Probing Uranium Complexation with Bio-Inspired Octadenate Hydroxypyridinonate (HOPO) and Catecholamide (CAM) Chelators

摘要

As the use of actinides in both the nuclear power anddefense sectors over the past 70 years has resulted inreleases of radionuclides generated during these activities,the concurrent development of a detailed knowledge ofactinide solution chemistry remains continuously relevant.More specifically, understanding the fundamental chelationchemistry of individual actinide cations is critical forongoing studies focused on improving actinidedecorporation therapies and developing new environmentalremediation strategies. The octadenate siderophore analogue3,4,3-LI(1,2-HOPO) has demonstrated significant promiseand efficacy as a chelator for trivalent and tetravalentactinides and has shown some utility as an in vivo chelatorof the uranyl cation. However, the coordination andsolution thermodynamics of [UO_2]~(2+)-HOPO binding, whichhave been previously explored, reveal that HOPO bindingwith the hexavalent uranyl cation is less thermodynamicallystable than that of other targets such as the tetravalentplutonium cation. Thus here we revisit the coordinationchemistry of the uranyl cation with HOPO and expand ourefforts to probe and understand both uranyl and U(Ⅳ)complexation with 3,4,3-LI(1,2-HOPO) and the relatedHOPO and CAM siderophore analogues 3,4,3-LI(CAM),343-LI-CHHC, and 343-LI-HCCH.