Heterogeneous Behaviour in Cross-Couplings
Pd-catalysed cross-couplings: A case study on the Suzuki-Miyaura reaction - For many years the active Pd catalyst phase has been thought to exclusively involve mononuclear Pd species, operating under homogeneous conditions, as described in common textbooks. The adjacent image, from a typical reaction seen in modern synthetic chemistry laboratories, in this case employing 5 mol% of the Pd(II) precatalyst, Pd(OAc)2, highlights the reality of cross-coupling chemistry and the in situ formation of aggregated ‘higher order’ Pd species that may actually play an important role in this chemistry. We have gathered evidence showing that aggregated (stabilised) nanoparticles can catalyse Suzuki-Miyaura cross-coupling, which exhibit behaviour typical of a catalyst surface. This work was part of a collaboration with surface scientist Prof. Adam Lee.
We are interested in how small, catalytically compentent Pd nanoparticles form under cross-coupling reaction conditions. We have gathered evidence showing that such species play a key role in many different types of reactions, including C-H bond functionalisation reactions.