Polymer-coated palladium nanoparticle catalysts for Suzuki coupling reactions

•We report the use of polymer-coated palladium nanoparticles in catalysis.•The effect of polymer structure on the catalytic activity was established.•A low concentration of stabilizer was used, compared to previous studies.•Yields of Suzuki couplings correlated with rate constants of a model reaction.•Macromolecules with pendant pyridyl moieties are unsuitable capping agents.

A set of seven different palladium nanoparticle (PdNP) systems stabilized by small amounts (1.0 mg/mL) of structurally related macromolecular capping agents were comparatively tested as catalyst in p-nitrophenol (Nip) reduction and Suzuki cross-coupling reactions. The observed rate constants (kobs) for Nip reduction were in the range of 0.052–3.120 × 10−2 s−1, and the variation reflected the effects of polymer chain conformation, ionic strength and palladium–polymer complex coordination. Macromolecules featuring pendant pyridyl moieties or inverse temperature-dependent solubility were found to be unsuitable capping agents for PdNPs catalysts, despite being active. The catalytic activity in Suzuki cross-coupling reactions followed the same behavior; the most active particles in the Nip reaction also mediated the cross-coupling reaction providing the expected products in quantitative yields under relatively mild conditions after only 4 h at 50 °C. Experiments involving the successive addition of reactants and catalyst recovery/re-use indicated that the recycling potential was comparable to those of the standards used in this field.

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