Interaction of niacin with copper ions

The interaction of copper(II) ions with nicotinic acid and nicotinamide in aqueous solutions was examined. Potentiometric and spectroscopic methods indicate formation of the MHL, ML and ML2 species in Cu(II)–nicotinic acid system whereas in Cu(II)–nicotinamide system the ML and ML(OH) species have been identified. The polarographic measurements have shown the stepwise reduction of Cu(II) complexes on the mercury electrode through an intermediate state of Cu(I). The values of stability constants for Cu(I) and Cu(II)–nicotinate and nicotinamide complexes were determined. The coordination mode of nicotinic acid and nicotinamide to copper ions is discussed.

The polarographic reduction of copper(II) in the presence of niacin reveals the stepwise reduction of Cu(II) through an intermediate state of Cu(I). The nicotinate ion and nicotinamide thermodynamically stabilizes Cu(I) ions through complex formation.Figure optionsDownload as PowerPoint slide