The interaction of pyridoxal isonicotinoyl hydrazone (PIH) and salicylaldehyde isonicotinoyl hydrazone (SIH) with iron

The hydrazone chelators pyridoxal isonicotinoyl hydrazone (PIH) and salicylaldehyde isonicotinoyl hydrazone (SIH) bind both iron(II) and iron(III) with high affinity. The tridentate ligands completely encompass the coordinated iron which renders it inaccessible to other potentially reactive molecules, including oxidising agents, reducing agents and complexing agents.88