Mechanistic study reveals switchable oxygen activation pathways in positional isomeric gold-cadmium clusters, highlighting surface motif rearrangement as a strategy to tune selectivity.
Key Points
To investigate how positional isomerism of surface motifs on identical Au13 cores influences electronic distribution, catalytic reactivity, and oxygen–oxygen bond activation pathways.
Synthesized positional isomeric nanoclusters Au14Cd2-1 and Au14Cd2-2 and demonstrated their reversible borane-mediated interconversion.
Assessed catalytic activity via styrene oxidation and analyzed intermediate pathways using TEMPO and triphenylphosphine (TPP) chemical trapping.
Characterized electronic states and binding interactions through density functional theory (DFT) calculations, X-ray photoelectron spectroscopy (XPS), and nuclear magnetic resonance (NMR) spectroscopy.
Au14Cd2-1 exhibited 93.1% styrene conversion with 77.3% epoxide selectivity, whereas Au14Cd2-2 showed 36.8% conversion with 88.9% benzaldehyde selectivity.
Au14Cd2-1 drove oxidation through heterolytic O–O bond cleavage (metal-oxo pathway), whereas Au14Cd2-2 proceeded via homolytic O–O bond cleavage (radical pathway).
DFT calculations and spectroscopy confirmed stronger styrene binding affinity on the electron-deficient Au14Cd2-1 cluster relative to Au14Cd2-2.