Molecular Complexes for Catalytic Ammonia Oxidation to Dinitrogen and the Cleavage of N−H Bonds

Abstract

The molecular complexes described herein use main-group elements or transition metals to control the stoichiometric cleavage of N−H bonds of ammonia (NH₃) and/or catalyze chemical and electrochemical NH₃ oxidation to dinitrogen (N₂). We highlight the phenomenon of coordination-induced bond weakening and a variety of N−H bond cleavage mechanisms of NH₃ including H atom abstraction, inter- and intra-molecular deprotonation reactions, oxidative addition, and σ-bond metathesis that have been demonstrated with molecular systems. We provide an overview of the molecular complexes reported for the rapidly developing field of NH₃ oxidation catalysis to form N₂. These systems exhibit several diverse structure types and innovative ligands to support transition metals capable of activating NH₃ and mediating a challenging chemical transformation that requires breaking strong N−H bonds and forming an N−N bond en route to N₂ formation.