Computational Mechanistic Studies on Reactions of Transition Metal Complexes with Noninnocent Pincer Ligands: Aromatization–Dearomatization or Not

Abstract

The development of green chemistry has attracted chemists’ attentions in recent years. Among them, Milstein and co-workers have discovered a new mode of metal–ligand cooperation in complexes in which an aromatization–dearomatization process of the pyridine- or acridine-based PNP and PNN “pincer” ligands appears to be a key element. These complexes were reported to lead to unusual X–H (X = H, C, O, N, and B) activation reactions and to environmentally benign catalysis involving dehydrogenative coupling reactions and hydrogenation reactions, representing an important development in green chemistry. This review provides a summary of theoretical studies on the mechanisms of the reactions mediated by transition metal complexes with noninnocent pincer ligands synthesized by Milstein and co-workers. The aromatization–dearomatization process of the pyridine- or acridine-based PNP and PNN “pincer” ligands were found to play important roles in some reactions, while other reactions do not involve the aromatization–d...