Open AccessTris‐amidoximate uranyl complexes via η 2 binding mode coordinated in aqueous solution shown by X‐ray absorption spectroscopy and density functional theory methods
Author(s) -
Zhang Linjuan,
Qie Meiying,
Su Jing,
Zhang Shuo,
Zhou Jing,
Li Jiong,
Wang Yu,
Yang Shitong,
Wang Shuao,
Li Jingye,
Wu Guozhong,
Wang Jian-Qiang
Publication year - 2018
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s160057751800067x
Subject(s) - uranyl , chemistry , aqueous solution , ligand (biochemistry) , density functional theory , absorption spectroscopy , uranium , crystallography , ion , computational chemistry , materials science , organic chemistry , biochemistry , physics , receptor , quantum mechanics , metallurgy
The present study sheds some light on the long‐standing debate concerning the coordination properties between uranyl ions and the amidoxime ligand, which is a key ingredient for achieving efficient extraction of uranium. Using X‐ray absorption fine structure combined with theoretical simulation methods, the binding mode and bonding nature of a uranyl–amidoxime complex in aqueous solution were determined for the first time. The results show that in a highly concentrated amidoxime solution the preferred binding mode between UO 2 2+ and the amidoxime ligand is η 2 coordination with tris‐amidoximate species. In such a uranyl–amidoximate complex with η 2 binding motif, strong covalent interaction and orbital hybridization between U 5 f /6 d and (N, O) 2 p should be responsible for the excellent binding ability of the amidoximate ligand to uranyl. The study was performed directly in aqueous solution to avoid the possible binding mode differences caused by crystallization of a single‐crystal sample. This work also is an example of the simultaneous study of local structure and electronic structure in solution systems using combined diagnostic tools.