Mesoionic 1,2,3-Triazoles and 1,2,3-Triazole Carbenes

摘要: Routine access to 1,2,3-triazoles through the copper-catalyzed azide-alkyne “click” cycloaddition reaction has promoted rapid development of 1,2,3-triazolylidenes as ligands for transition metals. The organometallic complexes containing this kind N-heterocyclic carbene (NHCs) have shown possess unique structural characteristics, including a relatively high covalent contribution metal–NHC bond, strong donor ability, and mesoionic character. Complexes triazolylidene carbenes (MICs) are readily available, among other methods, by metallation N3-substituted 1,2,3-triazolium salts, usually followed transmetallation reactions. A diverse array monodentate, polydentate, bridged 1,2,3-triazolylidene motif been described, structures them characterized in detail. Promising applications catalysis involving C–C C–X bond formation redox reactions emerged recent years metal complexes, and, owing modular multiple functionalization possibilities around 1,2,3-triazole scaffold, novel expected upcoming years.