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Landaeta VR, Horsley Downie TM, Wolf R. Low-Valent Transition Metalate Anions in Synthesis, Small Molecule Activation, and Catalysis. Chem Rev 2024; 124:1323-1463. [PMID: 38354371 PMCID: PMC10906008 DOI: 10.1021/acs.chemrev.3c00121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 10/09/2023] [Accepted: 10/09/2023] [Indexed: 02/16/2024]
Abstract
This review surveys the synthesis and reactivity of low-oxidation state metalate anions of the d-block elements, with an emphasis on contributions reported between 2006 and 2022. Although the field has a long and rich history, the chemistry of transition metalate anions has been greatly enhanced in the last 15 years by the application of advanced concepts in complex synthesis and ligand design. In recent years, the potential of highly reactive metalate complexes in the fields of small molecule activation and homogeneous catalysis has become increasingly evident. Consequently, exciting applications in small molecule activation have been developed, including in catalytic transformations. This article intends to guide the reader through the fascinating world of low-valent transition metalates. The first part of the review describes the synthesis and reactivity of d-block metalates stabilized by an assortment of ligand frameworks, including carbonyls, isocyanides, alkenes and polyarenes, phosphines and phosphorus heterocycles, amides, and redox-active nitrogen-based ligands. Thereby, the reader will be familiarized with the impact of different ligand types on the physical and chemical properties of metalates. In addition, ion-pairing interactions and metal-metal bonding may have a dramatic influence on metalate structures and reactivities. The complex ramifications of these effects are examined in a separate section. The second part of the review is devoted to the reactivity of the metalates toward small inorganic molecules such as H2, N2, CO, CO2, P4 and related species. It is shown that the use of highly electron-rich and reactive metalates in small molecule activation translates into impressive catalytic properties in the hydrogenation of organic molecules and the reduction of N2, CO, and CO2. The results discussed in this review illustrate that the potential of transition metalate anions is increasingly being tapped for challenging catalytic processes with relevance to organic synthesis and energy conversion. Therefore, it is hoped that this review will serve as a useful resource to inspire further developments in this dynamic research field.
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Affiliation(s)
| | | | - Robert Wolf
- University of Regensburg, Institute
of Inorganic Chemistry, 93040 Regensburg, Germany
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2
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Wilson DWN, Fataftah MS, Mathe Z, Mercado BQ, DeBeer S, Holland PL. Three-Coordinate Nickel and Metal-Metal Interactions in a Heterometallic Iron-Sulfur Cluster. J Am Chem Soc 2024; 146:4013-4025. [PMID: 38308743 PMCID: PMC10993082 DOI: 10.1021/jacs.3c12157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2024]
Abstract
Biological multielectron reactions often are performed by metalloenzymes with heterometallic sites, such as anaerobic carbon monoxide dehydrogenase (CODH), which has a nickel-iron-sulfide cubane with a possible three-coordinate nickel site. Here, we isolate the first synthetic iron-sulfur clusters having a nickel atom with only three donors, showing that this structural feature is feasible. These have a core with two tetrahedral irons, one octahedral tungsten, and a three-coordinate nickel connected by sulfide and thiolate bridges. Electron paramagnetic resonance (EPR), Mössbauer, and superconducting quantum interference device (SQUID) data are combined with density functional theory (DFT) computations to show how the electronic structure of the cluster arises from strong magnetic coupling between the Ni, Fe, and W sites. X-ray absorption spectroscopy, together with spectroscopically validated DFT analysis, suggests that the electronic structure can be described with a formal Ni1+ atom participating in a nonpolar Ni-W σ-bond. This metal-metal bond, which minimizes spin density at Ni1+, is conserved in two cluster oxidation states. Fe-W bonding is found in all clusters, in one case stabilizing a local non-Hund state at tungsten. Based on these results, we compare different M-M interactions and speculate that other heterometallic clusters, including metalloenzyme active sites, could likewise store redox equivalents and stabilize low-valent metal centers through metal-metal bonding.
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Affiliation(s)
- Daniel W. N. Wilson
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, Connecticut 06520, USA
| | - Majed S. Fataftah
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, Connecticut 06520, USA
| | - Zachary Mathe
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Brandon Q. Mercado
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, Connecticut 06520, USA
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Patrick L. Holland
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, Connecticut 06520, USA
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3
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Valdez-Moreira JA, Wannipurage DC, Pink M, Carta V, Moënne-Loccoz P, Telser J, Smith JM. Hydrogen atom abstraction by a high spin [Fe III=S] complex. Chem 2023; 9:2601-2609. [PMID: 39021493 PMCID: PMC11251717 DOI: 10.1016/j.chempr.2023.05.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Iron sulfur clusters are critical to a plethora of biological processes; however, little is known about the elementary unit of these clusters, namely the [Fe=S]n+ fragment. Here, we report the synthesis and characterization of a terminal iron sulfido complex. Despite its high spin (S = 5/2) ground state, structural, spectroscopic, and computational characterization provide evidence for iron sulfur multiple bond character. Intriguingly, the complex reacts with additional sulfur to afford an S = 3/2 iron(III) disulfido (S2 2-) complex. Preliminary studies reveal that the sulfido complex reacts with dihydroanthracene to afford an iron(II) hydrosulfido complex, akin to the reactivity of iron oxo complexes. By contrast, there is no reaction with the disulfido complex. These results provide important insight into the nature of the iron sulfide unit.
