Hexa(1,1,3,3-tetramethyl-butyl)-hexakis(dimethylphosphinoylmethoxy)-calix[6]arene: Synthesis, characterization and implementation as a synergistic agent in the solvent extraction of lanthanoids

摘要

A new lower rim phosphorus-containing calix[6]arene with six dimethyl-methylene phosphine oxide groups, namely 5,11,17,23,29,35-hexa(1,1,3,3-tetramethyl-butyl)-37,38,39,40,41,42-hexakis(dimethylphosphinoylmethyleneoxy)-calix[6]arene (S), has been synthesized and characterized. The structure of this calix[6]arene was identified and confirmed by elemental analysis, IR, H-1 and P-31{H} NMR spectroscopy and ESI-mass-spectrometry. The H-1 and P-31(H} NMR spectra indicate that at room temperature in DMSO-d(6) and 1,1,2,2-tetrachloroethane-d(2) solutions, S exists as a mixture of conformers. The synergistic solvent extraction of selected lanthanoid ions (La, Nd, Eu, Ho, Lu) with 4-benzoy1-3methyl-l-pheny1-5-pyrazolone (HP) and Sin chloroform has been studied. It was found that in the presence of S the lanthanoid ions have been extracted as LnP(3)S species. A very large synergistic enhancement (up to 10(5)) was established. The stoichiometry and the structure of the solid complex of Eu(III) with HP and S (1:3:1) were proposed based on elemental analysis, IR, H-1 NMR and P-31 NMR data. (C) 2017 Elsevier Ltd. All rights reserved.