Macropa Scaffold Expansion for Actinium-225 Chelation: A Synthetic Strategy, Labeling Kinetics, and Theoretical Calculations.

complexes of Megapa and Macropa. The computed low-energy structures were closely analogous for both chelators, indicating that the differing radiochemical behavior is unlikely to arise from intrinsic metal-ligand bonding. Instead, solvation effects and solution-phase molecular interactions are the most probable contributors to the poorer performance of Megapa.