Thermal Stability and Electronic Properties of N-Heterocyclic Carbene-Protected Au13 Nanocluster and Phosphine-Protected Analogues

Despite significant advances in manufacturing atomically precise gold nanoclusters protected by various ligands, there is a limited understanding of the thermal stability dynamics and electronic properties of ligand effects. We conducted ab initio molecular dynamics (AIMD) simulations on the well-characterized [Au-13(NHCMe)(9)Cl-3](2+) nanocluster and its counterpart [Au-13(PMe3)(9)Cl-3](2+) cluster to evaluate the thermal stability induced by N-heterocyclic carbene (NHC) and phosphine ligands. The result shows that under vacuum conditions, [Au-13(PMe3)(9)Cl-3](2+) is more stable than [Au-13(NHCMe)(9)Cl-3](2+), and both lead to metal nucleation decomposition, breaking into the Au-12 fragment and L-Au-Cl (L = NHCMe or PMe3) complexes eventually. The optical and electronic properties of these two clusters change significantly due to ligand alteration. Furthermore, we have designed a novel [Au-13(NHCMe)(PMe3)(8)Cl-3](2+) cluster coprotected by NHC and phosphine ligands, displaying higher thermal stability than the homoligand protected [Au-13(NHCMe)(9)Cl-3](2+) and [Au-13(PMe3)(9)Cl-3](2+). Our hypothetical species are an interesting model for nanostructured materials, facilitating the experimental exploration of cluster synthesis and catalytic applications.