Mode of iron(iii) chelation by hexadentate hydroxypyridinones

Abstract

Tripodal hexadentate hydroxypyridin-4-ones are increasingly utilised as iron(III) and gallium(III) ligands, their attachment to proteins being particularly useful for positron emission tomography (PET). A widely studied tripodal ligand NTA(BuHP)₃, which is reported to form 1 : 1 iron(III) and gallium(III) complexes in aqueous, media forms 2 : 2 complexes under physiological conditions. This important difference has implications for both iron chelation therapy and PET imaging.