I-[(5-BROMO-2-PYRIDYL)AZO]-2-NAPHTHOL AS A POSSIBLE NEW CHROMOGENIC REAGENT

The heterocyclic azo compound, 1-[(5-bromo-2-pyridyl)azo]-2-naphthol (5-Br-β-PAN), forms various coloured metal chelates, wliich can be extracted with different organic solvents. Most of the reacting metals form reddish chelates, except for cobalt-(III) and palladium(II) (green), and vanadium(V) (olive). Chelate stability is greatly affected by pH. The molar absorptivities are usually considerably greater than those of the β-PAN chelates. A correct choice of pH, solvent and masking reagents allows 5-Br-β-PAN to be made reasonably selective. © 1969.