北京,100871

Abstract: The solution structures of cryptand (2,2) and its Lanthanum nitrate cryptate intheir acetonitrile solution were studied, basing on their 1H, 13C, 1H-1H and 1H-13C NMR (Nuclear Magnetic Resonance) spectra. The cryptand has several distinct conformations in solution which are in equilibra of rapid interconversion. It also possesses the same symmetry as that of its crystal structure, For Lanthanum nitrate cryptate, its conformations are fixed to some extent by the action of coordination of La3+. It is deformed and rigid as well. However, it still keeps its original symmetry. By the method of heavy water exchange, we obtained the proton chemical shift of NH groupin cryptand (2,2).

Key words: cryptand (2, 2), rare earth crptate, NMR study, solution structure

摘要: 根据对穴醚(2,2)及其硝酸镧配合物在乙腈溶液中的1HNMR谱、13CNMR谱、1H-1H相关NMR谱及1H-13C相关NMR谱的分析,讨论了它们的溶液结构。穴醚(2,2)在乙腈溶液中具有几种不同的构象,它们处于快速互变的平衡中。在溶液中,穴醚(2,2)具有与晶体结构相同的对称性。在穴醚(2,2)硝酸镧配合物溶液中,La3+的配位作用把穴醚(2,2)的几种构象迅速平衡的结构固定下来,穴醚(2,2)有所变形并有一定的刚性,但仍保持原有对称性。并用重水交换法得到了NH基团的质子化学位移。

关键词: 穴醚(2, 2), 稀土配合物, 核磁共振, 溶液结构

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