Tailoring the Electron Affinity of Au 13 Superhalogen via Ligand Design

ABSTRACT The thiolate (RS)‐protected neutral gold cluster Au 25 (SR) 18 0 , which has an icosahedral Au 13 core, is regarded as a superhalogen due to its comparably high electron affinity (EA) to those of halogen atoms. Here, the EAs of Au 13 superhalogens protected by various thiophenolate derivatives were determined by using gas‐phase photoelectron spectroscopy of the corresponding anions Au 25 (SR) 18 − . Correlation analysis revealed a linear relationship between the EA and the dipole moment of the RS ligands. The relationship can be explained by the concept of surface potential, which has been widely used to describe changes in the work function of bulk metals modified by self‐assembled monolayers. Based on these results, we propose a unified design principle of ligand for tuning the EA of the Au 13 superhalogen.