Abstract
Amide-type bis (crown ether) s 3 and 4 were obtained from the reaction of aminomethyl crown ether 1 or morpholino crown ether 2 with alkylmalonyl dichloride. Amino-type bis (crown ether) s 5 and 6 were prepared by reduction of amides 3 and 4, respectively. Amide-type ligand 3 having two 15-crown-5 rings was highly selective toward potassium cation compared to sodium ion in the stability constant for complexation and transport through a liquid membrane. Amide 4 and amine ligands 5 and 6 were less selective than 3. The relationship between the molecular structures of crown ethers and complexing and transport properties is discussed.
