Enhanced Surface Ligands Reactivity of Metal Clusters by Bulky Ligands for Controlling Optical and Chiral Properties. (28th April 2021)

• Record Type: Journal Article
• Authors: Deng, Guocheng; Malola, Sami; Yuan, Peng; Liu, Xianhu; Teo, Boon K.; Häkkinen, Hannu; Zheng, Nanfeng
• Is Part Of: Angewandte Chemie. Volume 133:Number 23(2021)
• Page Start: 13007
• Page End: 13013
• Publication Date: 2021-04-28
• Subjects: chirality -- circular dichroism -- optical properties -- silver clusters -- surface reactivities; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202101141
• Languages: English
• ISSNs: 0044-8249

Abstract

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, [Ag14 (SPh(CF3 )2 )12 (PPh3 )4 (DMF)4 ] (Ag14 ‐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 Ag14 ‐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 Ag14 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 Ag14 clusters were converted to optically pure homochiral Ag14 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. Abstract : Bulky surface ligands greatly enhance the surface ligands reactivity of metal clusters, allowing easy modulation of their optical properties by reversible surface ligation. When chiral amines are introduced into the solution of racemic clusters, they are readily converted in full to optically pure homochiral clusters.