The apparent stability constants of the complexes of Cu+(aq) with several aromatic compounds, mainly substituted benzoic acids, were determined electrochemically. The results reveal that these complexes are surprisingly stable, 2.0 ≤ log K ≤ 4.0 at the pKa of the benzoic acids. The stability constants depend on the pH. This dependence is considerably stronger than that predicted from the pKa of the acids, suggesting that complexes of CuOH with the aromatic acids are also formed. Electron donating substituents increase the apparent stability constants. The results indicate that the complexes formed are due to d → π interactions between the copper d orbitals and the aromatic π system. The effect of Cu+(aq) on the 1H NMR of benzoic acid supports this conclusion.
|Number of pages||5|
|Journal||Journal of the Chemical Society. Dalton Transactions|
|State||Published - 7 Jun 1999|