Elucidating the Structural Stability of the Ligand Protected Ag Nanoclusters with 5e-8e Valence Electrons
摘要
The concept of superatoms has long been used as a guide to understand the stability of clusters. However, little work has been done to compare the structural stability of ligand-protected Ag nanoclusters with the same kernel using the superatom concept. In this study, we construct six clusters based on the same Ag13 kernel, including 5e Ag17(SR)12, 6e Ag20(SR)14, 6e Ag18(SR)12, 7e Ag19(SR)12(DMPA)3, 7e Ag25(SR)18, and 8e [Ag25(SR)18]– (where R = -CH3, Methyl; DMPA = C6H16P2, 1,2-Bis(dimethylphosphino)ethane). The regulation of the valence electron count is achieved by varying the outer motifs—Ag(SR)2, Ag2(SR)3, Ag(SR)3, and Ag2(SR)4(DMPA)—which withdraw 1, 1, 2, and 2 valence electrons from the inner kernel, respectively. The results show that the 8e [Ag25(SR)18]– cluster, with its closed 1S2|1P6 electron configuration, exhibits the least structural variation, a more balanced atomic charge distribution in the kernel Ag atoms, and a relatively large HOMO-LUMO gap. This work contributes to a better understanding of the superatom concept in the context of the structure of ligand-protected Ag nanoclusters.