Abstract
Synthesis and reactivity of iron-dinitrogen complexes have been extensively studied, because the iron atom plays an important role in the industrial and biological nitrogen fixation. As a result, iron-catalyzed reduction of molecular dinitrogen into ammonia has recently been achieved. Here we show that an iron-dinitrogen complex bearing an anionic PNP-pincer ligand works as an effective catalyst towards the catalytic nitrogen fixation, where a mixture of ammonia and hydrazine is produced. In the present reaction system, molecular dinitrogen is catalytically and directly converted into hydrazine by using transition metal-dinitrogen complexes as catalysts. Because hydrazine is considered as a key intermediate in the nitrogen fixation in nitrogenase, the findings described in this paper provide an opportunity to elucidate the reaction mechanism in nitrogenase.
Highlights
Synthesis and reactivity of iron-dinitrogen complexes have been extensively studied, because the iron atom plays an important role in the industrial and biological nitrogen fixation
In 2012, we found the first successful example of the iron-catalyzed reduction of molecular dinitrogen under ambient reaction conditions, where simple iron complexes such as [Fe(CO)5] and ferrocene derivatives worked as effective catalysts towards the formation of silylamine as an ammonia equivalent[18]
Based on the results of experimental and Density functional theory (DFT) calculations on the molybdenum-catalyzed nitrogen fixation under mild reaction conditions, we proposed that the transformation of molecular dinitrogen into ammonia under mild reaction conditions proceeds via hydrazide and nitride complexes (B and C, respectively) as key reactive intermediates as shown in Fig. 5a as a distal pathway[12,13,14,15,16]
Summary
Synthesis and reactivity of iron-dinitrogen complexes have been extensively studied, because the iron atom plays an important role in the industrial and biological nitrogen fixation. We show that an iron-dinitrogen complex bearing an anionic PNP-pincer ligand works as an effective catalyst towards the catalytic nitrogen fixation, where a mixture of ammonia and hydrazine is produced. We have found the most efficient catalytic nitrogen fixation system by using molybdenum-nitride complexes bearing a tridentate triphosphine (PPP 1⁄4 bis(di-tert-butylphosphinoethyl)phenylphosphine) as a ligand, where up to 63 equiv of ammonia were produced based on the catalyst[16]. In 2013, Peters and co-workers[19] reported the iron-catalyzed direct reduction of molecular dinitriogen into ammonia under mild reaction conditions (1 atm at À 78 °C), where a sophisticated iron-dinitrogen complex bearing a triphosphine-borane as a ligand worked as a catalyst (up to 7 equiv of ammonia based on the catalyst). We report the catalytic reduction of molecular dinitrogen into ammonia and hydrazine by using the iron complexes bearing an anionic PNP-pincer ligand as catalysts
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
