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 urani um and other actinides, the interaction of the clinically used 1,2-dimethyl -3-hydroxypyrid-4-one (Deferiprone or L1) with hexavalent uranium was inves tigated by using UV-VIS spectroscopy and solubility measurements. The compl ex stoichiometry estimation carried out by the Job plot method indicated th at under normal conditions up to pH 8.0 a 1[U(V1)]:1[L1] complex is formed. The stability constant of the UO(2)L1(+) complex was determined by spectro scopic and solubility experiments and found to be log beta(11)=9.1+/-0.3. T he molar extinction coefficient at pH 7.6 for the complex at 500 nm was est imated to be 650 l.mol(-1).cm(-1). At ligand concentrations higher than 6.1 0(-4) mol.l(-1) the formation of a precipitate was observed. The stoichiome try UO2(L1)(2) was identified following FTIR measurements of the red precip itate and UV/VIS spectroscopy after dissolution.