A 34-Electron Superatom Ag78 Cluster with Regioselective Ternary Ligands Shells and Its 2D Rhombic Superlattice Assembly

Herein, we report a 78-nuclei silver nanocluster (NC) [Ag-78((PrPhS)-Pr-i)(30)(dppm)(10)Cl-10](4+) (SD/Ag78a; dppm=bis-(diphenylphosphino)methane) that was synthesized through a one-pot reaction using [Ag(pz)](n) as precursor (Hpz=pyrazole) and further characterized by X-ray crystallography. SD/Ag78a shows a core-shell structure comprised of an all-metallic Ag-53 kernel surrounded by an Ag-25 discontinuous metal-organic shell. The Ag-53 kernel is an Ag-13 Ino decahedron encaged by an Ag-40 drum-like shell, while the Ag-25 shell consists of two Ag10S10P10Cl5 rings and five S-Ag-S staples. Three types of ligands regioselectively cap on the surface of the Ag-78 NC, forming diverse metal-ligand interfacial structures. The NC is a closed-shell 34-electron superatom with +4 charge state and shows highly featured molecule-like absorption spectra in the UV/Vis region with a maximum around 493 nm. The rhombic superlattice assembled from SD/Ag78a through intercluster C-H...pi interactions can be formed by a simple drop-casting treatment.

Automated summary

A 78-nuclei silver nanocluster with a core-shell structure of metallic Ag-53 kernel and discontinuous Ag-25 metal-organic shell was synthesized and characterized. The nanocluster exhibits molecule-like absorption spectra in the UV/Vis region and can form a rhombic superlattice through intercluster interactions.