Corrinoids are a group of compounds based on the skeleton of

corrin Corrin is a heterocyclic compound. It is the parent macrocycle related to the substituted derivative that is found in vitamin B12. Its name reflects that it is the "core" of vitamin B12 ( cobalamins).Nelson, D. L.; Cox, M. M. "Lehninger, Princ ...

, a cyclic system containing four

pyrrole Pyrrole is a heterocyclic aromatic organic compound, a five-membered ring with the formula C4 H4 NH. It is a colorless volatile liquid that darkens readily upon exposure to air. Substituted derivatives are also called pyrroles, e.g., ''N''-met ...

rings similar to

porphyrin Porphyrins ( ) are a group of heterocyclic macrocycle organic compounds, composed of four modified pyrrole subunits interconnected at their α carbon atoms via methine bridges (=CH−). The parent of porphyrin is porphine, a rare chemical ...

s. These include compounds based on octadehydrocorrin, which has the trivial name

corrole A corrole is an aromatic tetrapyrrole. The corrin ring is also present in cobalamin ( vitamin B12). The ring consists of nineteen carbon atoms, with four nitrogen atoms in the core of the molecule. In this sense, corrole is very similar to porph ...

. The

cobalamin Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. It is one of eight B vitamins. It is required by animals, which use it as a cofactor in DNA synthesis, in both fatty acid and amino acid metabolism. It ...

s ( vitamin B₁₂) are the best known members of the group. Other prominent examples include cobyrinic acid and its hexaamide cobyric acid; cobinic acid and its hexaamide cobinamide; cobamic acid and cobamide. Compounds containing the "Cob-" prefix (''not'' corrin) are cobalt derivatives, and may include an

oxidation state In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. ...

, as in "Cob(II)alamin". When cobalt is replaced by another metal or hydrogen, the name changes accordingly, as in ferrobamic acid or hydrogenobamic acid.

Reactions with cyanide

A solution of aquacyano-corrinoids, such as

or cobinamide, reacts with free cyanide in an aqueous sample. The binding of cyanide to the corrinoid cobalt center leads to a color change from orange to violet. Quantification of the cyanide content is feasible by UV-vis spectroscopy. Absorption of the corrinoid on a solid phase, allows detection of cyanide even in colored samples, rendering this method appropriate for the analysis of cyanide in water, wastewater, blood, and food. Furthermore, this technology is non-toxic and considerably less prone to interference than the pyridine-barbituric acid colorimetry method.

References

External links

*
"The Nomenclature of Corrinoids" at chem.qmul.ac.uk

Tetrapyrroles * {{heterocyclic-stub