Macrocuclic polyethers having polyethyleneoxy-sidechains extending from a nitrogen pivot bind ammonium ions quite strongly when an 18-memebered ring and a two-oxygen sidechain are present; a 15-memebered ring and other chain lengths give inferior binding.
当存在一个由18个成员组成的环和一个两个氧侧链时,具有从氮原子枢轴延伸出的聚氧
乙烯侧链的大分子聚醚会非常牢固地结合
铵离子。15元环和其他链长的结合力较差。