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Updated: Jan 26, 2026

Ligand-Mediated Nucleation and Growth of Palladium Metal Nanoparticles
Published on: June 25, 2018
Palladium-catalysed alkyne alkoxycarbonylation with P,N-chelating ligands revisited: a density functional theory
Shahbaz Ahmad1, Ashley Lockett, Timothy A Shuttleworth
1School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK. buehl@st-andrews.ac.uk.
Abstract:
A revised in situ base mechanism of alkyne alkoxycarbonylation via a Pd catalyst with hemilabile P,N-ligands (PyPPh2, Py = 2-pyridyl) has been fully characterised at the B3PW91-D3/PCM level of density functional theory. Key intermediates on this route are acryloyl and η3-propen-1-oyl complexes that readily undergo methanolysis. With two hemilabile P,N-ligands and one or both of them protonated, the overall computed barrier is 16.8 kcal mol-1. This new mechanism is consistent with all of the experimental data relating to substituent effects on relative reaction rates and branched/linear selectivities, including new results on the methoxycarbonylation of phenylacetylene using (4-Me2N-Py)PPh2 and (6-Cl-Py)PPh2 ligands. This ligand is found to decrease catalytic activity over PyPPh2, thus invalidating a formerly characterised in situ base mechanism.
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