(AuAg)(SPh Bu) versus (AuAg)(SPhF): Tailoring the Geometric Structures and Optical Properties of Nanocluster Analogues.

Monolayer-protected nanoclusters are ideal models for understanding the correlations between structures and properties of inorganic nanoparticles, especially for those molecules with identical sizes but comparable structures. Here, we controllably prepared and structurally determined a valence-neutral Au Ag (SPh Bu) (0 < < 4) nanocluster with comparable structure features to a well-known AuAg(SPhF) cluster. The Au Ag (SPh Bu) cluster contained a hollow Au@M metallic kernel (M = Au/Ag), 12 Au(SR) staples, and two bridging SR molecules, and its average molecular formula was determined to be AuAg(SPh Bu), as evidenced by X-ray crystallography and electrospray ionization mass spectrometry. Because of the ligand effect and the asymmetrical arrangement of the Au dopants in the dodecahedral cage, the Au Ag (SPh Bu) nanocluster exhibited lower molecular symmetry relative to AuAg(SPhF) in terms of the dodecahedral kernel and motif shell structures. Besides, the strong π-π interaction in Au Ag (SPh Bu) contributed to its enhanced photoluminescence intensity compared with AuAg(SPhF). The study, herein, extends the 44-metal-atom cluster family, thereby enabling us to better understand the correlations between their structures and properties at the atomic level.