Potentially Hemilabile N-Heterocyclic Carbene Palladium Complexes: Synthesis and Catalytic Applications

Palladium complexes containing hemilabile N-heterocyclic carbene (NHC) ligands have become a promising family of complexes due to an excellent balance between stability and reactivity that enables them to catalyze a wide range of organic reactions. This review will focus on the palladium complexes of hemilabile NHC ligands, especially their synthesis and catalytic applications in organic transformations. This article is organized in the following categories according to the additional donating atoms: i) Synthesis and catalytic applications of Pd complexes containing bidentate CE (E = N, O, S, or P) ligands, ii) Synthesis and catalytic applications of Pd complexes containing tridentate CE2 (E = N, O, S, or P) ligands, iii) Synthesis and catalytic applications of Pd complexes containing tridentate C2N ligands, iv) Synthesis and catalytic applications of Pd complexes containing tridentate CNO type ligands, and (V) Synthesis of Pd complexes containing tetradentate C2N2 ligands.