Functional monomers and polymers. LIII. Kinetic study on the oxidation of Cu(I)·polyvinylimidazole complexes by molecular oxygen

The autoxidation of Cu(I) complexes with imidazole and polyvinylimidazole derivatives was studied by observing the formation of the corresponding Cu(II) complexes with a stopped‐flow technique. The reaction was second order and proportional to the concentrations of Cu(I) and oxygen. In the Cu(I)‐imidazole complex pH variation was without effect in the range of 7.5‐8.6. The oxidation rate of Cu(I).polyvinylimidazole complexes, on the other hand, decreased with a rise in pH. The activation parameters of the Cu(I)·polyvinylimidazole complexes, compared with those of the Cu(I).imidazole complex, were characterized by large enthalpic requirements coupled with favorable entropies of activation. This was explained by the fact that a conformational change in the polymeric ligands took place during oxidation.