穴醚（2，2）及其硝酸镧配合物的核磁共振研究

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

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。

The solution structures of cryptand (2,2) and its Lanthanum nitrate cryptate in their acetonitrile solution were studied, basing on their 1H, 13 C, 1H 1H and 1H 13 C 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 La 3+ . 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 group in cryptand (2,2).