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Affiliation(s)
| | | | - Maren Pink
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | - Veronica Carta
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | - Pierre Moënne-Loccoz
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR 97239, USA
| | - Joshua Telser
- Department of Biological, Physical and Health Sciences, Roosevelt University, Chicago, IL 60605, USA
| | - Jeremy M. Smith
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
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4
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Brown AC, Thompson NB, Suess DLM. Evidence for Low-Valent Electronic Configurations in Iron-Sulfur Clusters. J Am Chem Soc 2022; 144:9066-9073. [PMID: 35575703 DOI: 10.1021/jacs.2c01872] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Although biological iron-sulfur (Fe-S) clusters perform some of the most difficult redox reactions in nature, they are thought to be composed exclusively of Fe2+ and Fe3+ ions, as well as mixed-valent pairs with average oxidation states of Fe2.5+. We herein show that Fe-S clusters formally composed of these valences can access a wider range of electronic configurations─in particular, those featuring low-valent Fe1+ centers. We demonstrate that CO binding to a synthetic [Fe4S4]0 cluster supported by N-heterocyclic carbene ligands induces the generation of Fe1+ centers via intracluster electron transfer, wherein a neighboring pair of Fe2+ sites reduces the CO-bound site to a low-valent Fe1+ state. Similarly, CO binding to an [Fe4S4]+ cluster induces electron delocalization with a neighboring Fe site to form a mixed-valent Fe1.5+Fe2.5+ pair in which the CO-bound site adopts partial low-valent character. These low-valent configurations engender remarkable C-O bond activation without having to traverse highly negative and physiologically inaccessible [Fe4S4]0/[Fe4S4]- redox couples.
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Affiliation(s)
- Alexandra C Brown
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Niklas B Thompson
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Daniel L M Suess
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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5
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Boncella AE, Sabo ET, Santore RM, Carter J, Whalen J, Hudspeth JD, Morrison CN. The expanding utility of iron-sulfur clusters: Their functional roles in biology, synthetic small molecules, maquettes and artificial proteins, biomimetic materials, and therapeutic strategies. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2021.214229] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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6
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Gao Y, Pink M, Smith JM. Alkali Metal Ions Dictate the Structure and Reactivity of an Iron(II) Imido Complex. J Am Chem Soc 2022; 144:1786-1794. [DOI: 10.1021/jacs.1c11429] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yafei Gao
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Maren Pink
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Jeremy M. Smith
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
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7
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Li S, Ouyang Z, Zou J, Wang D, Xu B, Deng L. A Mononuclear Iron Thiolate Complex with N-Heterocyclic Carbene Ligation. ACTA CHIMICA SINICA 2022. [DOI: 10.6023/a22010038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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8
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Schneider C, Groß SJ, Demeshko S, Bontemps S, Meyer F, Werncke CG. Synthesis and characterisation of a very low-coordinate diferrous [2Fe-2S] 0 unit. Chem Commun (Camb) 2021; 57:10751-10754. [PMID: 34585677 DOI: 10.1039/d1cc04196g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Here we present the synthesis of a unique diferrous [2Fe-2S]0 complex with only three-coordinate iron ions via reduction of a four-coordinate diferric [2Fe-2S]2+ complex with concomitant ligand loss. The obtained compounds were thoroughly examined for their properties (e.g. by 57Fe Mössbauer spectroscopy and magnetic susceptibility measurements). Facile cleavage of the [2Fe-2S] rhombus, commonly seen as rather stable, by CS2 is also shown.
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Affiliation(s)
- Christian Schneider
- Chemistry Department, Philipps-University, Hans-Meerwein-Str. 4, 35043 Marburg, Germany.
| | - Sophie J Groß
- University of Göttingen, Institute of Inorganic Chemistry, Tammannstr. 4, D-37077 Göttingen, Germany
| | - Serhiy Demeshko
- University of Göttingen, Institute of Inorganic Chemistry, Tammannstr. 4, D-37077 Göttingen, Germany
| | - Sébastien Bontemps
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, 31077 Toulouse, France.,Université de Toulouse, UPS, INPT, 31077 Toulouse, France
| | - Franc Meyer
- University of Göttingen, Institute of Inorganic Chemistry, Tammannstr. 4, D-37077 Göttingen, Germany
| | - C Gunnar Werncke
- Chemistry Department, Philipps-University, Hans-Meerwein-Str. 4, 35043 Marburg, Germany.
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9
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Wang CH, DeBeer S. Structure, reactivity, and spectroscopy of nitrogenase-related synthetic and biological clusters. Chem Soc Rev 2021; 50:8743-8761. [PMID: 34159992 DOI: 10.1039/d1cs00381j] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The reduction of dinitrogen (N2) is essential for its incorporation into nucleic acids and amino acids, which are vital to life on earth. Nitrogenases convert atmospheric dinitrogen to two ammonia molecules (NH3) under ambient conditions. The catalytic active sites of these enzymes (known as FeM-cofactor clusters, where M = Mo, V, Fe) are the sites of N2 binding and activation and have been a source of great interest for chemists for decades. In this review, recent studies on nitrogenase-related synthetic molecular complexes and biological clusters are discussed, with a focus on their reactivity and spectroscopic characterization. The molecular models that are discussed span from simple mononuclear iron complexes to multinuclear iron complexes and heterometallic iron complexes. In addition, recent work on the extracted biological cofactors is discussed. An emphasis is placed on how these studies have contributed towards our understanding of the electronic structure and mechanism of nitrogenases.
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Affiliation(s)
- Chen-Hao Wang
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany.
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany.
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10
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Schneider C, Demeshko S, Meyer F, Werncke CG. A Molecular Low-Coordinate [Fe-S-Fe] Unit in Three Oxidation States. Chemistry 2021; 27:6348-6353. [PMID: 33512018 PMCID: PMC8048577 DOI: 10.1002/chem.202100336] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Indexed: 11/10/2022]
Abstract
A [Fe-S-Fe] subunit with a single sulfide bridging two low-coordinate iron ions is the supposed active site of the iron-molybdenum co-factor (FeMoco) of nitrogenase. Here we report a dinuclear monosulfido bridged diiron(II) complex with a similar complex geometry that can be oxidized stepwise to diiron(II/III) and diiron(III/III) complexes while retaining the [Fe-S-Fe] core. The series of complexes has been characterized crystallographically, and electronic structures have been studied using, inter alia, 57 Fe Mössbauer spectroscopy and SQUID magnetometry. Further, cleavage of the [Fe-S-Fe] unit by CS2 is presented.
