Complexation of uranium(VI) with the siderophore desferrioxamine B

Siderophores are microbial produced low molecular weight iron chelators and strongly bind to hard Lewis acids. The siderophore desferrioxamine B (DFO) has hydroxamate functional groups, similar to acetohydroxamic acid (AHA), a ligand that is proposed for actinide complexation in advanced separations. In the proposed separation involving AHA, the exact role of the complex in the extraction behavior of actinides is unclear DFO can be used to clarify the role of AHA if the fundamental interactions of DFO with actinides are determined Experiments with uranyl are performed from pH 3.5 to pH 10 showing three complexes. UO2DFOH2, UO2DFOH, and UOOHDFOH with stability constants of log beta(UO2DFOH2) = 22.93 +/- 0.04, log beta(UO2DFOH) = 17.12 +/- 0.35, and log beta(UO2OHDFOH) = 22.76 +/- 0.34.