PA value (kJ mol−1) for LC, Ibu-phen ligands and copper(ii) complex in the gas phase at the M05-2X/6-311++g(2df,2p)//M05-2X/LanL2DZ level of theory, (values in parentheses correspond to PA obtained in water solvent).
| Proton donating position | Proton affinity (kJ mol−1) | ||
|---|---|---|---|
| Ibu-phen | LC | Copper(ii) complex | |
| Ibu-C11–H | 1401.0 | 1014.6 | |
| Ibu-C12–H | 1398.5 (249.3) | 1022.1 (226.8) | |
| Ibu-C6–H | 1457.9 | ||
| Ibu-C13–H | 1401.0 | 1208.5 | |
| Ibu-N32–H | 1400.0 | ||
| LC-C65–H | 1454.2 (461.8) | 844.8 (336.8) | |
| LC-C66–H | 1456.0 | ||
| LC-N57–H | 1465.0 | ||
| LC-C60–H | 1460.6 | ||
| LC-C56–H | 1531.1 | 856.9 | |