Atomically well-defined Au25(SR)17/18 nanoclusters deposited on silica supports for the aerobic epoxidation of trans-stilbene

• We synthesized gold-based catalysts from atomically well defined thiolate gold clusters.
• We showed that a good interaction between external amino functions of the gold nanoparticles and the hydrophilic substrate lead to stable catalyst.
• We showed that functionalized gold nanoparticles have higher catalytic activity than the unfunctionalized one.

Two atomically well-defined thiolate gold nanoclusters, Au25(SC2H4Ph)18 and Au25(SPhNH2)17, having the same gold core but different thiolate ligands have been deposited on silica supports and the obtained catalysts have been tested in the aerobic oxidation of trans-stilbene. By properly selecting the support to maximize cluster/surface interactions, it was possible to prepare materials with small nanoparticles and very narrow particle size distributions. Au25(SPhNH2)17@SBA-15 catalyst showed an activity and a trans-stilbene epoxide selectivity comparable to the best heterogeneous catalysts. Elimination of the thiolate molecules by calcination did not significantly modify the particle size but decreased the activity, pointing out the critical role of the ligands in the reaction.

High activity of trans-stilbene epoxidation by using thiolate Au25 clusters as precursors on SBA-15.Figure optionsDownload high-quality image (350 K)Download as PowerPoint slide