Ligand and Solvation Effects on the Structural and Electronic Properties of Small Gold Clusters

The catalytic, electrochemical, and optical properties of gold clusters and small nanoparticles depend on the cluster size, on the nature of the ligand shell and on the solvent environment. The structural and electronic properties of the neutral and trication bare cluster Au-11 are investigated using density functional theory. We focus on the influence of the cluster charge, the solvent, and the nature and number of the ligands (thiol, thiolate, thiyl radical, phosphine, chloride, and chlorine) on the cluster electronic structure and its geometry, with special attention to the structural motifs present in the metallic core of the different conformers. Single bindings are systematically studied and a comparison with full ligand coverage is discussed. Pure thiyl and phosphine ligand shells as well as mixed thiyl/phosphine shells are considered. This study provides a better understanding of the ligand shell and cooperative effects that could be probed experimentally.