CHEMICAL EFFECTS OF NUCLEAR TRANSFORMATIONS OF COMPLEXED METAL ATOMS .I. BETA-DECAY OF 144CE AND 143CE COMPLEXED WITH POLYAMINOPOLYCARBOXYLIC ACID CHELATING LIGANDS

The chemical effects of beta-decay of 144Ce and 143Ce complexed with polyaminopolycarboxylic acud chelating ligands have been further investigated. We have determined the extent of decomposition of the daughter complexes produced by beta-decay of 144Ce and 143Ce complexed, in aqueous solution, with the multidentate ligand DTPA. A marked difference in the effects of beta-decay was observed for the two isotopes. A value of 89±10 per cent, independent of pH, was determined for the percentage break-up of the daughter complex produced by beta-decay of 143Ce(DT-PA)2-, in contrast with our previously determined, pH dependent values, of between 30·9±1 per cent to 66·3±5·0 per cent for the 144Ce(DTPA)2- complex ions. The percentage break-up values have been calculated by a comprehensive treatment of results which makes allowance for associated isotopic exchange processes. A mechanism has been proposed which accounts for the different behaviour of the two cerium isotopes in terms of the positive charges acquired by the praseodymium daughter atoms as the result of the internal conversion of γ-rays and electron shake-off" processes. © 1969."