Catalytic Ammonia Oxidation to Dinitrogen by Hydrogen Atom Abstraction

Papri Bhattacharya, Zachariah M. Heiden, Geoffrey M. Chambers, Samantha I. Johnson, R. Morris Bullock, Michael T. Mock

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4 Citations (Scopus)

Abstract

Catalysts for the oxidation of NH3 are critical for the utilization of NH3 as a large-scale energy carrier. Molecular catalysts capable of oxidizing NH3 to N2 are rare. This report describes the use of [Cp*Ru(PtBu2NPh2)(15NH3)][BArF4], (PtBu2NPh2=1,5-di(phenylaza)-3,7-di(tert-butylphospha)cyclooctane; ArF=3,5-(CF3)2C6H3), to catalytically oxidize NH3 to dinitrogen under ambient conditions. The cleavage of six N−H bonds and the formation of an N≡N bond was achieved by coupling H+ and e transfers as net hydrogen atom abstraction (HAA) steps using the 2,4,6-tri-tert-butylphenoxyl radical (tBu3ArO.) as the H atom acceptor. Employing an excess of tBu3ArO. under 1 atm of NH3 gas at 23 °C resulted in up to ten turnovers. Nitrogen isotopic (15N) labeling studies provide initial mechanistic information suggesting a monometallic pathway during the N⋅⋅⋅N bond-forming step in the catalytic cycle.

Original languageEnglish
Pages (from-to)11618-11624
Number of pages7
JournalAngewandte Chemie - International Edition
Volume58
Issue number34
DOIs
Publication statusPublished - Jan 1 2019

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Keywords

  • ammonia oxidation
  • dinitrogen
  • homogeneous catalysis
  • radical reactions
  • ruthenium

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

Cite this

Bhattacharya, P., Heiden, Z. M., Chambers, G. M., Johnson, S. I., Bullock, R. M., & Mock, M. T. (2019). Catalytic Ammonia Oxidation to Dinitrogen by Hydrogen Atom Abstraction. Angewandte Chemie - International Edition, 58(34), 11618-11624. https://doi.org/10.1002/anie.201903221