Victorio Cadierno

N-Heterocyclic carbenes (NHCs) are nowadays one of the most widely employed ligands in organometallic chemistry and homogeneous catalysis due to the inherent stability of the metal-carbene bond and the ease of modification of the backbone as well as the N-wingtips substituents of these ligands. The functionalization of NHCs with hydrophilic groups offers the possibility of using NHC-metal complexes in aqueous catalysis, a hot topic within the Green Chemistry context due to the positive implications associated with the use of water as a reaction medium. In line with the enormous interest aroused by gold complexes in catalysis, significant efforts have been directed in the last years to the design and application of hydrophilic NHC-gold catalysts. This review is aimed to summarize the research in this area. The catalytic applications of water-soluble gold nanoparticles stabilized by hydrophilic NHCs are also covered.