Controlling the Atomic Structure of Au30 Nanoclusters by a Ligand-Based Strategy

We report the X-ray structure of a gold nanocluster with 30 gold atoms protected by 18 1-adamantanethiolate ligands (formulated as Au-30(S-Adm)(18)). This nanocluster exhibits a threefold rotationally symmetrical, hexagonal-close-packed (HCP) Au-18 kernel protected by six dimeric Au-2(SR)(3) staple motifs. This new structure is distinctly different from the previously reported Au30S(S-tBu)(18) nanocluster protected by 18 tert-butylthiolate ligands and one sulfido ligand with a face-centered cubic (FCC) Au-22 kernel. The Au-30(S-Adm)(18) nanocluster has an anomalous solubility (it is only soluble in benzene but not in other common solvents). This work demonstrates a ligand-based strategy for controlling nanocluster structure and also provides a method for the discovery of possibly overlooked clusters because of their anomalous solubility.