Nitrite reduction by copper complexes

A series of copper complexes have been synthesised as potential agents for the catalytic reduction of nitrite anions. The ligands and corresponding copper complexes have been characterised by using a range of techniques including X-ray crystallography, NMR, microanalysis, mass spectrometry, infra-red spectroscopy, electrochemical studies and density functional theory calculations. For complexes with simple aliphatic substituents bonded to the equatorial donor nitrogen atoms, catalytic studies on the conversion of NO₂⁻ anions into NO and N₂O gases revealed an excellent correlation between the initial rate of conversion and the experimental reduction potential as measured by cyclic voltammetry. Initial catalytic investigations reveal that these simple model complexes display a wide range of catalytic turnover rates, conversion yields and product gas compositions. Overall the results suggest that further investigations into the design and use of copper complexes as nitrite reduction catalysts are warranted.