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Affiliation(s)
- Christian Schneider
- Fachbereich ChemiePhilipps-UniversitätHans-Meerwein-Str. 435043MarburgGermany
| | - Serhiy Demeshko
- Institut für Anorganische ChemieUniversität GöttingenTammannstr. 437077GöttingenGermany
| | - Franc Meyer
- Institut für Anorganische ChemieUniversität GöttingenTammannstr. 437077GöttingenGermany
| | - C. Gunnar Werncke
- Fachbereich ChemiePhilipps-UniversitätHans-Meerwein-Str. 435043MarburgGermany
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11
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A computational study of isoprene polymerization catalyzed by iminopyridine-supported iron complexes: Ligand-controlled selectivity. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137811] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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12
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Tanifuji K, Ohki Y. Metal–Sulfur Compounds in N2 Reduction and Nitrogenase-Related Chemistry. Chem Rev 2020; 120:5194-5251. [DOI: 10.1021/acs.chemrev.9b00544] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Kazuki Tanifuji
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, California 92697-3900, United States
| | - Yasuhiro Ohki
- Department of Chemsitry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
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13
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Planar three-coordinate iron sulfide in a synthetic [4Fe-3S] cluster with biomimetic reactivity. Nat Chem 2019; 11:1019-1025. [PMID: 31611632 PMCID: PMC6858550 DOI: 10.1038/s41557-019-0341-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 08/19/2019] [Indexed: 11/25/2022]
Abstract
Iron-sulfur clusters are emerging as reactive sites for the reduction of small-molecule substrates. However, the four-coordinate iron sites of typical iron-sulfur clusters rarely react with substrates, implicating three-coordinate iron. This idea is untested because fully sulfide-coordinated three-coordinate iron is unprecedented. Here we report a new type of [4Fe-3S] cluster featuring an iron center with three bonds to sulfides. Although a high-spin electronic configuration is characteristic of other iron-sulfur clusters, the planar geometry and short Fe–S bonds lead to a surprising low-spin electronic configuration at the three-coordinate Fe center as determined by spectroscopy and ab initio calculations. In a demonstration of biomimetic reactivity, the [4Fe-3S] cluster reduces hydrazine, a natural substrate of nitrogenase. The product is the first example of NH2 bound to an iron-sulfur cluster. Our results demonstrate that three-coordinate iron supported by sulfide donors is a plausible precursor to reactivity in iron-sulfur clusters like the FeMoco of nitrogenase.
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14
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DeRosha DE, Arnet NA, Mercado BQ, Holland PL. A [2Fe-1S] Complex That Affords Access to Bimetallic and Higher-Nuclearity Iron-Sulfur Clusters. Inorg Chem 2019; 58:8829-8834. [PMID: 31247861 DOI: 10.1021/acs.inorgchem.9b01212] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Small, coordinatively unsaturated iron-sulfur clusters are conceived as building blocks for the diverse set of shapes of iron-sulfur clusters in biological and synthetic chemistry. Here we describe a synthetic method for preparing [2Fe-1S] clusters containing two iron(II) ions, which are supported by a relatively unhindered β-diketiminate supporting ligand. The [2Fe-1S] cluster can be isolated in the presence of trimethylphosphine, and the compound with one PMe3 on each iron(II) ion has been crystallographically characterized. The PMe3 ligands may be removed with B(C6F5)3 to give a spectroscopically characterized species with solvent ligands. This species is a versatile synthon for [2Fe-2S], [4Fe-3S], and [10Fe-8S] clusters. Crystallographic characterization of the 10Fe cluster shows that it has all iron(II) ions, and the core has two [4Fe-4S] cubes that share a face in a novel arrangement. This cluster also has two iron sites that are coordinated to solvent donors, suggesting the potential for using this type of cluster for reactivity in the future.
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Affiliation(s)
- Daniel E DeRosha
- Department of Chemistry , Yale University , 225 Prospect Street , New Haven , Connecticut 06511 , United States
| | - Nicholas A Arnet
- Department of Chemistry , Yale University , 225 Prospect Street , New Haven , Connecticut 06511 , United States
| | - Brandon Q Mercado
- Department of Chemistry , Yale University , 225 Prospect Street , New Haven , Connecticut 06511 , United States
| | - Patrick L Holland
- Department of Chemistry , Yale University , 225 Prospect Street , New Haven , Connecticut 06511 , United States
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15
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Meng YS, Ouyang Z, Yang MW, Zhang YQ, Deng L, Wang BW, Gao S. Multiple magnetic relaxation pathways in T-shaped N-heterocyclic carbene-supported Fe( i) single-ion magnets. Inorg Chem Front 2019. [DOI: 10.1039/c9qi00073a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The magnetic properties of T-shaped N-heterocyclic carbene-supported Fe(i) complexes were studied. Both of them exhibited multi-pathway magnetic relaxation behaviors.
