Complexation of High-Valency Mid-Actinides by a Lipophilic Schiff Base Ligand: Synthesis, Structural Characterization, and Progress toward Selective Extraction

• Published in: Inorganic chemistry Vol. 58; no. 6; pp. 3559 - 3563
• Main Authors: Bustillos, Christian G, Hawkins, Cory A, Copping, Roy, Reilly, Sean D, Scott, Brian L, May, Iain, Nilsson, Mikael
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 18-03-2019; American Chemical Society (ACS)
• Subjects: INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.8b02849

Separation of U, Np, and Pu from used nuclear fuel (UNF) would result in lower long-term radiotoxicity, alleviating constraints on the storage and handling of the material. The complexity of UNF requires several industrial-scale processes with multiple waste streams. A one-step solution to the group removal of the elements, U–Pu, is desirable. Here we present a possible solution to group actinide separation utilizing the unique dioxy conformation of An­(V/VI) cations and demonstrate the ability of a tetradentate lipophilic Schiff base ligand (L) to yield isostructural complexes of the general formula [(AnVIO2)­(L)­(CH3CN)] (where An = U, Np, or Pu). Extraction of An­(VI) with the ligand follows the order U > Pu > Np, likely reflecting the decreased stability of the hexavalent actinide across the series. While the results indicate a promising path toward a one-step process, further improvement in the ligand stability and control of the redox chemistry is required.