Observation of a Novel Interligand Chiral Arrangement in Metal Nanoclusters and Its Implication in Resisting Racemization

Given the scientifically significant importance of studying the chirality of clusters, the challenges of synthesizing chiral clusters are progressively surmounted. However, the racemization of clusters is unavoidable, and it limits the development of their follow-on chiral applications. To address this issue, chiral thiols are synthesized and used for the construction of high-stability optically pure nanoclusters in this work. As a result, a pair of chiral nanoclusters, Au₂₄Cd₂(SR)₁₄, is obtained with excellent stability under thermal, acidic, alkaline, oxidizing, and reducing environments. Unexpectedly, it can also maintain its optical activity with the introduction of Cu²⁺ ions and chiral ligand with opposite configuration. Structural relationship analysis indicates that the excellent stability is mainly dependent on the hierarchical assembly of the nanoclusters, in which the chiral assembly of chiral ligands (a new pattern of chiral arrangement of intramolecular ligands on the surface of clusters) may be a key factor.