Corrinoid

Corrinoids are a group of compounds based on the skeleton of corrin, a cyclic system containing four pyrrole rings similar to porphyrins.

Compounds containing the "Cob-" prefix (not corrin) are cobalt derivatives, and may include an oxidation state, as in "Cob(II)alamin".

A solution of aquacyano-corrinoids, such as cobalamin 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.

[8][9] Furthermore, this technology is non-toxic and considerably less prone to interference than the pyridine-barbituric acid colorimetry method.

Corrin ring, numbered according to the 1975 IUPAC standard. Note that for consistency with the porphyrin numbering system, there is no 20 position. Positions 21-24 were numbered 20-23 in earlier literature. [ 1 ]
Vitamin B 12 ( cyanocobalamin )