Deng Guocheng, Malola Sami, Yuan Peng, Liu Xianhu, Teo Boon K, Häkkinen Hannu, Zheng Nanfeng
State Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, and, National & Local Joint Engineering Research Center of Preparation Technology of Nanomaterials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
Departments of Physics and Chemistry, Nanoscience Center, University of Jyväskylä, 40014, Jyväskylä, Finland.
Angew Chem Int Ed Engl. 2021 Jun 1;60(23):12897-12903. doi: 10.1002/anie.202101141. Epub 2021 Apr 28.
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 (SPh(CF ) ) (PPh ) (DMF) ] (Ag -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 -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 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 clusters were converted to optically pure homochiral Ag 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.
表面配体在决定金属簇的表面性质方面起着关键作用。然而，通过表面封端剂置换来调节簇的性质并控制其表面结构具有挑战性。在此，通过混合配体策略合成了[Ag (SPh(CF ) ) (PPh ) (DMF) ]（Ag -DMF；DMF = N，N-二甲基甲酰胺），其表面银位点上具有弱配位的DMF配体。由于Ag -DMF具有高表面反应性，表面配体不稳定，容易被其他配体解离或交换。基于增强的表面反应性，通过可逆的“开-关”DMF连接实现了对Ag光学性质的轻松调节。当将手性胺引入到制备好的产物中时，所有八个表面配体都被胺取代，外消旋Ag簇转变为光学纯的同手性Ag簇，这通过圆二色性（CD）活性和单晶X射线衍射（SCXRD）得到证实。这项工作为金属簇光学性质的调节提供了新的见解，并获得了用于特定应用的原子精确同手性簇。
