Table 2.
The calculated pKa values of amine compounds in aqueous solution (based on the B3LYP/6-31+G*//B3LYP/6-31+G* energies) compared with the experimental dataa
| Amine compound | Calc.g | Expt. | |||
|---|---|---|---|---|---|
| COSMO | PCM | IEFPCM | SVPE | ||
| 1 | 7.38(8.96) | 8.55(9.80) | 8.32(9.33) | 11.18(10.16) | 9.43b |
| 2 | 8.95(9.87) | 8.87(9.99) | 9.78(10.20) | 10.37(9.59) | 9.85b |
| 3 | 6.72(8.57) | 6.53(8.61) | 7.44(8.80) | 9.91 (9.27) | 9.96b |
| 4 | 8.96(9.88) | 8.17(9.58) | 9.78(10.20) | 10.50(9.68) | 10.21b |
| 5 | 7.16(8.83) | 6.78(8.76) | 7.67(8.94) | 10.28(9.53) | 9.11b |
| 6 | 10.21(10.61) | 6.71(8.72) | 9.13(9.81) | 9.58 (9.03) | 9.64b |
| 7 | 7.25 (8.88) | 7.72(9.31) | 7.45(8.81) | 10.66(9.79) | 8.96c |
| 8 | 8.31(9.50) | 9.45(10.33) | 8.28(9.30) | 10.51(9.69) | 8.79c |
| 9 | 8.94(9.87) | 8.75(9.92) | 9.55(10.06) | 10.45(9.64) | 9.59c |
| 10 | 5.94(8.12) | 5.78(8.17) | 6.54(8.27) | 10.54(9.71) | 10.20c |
| 11 | 8.04(9.34) | 8.01(9.48) | 8.01(9.14) | 9.00(8.63) | 8.60d |
| 12 | 6.66(8.54) | 6.57(8.64) | 6.57(8.29) | 7.90(7.85) | 8.00e |
| 13 | −2.88(2.97) | −2.88(3.08) | −2.68(2.79) | 0.74(2.83) | 2.37f |
| 14 | −2.53(3.18) | −2.83(3.11) | −2.05(3.16) | 0.32(2.53) | 2.64f |
| 15 | −1.54(3.75) | −1.53(3.87) | −1.06(3.75) | 1.73(3.52) | 3.58f |
| 16 | −1.85(3.57) | −1.90(3.66) | −1.43(3.53) | 1.99(3.70) | 3.52f |
| 17 | −0.05(4.62) | 0.01(4.78) | 0.43(4.64) | 3.73(4.93) | 4.20f |
| 18 | 1.01 (5.24) | 0.97(5.34) | 1.42(5.22) | 4.84(5.71) | 5.36f |
| 19 | −2.08(3.44) | −2.19(3.48) | −1.69(3.38) | 2.37(3.97) | 3.99f |
| 20 | −0.49(4.36) | −0.63(4.40) | −0.03(4.36) | 4.03(5.14) | 5.08f |
| 21 | −2.87(2.98) | −2.80(3.13) | −2.41(2.94) | 1.35(3.26) | 3.20f |
| 22 | 0.70(5.06) | 0.59(5.12) | 1.26(5.13) | 3.04(4.45) | 4.65f |
| 23 | 4.91(7.51) | 4.17(7.23) | 5.37(7.57) | 5.36(6.07) | 6.56f |
| 24 | 4.07(7.03) | 2.30(6.13) | 4.48(7.05) | 5.26(6.00) | 7.18f |
| RMSD | 3.67(0.70) | 3.88(0.79) | 3.30(0.61) | 1.30(0.51) | |
The total Gibbs free energy of a molecular species is the gas phase energy calculated at the B3LYP/6-31+G*//B3LYP/6-31+G* level with the thermal corrections to the Gibbs free energy at the B3LYP/6-31+G* level plus the solvent shift calculated with a solvation model (SVPE, PCM, IEFPCM, or COSMO) at the HF/6-31+G* level.
The experimental data come from ref.71c.
The experimental data come from ref.71d.
The experimental value comes from ref.92.
The experimental values comes from ref.93.
The experimental data come from ref.94.
The pKa/RMSD values in the parentheses refer to the theoretical results with the empirical corrections using the linear correlation relationships.