SIDE ARM EFFECTS ON CATION-BINDING, EXTRACTION, AND TRANSPORT FUNCTIONS OF OLIGOPYRIDINE-FUNCTIONALIZED AZA-CROWN ETHERS

A new series of lariat ethers and double-armed crown ethers was prepar ed in which oligopyridine-functionalized side arms were attached as se condary donor sites. A novel preparative method of oligopyridine deriv atives was successfully applied to the synthesis of these crown ethers . Introduction of an oligopyridine-functionalized side arm into the cr own ether system, if of the proper chain length and geometrical arrang ement, significantly offered three-dimensional complexation with vario us metal cations suitable for extraction and transport. Liquid-liquid extraction, C-13-NMR binding, and liquid membrane transport experiment s revealed that the present type of double-armed crown ethers exhibite d cation-binding abilities superior to corresponding lariat ethers.