Phenanthroline

Phenanthroline (phen) is a heterocyclic organic compound. It is a white solid that is soluble in organic solvents. It is used as a ligand in coordination chemistry, it forms strong complexes with most metal ions. In terms of its coordination properties, phen is similar to 2,2'-bipyridine (bipy).

Synthesis

Phenanthroline may be prepared by two successive Skraup reactions of glycerol with o-phenylenediamine, catalyzed by sulfuric acid, and an oxidizing agent, traditionally aqueous arsenic acid or nitrobenzene. Dehydration of glycerol gives acrolein which condenses with the amine followed by a cyclization.

Peptidase inhibitor

1,10-Phenanthroline is an inhibitor of metallopeptidases, with one of the first observed instances reported in carboxypeptidase A. Inhibition of the enzyme occurs by removal and chelation of the metal ion required for catalytic activity, leaving an inactive apoenzyme. 1,10-Phenanthroline targets mainly zinc metallopeptidases, with a much lower affinity for calcium.