Elucidating the coordination chemistry of the radium ion for targeted alpha therapy.

The coordination chemistry of Ra is poorly defined, hampering efforts to design effective chelators for Ra-based targeted alpha therapy. Here, we report the complexation thermodynamics of Ra with the biomedically-relevant chelators DOTA and macropa. Our work reveals the highest affinity chelator to date for Ra and advances our understanding of key factors underlying complex stability and selectivity for this underexplored ion.