Theoretical study on a novel Au99+31n(SR)40+10n cluster sequence with D5 symmetry

Abstract

The cluster sequences with analogous structures are of significant importance for elucidating the evolutionary patterns in both structural configurations and electronic architectures of RS-AuNCs. Despite substantial efforts devoted to synthesizing and characterizing a series of single-crystal structures of RS-AuNCs, the scarcity of well-defined single-crystal structures for large-sized cluster sequences has impeded comprehensive understanding of structure–property correlations within this size regime. This work presents a theoretical investigation of a novel series of Au_99+31n(SR)_40+10n (where n = 0, 1, 2, 3) clusters exhibiting D₅ symmetry. The structural evolution of the cluster sequence emerges as a one-dimensional linear extension of the Au₉₉(SR)₄₀ (n = 0) kernel framework, demonstrating a quantized growth pattern where each successive expansion event is accompanied by a precise 21 valence electron increment. The DFT calculations reveal that this series of clusters exhibit significantly negative average formation energies (E_ave), confirming their exceptional thermodynamic stability. The sTDA calculations demonstrate that Au₁₆₁(SR)₆₀ and Au₁₉₂(SR)₇₀ clusters display characteristic surface plasmon resonance (SPR) peak in their UV-Vis, indicating a size-induced transition from molecular to metallic states in these clusters. Furthermore, the aspect ratio is proposed as a potential critical geometric parameter governing the emergence of metallic characteristics in the Au₁₉₂(SR)₇₀ cluster.