Atomically well-defined gold clusters: Oxidation reactions catalized by ultra-small gold core

International @ MATERIAUX+CLA:ATU:ADM; International audience; Recently, atomically well defined thiolate-capped gold nanoclusters (denoted Aun(SR)m with (10,10) < (n,m) < (333,79)) have been successfully isolated and few structures have been solved. Thus, these monodispersed functionalized clusters, with precise atomic positions and gold core less than 2 nm, hold promises as a new generation of catalysts. More importantly, these nanoclusters permit in-depth studies on the subtle correlation of the structure, core diameter, thiolate ligands effect and electronic state of gold nanoparticles with their catalytic activity. New clusters made of 4-aminothiophenol (HSPhNH2) have been isolated, such as Au25(SPhNH2)17, and fully characterized by mass spectrometry, X-ray diffraction and XPS.3 Moreover these clusters exhibit absorption bands related to their molecular state. Those clusters have then be used to investigate in aerobic oxidations reactions and compared to the Au25(SC2H4Ph)18 cluster, having the same Au core but different thiolate ligand. They have been deposited on silica supports (hydrophobic 16 nm-SiO2 nanoparticles and SBA-15 mesoporous silica) and by properly selecting the support to maximize clusters/support interactions, it was possible to prepare materials with ultra-small gold particles (