<i>Cis‐Trans</i> Isomerism Revealed in Circularly Polarized Luminescent Superatomic Ag ₂₈ Nanoclusters

Abstract

Abstract Atomically precise metal nanoclusters facilitate the exploration of chiral origin in metal nanomaterials, meanwhile, their structural isomers with subtle variations serve as ideal models for investigating the structure‐property relationship at the atomic level. Here, we obtained two pairs of chiral superatomic cis ‐ trans isomers with the formula [ R/S ‐Ag 28 (SOC 10 H 15 ) 14 (CF 3 COO) 10 ] (denoted as R/S ‐Ag 28 ‐ cis/trans ), where the cis and trans configurations coexist within the R and S chiral forms, respectively. Single crystal X‐ray diffraction (SCXRD) analysis revealed that Ag 28 clusters adopt a chiral core‐shell configuration of Ag 12 @Ag 14 S 12 , consisting of an Ag 12 kernel encapsulated within a chiral Ag 14 S 12 cage. The additional two AgS units are located in a different fashion on the flanks of the framework, leading to the cis ‐ trans isomerism of the silver clusters. DFT calculation reveals the distinctions in electronic structures and optical absorptions of the cis ‐ trans isomers. The enantiomeric R/S ‐Ag 28 exhibit intense red phosphorescence at 740 nm in the crystalline state, and hold a ∼28 nm blueshift in solution. Furthermore, R/S ‐Ag 28 display circularly polarized luminescence (CPL) activity, achieving a maximum (| g lum |) value of 1 × 10 −3 in the crystalline state. This study enriches the diversity of chiral superatomic clusters and introduces cis ‐ trans isomerism in metal clusters, establishing a novel platform to explore structure‐activity relationships.