2 Computational details
All of our calculations were conducted with the Gaussian 09 software20. The geometry optimization of all the complexes
were performed at the M06 level 21, and the basis set
lanL2DZ22 was used for Pd and Cl and
6-31g(d)23for other atoms. Polarization
functions24 were added for Pd with ζf= 1.472 and Cl withζd = 0.640 in the calculation.
Frequencies for all reported structures at the same level of theory were
analytically computed to confirm all the stationary points as minima
(zero imaginary frequency), or transition states (only one imaginary
frequency). An intrinsic reaction coordinate (IRC) 25analysis was carried out to identify that transition states smoothly
connect two relevant minima. To consider the effects of solvent,
single-point energy calculations for all the species were obtained using
a self-consistent reaction field (SCRF) method based on the polarizable
continuum model (PCM) 26 at a higher level of
M06/6-311++G (d, p) (SDD 27 basis set for Pd and Cl
atoms), using 1,4-dioxane as solvent corresponding to the experimental
conditions. The M06 functional28 has been confirmed to
provide accurate energy calculations for organic transition metal
systems 29-34. And the natural population analysis
(NPA) charge calculations were carried out for selected systems35.