A pair of diphosphine-protected gold nanoclusters differing by a single gold atom on the kernel surface

Abstract

Atom-level manipulation of atomically precise metal nanoclusters (NCs) has attracted considerable attention due to its potentials to facilitate elucidating the structure-property relationships. Herein, we report two atomically precise gold NCs, [Au₉(DPPF)₄]Cl₃ (DPPF = bis(diphenylphosphino)ferrocene) (Au₉) and [Au₈(DPPF)₄]Cl₂ (Au₈), identified by single crystal X-ray diffraction (SCXRD), electrospray ionization mass spectrometry (ESI-MS), etc. SCXRD analysis reveals that the two gold NCs contain a similar Au₈ unit enclosed by the tetrahedral framework consisting of four DPPF ligands, and only difference lies in that there is an addition gold atom on kernel surface of Au₉ NC, which can be resected to form the Au₈ NC. This represents the achievement of precise atomic “tailoring” exerted on surface of the kernel of a gold NC without altering the other parts of structures. Notably, the two NCs have the identification of free valence electrons (6e). Further investigation on their electronic structures and electrocatalytic CO₂ reduction reaction activity was implemented to explore the functionality of such a minimal kernel tailoring at the level of atom. This work not only enriches the family of diphosphine-protected small-size gold NCs but also realizes the atomic-level tailoring of specific sites on a nanoparticle.