title: Evaluating molecular cobalt complexes for the conversion of N2 to NH3.
abstract: Well-defined molecular catalysts for the reduction of N2 to NH3 with protons and electrons remain very rare despite decades of interest and are currently limited to systems featuring molybdenum or iron. This report details the synthesis of a molecular cobalt complex that generates superstoichiometric yields of NH3 (>200% NH3 per Co-N2 precursor) via the direct reduction of N2 with protons and electrons. While the NH3 yields reported herein are modest by comparison to those of previously described iron and molybdenum systems, they intimate that other metals are likely to be viable as molecular N2 reduction catalysts. Additionally, a comparison of the featured tris(phosphine)borane Co-N2 complex with structurally related Co-N2 and Fe-N2 species shows how remarkably sensitive the N2 reduction performance of potential precatalysts is. These studies enable consideration of the structural and electronic effects that are likely relevant to N2 conversion activity, including the π basicity, charge state, and geometric flexibility.
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States.
authors.forename: Trevor J
authors.initials: TJ
authors.lastname: Del Castillo
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States.
authors.forename: Niklas B
authors.initials: NB
authors.lastname: Thompson
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States.
authors.forename: Daniel L M
authors.initials: DL
authors.lastname: Suess
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States.
authors.forename: Gaël
authors.initials: G
authors.lastname: Ung
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States.
authors.forename: Jonas C
authors.initials: JC
authors.lastname: Peters
mesh_terms: D000641:Ammonia / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D009584:Nitrogen / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D009942:Organometallic Compounds; D003035:Cobalt; D000641:Ammonia; D009584:Nitrogen