| Abstract
| - According to molecular dynamics simulations, uncomplexed Cyanex-301-like ligands L- and LH (derivedfrom the dithiophosphinic acid R2PS2H) and their EuL3 complexes are surface active. They adsorb at a water/“oil” interface, where “oil” is modeled by chloroform. It is shown that addition of neutral phosphoryl ligandssuch as TBP (tri-n-butyl phosphate) is necessary to promote the extraction of the complex, via twocomplementary mechanisms. First, gradual co-complexation of TBP, forming EuL3(TBP)n species, enhancesthe interfacial activity and the hydrophobicity of the lanthanide complex. Second, high concentrations ofTBP are needed to saturate and modify the interface, leading to the migration of the EuL3(TBP)3 complex tothe oil phase. The effect of oil/water ratio is also investigated. At high ratio, one observes the formation ofwater-in-oil microdroplets onto which TBPs adsorb, while the complexes are fully extracted to the oil phase.These features make it possible to better understand synergistic and solvation effects in the assisted liquid−liquid extraction of lanthanide or actinide cations.
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