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Nitrogen Fixation via a Terminal Fe(IV) Nitride.

ABSTRACT: Terminal iron nitrides (Fe?N) have been proposed as intermediates of (bio)catalytic nitrogen fixation, yet experimental evidence to support this hypothesis has been lacking. In particular, no prior synthetic examples of terminal Fe?N species have been derived from N2. Here we show that a nitrogen-fixing Fe-N2 catalyst can be protonated to form a neutral Fe(NNH2) hydrazido(2-) intermediate, which, upon further protonation, heterolytically cleaves the N-N bond to release [FeIV?N]+ and NH3. These observations provide direct evidence for the viability of a Chatt-type (distal) mechanism for Fe-mediated N2-to-NH3 conversion. The physical oxidation state range of the Fe complexes in this transformation is buffered by covalency with the ligand, a feature of possible relevance to catalyst design in synthetic and natural systems that facilitate multiproton/multielectron redox processes.

SUBMITTER: Thompson NB

PROVIDER: S-EPMC6021180 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature

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Nitrogen Fixation via a Terminal Fe(IV) Nitride.

Thompson Niklas B NB Green Michael T MT Peters Jonas C JC

Journal of the American Chemical Society 20171019 43

Terminal iron nitrides (Fe≡N) have been proposed as intermediates of (bio)catalytic nitrogen fixation, yet experimental evidence to support this hypothesis has been lacking. In particular, no prior synthetic examples of terminal Fe≡N species have been derived from N2. Here we show that a nitrogen-fixing Fe-N2 catalyst can be protonated to form a neutral Fe(NNH2) hydrazido(2-) intermediate, which, upon further protonation, heterolytically cleaves the N-N bond to r ...[more]

PMID: 28992418

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