The overhanging carboxylic acid strategy: an alternative route to the porphyrin core expansion/modification for the coordination of large metal ions

Abstract

This account summarizes how the binding properties of a regular porphyrin macrocycle for large cations can be significantly modified and even tuned when the surrounding skeleton delivers at least one carboxylic acid group close to the N -core. While kinetics of metal insertion are drastically improved, unique dinuclear species can be obtained with a possible control of the nuclearity. The first incorporation of an α-core emitter radioisotope of particular interest for cancer therapy was recently demonstrated. All in all, this overhanging carboxylic acid strategy can be regarded as an alternative to either expanded porphyrins for the coordination of large cations from groups 14–15 (PbII, BiIII) or contracted and isomeric porphyrins for the coordination of smaller cations from group 12 (HgII)