Work

Catalytic Reduction of N2 to NH3 by an Fe–N2 Complex Featuring a C-Atom Anchor

Year: 2013

Type: article

Abstract: While recent spectroscopic studies have established the presence of an interstitial carbon atom at the center of the iron-molybdenum cofactor (FeMoco) of MoFe-nitrogenase, its role is unknown. We have pursued Fe-N2 model chemistry to explore a hypothesis whereby this C-atom (previously denoted as a light X-atom) may provide a flexible trans interaction with an Fe center to expose an Fe-N2 binding site. In this context, we now report on Fe complexes of a new tris(phosphino)alkyl (CP(iPr)3) ligand featuring an axial carbon donor. It is established that the iron center in this scaffold binds dinitrogen trans to the C(alkyl)-atom anchor in three distinct and structurally characterized oxidation states. Fe-C(alkyl) lengthening is observed upon reduction, reflective of significant ionic character in the Fe-C(alkyl) interaction. The anionic (CP(iPr)3)FeN2(-) species can be functionalized by a silyl electrophile to generate (CP(iPr)3)Fe-N2SiR3. (CP(iPr)3)FeN2(-) also functions as a modest catalyst for the reduction of N2 to NH3 when supplied with electrons and protons at -78 °C under 1 atm N2 (4.6 equiv NH3/Fe).

Source: Journal of the American Chemical Society

DOI: 10.1021/ja4114962

Authors: Sidney E. Creutz, Jonas C. Peters

Institution: California Institute of Technology

Language: English

Topic: Metalloenzymes and iron-sulfur proteins

Subfield: Renewable Energy, Sustainability and the Environment

Field: Energy

Domain: Physical Sciences

Open Access status: green

Funders: NIH Office of the Director, National Institute of General Medical Sciences

Awards: G3041826022, Functional LnFe-NxHy Models of Biological N2 Fixation, G718856125