The Behavior of Au55 nanoclusters on and in thiol-terminated dendrimer monolayers

The formation of perfect monolayers on to 9 × 9 mm silicon wafers that were fixed onto a spin-coater by adding six drops of a 10 6 M dendrimer solution onto the wafer rotating at 100 rpm was described. The reactivity of the dendrimer monolayer towards the gold particles was tested by investigating their interaction with 8-10 nm gold colloids in aqueous solution. In an atmosphere of dichloromethane the dendrimers take up solvent and the clusters become mobile and lose their original ligand shell. The extraordinary stability of naked Au 55 clusters allow them to grow slowly to form nanometer-sized well-structured crystallites which react with the thiol functions. The results show that the interaction of Au 55(PPh 3) 12Cl 6 clusters with G4-SH, a fourth-generation dendrimer equipped with 96 SH functions result in the formation of stable cluster monolayers on the dendrimer film.