Determination of Complexation Constants between Inorganic Ligands and At(I) and At(III) Species Present at Ultra-Trace Concentrations

摘要

Astatine (At, Z=85: [Xe]4f~(14) 5d~(10) 6s~2 6p~5 ) is below iodine and belongs to the halogen group. At-211 is a promising candidate for alpha-radioimmunotherapy applications if one considers the energy of the a particles emitted as well as its physical half-life (7.2h) [1]. By analogy to iodine, the labelling is generally performed by substitution reactions. However, the C-At bond was shown to be in some cases not stable in vivo [2]. Some articles report that astatine exhibits a metal-like behaviour when existing under the oxidation states +I and +III as At~+ and AtO~+ species (At(x) ~+), respectively [3,4]. Therefore, another labelling way would be to use a chelating approach to bind At-211 on the vector, as it is done for cations like Bi-213 [5].