Table 2.
Experimental and computed pKa values for the compounds from the SAMPL6 data set (Fig. 1). The difference Δ (Eq. 20) between computed and experimental pKa values is shown for each compound. The experimental values were provided by the SAMPL6 organizers. The root- mean-square error (RMSE), the mean absolute error (MAE), and the signed mean error (ME) were calculated according to Eqs. 21–23. The Pearson correlation coefficient R2 and the slope m were calculated from a linear regression.
| Compound | pKa | Exp. | QM computed | Linear fit global | Linear fit piecewise | |||
|---|---|---|---|---|---|---|---|---|
| ID | ID | pKa | pKa | Δ | pKa | Δ | pKa | Δ |
| SM01 | pKal | 9.53(1) | 15.81 | 6.28 | 12.33 | 2.80 | 11.55 | 2.02 |
| SM02 | pKal | 5.03(1) | 6.97 | 1.94 | 6.21 | 1.18 | 7.14 | 2.11 |
| SM03 | pKa1 | 7.02(1) | 1.40 | −5.62 | 11.06 | 4.04 | 10.27 | 3.25 |
| SM04 | pKa1 | 6.02(1) | 9.58 | 3.56 | 8.06 | 2.04 | 8.98 | 2.96 |
| SM05 | pKa1 | 4.59(1) | 0.95 | −3.64 | 2.02 | −2.57 | 2.17 | −2.42 |
| SM06 | pKa1 | 3.03(4) | 1.54 | −1.49 | 2.54 | −0.49 | 3.81 | 0.78 |
| SM06 | pKa2 | 11.74(1) | 17.43 | 5.69 | 13.45 | 1.71 | 12.95 | 1.21 |
| SM07 | pKa1 | 6.08(1) | 8.44 | 2.36 | 7.23 | 1.15 | 8.15 | 2.07 |
| SM08 | pKa1 | 4.22(1) | 10.17 | 5.95 | 8.43 | 4.21 | 7.80 | 3.58 |
| SM09 | pKa1 | 5.37(1) | 6.99 | 1.62 | 6.23 | 0.86 | 7.16 | 1.79 |
| SM10 | pKa1 | 9.02(1) | 14.82 | 5.80 | 11.81 | 2.79 | 12.31 | 3.29 |
| SM11 | pKa1 | 3.89(1) | 4.39 | 0.50 | 4.53 | 0.64 | 3.75 | −0.14 |
| SM12 | pKa1 | 5.28(1) | 6.55 | 1.27 | 5.96 | 0.68 | 6.89 | 1.61 |
| SM13 | pKa1 | 5.77(1) | 9.23 | 3.46 | 7.79 | 2.02 | 8.72 | 2.95 |
| SM14 | pKa1 | 2.58(1) | −0.31 | −2.89 | 1.16 | −1.42 | 1.56 | −1.02 |
| SM14 | pKa2 | 5.30(1) | 5.68 | 0.38 | 5.34 | 0.04 | 5.15 | −0.15 |
| SM15 | pKa1 | 4.70(1) | 5.51 | 0.81 | 5.21a | 0.51 | 6.14b | 1.44 |
| SM15 | pKa2 | 8.94(1) | 14.49 | 5.55 | 11.41a | 2.47 | 10.64b | 1.70 |
| SM16 | pKa1 | 5.37(1) | 5.04 | −0.33 | 4.88 | −0.49 | 6.17 | 0.80 |
| SM16 | pKa2 | 10.65(1) | 15.92 | 5.27 | 12.40 | 1.75 | 11.69 | 1.04 |
| SM17 | pKa1 | 3.16(1) | 2.26 | −0.90 | 2.96 | −0.20 | 3.90 | 0.74 |
| SM18 | pKa1 | 2.15(2) | 1.91 | −0.24 | 2.80 | 0.65 | 3.29 | 1.14 |
| SM18 | pKa2 | 9.58(3) | 3.54 | −6.04 | 13.27 | 3.69 | 12.49 | 2.91 |
| SM18 | pKa3 | 11.02(4) | 17.14 | 6.12 | 13.88 | 2.86 | 13.54 | 2.52 |
| SM19 | pKa1 | 9.56(2) | 4.81 | −4.75 | 11.78 | 2.22 | 11.00 | 1.44 |
| SM20 | pKa1 | 5.70(3) | 10.04 | 4.34 | 8.34a | 2.64 | 7.58b | 1.88 |
| SM21 | pKa1 | 4.10(1) | 4.68 | 0.58 | 4.63 | 0.53 | 5.56 | 1.46 |
| SM22 | pKa1 | 2.40(2) | −0.10 | −2.50 | 1.32a | −1.08 | 2.02b | −0.38 |
| SM22 | pKa2 | 7.43(1) | 9.44 | 2.01 | 7.93a | 0.50 | 7.41b | −0.02 |
| SM23 | pKa1 | 5.45(1) | 5.53 | 0.08 | 5.23 | −0.22 | 6.16 | 0.71 |
| SM24 | pKa1 | 2.60(1) | 6.13 | 3.53 | 5.65 | 3.05 | 5.25 | 2.65 |
| RMSE | 3.74 | 2.04 | 1.95 | |||||
| MAE | 3.08 | 1.66 | 1.68 | |||||
| ME | 1.25 | 1.24 | 1.42 | |||||
| R2 | 0.58 | 0.87 | 0.86 | |||||
| m | 1.45 | 1.31 | 1.17 | |||||
a
These results represent our submission 35bdm to SAMPL6.
b
These results represent our submission pQjba to SAMPL6.