1
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Steube J, Fritsch L, Kruse A, Bokareva OS, Demeshko S, Elgabarty H, Schoch R, Alaraby M, Egold H, Bracht B, Schmitz L, Hohloch S, Kühne TD, Meyer F, Kühn O, Lochbrunner S, Bauer M. Isostructural Series of a Cyclometalated Iron Complex in Three Oxidation States. Inorg Chem 2024; 63:16964-16980. [PMID: 39222251 DOI: 10.1021/acs.inorgchem.4c02576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
An isostructural series of FeII, FeIII, and FeIV complexes [Fe(ImP)2]0/+/2+ utilizing the ImP 1,1'-(1,3-phenylene)bis(3-methyl-1-imidazol-2-ylidene) ligand, combining N-heterocyclic carbenes and cyclometalating functions, is presented. The strong donor motif stabilizes the high-valent FeIV oxidation state yet keeps the FeII oxidation state accessible from the parent FeIII compound. Chemical oxidation of [Fe(ImP)2]+ yields stable [FeIV(ImP)2]2+. In contrast, [FeII(ImP)2]0, obtained by reduction, is highly sensitive toward oxygen. Exhaustive ground state characterization by single-crystal X-ray diffraction, 1H NMR, Mössbauer spectroscopy, temperature-dependent magnetic measurements, a combination of X-ray absorption near edge structure and valence-to-core, as well as core-to-core X-ray emission spectroscopy, complemented by detailed density functional theory (DFT) analysis, reveals that the three complexes [Fe(ImP)2]0/+/2+ can be unequivocally attributed to low-spin d6, d5, and d4 complexes. The excited state landscape of the FeII and FeIV complexes is characterized by short-lived 3MLCT and 3LMCT states, with lifetimes of 5.1 and 1.4 ps, respectively. In the FeII-compound, an energetically low-lying MC state leads to fast deactivation of the MLCT state. The distorted square-pyramidal state, where one carbene is dissociated, can not only relax into the ground state, but also into a singlet dissociated state. Its formation was investigated with time-dependent optical spectroscopy, while insights into its structure were gained by NMR spectroscopy.
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Affiliation(s)
- Jakob Steube
- Institute for Inorganic Chemistry, Paderborn University, 33098 Paderborn, Germany
- Center for Sustainable Systems Design (CSSD), Paderborn University, 33098 Paderborn, Germany
| | - Lorena Fritsch
- Institute for Inorganic Chemistry, Paderborn University, 33098 Paderborn, Germany
- Center for Sustainable Systems Design (CSSD), Paderborn University, 33098 Paderborn, Germany
| | - Ayla Kruse
- Department of Life, Light, and Matter, University of Rostock, 18051 Rostock, Germany
- Institute of Physics, University of Rostock, 18051 Rostock, Germany
| | - Olga S Bokareva
- Institute of Physics, University of Rostock, 18051 Rostock, Germany
| | - Serhiy Demeshko
- Institute of Inorganic Chemistry, University of Göttingen, 37077 Göttingen, Germany
| | - Hossam Elgabarty
- Center for Sustainable Systems Design (CSSD), Paderborn University, 33098 Paderborn, Germany
- Institute for Theoretical Chemistry, Paderborn University, 33098 Paderborn, Germany
| | - Roland Schoch
- Institute for Inorganic Chemistry, Paderborn University, 33098 Paderborn, Germany
- Center for Sustainable Systems Design (CSSD), Paderborn University, 33098 Paderborn, Germany
| | - Mohammad Alaraby
- Center for Sustainable Systems Design (CSSD), Paderborn University, 33098 Paderborn, Germany
- Institute for Theoretical Chemistry, Paderborn University, 33098 Paderborn, Germany
| | - Hans Egold
- Institute for Inorganic Chemistry, Paderborn University, 33098 Paderborn, Germany
| | - Bastian Bracht
- Institute for Inorganic Chemistry, Paderborn University, 33098 Paderborn, Germany
- Center for Sustainable Systems Design (CSSD), Paderborn University, 33098 Paderborn, Germany
| | - Lennart Schmitz
- Institute for Inorganic Chemistry, Paderborn University, 33098 Paderborn, Germany
- Center for Sustainable Systems Design (CSSD), Paderborn University, 33098 Paderborn, Germany
| | - Stephan Hohloch
- Institute for Inorganic Chemistry, Paderborn University, 33098 Paderborn, Germany
| | - Thomas D Kühne
- Center for Sustainable Systems Design (CSSD), Paderborn University, 33098 Paderborn, Germany
- Institute for Theoretical Chemistry, Paderborn University, 33098 Paderborn, Germany
| | - Franc Meyer
- Institute of Inorganic Chemistry, University of Göttingen, 37077 Göttingen, Germany
| | - Oliver Kühn
- Department of Life, Light, and Matter, University of Rostock, 18051 Rostock, Germany
- Institute of Physics, University of Rostock, 18051 Rostock, Germany
| | - Stefan Lochbrunner
- Department of Life, Light, and Matter, University of Rostock, 18051 Rostock, Germany
- Institute of Physics, University of Rostock, 18051 Rostock, Germany
| | - Matthias Bauer
- Institute for Inorganic Chemistry, Paderborn University, 33098 Paderborn, Germany
- Center for Sustainable Systems Design (CSSD), Paderborn University, 33098 Paderborn, Germany
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2
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Hertler PR, Sauza-de la Vega A, Darù A, Sarkar A, Lewis RA, Wu G, Gagliardi L, Hayton TW. A homoleptic Fe(iv) ketimide complex with a low-lying excited state. Chem Sci 2024:d4sc04880f. [PMID: 39309088 PMCID: PMC11411412 DOI: 10.1039/d4sc04880f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2024] [Accepted: 09/04/2024] [Indexed: 09/25/2024] Open
Abstract
The reaction of 4 equiv. of Li(N[double bond, length as m-dash]C( t Bu)Ph) with FeIICl2 results in isolation of [Li(Et2O)]2[FeII(N[double bond, length as m-dash]C( t Bu)Ph)4] (1), in good yields. The reaction of 1 with 1 equiv. of I2 leads to formation of [FeIV(N[double bond, length as m-dash]C( t Bu)Ph)4] (2), in moderate yields. 57Fe Mössbauer spectroscopy confirms the Fe(iv) oxidation state of 2, and X-ray crystallography reveals that 2 has a square planar coordination geometry along with several intramolecular H⋯C interactions. Furthermore, SQUID magnetometry indicates a small magnetic moment at room temperature, suggestive of an accessible S = 1 state. Both density functional theory and multiconfigurational calculations were done to elucidate the nature of the ground state. Consistent with the experimental results, the ground state was found to be an S = 0 state with an S = 1 excited state close in energy.
