Ligand Exchange Mechanism on Thiolate Monolayer Protected Au25(SR)18 Nanoclusters

Ligand exchange reactions are important to functionalize and modify the optical and electronic properties of thiolate-protected gold nanoparticles. A theoretical investigation of the kinetics of the ligand exchange process was performed for the Au-25(SH)(18)(-) nanoduster with CH3SH as the incoming thiol ligand. Three possible ligand exchange sites were investigated: between the core gold atom and the terminal -SH unit, between the staple gold atom and the terminal -SH unit, and between a staple gold atom and the central -SH unit. We found that the most favorable ligand exchange takes place between terminal -SH units and staple gold atoms.