PYRIDOXAL ISONICOTINOYL HYDRAZONE (PIH), A SYNTHETIC ION-CHELATING AGENT

Pyridoxal isonicotinoyl hydrazone [3-hydroxy-5-(hydroxymethyl)-2- meth yl-4-pyridinecarboxaldehyde 4-pyridinecarbonylhydrazone, C14H14N4O3] e xhibits a non-planar conformation. Non-H atoms lie almost in two plane s, one of the isonicotinoyl ring, the other of the remainder of the mo lecule, with a dihedral angle of 17.41 degrees between them. The centr al C=N-N'-C=O chain has an E configuration around the C=N double bond of the hydrazone bridge, a trans motif of the amide group along -N'-C= and an S-trans conformation along the N-N' bond. This geometry allows intramolecular hydrogen bonding between the hydrazone N atom and the 3-hydroxy group.