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Affiliation(s)
- Phoebe R Hertler
- Department of Chemistry and Biochemistry, University of California Santa Barbara Santa Barbara CA 93106 USA
| | - Arturo Sauza-de la Vega
- Department of Chemistry, Pritzker School of Molecular Engineering, James Franck Institute, University of Chicago Chicago IL 60637 USA
| | - Andrea Darù
- Department of Chemistry, Pritzker School of Molecular Engineering, James Franck Institute, University of Chicago Chicago IL 60637 USA
| | - Arup Sarkar
- Department of Chemistry, Pritzker School of Molecular Engineering, James Franck Institute, University of Chicago Chicago IL 60637 USA
| | - Richard A Lewis
- Department of Chemistry and Biochemistry, University of California Santa Barbara Santa Barbara CA 93106 USA
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara Santa Barbara CA 93106 USA
| | - Laura Gagliardi
- Department of Chemistry, Pritzker School of Molecular Engineering, James Franck Institute, University of Chicago Chicago IL 60637 USA
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara Santa Barbara CA 93106 USA
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3
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Yue D, Hirao H. Enhancing the high-spin reactivity in C-H bond activation by Iron (IV)-Oxo species: insights from paclitaxel hydroxylation by CYP2C8. Front Chem 2024; 12:1471741. [PMID: 39345859 PMCID: PMC11427847 DOI: 10.3389/fchem.2024.1471741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2024] [Accepted: 08/26/2024] [Indexed: 10/01/2024] Open
Abstract
Previous theoretical studies have revealed that high-spin states possess flatter potential energy surfaces than low-spin states in reactions involving iron(IV)-oxo species of cytochrome P450 enzymes (P450s), nonheme enzymes, or biomimetic complexes. Therefore, actively utilizing high-spin states to enhance challenging chemical transformations, such as C-H bond activation, represents an intriguing research avenue. However, the inherent instability of high-spin states relative to low-spin states in pre-reaction complexes often hinders their accessibility around the transition state, especially in heme systems with strong ligand fields. Counterintuitively, our investigation of the metabolic hydroxylation of paclitaxel by human CYP2C8 using a hybrid quantum mechanics and molecular mechanics (QM/MM) approach showed that the high-spin sextet state exhibits unusually high stability, when the reaction follows a secondary reaction pathway leading to 6β-hydroxypaclitaxel. We thoroughly analyzed the factors contributing to the enhanced stabilization of the high-spin state, and the knowledge obtained could be instrumental in designing competent biomimetic catalysts and biocatalysts for C-H bond activation.
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Affiliation(s)
| | - Hajime Hirao
- Warshel Institute for Computational Biology, School of Medicine, The Chinese University of Hong Kong, Shenzhen, China
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4
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Zhang B, Joyce JP, Wolford NJ, Brennessel WW, DeBeer S, Neidig ML. Unusual S=1 Four-Coordinate Fe(IV) Complexes Supported by Bisamide Ligands: Syntheses, Characterization, and Electronic Structures. Angew Chem Int Ed Engl 2024; 63:e202405113. [PMID: 38864588 DOI: 10.1002/anie.202405113] [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: 03/14/2024] [Revised: 06/11/2024] [Accepted: 06/12/2024] [Indexed: 06/13/2024]
Abstract
The catalytic relevance of Fe(IV) species in non-heme iron catalysis has motivated synthetic advances in well-defined five- and six-coordinate Fe(IV) complexes for a better understanding of their fundamental electronic structures and reactivities. Herein, we report the syntheses of FeDipp2 and FeMes2, a pair of unusual four-coordinate non-heme formally Fe(IV) complexes with S=1 ground states supported by strongly donating bisamide ligands. By combining spectroscopic characterization and computational modeling, we found that small variations in ligand aryl substituents resulted in substantial changes in both structures and bonding. This work highlights the strong donor capabilities and modularity of the bisamide ligand set. More broadly, it is a critical contribution to the utilization of ligand design to modulate molecular geometries and electronic structures of low-coordinate, high-valent iron complexes.
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Affiliation(s)
- Bufan Zhang
- Department of Chemistry, University of Rochester, Hutchison Hall, 120 Trustee Road, 14627, Rochester, NY, United States
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470, Mülheim an der Ruhr, Germany
| | - Justin P Joyce
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470, Mülheim an der Ruhr, Germany
| | - Nikki J Wolford
- Department of Chemistry, University of Rochester, Hutchison Hall, 120 Trustee Road, 14627, Rochester, NY, United States
| | - William W Brennessel
- Department of Chemistry, University of Rochester, Hutchison Hall, 120 Trustee Road, 14627, Rochester, NY, United States
| | - Serena DeBeer
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470, Mülheim an der Ruhr, Germany
| | - Michael L Neidig
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, OX1 3QR, Oxford, United Kingdom
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5
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Bhardwaj A, Mondal B. Unraveling the Geometry-Driven C═C Epoxidation and C-H Hydroxylation Reactivity of Tetra-Coordinated Nonheme Iron(IV)-Oxo Complexes. Inorg Chem 2024; 63:14468-14481. [PMID: 39030661 DOI: 10.1021/acs.inorgchem.4c01708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2024]
Abstract
The electronic structure and reactivity of tetra-coordinated nonheme iron(IV)-oxo complexes have remained unexplored for years. The recent synthesis of a closed-shell iron(IV)-oxo complex [(quinisox)FeIV(O)]+ (1) has set up a platform to understand how such complexes compare with the celebrated open-shell iron-oxo chemistry. Herein, using density functional theory and ab initio calculations, we present an in-depth electronic structure investigation of the C═C epoxidation [oxygen atom transfer (OAT)] and C-H hydroxylation [hydrogen atom transfer (HAT)] reactivity of 1. Using a solvent-coordinated geometry of 1 (1') and other potential tetra-coordinated iron(IV)-oxo complexes bearing rigid ligands (2 and 3), we established the geometric origin of spin-state energetics and reactivity of 1. Complex 1 featuring a strong Fe-O bond exhibits OAT and HAT reactivity in its quintet state. The lowest quintet OAT pathway has a lower barrier by ∼4 kcal/mol than the quintet HAT pathway, corroborating the experimentally observed gas-phase OAT reactivity preference. A conventional HAT reactivity preference for 2 and a comparable OAT and HAT reactivity for 3 are observed. This further supports the geometry-driven reactivity preference for 1. Noncovalent interaction analyses reveal a pronounced π-π interaction between the substrate and ligand in the OAT transition state, rationalizing the origin of the observed reactivity preference for 1.
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Affiliation(s)
- Akhil Bhardwaj
- School of Chemical Sciences, Indian Institute of Technology Mandi, Mandi, Himachal Pradesh 175075, India
| | - Bhaskar Mondal
- School of Chemical Sciences, Indian Institute of Technology Mandi, Mandi, Himachal Pradesh 175075, India
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6
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Paris JC, Hei Cheung Y, Zhang T, Chang WC, Liu P, Guo Y. New Frontiers in Nonheme Enzymatic Oxyferryl Species. Chembiochem 2024:e202400307. [PMID: 38900645 DOI: 10.1002/cbic.202400307] [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: 04/04/2024] [Revised: 06/13/2024] [Accepted: 06/20/2024] [Indexed: 06/22/2024]
Abstract
Non-heme mononuclear iron dependent (NHM-Fe) enzymes exhibit exceedingly diverse catalytic reactivities. Despite their catalytic versatilities, the mononuclear iron centers in these enzymes show a relatively simple architecture, in which an iron atom is ligated with 2-4 amino acid residues, including histidine, aspartic or glutamic acid. In the past two decades, a common high-valent reactive iron intermediate, the S=2 oxyferryl (Fe(IV)-oxo or Fe(IV)=O) species, has been repeatedly discovered in NHM-Fe enzymes containing a 2-His-Fe or 2-His-1-carboxylate-Fe center. However, for 3-His/4-His-Fe enzymes, no common reactive intermediate has been identified. Recently, we have spectroscopically characterized the first S=1 Fe(IV) intermediate in a 3-His-Fe containing enzyme, OvoA, which catalyzes a novel oxidative carbon-sulfur bond formation. In this review, we summarize the broad reactivities demonstrated by S=2 Fe(IV)-oxo intermediates, the discovery of the first S=1 Fe(IV) intermediate in OvoA and the mechanistic implication of such a discovery, and the intrinsic reactivity differences of the S=2 and the S=1 Fe(IV)-oxo species. Finally, we postulate the possible reasons to utilize an S=1 Fe(IV) species in OvoA and their implications to other 3-His/4-His-Fe enzymes.
