1
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Le LN, Joyce JP, Oyala PH, DeBeer S, Agapie T. Highly Activated Terminal Carbon Monoxide Ligand in an Iron-Sulfur Cluster Model of FeMco with Intermediate Local Spin State at Fe. J Am Chem Soc 2024; 146:5045-5050. [PMID: 38358932 PMCID: PMC10910499 DOI: 10.1021/jacs.3c12025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 01/29/2024] [Accepted: 01/30/2024] [Indexed: 02/17/2024]
Abstract
Nitrogenases, the enzymes that convert N2 to NH3, also catalyze the reductive coupling of CO to yield hydrocarbons. CO-coordinated species of nitrogenase clusters have been isolated and used to infer mechanistic information. However, synthetic FeS clusters displaying CO ligands remain rare, which limits benchmarking. Starting from a synthetic cluster that models a cubane portion of the FeMo cofactor (FeMoco), including a bridging carbyne ligand, we report a heterometallic tungsten-iron-sulfur cluster with a single terminal CO coordination in two oxidation states with a high level of CO activation (νCO = 1851 and 1751 cm-1). The local Fe coordination environment (2S, 1C, 1CO) is identical to that in the protein making this system a suitable benchmark. Computational studies find an unusual intermediate spin electronic configuration at the Fe sites promoted by the presence the carbyne ligand. This electronic feature is partly responsible for the high degree of CO activation in the reduced cluster.
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Affiliation(s)
- Linh N.
V. Le
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Justin P. Joyce
- Max
Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Paul H. Oyala
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Serena DeBeer
- Max
Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Theodor Agapie
- Division
of Chemistry and Chemical Engineering, California
Institute of Technology, Pasadena, California 91125, United States
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2
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Guan R, Huang J, Xin J, Chen M, Du P, Li Q, Tan YZ, Yang S, Xie SY. A stabilization rule for metal carbido cluster bearing μ 3-carbido single-atom-ligand encapsulated in carbon cage. Nat Commun 2024; 15:150. [PMID: 38167842 PMCID: PMC10761991 DOI: 10.1038/s41467-023-44567-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 12/19/2023] [Indexed: 01/05/2024] Open
Abstract
Metal carbido complexes bearing single-carbon-atom ligand such as nitrogenase provide ideal models of adsorbed carbon atoms in heterogeneous catalysis. Trimetallic μ3-carbido clusterfullerenes found recently represent the simplest metal carbido complexes with the ligands being only carbon atoms, but only few are crystallographically characterized, and its formation prerequisite is unclear. Herein, we synthesize and isolate three vanadium-based μ3-CCFs featuring V = C double bonds and high valence state of V (+4), including VSc2C@Ih(7)-C80, VSc2C@D5h(6)-C80 and VSc2C@D3h(5)-C78. Based on a systematic theoretical study of all reported μ3-carbido clusterfullerenes, we further propose a supplemental Octet Rule, i.e., an eight-electron configuration of the μ3-carbido ligand is needed for stabilization of metal carbido clusters within μ3-carbido clusterfullerenes. Distinct from the classic Effective Atomic Number rule based on valence electron count of metal proposed in the 1920s, this rule counts the valence electrons of the single-carbon-atom ligand, and offers a general rule governing the stabilities of μ3-carbido clusterfullerenes.
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Affiliation(s)
- Runnan Guan
- Key Laboratory of Precision and Intelligent Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Jing Huang
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, 230026, China
- School of Materials and Chemical Engineering, Anhui Jianzhu University, Hefei, 230601, China
| | - Jinpeng Xin
- Key Laboratory of Precision and Intelligent Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Muqing Chen
- Key Laboratory of Precision and Intelligent Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Pingwu Du
- Key Laboratory of Precision and Intelligent Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Qunxiang Li
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, 230026, China.
| | - Yuan-Zhi Tan
- State Key Lab for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
| | - Shangfeng Yang
- Key Laboratory of Precision and Intelligent Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, 230026, China.
