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 Au30 (S-Adm)18 ). This nanocluster exhibits a threefold rotationally symmetrical, hexagonal-close-packed (HCP) Au18 kernel protected by six dimeric Au2 (SR)3 staple motifs. This new structure is distinctly different from the previously reported Au30 S(S-(t) Bu)18 nanocluster protected by 18 tert-butylthiolate ligands and one sulfido ligand with a face-centered cubic (FCC) Au22 kernel. The Au30 (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.