Coupling reactions currently play a key role in organic chemistry, and the use of palladium catalytic systems to catalyze them is the most common practice, despite the interest in, say, nickel catalysts in recent years. When both complex Pd compounds and Pd nanoparticles are used as catalyst precursors, formation of dynamic catalytic systems is often observed. In the course of such coupling reactions, metal leaching from the surface of nanoparticles (NPs) can proceed simultaneously with de novo NPs formation (from decomposing metal complexes) or deposition on the surface of NPs (see the discussion in our previous work ). The role of the supporting substrate is also important, since leached (from NPs) and re-adsorbed monometallic centers can act as active catalysts on its surface . Classical mechanisms of coupling reactions take into account only one type of reaction center, namely, Pd(0)/Pd(II) metal complexes .
In this report, a series of our recent works will be covered. In our studies, we combine quantum chemical methods to decipher mechanisms of organic reactions catalyzed by transition metal compounds.
Recently we applied the quantum-chemical GFN2-xTB method and DFT methods to model the mechanism of Suzuki and Negishi reactions under dynamic catalytic conditions, i.e., taking into account the formation/presence of both Pd nanoparticles and metal complexes in the system, as well as the effect of an NP substrate. The calculations were performed using the software packages xtb 6.4.1 and ORCA 4.2.1.