Asymmetric Twinned-FCC Configuration Alone Cannot Effectively Induce Metallicity in ∼200-Atom Gold Nanoclusters: Design and Theoretical Study of Tetrahedral Au-Cored RS-AuNCs.

This study proposes a novel design strategy for thiolate-protected gold nanoclusters (RS-AuNCs) based on the truncated triangular Au unit on the [111] crystal plane. First, sandwich-type primary cores of Au, Au, and Au are constructed on the Au crystal plane, and then triangular Au units are introduced to obtain core structures of Au, Au, and Au, respectively. Finally, based on the Au core, four asymmetric twinned-FCC shell clusters (Au(SR), Au(SR), Au(SR), and Au(SR)) are successfully constructed through differentiated ligand protection modes. Calculations of average formation energy () and atomization energy () demonstrate exceptional structural stability in these clusters. Electronic structure analyses reveal their extremely narrow orbital energy gaps, while the absence of SPR peaks and limited electronic spatial extent (⟨⟩) confirm their nonmetallic nature. This work provides the first elucidation that asymmetric twinned-FCC structures cannot induce metallic characteristics, uncovering a synergistic regulation mechanism of cluster electronic states by multiple parameters including Au atom count, stacking configuration, and core symmetry. These findings offer new insights into structure-property relationships of RS-AuNCs and provide significant guidance for the precision design of functional metal nanomaterials.