The preparation and application of N-heterocyclic carbene/CO₂ adducts

The nucleophilic N-heterocyclic carbene (NHC) has emerged as a hot topic as organocatalyst in recent years. The two preparation methods and four important reactions are reviewed in this paper. The applications of N-heterocyclic carbene/CO₂ adducts in metal coordination as NHC transfer reagents, in CO₂ fixation and carbonate synthesis as catalysts and CO ₂ transfer reagents, in transition metal complexation as carboxylato-ligands, and as latent NHC in catalyzing ring-opening polymerization of cyclic monomers are summarized. The potential development of the research and application of NHC-CO₂ is discussed.