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Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O
Published on: October 7, 2020
Theoretical studies of N2 reduction to ammonia in Fe(dmpe)2N2
Robert B Yelle1, Justin L Crossland, Nathaniel K Szymczak
1Computational Science Institute, 5294 University of Oregon, 1600 Millrace Drive Suite 105, Eugene, Oregon 97403, USA.
Inorganic Chemistry
|January 27, 2009
Summary
Density functional theory calculations reveal the most favorable mechanism for the reaction of iron bis(1,2-bis(dimethylphosphino)ethane) dinitrogen (Fe(dmpe)2N2) with protons. The study identifies a pathway through diazene and hydrazine intermediates as the most energetically favorable route.
Area of Science:
- Inorganic Chemistry
- Computational Chemistry
- Organometallic Chemistry
Background:
- The reaction of iron complexes with dinitrogen is crucial for understanding nitrogen fixation.
- Fe(dmpe)2N2 serves as a model complex for studying dinitrogen activation and reduction.
Purpose of the Study:
- To elucidate the mechanism of protonation and reduction of the Fe(dmpe)2N2 complex.
- To compare the energetic favorability of different reaction pathways.
Main Methods:
- Density functional theory (DFT) calculations were employed.
- Electronic structure calculations were performed on potential reaction intermediates.
- Three distinct reaction mechanisms were investigated and compared.
Main Results:
- A Chatt-like mechanism involving stepwise proton addition was found to be least favorable.
- A pathway involving complex dimerization followed by protonation was energetically favorable but prone to monomer dissociation.
- A third mechanism, proceeding via diazene and hydrazine intermediates through alternating protonation, was determined to be the most energetically favorable.
Conclusions:
- The most energetically favorable pathway for the reaction of Fe(dmpe)2N2 with protons involves sequential protonation of nitrogen atoms leading to diazene and hydrazine.
- Understanding these mechanisms provides insights into catalytic nitrogen reduction processes.
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