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 Au₂₅(SH)₁₈^– nanocluster 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