Table 2: Characteristic IR absorption (cm−1) of ligands L1 and L2 and complexes 1 and 2.
| Compound | ν (OH) | ν (C=N) | ν (C−N) | ν (C=O) | ν (C=C) | ν (N−H) |
| 1,10-phenanthroline (L1) | — | 1,418 | — | — | 1,585, 1,506 | — |
| Thymine (L2) | — | — | 1,493 | 1,743 | 1,674 | 3,194 |
| [Cu(L1)2(H2O)2]Cl2 | 3,444 | 1,595 | — | — | 1,602 | — |
| [Cu(L1)2L2H2O]Cl | 3,507 | 1,516 | 1,587 | 1,732 | 1,619 | Merged with OH |