Abstract
Surface ligands play critical roles in determining the surface properties of metal clusters. However, modulating the properties and controlling the surface structure of clusters through surface-capping-agent displacement is challenging. Herein, [Ag-14(SPh(CF3)(2))(12)(PPh3)(4)(DMF)(4)] (Ag-14-DMF; DMF=N,N-dimethylformamide), with weakly coordinated DMF ligands on surface silver sites, was synthesized by a mixed-ligands strategy. Owing to the high surface reactivity of Ag-14-DMF, the surface ligands are labile, easily dissociated or exchanged by other ligands. Based on the enhanced surface reactivity, easy modulation of the optical properties of Ag-14 by reversible "on-off" DMF ligation was realized. When chiral amines were introduced to as-prepared products, all eight surface ligands were replaced by amines and the racemic Ag-14 clusters were converted to optically pure homochiral Ag-14 clusters as evidenced by circular dichroism (CD) activity and single-crystal X-ray diffraction (SCXRD). This work provides a new insight into modulation of the optical properties of metal clusters and atomically precise homochiral clusters for specific applications are obtained.