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Affiliation(s)
- Jared C Paris
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Ave., Pittsburgh, PA, 15213, USA
| | - Yuk Hei Cheung
- Department of Chemistry, Boston University, 590 Commonwealth Ave., Boston, MA, 02215, USA
| | - Tao Zhang
- Department of Chemistry, Boston University, 590 Commonwealth Ave., Boston, MA, 02215, USA
| | - Wei-Chen Chang
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Dr., Raleigh, NC, 27695, USA
| | - Pinghua Liu
- Department of Chemistry, Boston University, 590 Commonwealth Ave., Boston, MA, 02215, USA
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Ave., Pittsburgh, PA, 15213, USA
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7
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Sarkar W, LaDuca A, Wilson JR, Szymczak NK. Iron-Catalyzed C-H Oxygenation Using Perchlorate Enabled by Secondary Sphere Hydrogen Bonds. J Am Chem Soc 2024; 146:10508-10516. [PMID: 38564312 PMCID: PMC11137739 DOI: 10.1021/jacs.3c14433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Perchlorate (ClO4-) is a groundwater pollutant that is challenging to remediate. We report a strategy to use Fe(II) tris(2-pyridylmethyl)amine (TPA) complexes featuring appended aniline hydrogen bonds (H-bonds) to promote ClO4- reduction. These complexes facilitate oxygen atom transfer from ClO4- to PPh3 and C-H oxygenation reactions of organic substrates. Catalytic reactions using 15 mol % afforded excellent yields for oxygenation of anthracene and cyclic alkyl aromatics, and this methodology tolerates aryl halides as well as heterocycles containing either O, S, or N.
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Affiliation(s)
- Writhabrata Sarkar
- Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor, Michigan 48109, United States
| | - Andrew LaDuca
- Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor, Michigan 48109, United States
| | - Jessica R Wilson
- Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor, Michigan 48109, United States
| | - Nathaniel K Szymczak
- Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor, Michigan 48109, United States
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8
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Rasheed W, Pal N, Aboelenen AM, Banerjee S, Oloo WN, Klein JEMN, Fan R, Xiong J, Guo Y, Que L. NMR and Mössbauer Studies Reveal a Temperature-Dependent Switch from S = 1 to 2 in a Nonheme Oxoiron(IV) Complex with Faster C-H Bond Cleavage Rates. J Am Chem Soc 2024; 146:3796-3804. [PMID: 38299607 PMCID: PMC11238627 DOI: 10.1021/jacs.3c10694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
S = 2 FeIV═O centers generated in the active sites of nonheme iron oxygenases cleave substrate C-H bonds at rates significantly faster than most known synthetic FeIV═O complexes. Unlike the majority of the latter, which are S = 1 complexes, [FeIV(O)(tris(2-quinolylmethyl)amine)(MeCN)]2+ (3) is a rare example of a synthetic S = 2 FeIV═O complex that cleaves C-H bonds 1000-fold faster than the related [FeIV(O)(tris(pyridyl-2-methyl)amine)(MeCN)]2+ complex (0). To rationalize this significant difference, a systematic comparison of properties has been carried out on 0 and 3 as well as related complexes 1 and 2 with mixed pyridine (Py)/quinoline (Q) ligation. Interestingly, 2 with a 2-Q-1-Py donor combination cleaves C-H bonds at 233 K with rates approaching those of 3, even though Mössbauer analysis reveals 2 to be S = 1 at 4 K. At 233 K however, 2 becomes S = 2, as shown by its 1H NMR spectrum. These results demonstrate a unique temperature-dependent spin-state transition from triplet to quintet in oxoiron(IV) chemistry that gives rise to the high C-H bond cleaving reactivity observed for 2.
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Affiliation(s)
- Waqas Rasheed
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Nabhendu Pal
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Ahmed M Aboelenen
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Saikat Banerjee
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Williamson N Oloo
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Johannes E M N Klein
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Ruixi Fan
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Jin Xiong
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Lawrence Que
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
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9
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Hou K, Börgel J, Jiang HZH, SantaLucia DJ, Kwon H, Zhuang H, Chakarawet K, Rohde RC, Taylor JW, Dun C, Paley MV, Turkiewicz AB, Park JG, Mao H, Zhu Z, Alp EE, Zhao J, Hu MY, Lavina B, Peredkov S, Lv X, Oktawiec J, Meihaus KR, Pantazis DA, Vandone M, Colombo V, Bill E, Urban JJ, Britt RD, Grandjean F, Long GJ, DeBeer S, Neese F, Reimer JA, Long JR. Reactive high-spin iron(IV)-oxo sites through dioxygen activation in a metal-organic framework. Science 2023; 382:547-553. [PMID: 37917685 DOI: 10.1126/science.add7417] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 09/24/2023] [Indexed: 11/04/2023]
Abstract
In nature, nonheme iron enzymes use dioxygen to generate high-spin iron(IV)=O species for a variety of oxygenation reactions. Although synthetic chemists have long sought to mimic this reactivity, the enzyme-like activation of O2 to form high-spin iron(IV) = O species remains an unrealized goal. Here, we report a metal-organic framework featuring iron(II) sites with a local structure similar to that in α-ketoglutarate-dependent dioxygenases. The framework reacts with O2 at low temperatures to form high-spin iron(IV) = O species that are characterized using in situ diffuse reflectance infrared Fourier transform, in situ and variable-field Mössbauer, Fe Kβ x-ray emission, and nuclear resonance vibrational spectroscopies. In the presence of O2, the framework is competent for catalytic oxygenation of cyclohexane and the stoichiometric conversion of ethane to ethanol.
