Synthesis, characterization and extraction behaviour of calix[4]arene with four propylene phosphonic acid groups on the lower rim

A new calix[4]arene based ligand bearing four phosphonic acid groups was prepared by modification of p-tert-butylcalix[4]arene on the lower rim by bonding with four (CH2)(3)PO(OH)(2) groups. The compound was characterized by NMR spectroscopy. The compound obtained was used as an extractant for certain lanthanide ions (La3+, Eu3+, Yb3+). The extraction experiments were carried out at 25 +/- 2 degreesC and pH 5.5 for 2 h. The formation of the complexes with lanthanide ions was revealed by NMR experiments and luminescence spectroscopy. The extraction efficiencies of the prepared ligand decrease with decreasing radius of the lanthanide ions. (C) 2004 Elsevier Ltd. All rights reserved.