p-tert-Butylcalix[4]arene tetrakis(N,N-dimethylacetamide) as a second ligand in the complexation of trivalent lanthanoids with thenoyltrifluoroacetone in solution and investigation of a solid Eu(III) complex

The solvent extraction of 14 lanthanoids with a thenoyltrifluoroacetone (HTTA) in the presence of tert-butylcalix[4]arene tetrakis(N,N-dimethylacetamide) (S) from perchlorate medium at constant ionic strength μ = 0.1 was investigated. The complexation properties of the extractants in the organic phase were examined and the parameters of the extraction process were determined. The stoichiometry of the extracted species was determined by a classical log–log plot analysis. It was found that the composition of the extracted species is [Ln(TTA)3S2]. The presence of a calix[4]arene has caused a significant synergistic effect. The values of the synergistic coefficients as well as the values of separation factors of the ions of the entire 4f-series were calculated. The values of the equilibrium constants were calculated, too.The formation of a solid ternary complex of Eu(III), HTTA and S was studied using elemental analysis, IR, 1H NMR. The stoichiometry of the complex was found to be Eu(TTA)3·S.

Graphical abstractThe liquid extraction of 14 lanthanoids with a thenoyltrifluoroacetone (HTTA) in the presence of tert-butylcalix[4]arene tetrakis(N,N-dimethylacetamide)(S) was investigated. It was found that the composition of the extracted species is [Ln(TTA)3S2]. The values of the synergistic coefficients as well as the values of separation factors of the ions of the entire 4f-series were calculated.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► 14 lanthanoids were synergistically extracted. ► Thenoyltrifluoroacetone and amide-containing calix[4]arene were used. ► The composition of the extracted species was Ln(TTA)3·2S. ► The stoichiometry of the solid Eu3+ complex was found to be Eu(TTA)3·S. ► The used system offer higher synergistic enhancements and good selectivity.