A new class of PN3-pincer ligands for metal–ligand cooperative catalysis

• Introduction of PN3-pincer ligands for metal–ligand cooperative catalysis.
• Preparation and coordination chemistry of PN3-pincer ligands.
• Focus review on the role of dearomatization–rearomatization processes.
• Mechanistic insights form DFT calculations for thermodynamic and kinetic considerations.

Work on a new class of PN3-pincer ligands for metal–ligand cooperative catalysis is reviewed. While the field of the pyridine-based PN3-transition metal pincer complexes is still relatively young, many important applications of these complexes have already emerged. In several cases, the PN3-pincer complexes for metal–ligand cooperative catalysis result in significantly improved or unprecedented activities. The synthesis and coordination chemistry of PN3-pincer ligands are briefly summarized first to cover the synthetic routes for their preparation, followed by a focus review on their applications in catalysis. A specific emphasis is placed on the later section about the role of PN3-pincer ligands’ dearomatization–rearomatization steps during the catalytic cycles. The mechanistic insights from density functional theory (DFT) calculations are also discussed.