Figure 6.

A) Relationship between calculated electrostatic potentials taken over the nitrogen atom (ESP_N) and the N‐methylation of the 17 pyridine derivatives shown in Figure 1 B in [D₆]acetone at 298 K. ESPs were calculated using B3LYP/6‐31G* on the 0.002 electron/Bohr³ isosurface. B) Correlation of electrostatic potentials in X‐substituted phenyl derivatives (ESP_ipso) vs. corresponding X‐substituted pyridine derivatives (ESP_N). C) Correlation of conformational equilibrium constants measured in the 1‐X balance series vs. rate constants for the N‐methylation of correspondingly substituted 2‐X pyridine derivatives, when both sets of measurements were performed in [D₆]acetone. D) Improved correlations were found between rate constants measured in [D₆]acetone and conformational equilibrium constants measured in five other solvents including tetrahydrofuran (R²=0.88 to 0.94, Figures S38–S39). All experiments were performed at 298 K.