Thermodynamic Descriptors for Structural Stability and Ligand Compatibility of Thiolate-Protected Gold Nanoclusters

Despite great progress has been made in the synthesis andstructural determination of atomically accurate metal nanoclusters, there arefew theories that were developed to describe the thermodynamic stability ofthese nanoclusters as a function of their atomic-level structural characteristics.In this study, a new thermodynamic theory is proposed to correlate thethermodynamic stability of thiolate-protected gold clusters with their atomic-level structures and ligand stabilization effects. Two thermodynamicdescriptors, the averaged formation energy (Eave) and the averaged ligandstabilization energy (ALSE), are proposed. Based on thefirst-principlesdensity functional theory calculations ofEaveand the ALSE of 48experimentally determined thiolate-protected gold nanoclusters, we revealfine linearity betweenEaveand the number ratio of Au atoms and thiolategroup (SR) ligands (NAu/NSR) and between ALSE andNAu/NSR. The structural stability of thiolate-protected gold clusters istherefore assessed and predicted from theEave, and the compatibility between the thiolate ligand and the gold cluster is evaluated bythe ALSE. The present study introduces a new pathway for accelerating the discovery of atomically precise metal clusters with goodthermodynamically stability, which are synthesizable in the laboratory.