Synthesis and Optical Properties of Unique PtAg Nanoclusters with Mixed Exterior Motif Structures.

The atomic arrangement of metal nanoclusters plays a significant role in the structure-property correlation. Herein, we present a novel PtAg(SR)(PPh) nanocluster with a unique structure, different from two reported PtAg nanoclusters. The nanocluster was prepared via one-pot synthesis and solvent extraction. It has a centered icosahedral PtAg kernel and an open shell composed of three Ag(SR)(PPh) staple motifs and a unique trefoil-like Ag(SR) motif. The three kinds of PtAg nanoclusters have the same kernel but different shell configurations. The fine-tuning of structures is necessary and significant for the investigation of the relationship of structures and properties. The different UV-vis absorption spectra indicate that the optical properties of three PtAg nanoclusters mainly depend on the exterior shell configuration and the metal-ligand interface. This work provides insights toward growth mechanism and the structure-property correlation of metal nanoclusters.