Table 1. Comparison of Calculated and Experimental Energetics for All Species Examined in This Worka.
| Xb | RSc | TS1c | ISc | TS2c | PSc | Δgexp⧧d |
|---|---|---|---|---|---|---|
| CN | 0.0 | 16.2 | –8.1 | –3.3 | –33.7 | 17.8 |
| CF3 | 0.0 | 16.1 | –6.2 | –3.4 | –36.5 | 19.9 |
| Cl | 0.0 | 18.2 | 2.0 | 2.9 | –36.8 | 21.1 |
| COO– | 0.0 | 19.1 | –1.4 | 1.5 | –38.0 | 21.3 |
| Ph | 0.0 | 19.8 | 2.5 | 5.2 | –36.4 | 21.9 |
| H | 0.0 | 19.5 | 4.8 | 5.2 | –37.0 | 22.3 |
All energies are in kcal/mol, relative to the reactant complex, and including corrections for zero point energies and entropies, as well as a −7.2 kcal/mol correction applied to the solvation free energies of the reactant and product states to account for undersolvation of the hydroxide ion by the implicit solvent model (see discussion in ref (26) and the main text). The corresponding uncorrected energy decompositions are shown in Supplementary Table S1.
Substituent at 3-position, cf. Figure 1. All calculations presented in this Table were performed in implicit solvent with no extra explicit water molecules.
RS, TS1, IS, TS2, and PS denote the reactant complex, the transition state for proton abstraction, the carbanion intermediate, the transition state for leaving group expulsion, and the product complex, respectively.
Experimental activation barrier, based on kinetic data presented in ref (5). Since the calculated energetics are being considered relative to a reactant complex that has already been formed, for completeness, we have corrected the experimental value by 0.017 M–1 to take into account the entropic cost of bringing the reacting fragments into the encounter complex, following ref (27).