Simple Approach toward <i>N</i>-Heterocyclic Carbene-Protected Gold Nanoclusters
Jing Sun, Xiongkai Tang, Jiaqi Tang, Yuhao Zhang, Zilin Li, Chaolumen Chaolumen, Shuo Guo, Hui Shen
Abstract
Little advance has been made toward developing alternative bottom-up synthetic strategies for N -heterocyclic carbene (NHC)-stabilized gold nanoclusters, although this unique class of nanomaterials has exhibited exciting properties. We report in this work a simple and straightforward approach toward NHC-ligated gold nanoclusters by using imidazolium salts rather than free carbenes or NHC-coordinated gold complexes (NHC–Au-X, X is counterions) as precursors. Illustrated here is a one-pot and one-step preparation of an NHC-stabilized Au 13 Br 4 cluster that features a distinct molecular formula, surface motifs, and assembling modes via chemical reduction of dpaAu, NaOMe, and F NHC Bn ·HBr by NaBH 4 (Hdpa is dipyridylamine; F NHC Bn ·HBr is 1,3-dibenzyl-5,6-difluoro-1 H -benzo[ d ]imidazole-3-ium bromide). In situ UV–vis and NMR studies have elucidated the base-assisted formation of NHCs from imidazolium salts for the protection of the metal core. This work not only reports a new NHC-ligated superatom that completes the Au 13 library, thus facilitating structure–property studies, but also opens the door to explore underlying analogues in a facile and reasonable way.