Iron chelating agents

Three general classes of agents capable of chelating iron are shown here. In order to perform this function, the chelating molecule(s) must complex with all of the iron atom's six available coordination sites, as shown. Bidentate chelating agents are capable of providing two such links per molecule; thus, three molecules are required to chelate one atom of iron. Similarly, two tridentate molecules and only one hexadentate molecule are required to accomplish the same purpose.