Direct Synthesis of Mesoionic Carbene (MIC)-Stabilized Gold Nanoparticles from 1,2,3-Triazolium Salts

Significant achievements have been reported in the lastfew yearsregarding the stabilization and functionalization of gold nanoparticles(AuNPs), mainly through the use of thiols and imidazolylidene N-heterocycliccarbene-capping ligands. Herein, we report that mesoionic carbene(MIC) ligands, based on the 1,2,3-triazol-5-ylidene scaffold, allowthe expeditive preparation of AuNPs of very high stability througha simple and straightforward one-pot protocol directly from triazoliumsalts and separated Au(III) sources. Control over the size of AuNPshas been achieved by varying the Au/ligand ratio as well as the natureof the triazolium salts, the latter being facilitated by the easeof synthesis of the MIC precursors through click chemistry. Characterizationof these MIC-AuNPs by C-13 solid-state (ss) NMR and X-rayphotoelectron spectroscopy (XPS) hints at the exclusive presence ofMICs on the surface of nanoparticles solely comprising Au(0).