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Affiliation(s)
- Kaipeng Hou
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jonas Börgel
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Henry Z H Jiang
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Daniel J SantaLucia
- Max Planck Institute for Chemical Energy Conversion, D-45470 Mülheim an der Ruhr, Germany
- Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim an der Ruhr, Germany
| | - Hyunchul Kwon
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Hao Zhuang
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
| | | | - Rachel C Rohde
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Jordan W Taylor
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Chaochao Dun
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Maria V Paley
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ari B Turkiewicz
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Jesse G Park
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Haiyan Mao
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, USA
| | - Ziting Zhu
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
| | - E Ercan Alp
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Jiyong Zhao
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Michael Y Hu
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Barbara Lavina
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA
- Center for Advanced Radiation Sources, The University of Chicago, Chicago, IL 60637, USA
| | - Sergey Peredkov
- Max Planck Institute for Chemical Energy Conversion, D-45470 Mülheim an der Ruhr, Germany
| | - Xudong Lv
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Julia Oktawiec
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
| | - Katie R Meihaus
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | | | - Marco Vandone
- Department of Chemistry, University of Milan, 20133 Milan, Italy
| | - Valentina Colombo
- Department of Chemistry, University of Milan, 20133 Milan, Italy
- Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), UdR Milano, Via Golgi 19, 20133 Milano, Italy
| | - Eckhard Bill
- Max Planck Institute for Chemical Energy Conversion, D-45470 Mülheim an der Ruhr, Germany
| | - Jeffrey J Urban
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - R David Britt
- Department of Chemistry, University of California, Davis, CA 95616, USA
- Miller Institute for Basic Research in Science, University of California, Berkeley CA 94720, USA
| | - Fernande Grandjean
- Department of Chemistry, Missouri University of Science and Technology, University of Missouri, Rolla, MO 65409, USA
| | - Gary J Long
- Department of Chemistry, Missouri University of Science and Technology, University of Missouri, Rolla, MO 65409, USA
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, D-45470 Mülheim an der Ruhr, Germany
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim an der Ruhr, Germany
| | - Jeffrey A Reimer
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, USA
| | - Jeffrey R Long
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, USA
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10
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Follmer AH, Borovik AS. The role of basicity in selective C-H bond activation by transition metal-oxidos. Dalton Trans 2023; 52:11005-11016. [PMID: 37497779 PMCID: PMC10619463 DOI: 10.1039/d3dt01781h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
The development of (bio)catalysts capable of selectively activating strong C-H bonds is a continuing challenge in modern chemistry. In both metalloenzymes and synthetic systems capable of activating C-H bonds, transition metal-oxido intermediates serve as the active species for reactivity whose thermodynamic properties influence the bond strengths they are capable of activating. In this Frontier article, we present current ideas of how the basicity of transition metal-oxidos impacts their reactivity with C-H bonds and present new opportunities within this field. We highlight recent insights into the role basicity plays in the activation process and its influence on mechanism, as well as the important role that secondary coordination sphere effects, such as hydrogen bonds, in tuning the basicity of the metal-oxido species is discussed.
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Affiliation(s)
- Alec H Follmer
- Department of Chemistry, University of California-Irvine, Irvine, CA 92697-3900, USA.
| | - A S Borovik
- Department of Chemistry, University of California-Irvine, Irvine, CA 92697-3900, USA.
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11
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Sun C, Jaimes JL, Follmer AH, Ziller JW, Borovik AS. Selective C-H Bond Cleavage with a High-Spin Fe IV-Oxido Complex. Molecules 2023; 28:4755. [PMID: 37375309 DOI: 10.3390/molecules28124755] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/23/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023] Open
Abstract
Non-heme Fe monooxygenases activate C-H bonds using intermediates with high-spin FeIV-oxido centers. To mimic these sites, a new tripodal ligand [pop]3- was prepared that contains three phosphoryl amido groups that are capable of stabilizing metal centers in high oxidation states. The ligand was used to generate [FeIVpop(O)]-, a new FeIV-oxido complex with an S = 2 spin ground state. Spectroscopic measurements, which included low-temperature absorption and electron paramagnetic resonance spectroscopy, supported the assignment of a high-spin FeIV center. The complex showed reactivity with benzyl alcohol as the external substrate but not with related compounds (e.g., ethyl benzene and benzyl methyl ether), suggesting the possibility that hydrogen bonding interaction(s) between the substrate and [FeIVpop(O)]- was necessary for reactivity. These results exemplify the potential role of the secondary coordination sphere in metal-mediated processes.
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Affiliation(s)
- Chen Sun
- Department of Chemistry, University of California-Irvine, Irvine, CA 92697, USA
| | - Jennifer L Jaimes
- Department of Chemistry, University of California-Irvine, Irvine, CA 92697, USA
| | - Alec H Follmer
- Department of Chemistry, University of California-Irvine, Irvine, CA 92697, USA
| | - Joseph W Ziller
- Department of Chemistry, University of California-Irvine, Irvine, CA 92697, USA
| | - Andrew S Borovik
- Department of Chemistry, University of California-Irvine, Irvine, CA 92697, USA
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12
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Antolini C, Spellman CD, Otolski CJ, Doumy G, March AM, Walko DA, Liu C, Zhang X, Young BT, Goodwill JE, Hayes D. Photochemical and Photophysical Dynamics of the Aqueous Ferrate(VI) Ion. J Am Chem Soc 2022; 144:22514-22527. [PMID: 36454056 DOI: 10.1021/jacs.2c08048] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Ferrate(VI) has the potential to play a key role in future water supplies. Its salts have been suggested as "green" alternatives to current advanced oxidation and disinfection methods in water treatment, especially when combined with ultraviolet light to stimulate generation of highly oxidizing Fe(V) and Fe(IV) species. However, the nature of these intermediates, the mechanisms by which they form, and their roles in downstream oxidation reactions remain unclear. Here, we use a combination of optical and X-ray transient absorption spectroscopies to study the formation, interconversion, and relaxation of several excited-state and metastable high-valent iron species following excitation of aqueous potassium ferrate(VI) by ultraviolet and visible light. Branching from the initially populated ligand-to-metal charge transfer state into independent photophysical and photochemical pathways occurs within tens of picoseconds, with the quantum yield for the generation of reactive Fe(V) species determined by relative rates of the competing intersystem crossing and reverse electron transfer processes. Relaxation of the metal-centered states then occurs within 4 ns, while the formation of metastable Fe(V) species occurs in several steps with time constants of 250 ps and 300 ns. Results here improve the mechanistic understanding of the formation and fate of Fe(V) and Fe(IV), which will accelerate the development of novel advanced oxidation processes for water treatment applications.
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Affiliation(s)
- Cali Antolini
- Department of Chemistry, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
| | - Charles D Spellman
- Department of Civil and Environmental Engineering, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
| | - Christopher J Otolski
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, United States
| | - Gilles Doumy
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, United States
| | - Anne Marie March
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, United States
| | - Donald A Walko
- X-ray Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, United States
| | - Cunming Liu
- X-ray Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, United States
| | - Xiaoyi Zhang
- X-ray Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, United States
| | - Benjamin T Young
- Department of Physical Sciences, Rhode Island College, 600 Mt Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Joseph E Goodwill
- Department of Civil and Environmental Engineering, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
| | - Dugan Hayes
- Department of Chemistry, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
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13
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Sulfur ligated oxoiron(IV) centre in fenton-like reaction: Theoretical postulation and experimental verification. CATAL COMMUN 2022. [DOI: 10.1016/j.catcom.2022.106536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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14
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Dedushko MA, Greiner MB, Downing AN, Coggins M, Kovacs JA. Electronic Structure and Reactivity of Dioxygen-Derived Aliphatic Thiolate-Ligated Fe-Peroxo and Fe(IV) Oxo Compounds. J Am Chem Soc 2022; 144:8515-8528. [PMID: 35522532 DOI: 10.1021/jacs.1c07656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Herein, we examine the electronic and geometric structural properties of O2-derived aliphatic thiolate-ligated Fe-peroxo, Fe-hydroxo, and Fe(IV) oxo compounds. The latter cleaves strong C-H bonds (96 kcal mol-1) on par with the valine C-H bond cleaved by isopencillin N synthase (IPNS). Stopped-flow kinetics studies indicate that the barrier to O2 binding to [FeII(SMe2N4(tren))]+ (3) is extremely low (Ea = 36(2) kJ mol-1), as theoretically predicted for IPNS. Dioxygen binding to 3 is shown to be reversible, and a superoxo intermediate, [FeIII(SMe2N4(tren))(O2)]+ (6), forms in the first 25 ms of the reaction at -40 °C prior to the rate-determining (Ea = 46(2) kJ mol-1) formation of peroxo-bridged [(SMe2N4(tren))Fe(III)]2(μ-O2)2+ (7). A log(kobs) vs log([Fe]) plot for the formation of 7 is consistent with the second-order dependence on iron, and H2O2 assays are consistent with a 2:1 ratio of Fe/H2O2. Peroxo 7 is shown to convert to ferric-hydroxo [FeIII(SMe2N(tren))(OH)]+ (9, g⊥ = 2.24, g∥ = 1.96), the identity of which was determined via its independent synthesis. Rates of the conversion 7 → 9 are shown to be dependent on the X-H bond strength of the H-atom donor, with a kH/kD = 4 when CD3OD is used in place of CH3OH as a solvent. A crystallographically characterized cis thiolate-ligated high-valent iron oxo, [FeIV(O)(SMe2N4(tren))]+ (11), is shown to form en route to hydroxo 9. Electronic structure calculations were shown to be consistent with 11 being an S = 1 Fe(IV)═O with an unusually high νFe-O stretching frequency at 918 cm-1 in line with the extremely short Fe-O bond (1.603(7) Å).
