Design, Synthesis and Reactivity of new classes of Mn, Co and Fe-based Imido Complexes: Effects of Spin States and Lewis Acids

Project: Research

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This project is concerned with the development of highly reactive metal imido complexes for selective amination of organic substrates. Amination is the incorporation of nitrogen atoms into organic molecules to give amines, it is an important step in the synthesis of many pharmaceutical products and other useful organic compounds. The search for selective and efficient synthetic routes for amines continues to be a great challenge for chemists. Traditional methods for the synthesis of amines are generally inefficient and with relatively low atom economy. A more viable alternate is to employ a metal imido (M=NR’) species as amination regent, which can be generated by reacting a metal precursor (LM, L represents ligands) with a nitrene (NR’) precursor such as an organic azide (R’N3): M + R’N3 → M=NR’ + N2 and R-H + M=NR’ → R-NH-R’ + M. This approach has a higher atom economy and potentially higher catalytic activity. In addition, the electronic and steric properties of metal imido complexes can be tuned by varying the substituents on the imido group (R’) and other ancillary ligands (L). Although a variety of metal imido complexes are known, most of them are not active enough to undergo amination reaction, especially towards unactivated C-H bonds. In this project we propose to design new classes of highly active metal imido complexes based on earth abundant metals such as Mn, Fe and Co as catalysts for amination reactions. These complexes include M(II) monoimido and M(IV) bisimido complexes (M = Fe, Co) supported by N-heterocyclic carbene (NHC) and α,β-diimine ligands, as well as Mn(V) and Mn(VI) imido complexes supported by macrocyclic tetraamido ligands. Preliminary results show that the spin states of the imido complexes can be tuned by changing the imido substituents, which can be a key factor in determining the reactivity of the imido complexes. We plan to examine in details the effects of spin states of the imido complexes on their amination reactivity. 


Project number9054031
Grant typeNSFC
Effective start/end date1/01/21 → …