Chirality Transfer in Gold Nanoclusters: Insights from Chiral Spectroscopy and Theoretical Modeling

Chirality in atomically precise gold nanoclusters emerges from the interplay among the metal core, the metal-ligand interface, and the ligand shell, yet how these hierarchical elements influence ligand conformation remains unclear. This work investigates chirality transfer from the nanocluster framework to the ligand sphere by using vibrational circular dichroism (VCD) spectroscopy combined with density functional theory and SCC-DFTB calculations. Three enantiopure thiolate-protected gold nanoclustersAu₂₅(2-MeBuS)₁₈, Au₃₈(2-MeBuS)₂₄, and Au₁₄₄(2-MeBuS)₆₀were selected as model systems, representing one, two, and three hierarchical levels of chirality, respectively. VCD analysis reveals a progressive restriction and reorganization of the ligand conformations with increasing structural chirality. While the intrinsically achiral Au₂₅ induces only modest spectral changes, the chiral arrangement of the staple units in the Au₃₈ induces significant changes in both IR and VCD spectra. In Au₁₄₄, the additional chiral gold core leads to a strong amplification of the VCD response. Computational analysis shows that ligand conformations are governed by cluster geometry, with binding favoring the most stable free ligand conformer. These results provide direct insight into chirality transfer mechanisms in gold nanoclusters, leading to a better understanding of the design of chiral nanomaterials.