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Affiliation(s)
- Yin-Shan Meng
- State Key Laboratory of Fine Chemicals
- Dalian University of Technology
- Dalian 116024
- P. R. China
- Beijing National Laboratory for Molecular Sciences
| | - Zhengwu Ouyang
- State Key Laboratory of Organometallic Chemistry
- Shanghai Institute of Organic Chemistry
- Chinese Academy of Sciences
- Shanghai 200032
- P. R. China
| | - Mu-Wen Yang
- Beijing National Laboratory for Molecular Sciences
- Beijing Key Laboratory for Magnetoelectric Materials and Devices
- Peking University
- Beijing 100871
- 100871 P. R. China
| | - Yi-Quan Zhang
- Jiangsu Key Laboratory for NSLSCS
- School of Physical Science and Technology
- Nanjing Normal University
- Nanjing 210023
- P. R. China
| | - Liang Deng
- State Key Laboratory of Organometallic Chemistry
- Shanghai Institute of Organic Chemistry
- Chinese Academy of Sciences
- Shanghai 200032
- P. R. China
| | - Bing-Wu Wang
- Beijing National Laboratory for Molecular Sciences
- Beijing Key Laboratory for Magnetoelectric Materials and Devices
- Peking University
- Beijing 100871
- 100871 P. R. China
| | - Song Gao
- Beijing National Laboratory for Molecular Sciences
- Beijing Key Laboratory for Magnetoelectric Materials and Devices
- Peking University
- Beijing 100871
- 100871 P. R. China
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16
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Yang H, Luo M, Wu Z, Wang W, Xue C, Wu T. A semiconducting metal-chalcogenide–organic framework with square-planar tetra-coordinated sulfur. Chem Commun (Camb) 2018; 54:11272-11275. [DOI: 10.1039/c8cc06997b] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A semiconducting metal-chalcogenide–organic framework with square-planar tetra-coordinated sulfur is reported.
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Affiliation(s)
- Huajun Yang
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou
- China
| | - Min Luo
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou
- China
| | - Zhou Wu
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou
- China
| | - Wei Wang
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou
- China
| | - Chaozhuang Xue
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou
- China
| | - Tao Wu
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou
- China
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17
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Shon JH, Teets TS. Potent Bis-Cyclometalated Iridium Photoreductants with β-Diketiminate Ancillary Ligands. Inorg Chem 2017; 56:15295-15303. [PMID: 29172506 DOI: 10.1021/acs.inorgchem.7b02859] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this work, we outline a strategy to prepare a class of improved visible-light photosensitizers. Bis-cyclometalated iridium complexes with electron-rich β-diketiminate (NacNac) ancillary ligands are demonstrated to be potent excited-state electron donors. Evaluation of the photophysical and electrochemical properties establishes the excited-state redox potentials of the complexes, and Stern-Volmer quenching experiments inform on the kinetics of photoinduced electron transfer to the model substrates methyl viologen (MV2+) and benzophenone (BP). Compared to fac-Ir(ppy)3 (ppy = 2-phenylpyridine), widely regarded as a state-of-the-art photoreductant, the complexes we describe have excited-state redox potentials that are more potent by 300-400 mV and rates for photoinduced electron transfer that are accelerated by as much as a factor of 3. These complexes emerge as promising targets for application in photocatalytic reactions and other photochemical processes.
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Affiliation(s)
- Jong-Hwa Shon
- Department of Chemistry, University of Houston , 3585 Cullen Blvd., Room 112, Houston, Texas 77204-5003, United States
| | - Thomas S Teets
- Department of Chemistry, University of Houston , 3585 Cullen Blvd., Room 112, Houston, Texas 77204-5003, United States
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18
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Burcher B, Sanders KJ, Benda L, Pintacuda G, Jeanneau E, Danopoulos AA, Braunstein P, Olivier-Bourbigou H, Breuil PAR. A Straightforward Access to Stable, 16 Valence-electron Phosphine-Stabilized Fe 0 Olefin Complexes and their Reactivity. Organometallics 2017; 36:605-613. [PMID: 31031510 DOI: 10.1021/acs.organomet.6b00803] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The use of the dialkene divinyltetramethyldisiloxane (dvtms) allows easy access to the reactive 16 valence-electron complexes [Fe0(L-L)(dvtms)], (L-L) = dppe (1,2-bis(diphenylphosphino)ethane), (1), dppp (1,2-bis(diisopropylphosphino)propane), (2), pyNMeP(iPr)2 (N-(diisopropylphosphino)-N-methylpyridin-2-amine), (4), dipe (1,2-bis(diisopropylphosphino)ethane), (5), and [Fe0(L)2(dvtms)], L = PMe3, (3), by a mild reductive route using AlEt2(OEt) as reducing agent. In contrast, by the same methodology, the 18 valence-electron complexes [Fe0(L-L)2(ethylene)], (L-L) = dppm (1,2-bis(diphenylphosphino)methane), 6, (L-L) = dppa (1,2-bis(diphenylphosphino)amine) 7 or (L-L)=dppe, 8, were obtained, which do not contain dvtms. In addition, a combined DFT and solid-state paramagnetic NMR methodology is introduced for the structure determination of 5. A comparative study of the reactivity of 1,2,4-6 and 8 with 3-hexyne highlights emerging mechanistic implications for C-C coupling reactions using these complexes as catalysts.
