Iminodiacetic acid


Iminodiacetic acid is the organic compound with the formula HN2, often abbreviated to IDA. A white solid, the compound is a dicarboxylic acid amine. IDA is a popular chelating ligand, first introduced in the early 1950s by Schwarzenbach.

Ligand

The iminodiacetate dianion is typically a tridentate ligand, forming metal complexes by forming two, fused, five membered chelate rings. IDA thus forms stronger complexes than the bidentate ligand glycine and weaker complexes than the tetradentate ligand nitrilotriacetic acid.
IDA can also act as a bidentate ligand through its two carboxylate groups. Several technetium-99m complexes with bidentate IDA derivatives are used in cholescintigraphy scans to evaluate the health and function of the gallbladder. Common IDA derivatives include lidofenin, mebrofenin, and disofenin that replace the secondary amine proton with an amide and aromatic substituent.
The proton on the nitrogen atom can be replaced by a carbon atom of a polymer to create an ion-exchange resin, such as chelex 100.

Other applications

Iminodiacetic acid is an important intermediate in one of the two main industrial processes used to manufacture the herbicide glyphosate. It is used in capillary electrophoresis for modulating peptide mobility. It is also used as a precursor for the manufacture of the indicator xylenol orange.

Synthesis

A most efficient iminodiacetic synthesis dehydrogenates diethanolamine over a catalyst.

Related compounds