Expanding the Scope of Clickable Azide-Functionalized Nanoclusters to include Au144

Johanna A. de Jong, The University of Western Ontario

Abstract

Thiolate-protected Au₁₄₄ nanoclusters (NCs) are an intriguing member of the gold NC family. Their geometric structure, distinct electrochemical features, and susceptibility to structural rearrangement under the duress of ligand exchange have been studied. However, there are currently no established protocols for surface modification or tuning of their ligand shells post synthesis. Here, the direct synthesis of three regioisomers of azide-modified Au₁₄₄ NCs with 60 azide moieties, i.e., Au₁₄₄(SC₂H₄C₆H₄-N₃)₆₀, is reported, in which the azide functionality is located at the ortho-, meta-, or para position of the ligand’s phenyl ring. The regioisomeric effect of the azide group on Au₁₄₄(SC₂H₄C₆H₄-N₃)₆₀ synthesis and physical properties are described. A proof-of-concept cluster surface strain promoted alkyne-azide cycloaddition (CS-SPAAC) reaction is also demonstrated, revealing all 60 azides can be accessible in the para derivative. The CS-SPAAC chemistry was further extended to append a functional TEMPO group, which can be utilized towards an alcohol electro-oxidation application.