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Affiliation(s)
- Benjamin Burcher
- IFP Energies nouvelles, Rond-point de l'échangeur de Solaize, BP 3, 69360 Solaize, France
| | - Kevin J Sanders
- Institut des Sciences Analytiques, UMR 5280 CNRS, Université de Lyon, École Normale Supérieure de Lyon, 5 rue de la Doua, 69100 Villeurbanne, France
| | - Ladislav Benda
- Institut des Sciences Analytiques, UMR 5280 CNRS, Université de Lyon, École Normale Supérieure de Lyon, 5 rue de la Doua, 69100 Villeurbanne, France
| | - Guido Pintacuda
- Institut des Sciences Analytiques, UMR 5280 CNRS, Université de Lyon, École Normale Supérieure de Lyon, 5 rue de la Doua, 69100 Villeurbanne, France
| | - Erwann Jeanneau
- Centre de Diffractométrie Henri Longchambon, Site CLEA - Bât. ISA, 3ème étage, 5 rue de La Doua, 69100 Villeurbanne, France
| | - Andreas A Danopoulos
- Université de Strasbourg, CNRS, CHIMIE UMR 7177, Laboratoire de Chimie de Coordination, 4 rue Blaise Pascal, CS90032, 67081 Strasbourg, France
| | - Pierre Braunstein
- Université de Strasbourg, CNRS, CHIMIE UMR 7177, Laboratoire de Chimie de Coordination, 4 rue Blaise Pascal, CS90032, 67081 Strasbourg, France
| | | | - Pierre-Alain R Breuil
- IFP Energies nouvelles, Rond-point de l'échangeur de Solaize, BP 3, 69360 Solaize, France
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19
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McWilliams SF, Rodgers KR, Lukat-Rodgers G, Mercado BQ, Grubel K, Holland PL. Alkali Metal Variation and Twisting of the FeNNFe Core in Bridging Diiron Dinitrogen Complexes. Inorg Chem 2016; 55:2960-8. [PMID: 26925968 PMCID: PMC4856002 DOI: 10.1021/acs.inorgchem.5b02841] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Indexed: 11/28/2022]
Abstract
Alkali metal cations can interact with Fe-N2 complexes, potentially enhancing back-bonding or influencing the geometry of the iron atom. These influences are relevant to large-scale N2 reduction by iron, such as in the FeMoco of nitrogenase and the alkali-promoted Haber-Bosch process. However, to our knowledge there have been no systematic studies of a large range of alkali metals regarding their influence on transition metal-dinitrogen complexes. In this work, we varied the alkali metal in [alkali cation]2[LFeNNFeL] complexes (L = bulky β-diketiminate ligand) through the size range from Na(+) to K(+), Rb(+), and Cs(+). The FeNNFe cores have similar Fe-N and N-N distances and N-N stretching frequencies despite the drastic change in alkali metal cation size. The two diketiminates twist relative to one another, with larger dihedral angles accommodating the larger cations. In order to explain why the twisting has so little influence on the core, we performed density functional theory calculations on a simplified LFeNNFeL model, which show that the two metals surprisingly do not compete for back-bonding to the same π* orbital of N2, even when the ligand planes are parallel. This diiron system can tolerate distortion of the ligand planes through compensating orbital energy changes, and thus, a range of ligand orientations can give very similar energies.
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Affiliation(s)
- Sean F. McWilliams
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Kenton R. Rodgers
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58105, United States
| | - Gudrun Lukat-Rodgers
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58105, United States
| | - Brandon Q. Mercado
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Katarzyna Grubel
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Patrick L. Holland
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
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20
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Ouyang Z, Meng Y, Cheng J, Xiao J, Gao S, Deng L. Three- and Four-Coordinate Homoleptic Iron(I)–NHC Complexes: Synthesis and Characterization. Organometallics 2016. [DOI: 10.1021/acs.organomet.6b00047] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhenwu Ouyang
- State
Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Yinshan Meng
- Beijing
National Laboratory for Molecular Sciences, State Key Laboratory of
Rare Earth Materials Chemistry and Applications, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, China
| | - Jun Cheng
- State
Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Jie Xiao
- State
Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Song Gao
- Beijing
National Laboratory for Molecular Sciences, State Key Laboratory of
Rare Earth Materials Chemistry and Applications, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, China
| | - Liang Deng
- State
Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
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21
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Arnet NA, Dugan TR, Menges FS, Mercado BQ, Brennessel WW, Bill E, Johnson MA, Holland PL. Synthesis, Characterization, and Nitrogenase-Relevant Reactions of an Iron Sulfide Complex with a Bridging Hydride. J Am Chem Soc 2015; 137:13220-3. [PMID: 26457740 PMCID: PMC4818001 DOI: 10.1021/jacs.5b06841] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
![]()
The
FeMoco of nitrogenase is an iron–sulfur cluster with
exceptional bond-reducing abilities. ENDOR studies have suggested
that E4, the state that binds and reduces N2, contains bridging hydrides as part of the active-site iron-sulfide
cluster. However, there are no examples of any isolable iron-sulfide
cluster with a hydride, which would test the feasibility of such a
species. Here, we describe a diiron sulfide hydride complex that is
prepared using a mild method involving C–S cleavage of added
thiolate. Its reactions with nitrogenase substrates show that the
hydride can act as a base or nucleophile and that reduction can cause
the iron atoms to bind N2. These results add experimental
support to hydride-based pathways for nitrogenase.
