Direct N-N Coupling between a Transient Iron(V)-Nitrido Complex and Nitrosobenzene Affording an
Wang Chen1,2,3, Xinchao Zhang1,2,3, Gao-Xiang Wang2
1State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China.
Journal of the American Chemical Society
|March 19, 2026
Summary
Researchers report a novel iron-nitrido complex that facilitates N-N bond formation with nitrosoarenes. This discovery offers new insights into metal-nitride reactivity and nitrogen fixation processes.
Area of Science:
- Inorganic Chemistry
- Organometallic Chemistry
- Catalysis
Background:
- Metal nitrides are crucial intermediates in nitrogen fixation and ammonia oxidation.
- Direct N-N coupling initiated by metal nitrides remains challenging and underexplored.
- Understanding metal-nitride reactivity is key to developing new nitrogen transformation processes.
Purpose of the Study:
- To investigate the reactivity of a high-valent iron-nitrido complex with nitrosoarenes.
- To explore the potential of iron-nitrido species in mediating N-N bond formation.
- To elucidate the electronic structure and reaction mechanisms involved in these transformations.
Main Methods:
- Synthesis and characterization of a transient iron(V)-nitrido complex ([FeV(N)(cyclam-ac)][BArF4]).
- Reaction of the iron-nitrido complex with pentafluoronitrosobenzene (PFPhNO) and other nitrosoarenes.
- Spectroscopic (EPR, Mössbauer, UV-vis-NIR) and structural characterization of reaction products.
- Computational analysis (wave function-based ab initio calculations) of electronic structure and reaction pathways.
Main Results:
- A transient iron(V)-nitrido complex reacted quantitatively with pentafluoronitrosobenzene to form an iron(III)-phenyldiazene-N-oxide complex.
- The iron(III)-phenyldiazene-N-oxide product was structurally and spectroscopically characterized, revealing a low-spin ferric center and a N=N double bond.
- Electronic structure analysis indicated barrierless and highly exothermic N-N coupling due to favorable frontier orbital interactions.
- The iron(III)-phenyldiazene-N-oxide complex decomposed under vacuum to release N2 and form a ferric phenolate complex.
Conclusions:
- High-valent iron-nitrido complexes exhibit previously unrecognized reactivity towards nitrosoarenes, enabling N-N bond formation.
- The study provides a new example of N-N coupling mediated by a metal-nitride species.
- The findings offer valuable insights into the mechanisms of nitrogen bond transformations and potential applications in catalysis.
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