| | - Su-Yuan Xie
- State Key Lab for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
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3
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Tokmina-Lukaszewska M, Huang Q, Berry L, Kallas H, Peters JW, Seefeldt LC, Raugei S, Bothner B. Fe protein docking transduces conformational changes to MoFe nitrogenase active site in a nucleotide-dependent manner. Commun Chem 2023; 6:254. [PMID: 37980448 PMCID: PMC10657360 DOI: 10.1038/s42004-023-01046-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Accepted: 10/30/2023] [Indexed: 11/20/2023] Open
Abstract
The reduction of dinitrogen to ammonia catalyzed by nitrogenase involves a complex series of events, including ATP hydrolysis, electron transfer, and activation of metal clusters for N2 reduction. Early evidence shows that an essential part of the mechanism involves transducing information between the nitrogenase component proteins through conformational dynamics. Here, millisecond time-resolved hydrogen-deuterium exchange mass spectrometry was used to unravel peptide-level protein motion on the time scale of catalysis of Mo-dependent nitrogenase from Azotobacter vinelandii. Normal mode analysis calculations complemented this data, providing insights into the specific signal transduction pathways that relay information across protein interfaces at distances spanning 100 Å. Together, these results show that conformational changes induced by protein docking are rapidly transduced to the active site, suggesting a specific mechanism for activating the metal cofactor in the enzyme active site.
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Affiliation(s)
| | - Qi Huang
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Luke Berry
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
| | - Hayden Kallas
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, USA
| | - John W Peters
- Institute of Biological Chemistry, The University of Oklahoma, Norman, OK, USA
| | - Lance C Seefeldt
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, USA
| | - Simone Raugei
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA.
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4
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Badding ED, Srisantitham S, Lukoyanov DA, Hoffman BM, Suess DLM. Connecting the geometric and electronic structures of the nitrogenase iron-molybdenum cofactor through site-selective 57Fe labelling. Nat Chem 2023; 15:658-665. [PMID: 36914792 PMCID: PMC10710871 DOI: 10.1038/s41557-023-01154-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 01/26/2023] [Indexed: 03/16/2023]
Abstract
Understanding the chemical bonding in the catalytic cofactor of the Mo nitrogenase (FeMo-co) is foundational for building a mechanistic picture of biological nitrogen fixation. A persistent obstacle towards this goal has been that the 57Fe-based spectroscopic data-although rich with information-combines responses from all seven Fe sites, and it has therefore not been possible to map individual spectroscopic responses to specific sites in the three-dimensional structure. Here we have addressed this challenge by incorporating 57Fe into a single site of FeMo-co. Spectroscopic analysis of the resting state informed on the local electronic structure of the terminal Fe1 site, including its oxidation state and spin orientation, and, in turn, on the spin-coupling scheme for the entire cluster. The oxidized resting state and the first intermediate in nitrogen fixation were also characterized, and comparisons with the resting state provided molecular-level insights into the redox chemistry of FeMo-co.
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Affiliation(s)
- Edward D Badding
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | | | - Brian M Hoffman
- Department of Chemistry, Northwestern University, Evanston, IL, USA
| | - Daniel L M Suess
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA.
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5
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Dance I. The HD Reaction of Nitrogenase: a Detailed Mechanism. Chemistry 2023; 29:e202202502. [PMID: 36274057 PMCID: PMC10099629 DOI: 10.1002/chem.202202502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Indexed: 11/06/2022]
Abstract
Nitrogenase is the enzyme that converts N2 to NH3 under ambient conditions. The chemical mechanism of this catalysis at the active site FeMo-co [Fe7 S9 CMo(homocitrate)] is unknown. An obligatory co-product is H2 , while exogenous H2 is a competitive inhibitor. Isotopic substitution using exogenous D2 revealed the N2 -dependent reaction D2 +2H+ +2e- →2HD (the 'HD reaction'), together with a collection of additional experimental characteristics and requirements. This paper describes a detailed mechanism for the HD reaction, developed and elaborated using density functional simulations with a 486-atom model of the active site and surrounding protein. First D2 binds at one Fe atom (endo-Fe6 coordination position), where it is flanked by H-Fe6 (exo position) and H-Fe2 (endo position). Then there is synchronous transfer of these two H atoms to bound D2 , forming one HD bound to Fe2 and a second HD bound to Fe6. These two HD dissociate sequentially. The final phase is recovery of the two flanking H atoms. These H atoms are generated, sequentially, by translocation of a proton from the protein surface to S3B of FeMo-co and combination with introduced electrons. The first H atom migrates from S3B to exo-Fe6 and the second from S3B to endo-Fe2. Reaction energies and kinetic barriers are reported for all steps. This mechanism accounts for the experimental data: (a) stoichiometry; (b) the N2 -dependence results from promotional N2 bound at exo-Fe2; (c) different N2 binding Km for the HD reaction and the NH3 formation reaction results from involvement of two different sites; (d) inhibition by CO; (e) the non-occurrence of 2HD→H2 +D2 results from the synchronicity of the two transfers of H to D2 ; (f) inhibition of HD production at high pN2 is by competitive binding of N2 at endo-Fe6; (g) the non-leakage of D to solvent follows from the hydrophobic environment and irreversibility of proton introduction.