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Affiliation(s)
- Nicholas A Arnet
- Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States
| | - Thomas R Dugan
- Department of Chemistry, University of Rochester , Rochester, New York 14627, United States
| | - Fabian S Menges
- Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States
| | - Brandon Q Mercado
- Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States
| | - William W Brennessel
- Department of Chemistry, University of Rochester , Rochester, New York 14627, United States
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion , Mülheim an der Ruhr, Germany
| | - Mark A Johnson
- Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States
| | - Patrick L Holland
- Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States
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22
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Luo L, Chen S, Luo Y, Qu J. A theoretical study on single-electron reduction of a thiolate-bridged diiron diazene complex. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.09.050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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23
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Ouyang Z, Du J, Wang L, Kneebone JL, Neidig ML, Deng L. Linear and T-Shaped Iron(I) Complexes Supported by N-Heterocyclic Carbene Ligands: Synthesis and Structure Characterization. Inorg Chem 2015; 54:8808-16. [PMID: 26273996 PMCID: PMC4894307 DOI: 10.1021/acs.inorgchem.5b01522] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The use of the N-heterocyclic carbene (NHC) ligands 1,3-bis(2',6'-diethylphenyl)-4,5-(CH2)4-imidazol-2-ylidene (cyIDep), 1,3-bis(2',6'-diethylphenyl)-imidazolin-2-ylidene (sIDep), and its N-mesityl analogue sIMes enables the preparation of the two-coordinate homoleptic iron(I)-NHC complexes [(cyIDep)2Fe][BAr(F)4] (3, Ar(F) denoted for 3,5-di(trifluoromethyl)phenyl) and [(sIDep)2Fe][BAr(F)4] (4) and the T-shaped iron(I)-NHC complex [(sIMes)2Fe(THF)][BPh4] (5, THF = tetrahydrofuran). Complexes 3-5 were prepared via the sequential protocol of control reduction of iron(II) dihalides by KC8 in the presence of the corresponding NHC ligands followed by halide-abstraction with NaBAr4. Spectroscopic characterization, including single-crystal X-ray diffraction studies and (57)Fe Mössbauer spectroscopy, in combination with density functional theory calculations, suggest their high-spin nature. Solution property study (absorption spectroscopy and cyclic voltammetry) indicates that 3 and 5 keep their corresponding two- and three-coordinate nature in THF solution, and 4 might reversibly coordinate a THF molecule to form, presumably, the T-shaped species [(sIDep)2Fe(THF)][BAr(F)4]. The isolation of 3 and 4 demonstrates the accessibility of homoleptic two-coordinate iron(I)-NHC complexes.
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Affiliation(s)
- Zhenwu Ouyang
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Jingzhen Du
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Lei Wang
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Jared L. Kneebone
- Department of Chemistry, University of Rochester, New York 14627, United States
| | - Michael L. Neidig
- Department of Chemistry, University of Rochester, New York 14627, United States
| | - Liang Deng
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
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24
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Abstract
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The iron–molybdenum cofactor of nitrogenase has unprecedented
coordination chemistry, including a high-spin iron cluster called
the iron-molybdenum cofactor (FeMoco). Thus, understanding the mechanism
of nitrogenase challenges coordination chemists to understand the
fundamental N2 chemistry of high-spin iron sites. This
Account summarizes a series of studies in which we have synthesized
a number of new compounds with multiple iron atoms, characterized
them using crystallography and spectroscopy, and studied their reactions
in detail. These studies show that formally iron(I) and iron(0) complexes
with three- and four-coordinate metal atoms have the ability to weaken
and break the triple bond of N2. These reactions occur
at or below room temperature, indicating that they are kinetically
facile. This in turn implies that iron sites in the FeMoco are chemically
reasonable locations for N2 binding and reduction. The careful evaluation of these compounds and their reaction pathways
has taught important lessons about what characteristics make iron
more effective for N2 activation. Cooperation of two iron
atoms can lengthen and weaken the N–N bond, while three working
together enables iron atoms to completely cleave the N–N bond
to nitrides. Alkali metals (typically introduced into the reaction
as part of the reducing agent) are thermodynamically useful because
the alkali metal cations stabilize highly reduced complexes, pull
electron density into the N2 unit, and make reduced nitride
products more stable. Alkali metals can also play a kinetic role,
because cation−π interactions with the supporting ligands
can hold iron atoms near enough to one another to facilitate the cooperation
of multiple iron atoms. Many of these principles may also be relevant
to the iron-catalyzed Haber–Bosch process, at which collections
of iron atoms (often promoted by the addition of alkali metals) break
the N–N bond of N2. The results of these studies
teach more general lessons as well.
They have demonstrated that N2 can be a redox-active ligand,
accepting spin and electron density in complexes of N22–. They have shown the power of cooperation between
multiple transition metals, and also between alkali metals and transition
metals. Finally, alkali metal based cation−π interactions
have the potential to be broadly useful for bringing metals close
together with sufficient flexibility to allow multistep, multielectron
reactions. At the same time, the positive charge on the alkali metal
cation stabilizes charge buildup in intermediates.
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Affiliation(s)
- Sean F. McWilliams
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - Patrick L. Holland
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
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25
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Creutz SE, Peters JC. Diiron bridged-thiolate complexes that bind N2 at the Fe(II)Fe(II), Fe(II)Fe(I), and Fe(I)Fe(I) redox states. J Am Chem Soc 2015; 137:7310-3. [PMID: 26039253 PMCID: PMC4603983 DOI: 10.1021/jacs.5b04738] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
All known nitrogenase cofactors are rich in both sulfur and iron and are presumed capable of binding and reducing N2. Nonetheless, synthetic examples of transition metal model complexes that bind N2 and also feature sulfur donor ligands remain scarce. We report herein an unusual series of low-valent diiron complexes featuring thiolate and dinitrogen ligands. A new binucleating ligand scaffold is introduced that supports an Fe(μ-SAr)Fe diiron subunit that coordinates dinitrogen (N2-Fe(μ-SAr)Fe-N2) across at least three oxidation states (Fe(II)Fe(II), Fe(II)Fe(I), and Fe(I)Fe(I)). The (N2-Fe(μ-SAr)Fe-N2) system undergoes reduction of the bound N2 to produce NH3 (∼50% yield) and can efficiently catalyze the disproportionation of N2H4 to NH3 and N2. The present scaffold also supports dinitrogen binding concomitant with hydride as a co-ligand. Synthetic model complexes of these types are desirable to ultimately constrain hypotheses regarding Fe-mediated nitrogen fixation in synthetic and biological systems.
