Computational exploration of N-heterocyclic carbene (NHC)-for-phenylacetylene ligand exchange in IrAu 12 alloy clusters

were systematically studied. The results showed that the acid-induced PA removal is the rate-determining step, with the energy barrier strongly influenced by the central metal (Pt < Rh < Ir ∼ Pd < Au), the acidity, the size and the number of attackable hydrogen atoms in the attacking acid. After the selective PA removal, the incoming NHC ligand can spontaneously adsorb at the exposed Au sites, which is a barrierless process. Moreover, the strong electron-donating ability of the NHC ligand increases the electron density on the cluster core, which widens the HOMO-LUMO gap and greatly enhances the electronic stability of the NHC-modified clusters. The results of this study shed light on the exciting opportunity of post-synthetic ligand exchange to create NHC-stabilized superatom nanoclusters, which expands the horizons of predesigned and controllable structure design of novel metal nanoclusters.