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Affiliation(s)
- Ian Dance
- School of Chemistry, UNSW, Sydney, Australia
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6
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Threatt SD, Rees DC. Biological nitrogen fixation in theory, practice, and reality: a perspective on the molybdenum nitrogenase system. FEBS Lett 2023; 597:45-58. [PMID: 36344435 PMCID: PMC10100503 DOI: 10.1002/1873-3468.14534] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 10/30/2022] [Accepted: 10/31/2022] [Indexed: 11/09/2022]
Abstract
Nitrogenase is the sole enzyme responsible for the ATP-dependent conversion of atmospheric dinitrogen into the bioavailable form of ammonia (NH3 ), making this protein essential for the maintenance of the nitrogen cycle and thus life itself. Despite the widespread use of the Haber-Bosch process to industrially produce NH3 , biological nitrogen fixation still accounts for half of the bioavailable nitrogen on Earth. An important feature of nitrogenase is that it operates under physiological conditions, where the equilibrium strongly favours ammonia production. This biological, multielectron reduction is a complex catalytic reaction that has perplexed scientists for decades. In this review, we explore the current understanding of the molybdenum nitrogenase system based on experimental and computational research, as well as the limitations of the crystallographic, spectroscopic, and computational techniques employed. Finally, essential outstanding questions regarding the nitrogenase system will be highlighted alongside suggestions for future experimental and computational work to elucidate this essential yet elusive process.
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Affiliation(s)
- Stephanie D Threatt
- Division of Chemistry and Chemical Engineering, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA, USA
| | - Douglas C Rees
- Division of Chemistry and Chemical Engineering, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA, USA
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7
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Lukoyanov DA, Yang ZY, Pérez-González A, Raugei S, Dean DR, Seefeldt LC, Hoffman BM. 13C ENDOR Characterization of the Central Carbon within the Nitrogenase Catalytic Cofactor Indicates That the CFe 6 Core Is a Stabilizing "Heart of Steel". J Am Chem Soc 2022; 144:18315-18328. [PMID: 36166637 DOI: 10.1021/jacs.2c06149] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Substrates and inhibitors of Mo-dependent nitrogenase bind and react at Fe ions of the active-site FeMo-cofactor [7Fe-9S-C-Mo-homocitrate] contained within the MoFe protein α-subunit. The cofactor contains a CFe6 core, a carbon centered within a trigonal prism of six Fe, whose role in catalysis is unknown. Targeted 13C labeling of the carbon enables electron-nuclear double resonance (ENDOR) spectroscopy to sensitively monitor the electronic properties of the Fe-C bonds and the spin-coupling scheme adopted by the FeMo-cofactor metal ions. This report compares 13CFe6 ENDOR measurements for (i) the wild-type protein resting state (E0; α-Val70) to those of (ii) α-Ile70, (iii) α-Ala70-substituted proteins; (iv) crystallographically characterized CO-inhibited "hi-CO" state; (v) E4(4H) Janus intermediate, activated for N2 binding/reduction by accumulation of 4[e-/H+]; (vi) E4(2H)* state containing a doubly reduced FeMo-cofactor without Fe-bound substrates; and (vii) propargyl alcohol reduction intermediate having allyl alcohol bound as a ferracycle to FeMo-cofactor Fe6. All states examined, both S = 1/2 and 3/2 exhibited near-zero 13C isotropic hyperfine coupling constants, Ca = [-1.3 ↔ +2.7] MHz. Density functional theory computations and natural bond orbital analysis of the Fe-C bonds show that this occurs because a (3 spin-up/3 spin-down) spin-exchange configuration of CFe6 Fe-ion spins produces cancellation of large spin-transfers to carbon in each Fe-C bond. Previous X-ray diffraction and DFT both indicate that trigonal-prismatic geometry around carbon is maintained with high precision in all these states. The persistent structure and Fe-C bonding of the CFe6 core indicate that it does not provide a functionally dynamic (hemilabile) "beating heart"─instead it acts as "a heart of steel", stabilizing the structure of the FeMo-cofactor-active site during nitrogenase catalysis.
