Recent Progress on the Structure-Performance Relationship between Diglycolamide Extractants and f-Elements

Diglycolamides (DGAs) belong to the class of "CHON" type compounds and can form tridentate complexes with metal ions. DGA-based extractants are a subject of great interest in actinide partitioning due to their exceptionally high affinity for trivalent actinides and lanthanides. Since the separation performance of DGAs are closely related to their molecular structures, many structure-modification schemes have been proposed such as the attachment of different alkyl substituents to an amidic N atom or anchoring multiple DGA arms onto a scaffold. In this paper, literature reports that describe the effects of such modifications on the structure and performance of DGAs are summarized. By comparing the extraction and separation properties of DGA extractants with different structures, the relationship between the structure and properties of DGAs is discussed. Such work should be helpful for gaining a more comprehensive, accurate and in-depth understanding of the relationship between structure and property of DGAs to be developed. It should also be beneficial for the structural design of more new DGA extractants.