Reactivity of Au25 clusters with Au3+

We report the instantaneous decomposition of the small molecular gold cluster, Au25SG18 (SG-glutathione thiolate) in the presence of externally added chloroaurate ions resulting in the instantaneous formation of the insoluble gold–glutathione polymer. The rate of decomposition, however, was much slower for the metal ions such as Ag+, Fe3+, Cu2+, Ni2+, Cd2+, Zn2+ and Sr2+. This chemical reactivity is shown to have no direct correlation with the electrochemical potential of the added ions.