Effect of Ligand Structures on Ligand-Protected Gold Clusters: [Au-(p-/m-/o-MBT)]_1-8 Clusters

The controllable preparation of ligand-protected clusters is still an unresolved problem, which may be due to that their formation mechanism is unclear. We propose that the ligand is the key to solve the above problems. Here, by using p-, m-, and o-methylbenzenethiol ligand protected gold clusters as examples, we try to explore the effect of ligand structures on ligand-protected gold clusters. The geometrical structures, relative stabilities and surface properties of small-sized ligand-protected gold clusters [Au-SR]_1-8 (SR = p-/m-/o-MBT) have been systematically studied based on the density functional theory. The results show that the ground state structures of [Au-SR]_1-8 clusters tend to form closed rings except for [Au-SR]_1,2. The different structures of ligand have significant effect on the structures and stabilities of ligand-protected clusters. By analyzing their surface properties and possible growth patterns, it is found that [Au-SR]_1,2 clusters serve as the basic building blocks, and the larger clusters can be regarded as the combinations of them. This study provides some insights into the effect of ligands on ligand-protected clusters, which is useful for understanding the formation mechanism of ligand-protected clusters.