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Updated: Jul 3, 2026

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes
Published on: April 10, 2015
Mechanistic insight into N=N cleavage by a low-coordinate iron(II) hydride complex
Azwana R Sadique1, Elizabeth A Gregory, William W Brennessel
1Department of Chemistry, University of Rochester, Rochester, NY 14627, USA.
Abstract:
The reaction pathways of high-spin iron hydride complexes are relevant to the mechanism of N2 reduction by nitrogenase, which has been postulated to involve paramagnetic iron-hydride species. However, almost all known iron hydrides are low-spin, diamagnetic Fe(II) compounds. We have demonstrated that the first high-spin iron hydride complex, LtBuFeH (LtBu = bulky beta-diketiminate), reacts with PhN=NPh to completely cleave the N-N double bond, giving LtBuFeNHPh. Here, we disclose a series of experiments that elucidate the mechanism of this reaction. Crossover and kinetic experiments rule out common nonradical mechanisms, and support a radical chain mechanism mediated by iron(I) species including a rare eta2-azobenzene complex. Therefore, this high-spin iron(II) hydride can break N-N bonds through both nonradical and radical insertion mechanisms, a special feature that enables novel reactivity.
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