Cocrystallization and Separation of Optically Active Atom-Precise Ag₃₂ and Ag₂₀ Clusters

Cocrystals based on metal nanoclusters (NCs) are ideal platforms to elucidate both intracluster and intercluster packing modes, as well as providing additional avenues for tailoring collective physicochemical properties. Herein, we report optically active cocrystals, [Ag32(tBuS)16(La/Lb)6(CF3COO)2]2·[CO3@Ag20(tBuS)10(CF3COO)8] (Ag32-a·Ag20 and Ag32-b·Ag20; La/Lb = (2S,3R)/(2R,3S)-3-methyloxiran-2-yl phosphonate), where Ag32 and Ag20 NCs cocrystallize in a 2:1 ratio. Circular dichroism (CD) spectroscopy of Ag32-a·Ag20 and Ag32-b·Ag20 demonstrates an excellent mirror image relationship, which is consistent with their UV–vis absorption spectra. Notably, the individual Ag32 and Ag20 NCs were isolated, and the enantiomeric relationship of them was confirmed by CD spectroscopy. Remarkably, Ag32-a displays superior antibacterial activity against E. coli compared with Ag32-b. This work expands the diversity and functional potential of silver cluster-based materials.