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Affiliation(s)
- Dmitriy A Lukoyanov
- Departments of Chemistry and Molecular Biosciences, Northwestern University, Evanston, Illinois60208, United States
| | - Zhi-Yong Yang
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah84322, United States
| | - Ana Pérez-González
- Biochemistry Department, Virginia Tech, Blacksburg, Virginia24061, United States
| | - Simone Raugei
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington99352, United States
| | - Dennis R Dean
- Biochemistry Department, Virginia Tech, Blacksburg, Virginia24061, United States
| | - Lance C Seefeldt
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah84322, United States
| | - Brian M Hoffman
- Departments of Chemistry and Molecular Biosciences, Northwestern University, Evanston, Illinois60208, United States
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8
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Decamps L, Rice DB, DeBeer S. An Fe 6 C Core in All Nitrogenase Cofactors. Angew Chem Int Ed Engl 2022; 61:e202209190. [PMID: 35975943 PMCID: PMC9826452 DOI: 10.1002/anie.202209190] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Indexed: 01/11/2023]
Abstract
The biological process of dinitrogen reduction to ammonium occurs at the cofactors of nitrogenases, the only enzymes that catalyze this challenging chemical reaction. Three types of nitrogenases have been described, named according to the heterometal in their cofactor: molybdenum, vanadium or iron nitrogenases. Spectroscopic and structural characterization allowed the unambiguous identification of the cofactors of molybdenum and vanadium nitrogenases and revealed a central μ6 -carbide in both of them. Although genetic studies suggested that the cofactor of the iron nitrogenase contains a similar Fe6 C core, this has not been experimentally demonstrated. Here we report Valence-to-Core X-ray Emission Spectroscopy providing experimental evidence that this cofactor contains a carbide, thereby making the Fe6 C core a feature of all nitrogenase cofactors.
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Affiliation(s)
- Laure Decamps
- Department of Inorganic SpectroscopyMax Planck Institute for Chemical Energy ConversionStiftstrasse 34–3645470Mülheim an derRuhrGermany
| | - Derek B. Rice
- Department of Inorganic SpectroscopyMax Planck Institute for Chemical Energy ConversionStiftstrasse 34–3645470Mülheim an derRuhrGermany
| | - Serena DeBeer
- Department of Inorganic SpectroscopyMax Planck Institute for Chemical Energy ConversionStiftstrasse 34–3645470Mülheim an derRuhrGermany
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9
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Zhang Q, Liu H, Shui X, Li Y, Zhang Z. Research progress of additives in photobiological hydrogen production system to enhance biohydrogen. BIORESOURCE TECHNOLOGY 2022; 362:127787. [PMID: 35985465 DOI: 10.1016/j.biortech.2022.127787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
Photosynthetic biohydrogen has the advantages of extensive raw materials, clean and renewable, etc. But, its low substrate utilization rate limit its commercial application. It is reported that the use of additives in the process of biohydrogen by photofermentation is beneficial to increase biohydrogen. However, in practical application, the mechanism of additives in hydrogen production is not understood. This paper, the promotion effect of some additives on biohydrogen by photofermentation was reviewed. Whatever, the existing problems and development trends of various additives are also discussed. It is necessary to select appropriate additives according to the hydrogen-producing characteristics. The use of composite additives may further enhance biohydrogen, but the specific situation needs further exploration. The research results of this paper can help readers to further understand the role of additives in the crouse of photofermentative biohydrogen, provide reference for the research of photofermentative biohydrogen.