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Affiliation(s)
- Sidney E. Creutz
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Jonas C. Peters
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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26
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Reesbeck ME, Rodriguez MM, Brennessel WW, Mercado BQ, Vinyard D, Holland PL. Oxidized and reduced [2Fe-2S] clusters from an iron(I) synthon. J Biol Inorg Chem 2015; 20:875-83. [PMID: 26044124 DOI: 10.1007/s00775-015-1272-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 05/20/2015] [Indexed: 02/06/2023]
Abstract
Synthetic [2Fe-2S] clusters are often used to elucidate ligand effects on the reduction potentials and spectroscopy of natural electron-transfer sites, which can have anionic Cys ligands or neutral His ligands. Current synthetic routes to [2Fe-2S] clusters are limited in their feasibility with a range of supporting ligands. Here, we report a new synthetic route to synthetic [2Fe-2S] clusters, through oxidation of an iron(I) source with elemental sulfur. This method yields a neutral diketiminate-supported [2Fe-2S] cluster in the diiron(III)-oxidized form. The oxidized [2Fe-2S] cluster can be reduced to a mixed valent iron(II)-iron(III) compound. Both the diferric and reduced mixed valent clusters are characterized using X-ray crystallography, Mössbauer spectroscopy, EPR spectroscopy and cyclic voltammetry. The reduced compound is particularly interesting because its X-ray crystal structure shows a difference in Fe-S bond lengths to one of the iron atoms, consistent with valence localization. The valence localization is also evident from Mössbauer spectroscopy.
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Affiliation(s)
- Megan E Reesbeck
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT, 06520, USA
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27
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Lichtenberg C, Viciu L, Adelhardt M, Sutter J, Meyer K, de Bruin B, Grützmacher H. Low-Valent Iron(I) Amido Olefin Complexes as Promotors for Dehydrogenation Reactions. Angew Chem Int Ed Engl 2015; 54:5766-71. [DOI: 10.1002/anie.201411365] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Indexed: 11/08/2022]
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28
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Lichtenberg C, Viciu L, Adelhardt M, Sutter J, Meyer K, de Bruin B, Grützmacher H. Niedervalente Eisen(I)-Amido-Olefinkomplexe als Promotoren von Dehydrierungsreaktionen. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201411365] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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29
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Samuel PP, Mondal KC, Amin Sk N, Roesky HW, Carl E, Neufeld R, Stalke D, Demeshko S, Meyer F, Ungur L, Chibotaru LF, Christian J, Ramachandran V, van Tol J, Dalal NS. Electronic Structure and Slow Magnetic Relaxation of Low-Coordinate Cyclic Alkyl(amino) Carbene Stabilized Iron(I) Complexes. J Am Chem Soc 2014; 136:11964-71. [DOI: 10.1021/ja5043116] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Prinson P. Samuel
- Institut
für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, D-37077, Göttingen, Germany
| | - Kartik Chandra Mondal
- Institut
für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, D-37077, Göttingen, Germany
| | - Nurul Amin Sk
- Institut
für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, D-37077, Göttingen, Germany
| | - Herbert W. Roesky
- Institut
für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, D-37077, Göttingen, Germany
| | - Elena Carl
- Institut
für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, D-37077, Göttingen, Germany
| | - Roman Neufeld
- Institut
für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, D-37077, Göttingen, Germany
| | - Dietmar Stalke
- Institut
für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, D-37077, Göttingen, Germany
| | - Serhiy Demeshko
- Institut
für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, D-37077, Göttingen, Germany
| | - Franc Meyer
- Institut
für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, D-37077, Göttingen, Germany
| | - Liviu Ungur
- KU Leuven, Celestijnenlaan,
200F, 3001, Leuven, Belgium
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30
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Anderson JS, Peters JC. Low-spin pseudotetrahedral iron(I) sites in Fe₂(μ-S) complexes. Angew Chem Int Ed Engl 2014; 53:5978-81. [PMID: 24753364 DOI: 10.1002/anie.201401018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Indexed: 11/06/2022]
Abstract
Fe(I) centers in iron-sulfide complexes have little precedent in synthetic chemistry despite a growing interest in the possible role of unusually low valent iron in metalloenzymes that feature iron-sulfur clusters. A series of three diiron [(L3Fe)2(μ-S)] complexes that were isolated and characterized in the low-valent oxidation states Fe(II)-S-Fe(II), Fe(II)-S-Fe(I), and Fe(I)-S-Fe(I) is described. This family of iron sulfides constitutes a unique redox series comprising three nearly isostructural but electronically distinct Fe2(μ-S) species. Combined structural, magnetic, and spectroscopic studies provided strong evidence that the pseudotetrahedral iron centers undergo a transition to low-spin S=1/2 states upon reduction from Fe(II) to Fe(I). The possibility of accessing low-spin, pseudotetrahedral Fe(I) sites compatible with S(2-) as a ligand was previously unknown.
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Affiliation(s)
- John S Anderson
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125 (USA)
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31
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Anderson JS, Peters JC. Low-Spin Pseudotetrahedral Iron(I) Sites in Fe2(μ-S) Complexes. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201401018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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32
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Holze P, Horn B, Limberg C, Matlachowski C, Mebs S. Aktivierung von Schwefelhexafluorid an hoch reduzierten niedrig koordinierten Nickel-Distickstoff-Komplexen. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201308270] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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33
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Holze P, Horn B, Limberg C, Matlachowski C, Mebs S. The activation of sulfur hexafluoride at highly reduced low-coordinate nickel dinitrogen complexes. Angew Chem Int Ed Engl 2014; 53:2750-3. [PMID: 24481669 DOI: 10.1002/anie.201308270] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Indexed: 11/07/2022]
Abstract
The greenhouse gas sulfur hexafluoride is the common standard example in the literature of a very inert inorganic small molecule that is even stable against O2 in an electric discharge. However, a reduced β-diketiminate nickel species proved to be capable of converting SF6 into sulfide and fluoride compounds at ambient standard conditions. The fluoride product complex features an unprecedented [NiF](+) unit, where the Ni atom is only three-coordinate, while the sulfide product exhibits a rare almost linear [Ni(μ-S)Ni](2+) moiety. The reaction was monitored applying (1)H NMR, IR and EPR spectroscopic techniques resulting in the identification of an intermediate nickel complex that gave insight into the mechanism of the eight-electron reduction of SF6.
