Effect of p-tert-butylcalix[4]arene fitted with phosphinoyl pendant arms as synergistic agent in the solvent extraction of trivalent lanthanoids with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione and structural study of solid complexes by IR, NMR and X-ra

The synergistic solvent extraction of five selected lanthanoid ions (La3+, Nd3+, Eu3+, Ho3+ and Lu3+) with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (HL) and 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis-(dimethylphosphinoylmethoxy)calix[4]arene, (S) in CHCl3 has been studied. It was found that in presence of this phosphorus-containing calix[4]arene the lanthanoid ions have been extracted as [LnL3S2]. The values of the equilibrium constants and the separation factor have been calculated. The influence of the synergistic agent on the extraction process has been discussed.Elemental analysis, IR, 1H NMR, 19F NMR spectra and X-ray have shown that the complex of Eu(III) with HL is eight coordinated and its composition can be represented with the formula [EuL2(C2H5OH)4]Cl as well as that the coordination polyhedron is distorted square antiprism. The stoichiometry ([EuL2S]Cl) and the structure of the solid complex of Eu(III) with HL and S were proposed using elemental analysis, IR, 1H NMR, 19F NMR and 31P NMR data.

Graphical abstractThe synergistic solvent extraction of five selected lanthanoid ions with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (HL) and 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis-(dimethylphosphinoylmethoxy)calix[4]arene, (S) in CHCl3 has been studied. The solvent extraction data showed that the composition of the mixed complex is [LnL3S2], while the composition of the synthesized solid complex is [EuL2S]Cl. On the basis of the X-ray data, the structure of the Eu(III) complex with HL was determined.Figure optionsDownload full-size imageDownload as PowerPoint slide