Correlating Kernel-Shell Structures with Optical Properties of Pt1Ag24 and Pt1Ag14 Nanoclusters

With considerable attention focusing on metal nanoclusters, to explore the relationship of structures and their properties is of prime importance for designing novel functional nanoclusters and promoting their applications. Here we reported two novel alloy nanoclusters, [Pt1Ag24(SR)(20)](4-) and Pt1Ag14(SR)(6)(PPh3)(8) (H-SR: 2-chloro-4-fluorobenzenethiol), determined by X-ray crystallography. Interestingly, the two alloy nanoclusters have the same centered icosahedral Pt(1)Ag(12 )kernel, but shell structures are totally different due to the addition of PPh3 in the synthesis. Upon removal of the kernel, the shell of the Pt1Ag24 nanocluster is composed of two unique trefoil-like Ag-6(SR)(10 )motifs, while the Pt1Ag14 nanocluster has six PPh3 and two Ag(SR)(3)(PPh3) motifs. Furthermore, fluorescence spectros- copy and ultraviolet-visible absorption spectroscopy (UV-vis) were carried out to investigate the optical properties. The Pt1Ag24 nanocluster has near-infrared photoluminescence at 738 nm, whereas the emission of the Pt1Ag14 nanocluster is at 639 nm, demonstrating a blue shift of 99 nm. The two nanoclusters exhibit distinct optical fingerprints. Furthermore, the predicted partial density of states and UV-vis spectra assignments reveal the relationship of the crystal structures, electronic structures, and optical properties. These findings not only provide a feasible strategy to synthesize functional metal nanoclusters with distinctive structures but also give direct insight into understanding the structure-property correlations at the atomic level.

Automated summary

This study reported two novel alloy nanoclusters with similar core structures but different shell structures, showing distinct optical properties. Fluorescence spectroscopy and UV-vis spectroscopy analyses revealed the emission wavelengths and optical fingerprints of the two nanoclusters. Additionally, predicted partial density of states and UV-vis spectra assignments provided insights into the relationship between crystal structures, electronic structures, and optical properties.