Volume 3, Issue 6 1800340
Full Paper

N2 Reduction on Fe-Based Complexes with Different Supporting Main-Group Elements: Critical Roles of Anchor and Peripheral Ligands

Ya-Fei Jiang

Ya-Fei Jiang

Department of Chemistry and Key Laboratory of Organic Optoelectronics & Molecular Engineering of the Ministry of Education, Tsinghua University, Beijing, 100084 China

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Xue-Lu Ma

Xue-Lu Ma

Department of Chemistry and Key Laboratory of Organic Optoelectronics & Molecular Engineering of the Ministry of Education, Tsinghua University, Beijing, 100084 China

School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing, 100083 China

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Jun-Bo Lu

Jun-Bo Lu

Department of Chemistry and Key Laboratory of Organic Optoelectronics & Molecular Engineering of the Ministry of Education, Tsinghua University, Beijing, 100084 China

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Jia-Qi Wang

Jia-Qi Wang

Department of Chemistry and Key Laboratory of Organic Optoelectronics & Molecular Engineering of the Ministry of Education, Tsinghua University, Beijing, 100084 China

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Hai Xiao

Corresponding Author

Hai Xiao

Department of Chemistry and Key Laboratory of Organic Optoelectronics & Molecular Engineering of the Ministry of Education, Tsinghua University, Beijing, 100084 China

E-mail: [email protected], [email protected]Search for more papers by this author
Jun Li

Corresponding Author

Jun Li

Department of Chemistry and Key Laboratory of Organic Optoelectronics & Molecular Engineering of the Ministry of Education, Tsinghua University, Beijing, 100084 China

E-mail: [email protected], [email protected]Search for more papers by this author
First published: 17 October 2018
Citations: 20

Abstract

Due to the enigmatic existence of the carbon atom in the MoFeS cluster of iron-molybdenum cofactor (FeMoco), the design of biomimetic model catalysts featuring a dative bond between a transition metal and a main group atom is an important topic for efficient reduction of N2 to NH3 at ambient conditions. Different anchor atoms (X) for the trigonal bipyramidal (XPiPr 3)Fe (X = B, C, N) catalyst scaffold are investigated by theory. The calculations show that from Lewis acidic B anchor to Lewis basic N or P anchor, the molecular orbital energy levels consisting mainly of Fe 3d orbitals are pushed higher, thus causing stronger backdonation bonding with the π* orbitals of N2, which promotes activation of N2 but impedes reduction of N2. The redox-flexible bonding can act as an electron reservoir and buffer the oxidation state variation of Fe. However, when the FeX bond is less flexible, the peripheral ligands can serve as an extra electron reservoir in the model with Lewis basic anchor. Thus, engineering the peripheral ligand with proper electron-withdrawing substituent groups can promote reduction of N2. The ability to balance well the electron-donating ability of anchor and electrophilicity of the peripheral ligand is a promising direction toward novel efficient catalysts for N2 fixation.

Conflict of Interest

The authors declare no conflict of interest.

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