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Affiliation(s)
- Maksym A Dedushko
- Department of Chemistry, University of Washington, Campus Box 351700, Seattle, Washington 98195-1700, United States
| | - Maria B Greiner
- Department of Chemistry, University of Washington, Campus Box 351700, Seattle, Washington 98195-1700, United States
| | - Alexandra N Downing
- Department of Chemistry, University of Washington, Campus Box 351700, Seattle, Washington 98195-1700, United States
| | - Michael Coggins
- Department of Chemistry, University of Washington, Campus Box 351700, Seattle, Washington 98195-1700, United States
| | - Julie A Kovacs
- Department of Chemistry, University of Washington, Campus Box 351700, Seattle, Washington 98195-1700, United States
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15
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Morimoto Y, Itoh S. Hydroxylation of Aliphatic and Aromatic C-H Bonds Catalyzed by Biomimetic Transition-metal Complexes. J SYN ORG CHEM JPN 2022. [DOI: 10.5059/yukigoseikyokaishi.80.506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | - Shinobu Itoh
- Graduate School of Engineering, Osaka University
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16
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Bleher K, Comba P, Gross JH, Josephy T. ESI and tandem MS for mechanistic studies with high-valent transition metal species. Dalton Trans 2022; 51:8625-8639. [DOI: 10.1039/d2dt00809b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The analysis of high-valent metal species has been in the focus of research for over 20 years. Mass spectrometry (MS) represents a technique routinely used for their characterization, in particular...
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17
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Gordon JB, Albert T, Dey A, Sabuncu S, Siegler MA, Bill E, Moënne-Loccoz P, Goldberg DP. A Reactive, Photogenerated High-Spin ( S = 2) Fe IV(O) Complex via O 2 Activation. J Am Chem Soc 2021; 143:21637-21647. [PMID: 34913683 PMCID: PMC9109941 DOI: 10.1021/jacs.1c10051] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Addition of dioxygen at low temperature to the non-heme ferrous complex FeII(Me3TACN)((OSiPh2)2O) (1) in 2-MeTHF produces a peroxo-bridged diferric complex Fe2III(μ-O2)(Me3TACN)2((OSiPh2)2O)2 (2), which was characterized by UV-vis, resonance Raman, and variable field Mössbauer spectroscopies. Illumination of a frozen solution of 2 in THF with white light leads to homolytic O-O bond cleavage and generation of a FeIV(O) complex 4 (ν(Fe=O) = 818 cm-1; δ = 0.22 mm s-1, ΔEQ = 0.23 mm s-1). Variable field Mössbauer spectroscopy measurements show that 4 is a rare example of a high-spin S = 2 FeIV(O) complex and the first synthetic example to be generated directly from O2. Complex 4 is highly reactive, as expected for a high-spin ferryl, and decays rapidly in fluid solution at cryogenic temperatures. This decay process in 2-MeTHF involves C-H cleavage of the solvent. However, the controlled photolysis of 2 in situ with visible light and excess phenol substrate leads to competitive phenol oxidation, via the proposed transient generation of 4 as the active oxidant.
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Affiliation(s)
- Jesse B. Gordon
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
| | - Therese Albert
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Aniruddha Dey
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
| | - Sinan Sabuncu
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Maxime A. Siegler
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
| | - Eckhard Bill
- Department of Inorganic Spectroscopy / Joint Workspace, Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34−36, 45470 Mülheim-an-der-Ruhr, Germany,Corresponding Author: , ,
| | - Pierre Moënne-Loccoz
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239, USA,Corresponding Author: , ,
| | - David P. Goldberg
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA,Corresponding Author: , ,
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18
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Kumar R, Sundararajan M, Rajaraman G. A six-coordinate high-spin Fe IVO species of cucurbit[5]uril: a highly potent catalyst for C-H hydroxylation of methane, if synthesised. Chem Commun (Camb) 2021; 57:13760-13763. [PMID: 34854853 DOI: 10.1039/d1cc06391j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
DFT and ab initio DLPNO-CCSD(T) calculations predict a stable S = 2 six-coordinate FeIVO species with cucurbit[5]uril (CB[5]) as a ligand ([(CB[5])FeIVO(H2O)]2+(1)). The strong oxidising capability of 1 far exceeds even that of metalloenzymes such as sMMOs in activating inert substrates such as methane, setting the stage for a new generation of biomimetic catalysts.
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Affiliation(s)
- Ravi Kumar
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Mahesh Sundararajan
- Theoretical Chemistry Section, Chemistry Division, Bhabha Atomic Research Centre, Mumbai-400085, India.
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
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19
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Heim P, Twamley B, O'Brien J, McDonald AR. Unexpected Intramolecular Phosphite‐Mediated Amide Coupling To Yield 3,5‐Dioxo‐1‐Piperazines. ChemistrySelect 2021. [DOI: 10.1002/slct.202102576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Philipp Heim
- School of Chemistry and CRANN/AMBER Nanoscience Institute Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
| | - Brendan Twamley
- School of Chemistry and CRANN/AMBER Nanoscience Institute Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
| | - John O'Brien
- School of Chemistry and CRANN/AMBER Nanoscience Institute Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
| | - Aidan R. McDonald
- School of Chemistry and CRANN/AMBER Nanoscience Institute Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
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20
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Lee JL, Ross DL, Barman SK, Ziller JW, Borovik AS. C-H Bond Cleavage by Bioinspired Nonheme Metal Complexes. Inorg Chem 2021; 60:13759-13783. [PMID: 34491738 DOI: 10.1021/acs.inorgchem.1c01754] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The functionalization of C-H bonds is one of the most challenging transformations in synthetic chemistry. In biology, these processes are well-known and are achieved with a variety of metalloenzymes, many of which contain a single metal center within their active sites. The most well studied are those with Fe centers, and the emerging experimental data show that high-valent iron oxido species are the intermediates responsible for cleaving the C-H bond. This Forum Article describes the state of this field with an emphasis on nonheme Fe enzymes and current experimental results that provide insights into the properties that make these species capable of C-H bond cleavage. These parameters are also briefly considered in regard to manganese oxido complexes and Cu-containing metalloenzymes. Synthetic iron oxido complexes are discussed to highlight their utility as spectroscopic and mechanistic probes and reagents for C-H bond functionalization. Avenues for future research are also examined.
