Insights into the active catalyst formation in palladium catalyzed coupling reaction from di-nuclear palladium acetate: A DFT study

We explored the formation of active palladium catalyst species by degradation of Pd-acetate dimer with the addition of phosphine ligands (PH3 and PPh3 ) with an automated reaction search employing Density Functional Theory calculations followed by kinetic studies with stochastic simulation analysis. Our reaction search starting from dimeric form, considered a resting state of the catalyst, produced similar monomeric species by sequential ligand addition as found in the experimental investigation of the active catalytic species in Heck reactions. We analyzed the bonding in the Pd-acetate dimer and the role of Pd in the stability of the dimeric species. We implemented the Gillespie Stochastic Simulation Algorithm and applied it to the degradation reaction path. This algorithm can give more insights into multi-channel reaction paths. The energetics of the degradation path is reasonably achievable in the experimental reaction conditions that make dimeric species a potential catalytic precursor in the Pd-acetate catalyzed coupling reactions.