Atomic Ligands on Iron

Atomic ligands are found in key intermediates for a number of enzymatic and heterogeneous catalysis, such as industrial ammonia synthesis and biological hydrocarbon oxidation. Molecular complexes can provide well-defined molecular models that provide chemical insight into structure and bonding, spectroscopy, and reactivity of these often transient species. Synthesis of these complexes is often highly challenging, and molecular design can play a critical role in enabling access. In a long-standing project, we have shown that a modular family of strong donor ligands are able to enforce three-fold symmetry at metal ions, providing a platform for stabilizing iron complexes containing metal-ligand multiple bonds. In early work, we demonstrated that isolable nitride complexes are active in multielectron nitrogen atom transfer reactions to a variety of substrates, including unsaturated hydrocarbons. Further elaboration of nitrogen atom transfer as a synthetic strategy has enabled the construction of new ligands and binuclear complexes. More recently, we have successfully created iron complexes with other multiply bonded atomic ligands, including oxo, sulfido and carbide. The accumulating library of complexes provides the foundation for ongoing studies aimed at understanding underlying trends in the fundamental reactions of these multiply bonded atomic ligands.