All‐ <i>N</i> ‐Heterocyclic‐Carbene Protected Superatomic Ag ₈ Cluster

Abstract

Abstract Atomically precise monolayer‐protected coinage metal nanoclusters (CMNCs) have drawn increasing attention for their diverse structures and intriguing properties. Nevertheless, not all‐ N ‐heterocyclic‐carbene (NHC)‐protected atomically precise silver nanoclusters have been synthesized yet. Herein, we report the synthesis and crystal structure of the first all‐NHC‐protected superatomic silver cluster. This NHC‐ligand‐stabilized Ag 8 cluster, characterized as Ag 8 K 2 L 4 (CO 3 ) 2 (PF 6 ) 6 , was prepared by reacting Ag 2 O with bisimidazolium salt H 2 ‐ L (PF 6 ) 2 under alkaline conditions in dimethylformamide via a one‐pot reaction. The results of single‐crystal X‐ray diffraction analysis, multinuclear nuclear magnetic resonance (NMR) spectroscopy, and high‐resolution electrospray‐ionization (HR‐ESI) mass spectrometry revealed a cluster centered with a stable Ag 8 ring. Energy decomposition analysis combined with the natural orbital for chemical valence method (EDA‐NOCV) was employed to analyze the nature of the Ag–ligand bonding, and the results suggested that the stabilization energy originated from the strong electrostatic attraction of the Ag 8 ring to the NHC ligand. This work is expected to enable new applications of various NHC ligands in the formation of NHC‐protected metal clusters with attractive properties.