Catalytic Reduction of N_2 to NH_3 by an Fe−N_2 Complex Featuring a C‑Atom Anchor
- Creators
- Creutz, Sidney E.
- Peters, Jonas C.
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–N_2 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–N_2 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)FeN_2^– species can be functionalized by a silyl electrophile to generate (CP^(iPr)_3)Fe–N_2SiR_3. (CP^(iPr)_3)FeN_2^– also functions as a modest catalyst for the reduction of N_2 to NH_3 when supplied with electrons and protons at −78 °C under 1 atm N_2 (4.6 equiv NH_3/Fe).
Additional Information
© 2013 American Chemical Society. Published In Issue January 22, 2014; Article ASAP January 09, 2014; Just Accepted ManuscriptDecember 18, 2013; Received: November 11, 2013. This work was supported by the NIH (GM 070757) and the Gordon and Betty Moore Foundation, and through the NSF via a GRFP award to S.E.C. Larry Henling and Dr. Tzu-Pin Lin are thanked for their assistance with X-ray crystallography. Jon Rittle is thanked for testing the catalytic activity of [C^(Si)P^(Ph)_3]-FeN_2^−.Attached Files
Accepted Version - nihms555130.pdf
Supplemental Material - ja4114962_si_001.pdf
Supplemental Material - ja4114962_si_002.cif
Files
Additional details
- PMCID
- PMC3933546
- Eprint ID
- 43344
- Resolver ID
- CaltechAUTHORS:20140113-132603289
- GM 070757
- NIH
- Gordon and Betty Moore Foundation
- NSF Graduate Research Fellowship
- Created
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2014-01-13Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field