Abstract
The effect of the structure of cyclic poly (oxyethylene) compounds (crown compounds) on their complexation properties toward alkali metal cations was examined. Introduction of an electron-donating side arm on the crown ring was found to be an effective method for developing a host for a specific cation. A new ion transport system has been developed which incorporates a structural device which assists in the cation release process by using intramolecular complexation of an 18-crown-6 and a primary ammonium ion. Lipophilic monoazacrown ethers selectively transported a specific cation against its concentration gradient by pH control in a liquid membrane.
The results obtained in this study demonstrate that an appropriate design of coordination sites markedly affects the complexing ability of host compounds.
