TABLE II.
Absolute chemical shifts (ppm) of pyridazine in vacuo and solvent shifts (ppm) as obtained with different solvent representations. For the cluster approaches, two explicit water molecules are included at the QM, classical MM and FQ levels of theory, respectively, possibly including the PCM embedding (/PCM). The RMS and Max errors are reported with respect to QM/PCM.
| Atom | Vacuum | QM | QEq | FQ | PCM | QM/PCM | QEq/PCM | FQ/PCM |
|---|---|---|---|---|---|---|---|---|
|
| ||||||||
| C2 | 25.82 | 0.07 | −0.14 | −0.20 | −2.24 | −1.04 | −1.79 | −1.85 |
| C3 | 55.94 | −3.21 | −1.83 | −2.14 | −4.45 | −7.40 | −5.68 | −6.44 |
| N1 | −212.27 | 36.85 | 25.76 | 29.49 | 28.98 | 60.00 | 47.11 | 54.89 |
| H-C3 | 22.16 | 0.01 | 0.00 | 0.01 | −0.03 | 0.04 | 0.01 | 0.03 |
| H-C2 | 24.40 | −0.26 | −0.17 | −0.20 | −0.50 | −0.71 | −0.59 | −0.66 |
|
| ||||||||
| RMS | 10.53 | 15.52 | 13.85 | 13.94 | - | 5.82 | 2.35 | |
| MAX | 23.14 | 34.24 | 30.51 | 31.01 | - | 12.89 | 5.11 | |