Atomically Precise Pt19: The Largest All-Organic Ligand-Protected Platinum Nanocluster with Enhanced Stability and Electrocatalytic Activity.

Versatile organic ligands can notably enhance the stability and tunability of metal nanoclusters (NCs), and, consequently, all-organic ligand-protected metal nanoclusters have recently attracted widespread attention. Platinum (Pt) remains an indispensable metal in various fields, particularly in catalysis and cancer therapeutics. However, all-organic ligand-protected Pt nanoclusters are rarely reported due to substantial synthesis challenges, which have hindered progress in Pt nanocluster research and their practical applications. Herein, we report the successful synthesis of the largest all-organic ligand-protected Pt nanocluster to date, [Pt19(NapNC)27][PF6]2 (abbreviated as Pt19; NapNC: isocyanonaphthalene), achieved through the development of a ligand-exchange method. Single-crystal X-ray diffraction (SC-XRD) revealed a face-centered cubic (FCC), nonequivalent structure that has not been previously documented for all-organic ligand-protected Pt nanoclusters. Compared with its partially organic parent nanoclusters, this novel nanocluster exhibits considerably enhanced stability in both the ground and excited states. Furthermore, the Pt19 nanocluster demonstrates superior activity in the electrocatalytic methanol oxidation reaction (MOR) relative to its parent nanoclusters and commercial Pt/C. Based on its well-defined structure, we gained deep insights into the exceptional MOR activity of Pt19 and revealed, for the first time, the steric and electronic preferences of the active sites for electrocatalytic MOR.