“…14,15 Indeed, thermodynamic stability of a UO 2 2+ -halido complex in DMF follows the order of hardness of halide ligands, Cl − > Br − > I − . 16 In contrast, such a trend in complexation between UO 2 2+ and heteroatoms like N, O and S, seems not to be well understood systematically, although it would provide essential information to understand the fundamental nature of UO 2 2+ in more depth and to design molecular structures of ligands exclusively interacting with UO 2 2+ . Indeed, several extracting reagents have been successfully developed for separation of Am( iii ) and Cm( iii ) from Ln( iii ) on the basis of difference in coordinating affinities of these metal ions with soft-donor atoms incorporated in the designed ligands.…”