Use of hetero N,O-donor ligands for selective actinide extraction; Complexation study of actinides and lanthanides with N-octyl-N-tolyl-1,10-phenanthroline-2-carboxamide (OcTolPTA)

Ikeda, Atsushi  ; Kobayashi, Toru ; Shiwaku, Hideaki   ; Okamoto, Yoshihiro  ; Suzuki, Shinichi; Yaita, Tsuyoshi; Hennig, C.*

We have recently develop a new hereto N,O-donor extractant, N-alkyl-N-phenyl-1,10-phenanthlorine-2-carboxamide (PTA), for the lump separation of An from other fission products (FPs) containing lanthanides (Ln). These recent studies have suggested that this hetero-donor ligand possessing both hard O donor- and soft N donor atoms is very effective in the separation of several different An (i.e. U, Np, Pu, Am, and Cm) from Ln. Further development of this extractant, such as improving its separation efficiency, requires the basic understanding of its complexation properties with An and other metals. In the present study, the complexation of An and Ln with N-octyl-N-tolyl-1,10-phenanthroline-2-carboxamide (OcTolPTA) was studied by means of UV-visible and X-ray absorption spectroscopies. The results are discussed from the viewpoint of complexation behavior (i.e. formation constants) and complex structure.