New type of lariat ethers: Synthesis and cation binding ability of phosphonoalkyl-azacrown ethers

The synthesis of azacrown ethers with phosphonoalkyl side chains of two to five carbon atoms (3-8, 10), potentially useful as a new type of cation bin ding agent, is described. Introduction of the phosphonoalkyl moiety into th e parent monoaza-15-crown-5 (1) decreases the cation extraction ability, bu t results in an increase in the selectivity towards the cations examined. T he effect of the phosphonoalkyl-azacrown ethers on the properties of membra nes used in ion-selective electrodes is also reported.