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Affiliation(s)
- Justin L Lee
- Department of Chemistry, University of California-Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
| | - Dolores L Ross
- Department of Chemistry, University of California-Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
| | - Suman K Barman
- Department of Chemistry, University of California-Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
| | - Joseph W Ziller
- Department of Chemistry, University of California-Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
| | - A S Borovik
- Department of Chemistry, University of California-Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
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21
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Sheng Y, Abelson CS, Prakash J, Draksharapu A, Young VG, Que L. Unmasking Steps in Intramolecular Aromatic Hydroxylation by a Synthetic Nonheme Oxoiron(IV) Complex. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202108309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Yuan Sheng
- Department of Chemistry University of Minnesota Minneapolis MN 55455 USA
| | - Chase S. Abelson
- Department of Chemistry University of Minnesota Minneapolis MN 55455 USA
| | - Jai Prakash
- Department of Chemistry University of Minnesota Minneapolis MN 55455 USA
| | | | - Victor G. Young
- Department of Chemistry University of Minnesota Minneapolis MN 55455 USA
| | - Lawrence Que
- Department of Chemistry University of Minnesota Minneapolis MN 55455 USA
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22
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Sheng Y, Abelson CS, Prakash J, Draksharapu A, Young VG, Que L. Unmasking Steps in Intramolecular Aromatic Hydroxylation by a Synthetic Nonheme Oxoiron(IV) Complex. Angew Chem Int Ed Engl 2021; 60:20991-20998. [PMID: 34292639 PMCID: PMC8429247 DOI: 10.1002/anie.202108309] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Indexed: 11/09/2022]
Abstract
In this study, a methyl group on the classic tetramethylcyclam (TMC) ligand framework is replaced with a benzylic group to form the metastable [FeIV (Osyn )(Bn3MC)]2+ (2-syn; Bn3MC=1-benzyl-4,8,11-trimethyl-1,4,8,11-tetraazacyclotetradecane) species at -40 °C. The decay of 2-syn with time at 25 °C allows the unprecedented monitoring of the steps involved in the intramolecular hydroxylation of the ligand phenyl ring to form the major FeIII -OAr product 3. At the same time, the FeII (Bn3MC)2+ (1) precursor to 2-syn is re-generated in a 1:2 molar ratio relative to 3, accounting for the first time for all the electrons involved and all the Fe species derived from 2-syn as shown in the following balanced equation: 3 [FeIV (O)(LPh )]2+ (2-syn)→2 [FeIII (LOAr )]2+ (3)+[FeII (LPh )]2+ (1)+H2 O. This system thus serves as a paradigm for aryl hydroxylation by FeIV =O oxidants described thus far. It is also observed that 2-syn can be intercepted by certain hydrocarbon substrates, thereby providing a means to assess the relative energetics of aliphatic and aromatic C-H hydroxylation in this system.
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Affiliation(s)
- Yuan Sheng
- Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Chase S Abelson
- Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Jai Prakash
- Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Apparao Draksharapu
- Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Victor G Young
- Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Lawrence Que
- Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA
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23
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Barman SK, Yang MY, Parsell TH, Green MT, Borovik AS. Semiempirical method for examining asynchronicity in metal-oxido-mediated C-H bond activation. Proc Natl Acad Sci U S A 2021; 118:e2108648118. [PMID: 34465626 PMCID: PMC8433561 DOI: 10.1073/pnas.2108648118] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The oxidation of substrates via the cleavage of thermodynamically strong C-H bonds is an essential part of mammalian metabolism. These reactions are predominantly carried out by enzymes that produce high-valent metal-oxido species, which are directly responsible for cleaving the C-H bonds. While much is known about the identity of these transient intermediates, the mechanistic factors that enable metal-oxido species to accomplish such difficult reactions are still incomplete. For synthetic metal-oxido species, C-H bond cleavage is often mechanistically described as synchronous, proton-coupled electron transfer (PCET). However, data have emerged that suggest that the basicity of the M-oxido unit is the key determinant in achieving enzymatic function, thus requiring alternative mechanisms whereby proton transfer (PT) has a more dominant role than electron transfer (ET). To bridge this knowledge gap, the reactivity of a monomeric MnIV-oxido complex with a series of external substrates was studied, resulting in a spread of over 104 in their second-order rate constants that tracked with the acidity of the C-H bonds. Mechanisms that included either synchronous PCET or rate-limiting PT, followed by ET, did not explain our results, which led to a proposed PCET mechanism with asynchronous transition states that are dominated by PT. To support this premise, we report a semiempirical free energy analysis that can predict the relative contributions of PT and ET for a given set of substrates. These findings underscore why the basicity of M-oxido units needs to be considered in C-H functionalization.
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Affiliation(s)
- Suman K Barman
- Department of Chemistry, University of California Irvine, CA 92697;
| | - Meng-Yin Yang
- Department of Chemistry, University of California Irvine, CA 92697
| | | | - Michael T Green
- Department of Chemistry, University of California Irvine, CA 92697;
- Department of Molecular Biosciences and Biochemistry, University of California Irvine, CA 92697
| | - A S Borovik
- Department of Chemistry, University of California Irvine, CA 92697;
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24
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Crossland PM, Guo Y, Que L. Spontaneous Formation of an Fe/Mn Diamond Core: Models for the Fe/Mn Sites in Class 1c Ribonucleotide Reductases. Inorg Chem 2021; 60:8710-8721. [PMID: 34110143 PMCID: PMC8997264 DOI: 10.1021/acs.inorgchem.1c00684] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A handful of oxygen-activating enzymes has recently been found to contain Fe/Mn active sites, like Class 1c ribonucleotide reductases and R2-like ligand-binding oxidase, which are closely related to their better characterized diiron cousins. These enzymes are proposed to form high-valent intermediates with Fe-O-Mn cores. Herein, we report the first examples of synthetic Fe/Mn complexes that mimic doubly bridged intermediates proposed for enzymatic oxygen activation. Fe K-edge extended X-ray absorption fine structure (EXAFS) analysis has been used to characterize the structures of each of these compounds. Linear compounds accurately model the Fe···Mn distances found in Fe/Mn proteins in their resting states, and doubly bridged diamond core compounds accurately model the distances found in high-valent biological intermediates. Unlike their diiron analogues, the paramagnetic nature of Fe/Mn compounds can be analyzed by EPR, revealing S = 1/2 signals that reflect antiferromagnetic coupling between the high-spin Fe(III) and Mn(III) units of heterobimetallic centers. These compounds undergo electron transfer with various ferrocenes, linear compounds being capable of oxidizing diacetyl ferrocene, a weak reductant, and diamond core compounds being capable of oxidizing acetyl ferrocene. Diamond core compounds can also perform HAT reactions from substrates with X-H bonds with bond dissociation free energies (BDFEs) up to 75 kcal/mol and are capable of oxidizing TEMPO-H at rates of 0.32-0.37 M-1 s-1, which are comparable to those reported for some mononuclear FeIII-OH and MnIII-OH compounds. However, such reactivity is not observed for the corresponding diiron compounds, a difference that Nature may have taken advantage of in evolving enzymes with heterobimetallic active sites.
