Secondly, among the intermediates refined at the previous step, their relative Gibbs energies can be used to set a threshold establishing the likeliness of electrophilic aromatic substitution mechanism for C-H activation of a particular substrate. The more stable the ipso-complex between palladium acetate and the substrate is, the more likely the substrate is to follow the electrophilic mechanism. After performing the computational analysis of 12 examples which include five structures following the electrophilic mechanism, a threshold has been developed by choosing the example 6 as the reference, Table , and introducing the ipso-complex stability parameter. We define this parameter to be the energy difference between the most stable intermediate of the SEAr mechanism and the one of the PA mechanism. By comparing the computational results obtained to the literature experimental data, the two mechanisms can be segregated based on the following rules: