Chiral recognition via symmetry-dependent luminescence in zero-dimensional hybrid copper halides.

Abstract

Chiral recognition through fluorescence changes enables the rapid and sensitive determination of enantiomers. However, the rational design and synthesis of fluorescent probes for efficient chiral recognition remain a challenge. Here we present a novel platform for chiral recognition based on zero-dimensional hybrid copper halides with unique symmetry-dependent properties. The use of mesomeric 1,2-diaminocyclohexane (DACH) ligands promotes the formation of centrosymmetric, non-luminescent Cu₂I₆^4- units. The incorporation of enantiopure S- or R-DACH ligands into these mesomeric compounds breaks their symmetry, spontaneously transforming them into chiral compounds and generating Cu₄I₆^2- units that exhibit intense circularly polarized luminescence. Additionally, introducing opposite chiral ligands into these chiral compounds leads to the formation of racemic, non-luminescent CuI₃^2- units, whereas the addition of same-chirality ligands preserves the structure and optical properties of the chiral Cu₄I₆^2- units. This enantioselective response by utilizing symmetry-dependent optical properties offers a pathway toward advanced chiral sensing technologies.