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Affiliation(s)
- Patrick M. Crossland
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
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25
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Møller MS, Kongsted J, McKenzie CJ. Preparation of organocobalt(iii) complexes via O 2 activation. Dalton Trans 2021; 50:4819-4829. [PMID: 33877179 DOI: 10.1039/d1dt00563d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The coupling of selective C-H activation with O2 activation is an important goal for organic synthesis. New experimental and computational results, along with the results from experimental work accumulated over many decades, now unequivocally link O2 activation with C-H activation by the classic Co(salen) complexes. A common holistic mechanistic framework can rationalise the formation of ostensibly diverse peroxo, superoxo, organo and alkoxide complexes of CoIII(salen). DFT calculations show that cobalt(iii)superoxo, dicobalt(iii)peroxo and cobalt(iii)hydroperoxo complexes are all viable intermediates as participants in hydrogen atom transfer reactions, whereas a Co(iv)oxo intermediate is unlikely. The reaction conditions will determine the pathway followed and all pathways are initiated through the initial formation of a superoxo complex, CoIII(salen)(O2˙)(MeOH) (EPR: g = 2.025, A = 19 G). Organo and alkoxide ligands are derived from solvent media and the trends in reactivity reveal that combination of the pKa and BDE of the C-H of the respective solvent substrates are important. These data explain why landmark, structurally characterized, μ2-η1,η2-peroxide and η1-superoxide Co(salen)-O2 adducts were predominantly isolated from solvents with high C-H pKa values (DMSO, DMF, DMA).
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Affiliation(s)
- Mads Sondrup Møller
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.
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26
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Warm K, Paskin A, Kuhlmann U, Bill E, Swart M, Haumann M, Dau H, Hildebrandt P, Ray K. A Pseudotetrahedral Terminal Oxoiron(IV) Complex: Mechanistic Promiscuity in C-H Bond Oxidation Reactions. Angew Chem Int Ed Engl 2021; 60:6752-6756. [PMID: 33348460 PMCID: PMC7985879 DOI: 10.1002/anie.202015896] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Indexed: 11/12/2022]
Abstract
S=2 oxoiron(IV) species act as reactive intermediates in the catalytic cycle of nonheme iron oxygenases. The few available synthetic S=2 FeIV =O complexes known to date are often limited to trigonal bipyramidal and very rarely to octahedral geometries. Herein we describe the generation and characterization of an S=2 pseudotetrahedral FeIV =O complex 2 supported by the sterically demanding 1,4,7-tri-tert-butyl-1,4,7-triazacyclononane ligand. Complex 2 is a very potent oxidant in hydrogen atom abstraction (HAA) reactions with large non-classical deuterium kinetic isotope effects, suggesting hydrogen tunneling contributions. For sterically encumbered substrates, direct HAA is impeded and an alternative oxidative asynchronous proton-coupled electron transfer mechanism prevails, which is unique within the nonheme oxoiron community. The high reactivity and the similar spectroscopic parameters make 2 one of the best electronic and functional models for a biological oxoiron(IV) intermediate of taurine dioxygenase (TauD-J).
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Affiliation(s)
- Katrin Warm
- Institut für ChemieHumboldt-Universität zu BerlinBrook-Taylor-Str. 212489BerlinGermany
| | - Alice Paskin
- Institut für ChemieHumboldt-Universität zu BerlinBrook-Taylor-Str. 212489BerlinGermany
| | - Uwe Kuhlmann
- Institut für ChemieTechnische Universität Berlin, Fakultät IIStraße des 17. Juni 13510623BerlinGermany
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion (CEC)Stiftstraße 34–3645470MülheimGermany
| | - Marcel Swart
- Institut de Química Computacional i CatàlisiUniversitat de GironaCampus Montilivi (Ciències)Maria Aurèlia Capmany i Farnés, 6917003GironaSpain
- ICREAPg. Lluís Companys 2308010BarcelonaSpain
| | - Michael Haumann
- Institut für PhysikFreie Universität BerlinArnimallee 1414195BerlinGermany
| | - Holger Dau
- Institut für PhysikFreie Universität BerlinArnimallee 1414195BerlinGermany
| | - Peter Hildebrandt
- Institut für ChemieTechnische Universität Berlin, Fakultät IIStraße des 17. Juni 13510623BerlinGermany
| | - Kallol Ray
- Institut für ChemieHumboldt-Universität zu BerlinBrook-Taylor-Str. 212489BerlinGermany
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27
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Warm K, Paskin A, Kuhlmann U, Bill E, Swart M, Haumann M, Dau H, Hildebrandt P, Ray K. A Pseudotetrahedral Terminal Oxoiron(IV) Complex: Mechanistic Promiscuity in C−H Bond Oxidation Reactions. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202015896] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Katrin Warm
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Str. 2 12489 Berlin Germany
| | - Alice Paskin
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Str. 2 12489 Berlin Germany
| | - Uwe Kuhlmann
- Institut für Chemie Technische Universität Berlin, Fakultät II Straße des 17. Juni 135 10623 Berlin Germany
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion (CEC) Stiftstraße 34–36 45470 Mülheim Germany
| | - Marcel Swart
- Institut de Química Computacional i Catàlisi Universitat de Girona Campus Montilivi (Ciències) Maria Aurèlia Capmany i Farnés, 69 17003 Girona Spain
- ICREA Pg. Lluís Companys 23 08010 Barcelona Spain
| | - Michael Haumann
- Institut für Physik Freie Universität Berlin Arnimallee 14 14195 Berlin Germany
| | - Holger Dau
- Institut für Physik Freie Universität Berlin Arnimallee 14 14195 Berlin Germany
| | - Peter Hildebrandt
- Institut für Chemie Technische Universität Berlin, Fakultät II Straße des 17. Juni 135 10623 Berlin Germany
| | - Kallol Ray
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Str. 2 12489 Berlin Germany
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28
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Karuppasamy P, Thiruppathi D, Sundar JV, Ganesan M, Rajendran T, Meena SS, Rajagopal S, Sivasubramanian VK, Rajapandian V. Insight into structural aspects and study of reaction kinetics of model [oxo(salen)iron(IV)] complexes with dipeptides. Polyhedron 2021. [DOI: 10.1016/j.poly.2020.114952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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29
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Schneider JE, Goetz MK, Anderson JS. Statistical analysis of C-H activation by oxo complexes supports diverse thermodynamic control over reactivity. Chem Sci 2021; 12:4173-4183. [PMID: 34163690 PMCID: PMC8179456 DOI: 10.1039/d0sc06058e] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/28/2021] [Indexed: 01/29/2023] Open
Abstract
Transition metal oxo species are key intermediates for the activation of strong C-H bonds. As such, there has been interest in understanding which structural or electronic parameters of metal oxo complexes determine their reactivity. Factors such as ground state thermodynamics, spin state, steric environment, oxygen radical character, and asynchronicity have all been cited as key contributors, yet there is no consensus on when each of these parameters is significant or the relative magnitude of their effects. Herein, we present a thorough statistical analysis of parameters that have been proposed to influence transition metal oxo mediated C-H activation. We used density functional theory (DFT) to compute parameters for transition metal oxo complexes and analyzed their ability to explain and predict an extensive data set of experimentally determined reaction barriers. We found that, in general, only thermodynamic parameters play a statistically significant role. Notably, however, there are independent and significant contributions from the oxidation potential and basicity of the oxo complexes which suggest a more complicated thermodynamic picture than what has been shown previously.
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Affiliation(s)
| | - McKenna K Goetz
- Department of Chemistry, University of Chicago Chicago IL 60637 USA
| | - John S Anderson
- Department of Chemistry, University of Chicago Chicago IL 60637 USA
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30
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Lin J, Sun Q, Sun W. A DFT study on the C-H oxidation reactivity of Fe(iv)-oxo species with N4/N5 ligands derived from l-proline. RSC Adv 2021; 11:2293-2297. [PMID: 35424189 PMCID: PMC8693871 DOI: 10.1039/d0ra08496d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 12/08/2020] [Indexed: 11/26/2022] Open
Abstract
The hydroxylation of hexane by two FeIVO complexes bearing a pentadentate ligand (N5, Pro3Py) and a tetradentate ligand (N4, Pro2PyBn) derived from l-proline was studied by DFT calculations. Theoretical results predict that both FeIVO complexes hold triplet ground states. The hydrogen atom abstraction (HAA) processes by both FeIVO species proceed through a two-state reactivity, thus indicating that HAA occurs via a low-barrier quintet surface. Beyond the conventional rebound step, the dissociation path is also calculated and is found to potentially occur after HAA.
