Visualizing the fluorescence of AgPt NCs by an asymmetrical pseudo-ligand exchange method

Abstract

Precisely tailoring the structure of bimetal nanoclusters (NCs) at the atomic level has been proven to be an effective way to tune their physicochemical properties; however, achieving this remains challenging. Herein, the regulation from the reported Ag₂₆Pt(2-EBT)₁₈(PPh₃)₆ (Ag₂₆Pt) to Ag₁₆Pt(2-EBT)₆(dppm)₄Cl₂ (Ag₁₆Pt; 2-EBTH = 2-ethylbenzenethiol; dppm = bis-(diphenylphosphino)methane) NC was instantaneously (within one minute) realized through an asymmetrical pseudo-ligand exchange strategy. Single crystal X-ray crystallography (SCXC) combined with X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) confirmed its composition and structure. The target Ag₁₆Pt NC consists of a Pt@Ag₁₂ icosahedral core capped by a ligand shell of a pair of dimetric -SR-Ag-SR-Ag-SR- staple motifs, four dppm ligands, and two chlorine atoms. Their geometrical, electronic and crystallographical structures were comparatively investigated before and after regulation, which also provides some clues for understanding the blueshift of the emission center (Ag₂₆Pt: 845 nm vs. Ag₁₆Pt: 675 nm). This work provides important insights into the regulation of structures and photoluminescence of bimetal NCs protected by co-ligands.