Effective complex formation in the interaction of 1,2-dimethyl-3-hydroxypyrid-4-one (Deferiprone or L1) with uranium(VI)

In an effort to develop new chelating agents for the decorporation of uranium and other actinides, the interaction of the clinically used 1,2-dimethyl-3-hydroxypyrid-4-one (Deferiprone or L1) with hexavalent uranium was investigated by using UV-VIS spectroscopy and solubility measurements. The complex stoichiometry estimation carried out by the Job plot method indicated that under normal conditions up to pH 8.0 a 1[U(VI)]∶1[L1] complex is formed. The stability constant of the UO2L1+ complex was determined by spectroscopic and solubility experiments and found to be log β11=9.1±0.3. The molar extinction coefficient at pH 7.6 for the complex at 500 nm was estimated to be 650 l·mol−1·cm−1. At ligand concentrations higher than 6·10−4 mol·l−1 the formation of a precipitate was observed. The stoichiometry UO2(L1)2 was identified following FTIR measurements of the red precipitate and UV/VIS spectroscopy after dissolution.