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Affiliation(s)
- Patrick Holze
- Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Strasse 2, 12489 Berlin (Germany) http://www.chemie.hu-berlin.de/aglimberg/
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34
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Chiang KP, Bellows SM, Brennessel WW, Holland PL. Multimetallic Cooperativity in Activation of Dinitrogen at Iron-Potassium Sites. Chem Sci 2014; 5. [PMID: 24379972 DOI: 10.1039/c3sc52487f] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The reaction of soluble iron-oxygen-potassium assemblies with N2 gives insight into the mechanisms of multimetallic N2 coordination. We report a series of very electron-rich three-coordinate, β-diketiminate-supported iron(I) phenoxide complexes, which are metastable but have been characterized under Ar by both crystallography and solution methods. Both monomeric and dimeric Fe-OPh-K compounds have been characterized, and their iron environments are very similar in the solid and solution states. In the dimer, potassium ions hold together the phenoxide oxygens and aryl rings of the two halves, to give a flexible diiron core. The reactions of the monomeric and dimeric iron(I) compounds with N2 are surprisingly different: the mononuclear iron(I) complexes give no reaction with N2, but the dimeric Fe2K2 complex reacts rapidly to give a diiron-N2 product. Computational studies show that the key to the rapid N2 reaction of the dimer is the preorganization of the two iron atoms. Thus, cooperation between Fe (which weakens the N-N bond) and K (which orients the Fe atoms) can be used to create a low-energy pathway for N2 reactions.
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Affiliation(s)
- Karen P Chiang
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
| | - Sarina M Bellows
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
| | - William W Brennessel
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
| | - Patrick L Holland
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
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35
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Mo Z, Ouyang Z, Wang L, Fillman KL, Neidig ML, Deng L. Two- and three-coordinate formal iron(i) compounds featuring monodentate aminocarbene ligands. Org Chem Front 2014. [DOI: 10.1039/c4qo00175c] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Monodentate aminocarbene ligands, both NHC and cAAC, are capable of stabilizing low-coordinate iron(i) compounds.
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Affiliation(s)
- Zhenbo Mo
- State Key Laboratory of Organometallic Chemistry
- Shanghai Institute of Organic Chemistry
- Chinese Academy of Sciences
- Shanghai 200032, China
| | - Zhenwu Ouyang
- State Key Laboratory of Organometallic Chemistry
- Shanghai Institute of Organic Chemistry
- Chinese Academy of Sciences
- Shanghai 200032, China
| | - Lei Wang
- State Key Laboratory of Organometallic Chemistry
- Shanghai Institute of Organic Chemistry
- Chinese Academy of Sciences
- Shanghai 200032, China
| | | | | | - Liang Deng
- State Key Laboratory of Organometallic Chemistry
- Shanghai Institute of Organic Chemistry
- Chinese Academy of Sciences
- Shanghai 200032, China
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36
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Stubbert BD, Vela J, Brennessel WW, Holland PL. A Sulfide-Bridged Diiron(II) Complex with a cis-N 2H 4Ligand. Z Anorg Allg Chem 2013; 639:1351-1355. [PMID: 24678131 PMCID: PMC3963182 DOI: 10.1002/zaac.201300163] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 05/24/2013] [Indexed: 11/07/2022]
Abstract
A sulfide-bridged diiron(II) complex bearing a cis-N2H4 (hydrazine) ligand has been prepared by reaction of LFeII(μ-S)FeIIL (1; L = sterically encumbered βdiketiminate ligand) with 2 molar equivalents of N2H4. The metastable diiron(II) hydrazine complex LFeII(μ-S)(μH N-NH2)FeII (3) is formed, as shown by crystallography, and NMR, vibrational, and electronic absorption spectroscopies. Compound 3 has been crystallographically characterized as its DBU (1,8-diazabicyclo[5.4.0]undec-7$ene) adduct, which exhibits weak N-H···DBU hydrogen bonding. The synthetic process evolves roughly 2 equivalents of NH3. The cis-N2H4 bridge in 3 may be relevant to the structure and function of intermediates on the FeMoco of nitrogenase.
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Affiliation(s)
- Bryan D. Stubbert
- Department of Chemistry University of Rochester Rochester, NY, USA 14627
| | - Javier Vela
- Department of Chemistry University of Rochester Rochester, NY, USA 14627
| | | | - Patrick L. Holland
- Department of Chemistry University of Rochester Rochester, NY, USA 14627
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37
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Davydov RM, McLaughlin MP, Bill E, Hoffman BM, Holland PL. Generation of high-spin iron(I) in a protein environment using cryoreduction. Inorg Chem 2013; 52:7323-5. [PMID: 24004284 DOI: 10.1021/ic4011339] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
High-spin Fe(1+) sites are potentially important in iron-sulfur proteins but are rare in synthetic compounds and unknown in metalloproteins. Here, we demonstrate a spectroscopically characterized example of high-spin non-heme Fe(1+) in a protein environment. Cryoreduction of Fe(2+)-substituted azurin at 77 K with (60)Co γ radiation generates a new species with a S = (3)/2 (high-spin) Fe(1+) center having D > 0 and E/D ~ 0.25. This transient species is stable in a glycerol-water glass only up to ~170 K. A combination of electron paramagnetic resonance and Mössbauer spectroscopies provides a powerful means of identifying a transient high-spin Fe(1+) site in a protein scaffold.
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Affiliation(s)
- Roman M Davydov
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
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