Table 2: Assignments of the important experimental and calculated vibrational modes and 1H NMR data of HL ligand.
| Experimental IR (cm−1)∗ | Calculated frequencies | Intensity | Assignment | 1H NMR data (ppm) |
| 3,431 (s,b) | — | — | νOH (water of crystallization) | 10.31 s (OH), 9.54 s (HC=N), |
| 2,920 (m) | 2,507 | 85 | νOH | 9.06–8.03 m (quinoline ring), |
| — | 1,681 | 25 | νR, δOH, νC=N | 7.81–6.86 (phenyl ring) |
| — | 1,661 | 8 | νC=Nquinoline, νR | |
| — | 1,651 | 21 | νR, νC=Nazomethine | |
| 1,623 (s) | 1,628 | 10 | νR, νC=Nquinoline, νC=Nazomethine | |
| 1,542 (m) | 1,559, 1,553 | 10, 6 | νR, δOH | |
| 1,437 (m) | 1,470, 1,446 | 10, 7 | δCH, νC−O, νsym(NO2) | |
| 1,238 (m) | 1,276 | 50 | δCH, νC−O, νsym(NO2) | |
| 826 (mw) | 820 | 11 | νR, δscissor(NO2) | |
| ∗ν, stretch; δ, in-plane bend; m, medium; s, strong; b, broad; mw, medium weak. | ||||