Figure 4.

Linear relationships between logarithmic bond orders ($\log N_{\mathrm{P}-\mathrm{Nu}}^1$ and $\log N_{\mathrm{P}-\mathrm{Lg}}^1$) of early transition states (TS1) and the corresponding rate constants (logk¹) and experimental pK_as of leaving groups. The calculation were performed using density-functional method with PCM solvation model and UFF (left) and UAKS (right) radii. Red down triangle, blue up triangle, purple round and green diamond symbols correspond to alkyl, hetero-alkyl, phenyl and acid leaving groups, respectively. Regression parameters for logN¹ are given as well as linear correlation coefficient for r.