β-Protic Pyrazole and N-Heterocyclic Carbene Complexes: Synthesis, Properties, and Metal-Ligand Cooperative Bifunctional Catalysis

This Minireview provides an overview of the chemistry of pyrazole and N-heterocyclic carbene (NHC) complexes bearing an NH group at the beta-position to the metal. The synthesis and structures as well as the Bronsted acidic nature of the beta-NH group are described in detail. These complexes are attractive candidates for novel metal-ligand cooperative bifunctional catalysts, which would benefit highly effective molecular and energy transformations.