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Affiliation(s)
- Quanguo Zhang
- Key Laboratory of New Materials and Facilities for Rural Renewable Energy (MOA of China), Henan Agricultural University, Zhengzhou 450002, China; Institute of Agricultural Engineering, Huanghe S & T University, Zhengzhou 450006, China.
| | - Hong Liu
- Key Laboratory of New Materials and Facilities for Rural Renewable Energy (MOA of China), Henan Agricultural University, Zhengzhou 450002, China; Institute of Agricultural Engineering, Huanghe S & T University, Zhengzhou 450006, China
| | - Xuenan Shui
- Key Laboratory of New Materials and Facilities for Rural Renewable Energy (MOA of China), Henan Agricultural University, Zhengzhou 450002, China
| | - Yameng Li
- Key Laboratory of New Materials and Facilities for Rural Renewable Energy (MOA of China), Henan Agricultural University, Zhengzhou 450002, China
| | - Zhiping Zhang
- Key Laboratory of New Materials and Facilities for Rural Renewable Energy (MOA of China), Henan Agricultural University, Zhengzhou 450002, China
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10
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Decamps L, Rice D, DeBeer S. An Fe6C Core in All Nitrogenase Cofactors. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202209190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Laure Decamps
- Max-Planck-Institute for Chemical Energy Conversion: Max-Planck-Institut fur chemische Energiekonversion Inorganic Spectroscopy GERMANY
| | - Derek Rice
- Max-Planck-Institute for Chemical Energy Conversion: Max-Planck-Institut fur chemische Energiekonversion Inorganic Spectroscopy GERMANY
| | - Serena DeBeer
- MPI CEC Molecular Theory and Spectroscopy Stidtstr. 34-36 45470 Muelheim an der Ruhr GERMANY
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11
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McSkimming A, Thompson NB. Four-Coordinate Fe N 2 and Imido Complexes Supported by a Hemilabile NNC Heteroscorpionate Ligand. Inorg Chem 2022; 61:12318-12326. [PMID: 35895990 PMCID: PMC9367695 DOI: 10.1021/acs.inorgchem.2c01656] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Inspired by mechanistic proposals for N2 reduction
at
the nitrogenase FeMo cofactor, we report herein a new, strongly σ-donating
heteroscorpionate ligand featuring two weak-field pyrazoles and an
alkyl donor. This ligand supports four-coordinate Fe(I)-N2, Fe(II)-Cl, and Fe(III)-imido complexes, which we have characterized
using a variety of spectroscopic and computational methods. Structural
and quantum mechanical analysis reveal the nature of the Fe–C
bonds to be essentially invariant between the complexes, with conversion
between the (formally) low-valent Fe-N2 and high-valent
Fe-imido complexes mediated by pyrazole hemilability. This presents
a useful strategy for substrate reduction at such low-coordinate centers
and suggests a mechanism by which FeMoco might accommodate the binding
of both π-acidic and π-basic nitrogenous substrates. We report a new, strongly σ-donating
NNC heteroscorpionate
ligand and its Fe(I)-N2, Fe(II)-Cl and Fe(III)-imido complexes.
Conversion between the low-valent Fe-N2 and high-valent
Fe-imido complexes is mediated by pyrazole hemilability, presenting
a useful strategy for substrate reduction at such low-coordinate centers.
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Affiliation(s)
- Alex McSkimming
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Niklas B Thompson
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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12
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Kim J. Metal complexes containing
silicon‐based
pincer ligands: Reactivity and application in small molecule activation. B KOREAN CHEM SOC 2022. [DOI: 10.1002/bkcs.12491] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jin Kim
- Department of Chemistry Sunchon National University Suncheon Jeollanam‐do Republic of Korea
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