Directing Intrinsic Chirality in Gold Nanoclusters: Preferential Formation of Stable Enantiopure Clusters in High Yield and Experimentally Unveiling the "Super" Chirality of Au₁₄₄.

ABSTRACT: Chiral gold nanoclusters offer significant potential for exploring chirality at a fundamental level and for exploiting their applications in sensing and catalysis. However, their widespread use is impeded by low yields in synthesis, tedious separation procedures of their enantiomeric forms, and limited thermal stability. In this study, we investigated the direct synthesis of enantiopure chiral nanoclusters using the chiral ligand 2-MeBuSH in the fabrication of Au₂₅, Au₃₈, and Au₁₄₄ nanoclusters. Notably, this approach leads to the unexpected formation of intrinsically chiral clusters with high yields for chiral Au₃₈ and Au₁₄₄ nanoclusters. Experimental evaluation of chiral activity by circular dichroism (CD) spectroscopy corroborates previous theoretical calculations, highlighting the stronger CD signal exhibited by Au₁₄₄ compared to Au₃₈ or Au₂₅. Furthermore, the formation of a single enantiomeric form is experimentally confirmed by comparing it with intrinsically chiral Au₃₈(2-PET)₂₄ (2-PET: 2-phenylethanethiol) and is supported theoretically for both Au₃₈ and Au₁₄₄. Moreover, the prepared chiral clusters show stability against diastereoisomerization, up to temperatures of 80 °C. Thus, our findings not only demonstrate the selective preparation of enantiopure, intrinsically chiral, and highly stable thiolate-protected Au nanoclusters through careful ligand design but also support the predicted "super" chirality in the Au₁₄₄ cluster, encompassing hierarchical chirality in ligands, staple configuration, and core structure.

SUBMITTER: Truttmann V 

PROVIDER: S-EPMC10604085 | biostudies-literature | 2023 Oct

REPOSITORIES: biostudies-literature