Enhanced Surface Ligands Reactivity of Metal Clusters by Bulky Ligands for Controlling Optical and Chiral Properties

Abstract

Surface ligands play critical roles in determining the surface properties of metal clusters.H owever,m odulating the properties and controlling the surface structure of clusters through surface-capping-agent displacement is challenging. Herein, [Ag 14 (SPh(CF 3 ) 2 ) 12 (PPh 3 ) 4 (DMF) 4 ]( Ag 14 -DMF; DMF = N,N-dimethylformamide), with weakly coordinated DMF ligands on surface silver sites,w as synthesized by am ixed-ligands strategy.O wing 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"D MF ligation was realized. When chiral amines were introduced to as-prepared products,a ll 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-raydiffraction (SCXRD). This work provides anew insight into modulation of the optical properties of metal clusters and atomically precise homochiral clusters for specific applications are obtained.

Enhanced Surface Ligands Reactivity of Metal Clusters by Bulky Ligands for Controlling Optical and Chiral Properties

“…Color legend: green sphere, Ag;y ellow sphere, S; pink sphere, P; blue sphere, N; red sphere, O. [15] Figure 8.…”

“…Figure1. a) Molecular structure of Ag 14 -DMF.b)Core structure of Ag 14 -DMF.C olor legend:g reen, Ag;y ellow,S;p ink, P; red, O; blue, N; sky blue, F; grey,C .All hydrogen atoms are omitted for clarity [15]. …”

“…a) Core structures of the Ag 14 -DMF enantiomer pair.b)Core structures of Ag 14 -R-1-PPA (left) and Ag 14 -S-1-PPA (right). Color legend: green sphere, Ag;y ellow sphere, S; pink sphere, P; blue sphere, N; red sphere, O [15]. Figure8.…”

Synthesis and multifunctional sensing ability of axially chiral tetranuclear europium clusters

“…Chirality, which describes an object that is non-superimposable on its mirror image, 20,21 is an essential feature of life and plays a vital role in various chemical and biological processes. 18,22–24 As a special chiral molecule, axially chiral compounds not only exist in natural products and drugs but also are widely used in laboratory synthesis and industrial production. 25–27 These molecules, such as biaryl compounds, have one or more chiral axes with hindered rotation.…”

Assembly of Chiral Cluster-Based Metal–Organic Frameworks and the Chirality Memory Effect during their Disassembly

“…The as-prepared Ag 14 cluster is a racemic mixture of the mirror-imaged enantiomers R-Ag 14 and S-Ag 14 . Furthermore, the as-prepared racemate clusters can be converted to optically pure enantiomers through post-treatment with small chiral molecules such as R- or S-1-phenylpropylamine (which replaces all surface PPh 3 and DMF ligands) . The high flexibility of the ligand shell of the Ag 14 cluster as well as the existence of the weak coordination DMF ligands make it a good candidate as a building block for constructing CMOFs and investigating the relationship between the linkers and building units.…”