We have used dispersion-corrected DFT (DFT-D) together with solvation to examine possible mechanisms for reaction of PhX (X = Cl, Br, I) with Pd(P(t)Bu(3))(2) and compare our results to recently published kinetic data (F. Barrios-Landeros, B. P. Carrow and J. F. Hartwig, J. Am. Chem. Soc., 2009, 131, 8141-8154). The calculated activation free energies agree near-quantitatively with experimental...