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

Significant achievements have been reported in the last few years regarding the stabilization and functionalization of gold nanoparticles (AuNPs), mainly through the use of thiols and imidazolylidene N-heterocyclic carbene-capping ligands. Herein, we report that mesoionic carbene (MIC) ligands, based on the 1,2,3-triazol-5-ylidene scaffold, allow the expeditive preparation of AuNPs of very high stability through a simple and straightforward one-pot protocol directly from triazolium salts and separated Au(III) sources. Control over the size of AuNPs has been achieved by varying the Au/ligand ratio as well as the nature of the triazolium salts, the latter being facilitated by the ease of synthesis of the MIC precursors through click chemistry. Characterization of these MIC-AuNPs by 13 C solid-state (ss) NMR and X-ray photoelectron spectroscopy (XPS) hints at the exclusive presence of MICs on the surface of nanoparticles solely comprising Au(0).