Complexation of trivalent lanthanoid ions with 4-benzoyl-3-phenyl-5-isoxazolone and p- tert-butylcalix[4]arene fitted with phosphinoyl pendant arms in solution during synergistic solvent extraction and structural study of solid complexes by IR and NMR

Abstract

The liquid extraction of 14 lanthanoids with a 4-benzoyl-3-phenyl-5-isoxazolone (HPBI) alone in CHCl 3 as a diluent from perchlorate medium at constant ionic strength μ = 0.1 is investigated. The synergistic solvent extraction of five selected lanthanoid ions (La 3+, Nd 3+, Eu 3+, Ho 3+ and Lu 3+) with 4-benzoyl-3-phenyl-5-isoxazolone (HPBI) and 5,11,17,23-tetra- tert-butyl-25,26,27,28-tetrakis-(dimethylphosphinoylmethoxy)calix[4]arene, (S) in CHCl 3 has been studied too. The stoichiometry of the extracted species was characterised by a classical log–log plot analysis. It was found that the composition of the extracted species with HPBI are Ln(PBI) 3 and in the presence of the phosphorus-containing calix[4]arene the lanthanoid ions have been extracted as [Ln(PBI) 3S 2]. The values of the equilibrium constants and the separation factors have been calculated. The influence of the synergistic agent on the extraction process has been discussed. The formation of ternary complexes of Eu(III), HPBI and the used calix[4]arene was studied at three mole ratios of the reagents viz. 1:3:1, 1:3:2 and 1:2:1. The stoichiometry ([Eu(PBI) 2S]Cl and Eu(PBI) 3S) and the structure of the solid complexes were proposed using elemental analysis, IR, 1H NMR, and 31P NMR data.