Lower rim substituted p-tert-butyl-calix[4]arene. Part 17. Synthesis, extractive and ionophoric properties of p-tert-butylcalix[4]arene appended with hydroxamic acid moieties

The synthesis and characterization of four p-tert-butylcalix[4]arene-hydroxamic acids are reported. The dependence of the metal ion binding, assessed by liquid–liquid extraction of the metal nitrates from water into dichloromethane in individual and competitive experiments, on the ligand structure, is presented. The results showed that those ligands could be successfully used in separation process of transition and heavy metals often present together. Two of the ligands were used as active materials in Pb-ion-selective membrane electrodes. The characteristics of these electrodes, in particular their selectivity coefficients for Pb over other metal ions, are discussed. 2014 Elsevier Ltd. All rights reserved.