Organic chemistry

In organic chemistry, imide is a functional group consisting of two carbonyl groups bound to nitrogen. Imides are generally prepared directly from ammonia or a primary amine, and either carboxylic acid(s) or acid anhydrides. The structure of the imide moiety is as shown to the left.

In chemical industry, many imides are monomers used to make polyimides. The imides most commonly used for this are based on aromatic dicarboxylic acids of moderately high molecular weight. Such imides contain a heterocyclic ring, shown to the right. This particular imide is phthalimide, the heterocyclic imide of phthalic acid. It is an intermediate in the preparation of phthalocyanine dyes. Some phthalimides have luminescent qualities.

The imide functionality is present in the RNA nucleotide uracil and the DNA nucleotide thymine, and participates in Watson-Crick hydrogen bonding, where the carbonyl oxygens act as hydrogen-bond acceptors and the imide nitrogen acts as a hydrogen-bond donor.

Imides can be prepared in the isoimide-to-imide Mumm rearrangement.

Inorganic chemistry

Imide may also refer to the diatomic ion NH²⁻, which is a powerful base and will readily abstract two protons from water, yielding the ammonium ion.

External links

• IUPAC: imides