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The NMR methods (including ~1H NMR, ~(13)C NMR, variable temperature method and thenovel 1D EXSY technique) were employed to study the conformation of azacrown ethers 1-5 insolution. There are two classes of conformation in which the azacrown ethers exist in solution ac-cording to their molecular structure. Two kinds of intramolecular motion of the azacrown etherswere observed, one is the vibration of the macrocyclic ring and the other is its inversion. The ether ringswhich contain oxygens are more flexible than that constructed by nitrogens in the present case becauseof the tetrahedron structure of the nitrogen atoms and the hindrance of the groups Ts connected tothe nitrogens. Some thermodynamical parameters of the ring inversion process were obtained.
The NMR methods (including ~ 1H NMR, ~ (13) C NMR, variable temperature method and thenvel 1D EXSY technique) were employed to study the conformation of azacrown ethers 1-5 insolution. There are two classes of conformation in which the azacrown ethers exist in solution ac-cording to their molecular structure. Two kinds of intramolecular motion of the azacrown etherswere observed, one is the vibration of the macrocyclic ring and the other is its inversion. The ether ringswhich contain oxygens are more flexible than that constructed by nitrogens in the present case because of the tetrahedron structure of the nitrogen atoms and the hindrance of the groups Ts connected tothe nitrogens. Some thermodynamical parameters of the ring inversion process were obtained.