N-heterocyclic carbene-stabilized Au13 superatom clusters
Magic number Au13 nanoclusters stabilized entirely by N-heterocyclic carbenes (NHCs) have been prepared by the bottom-up reduction of well-defined molecular NHC–Au–Cl complexes with sodium borohydride. The nature of the wingtip groups was shown to be critical in the preparation of stable clusters. The all NHC-clusters are prepared in high yield by this straight-forward method, display higher stability than related all phosphine clusters, and possess extremely high emission quantum yield. DFT analysis of these clusters based on the resolved crystal structure reveals their electronic structure as 8-electron superatoms.