A 59-Electron Non-Magic-Number Gold Nanocluster Au<sub>99</sub>(C≡CR)<sub>40</sub> Showing Unexpectedly High Stability
Jiao‐Jiao Li, Zhikun Liu, Zong‐Jie Guan, Xu‐Shuang Han, Wan-Qi Shi, Quan‐Ming Wang
Abstract
An atomically resolved gold nanocluster Au99(C≡CC6H3-2,4-F2)40 (Au99) with an unusual 59 valence electrons has been synthesized. Single-crystal X-ray diffraction reveals that its Au79 kernel is a Au49 Marks decahedron capped by two Au15 units. The surface structure of Au99 consists of 20 linear Au(C≡CR)2 staples. Intercluster interactions are observed between these D5 symmetric clusters. The existence of an unpaired electron is verified by magnetic measurement. Interestingly, this open-shell gold cluster Au99 stays intact in toluene solution at 80 °C for more than a week, and it has good charging–discharging capability under electrochemical conditions. The compact ligand shell protection around the symmetric core accounts for the high stability. This work suggests that geometric factors may play a crucial role in determining the stability of a metal nanocluster, even though the cluster has an open-shell electronic structure.