Atomically Well-Defined Thiolate Gold Nanoclusters for Heterogeneous Catalysis

National @ MATERIAUX+CLA:ADM:ATU; International audience; Gold nanoparticles exhibit catalytic activity in many chemical processes.1 However, fundamental investigations on the structure-catalytic activity relationships still lag behind, partly due to the polydispersity issue of gold nanoparticles. Indeed polydisperse particles obscure the interesting size-dependent catalytic activity of nanogold and preclude an in-depth understanding of the origin of this size dependence. Recently, atomically monodisperse, thiolate-capped Au nanoclusters (denoted as Aun(SR)m) have been successfully isolated and their catalytic properties have been demonstrated.2 These well-defined gold clusters hold promises as a new generation of catalysts and, more importantly, permit in-depth studies on the subtle correlation of structure and catalytic activity, since these nanoclusters are atomically well defined and some of their structures have been solved by single crystal X-ray diffraction.3 To investigate the influence of the size, the type of ligands at the surface and also the support effect, different nanoclusters have been synthesized. Here we present the synthesis of new clusters made of 4-aminothiophenol (HSPhNH2). Among them Au10(SPhNH2)9/10 and Au25(SPhNH2)17 have been isolated and fully characterized by mass spectrometry, X-ray diffraction and XPS.4 Moreover these clusters exhibit characteristic absorption behaviors related to their molecular state. Catalytic activity for oxidation of alkene derivatives of these colloidal or supported clusters were investigated and compared to commonly used Aun(SCH2CH2Ph)m nanoclusters or bared nanoparticles. (1) Hashmi, A. S. K.; Hutchings, G. J. Angew. Chem.-Int. Edit. 2006, 45, 7896. (2) Jin, R. C.; Zhu, Y.; Qian, H. Chem. Eur. J. 2011, 17, 6584. (3) Zhu, Y.; Qian, H. F.; Zhu, M. Z.; Jin, R. C. Adv. Mater. 2010, 22, 1915. (4) Lavenn, C.; Albrieux, Bergeret, G.; F.; Chiriac, R., Delichčre P.; Tuel, A.; Demessence, A. Nanoscale , 2012, 4, 7334.