A molecular dynamics study on the ion-mediated self-assembly of monolayer-protected nanoclusters.

We studied the effects of metal and molecular cations on the aggregation of atomically precise monolayer-protected nanoclusters (MPCs) in an explicit solvent using atomistic molecular dynamics simulations. While divalent cations such as Zn 2+ and Cd 2+ promote aggregation by forming ligand-cation-ligand bridges between the MPCs, molecular cations such as tetraethylammonium and cholinium inhibit their aggregation by getting adsorbed into the MPC's ligand shell and reducing the ligand's motion. Here, we studied the aggregation of Au 25 (SR) 18 nanoclusters with two types of ligands, para -mercaptobenzoic acid and D-penicillamine, as prototypical examples.