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 functionalisation of gold nanoparticles (AuNPs), mainly through the use of thiols and imidazolylidene N-heterocyclic carbenes capping ligands. Herein, we report that mesoionic carbenes (MICs) ligands, based on the 1,2,3-triazol-5-ylidene scaffold, allow the expeditive preparation of AuNPs of exceptional stability through a simple and straightforward one-pot protocol directly from triazolium salts and discrete Au(III) sources. Control over the size of the 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. Characterisation of these MIC-AuNPs by X-ray photoelectron spectroscopy (XPS) hints at the exclusive presence of MICs on the nanoparticle surface.