Silver and thallium(I) complexation with dibenzo-16-crown-4

Dibenzo-16-crown-4 (1) indicates high silver and thallium(I) ion selectivit y over sodium, potassium, and rubidium ion evaluated from the solvent extra ction of metal picrates, while its cation-binding ability is lower than tho se of dibenzo-18-crown-6 (2) and dibenzo-22-crown-6 (3). Taking account of the highest thallium(I) ion selectivity for 1 obtained from extraction expe riments, PVC membrane thallium(I)-selective electrodes based on 1 are prepa red. The electrode shows the best potentiometric selectivity coefficients f or thallium(I) over potassium and rubidium than those of 2 and 3, and comme rcially available bis(crown ether)s (4). (C) 1999 Elsevier Science Ltd. All rights reserved.