Solvent Extraction Investigations on Pu(IV) and Th(IV) Complexes with Hydrophilic SO3-Ph-BTP and SO3-Ph-BTBP Ligands

International audience; Complexation of Pu(IV) and Th(IV) cations by the title ligands hydrophilic triazinyl derivatives of pyridine and bipyridine was studied by solvent extraction with TODGA. Stoichiometries and stability constants of the complexes in the aqueous phase have been determined, the Pu(IV) complexes being significantly stronger than their Th(IV) analogues. Only two kinds (11 and 12) of the complexes with SO3 Ph BTP have been detected, and only one kind (11) with SO3 Ph BTBP. These numbers are lower than those expected based on the coordination numbers of the metal ions and on the denticities of the ligands. Possible reasons of this discrepancy were discussed.