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Affiliation(s)
- Jin Lin
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Center for Excellence in Molecular Synthesis, Suzhou Research Institute of LICP, Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences Lanzhou 730000 P. R. China
- University of Chinese Academy of Sciences Beijing 100049 P. R. China
| | - Qiangsheng Sun
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Center for Excellence in Molecular Synthesis, Suzhou Research Institute of LICP, Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences Lanzhou 730000 P. R. China
| | - Wei Sun
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Center for Excellence in Molecular Synthesis, Suzhou Research Institute of LICP, Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences Lanzhou 730000 P. R. China
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31
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Fields K, Barngrover BM, Gary JB. Computational Investigation of the Preferred Binding Modes of N 2O in Group 8 Metal Complexes. Inorg Chem 2020; 59:18314-18318. [DOI: 10.1021/acs.inorgchem.0c02903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kylie Fields
- Department of Chemistry and Biochemistry, Stephen F. Austin State University, P.O. Box 13006 SFA Station, Nacogdoches, Texas 75962-3006, United States
| | - Brian M. Barngrover
- Department of Chemistry and Biochemistry, Stephen F. Austin State University, P.O. Box 13006 SFA Station, Nacogdoches, Texas 75962-3006, United States
| | - J. Brannon Gary
- Department of Chemistry and Biochemistry, Stephen F. Austin State University, P.O. Box 13006 SFA Station, Nacogdoches, Texas 75962-3006, United States
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32
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Prakash O, Chábera P, Rosemann NW, Huang P, Häggström L, Ericsson T, Strand D, Persson P, Bendix J, Lomoth R, Wärnmark K. A Stable Homoleptic Organometallic Iron(IV) Complex. Chemistry 2020; 26:12728-12732. [PMID: 32369645 PMCID: PMC7590184 DOI: 10.1002/chem.202002158] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Indexed: 11/08/2022]
Abstract
A homoleptic organometallic FeIV complex that is stable in both solution and in the solid state at ambient conditions has been synthesized and isolated as [Fe(phtmeimb)2 ](PF6 )2 (phtmeimb=[phenyl(tris(3-methylimidazolin-2-ylidene))borate]- ). This FeIV N-heterocyclic carbene (NHC) complex was characterized by 1 H NMR, HR-MS, elemental analysis, scXRD analysis, electrochemistry, Mößbauer spectroscopy, and magnetic susceptibility. The two latter techniques unequivocally demonstrate that [Fe(phtmeimb)2 ](PF6 )2 is a triplet FeIV low-spin S=1 complex in the ground state, in agreement with quantum chemical calculations. The electronic absorption spectrum of [Fe(phtmeimb)2 ](PF6 )2 in acetonitrile shows an intense absorption band in the red and near IR, due to LMCT (ligand-to-metal charge transfer) excitation. For the first time the excited state dynamics of a FeIV complex was studied and revealed a ≈0.8 ps lifetime of the 3 LMCT excited state of [Fe(phtmeimb)2 ](PF6 )2 in acetonitrile.
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Affiliation(s)
- Om Prakash
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, Lund, 22100, Sweden
| | - Pavel Chábera
- Division of Chemical Physics, Department of Chemistry, Lund University, Box 124, Lund, 22100, Sweden
| | - Nils W Rosemann
- Division of Chemical Physics, Department of Chemistry, Lund University, Box 124, Lund, 22100, Sweden
| | - Ping Huang
- Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, Uppsala, 75120, Sweden
| | - Lennart Häggström
- Department of Physics, Ångström Laboratory, Uppsala University, Box 528, Uppsala, 751 21, Sweden
| | - Tore Ericsson
- Department of Physics, Ångström Laboratory, Uppsala University, Box 528, Uppsala, 751 21, Sweden
| | - Daniel Strand
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, Lund, 22100, Sweden
| | - Petter Persson
- Theoretical Chemistry Division, Department of Chemistry, Lund University, Box 124, Lund, 22100, Sweden
| | - Jesper Bendix
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen, Denmark
| | - Reiner Lomoth
- Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, Uppsala, 75120, Sweden
| | - Kenneth Wärnmark
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, Lund, 22100, Sweden
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33
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Larson VA, Battistella B, Ray K, Lehnert N, Nam W. Iron and manganese oxo complexes, oxo wall and beyond. Nat Rev Chem 2020; 4:404-419. [PMID: 37127969 DOI: 10.1038/s41570-020-0197-9] [Citation(s) in RCA: 139] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/15/2020] [Indexed: 11/09/2022]
Abstract
High-valent metal-oxo species with multiply-bonded M-O groups have been proposed as key intermediates in many biological and abiological catalytic oxidation reactions. These intermediates are implicated as active oxidants in alkane hydroxylation, olefin epoxidation and other oxidation reactions. For example, [FeivO(porphyrinato•-)]+ cofactors bearing π-radical porphyrinato•- ligands oxidize organic substrates in cytochrome P450 enzymes, which are common to many life forms. Likewise, high-valent Mn-oxo species are active for H2O oxidation in photosystem II. The chemistry of these native reactive species has inspired chemists to prepare highly oxidized transition-metal complexes as functional mimics. Although many synthetic Fe-O and Mn-O complexes now exist, the analogous oxo complexes of the late transition metals (groups 9-11) are rare. Indeed, late-transition-metal-oxo complexes of tetragonal (fourfold) symmetry should be electronically unstable, a rule commonly referred to as the 'oxo wall'. A few late metal-oxos have been prepared by targeting other symmetries or unusual spin states. These complexes have been studied using spectroscopic and theoretical methods. This Review describes mononuclear non-haem Fe-O and Mn-O species, the nature of the oxo wall and recent advances in the preparation of oxo complexes of Co, Ni and Cu beyond the oxo wall.
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34
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Oswald VF, Lee JL, Biswas S, Weitz AC, Mittra K, Fan R, Li J, Zhao J, Hu MY, Alp EE, Bominaar EL, Guo Y, Green MT, Hendrich MP, Borovik AS. Effects of Noncovalent Interactions on High-Spin Fe(IV)-Oxido Complexes. J Am Chem Soc 2020; 142:11804-11817. [PMID: 32489096 DOI: 10.1021/jacs.0c03085] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
High-valent nonheme FeIV-oxido species are key intermediates in biological oxidation, and their properties are proposed to be influenced by the unique microenvironments present in protein active sites. Microenvironments are regulated by noncovalent interactions, such as hydrogen bonds (H-bonds) and electrostatic interactions; however, there is little quantitative information about how these interactions affect crucial properties of high valent metal-oxido complexes. To address this knowledge gap, we introduced a series of FeIV-oxido complexes that have the same S = 2 spin ground state as those found in nature and then systematically probed the effects of noncovalent interactions on their electronic, structural, and vibrational properties. The key design feature that provides access to these complexes is the new tripodal ligand [poat]3-, which contains phosphinic amido groups. An important structural aspect of [FeIVpoat(O)]- is the inclusion of an auxiliary site capable of binding a Lewis acid (LAII); we used this unique feature to further modulate the electrostatic environment around the Fe-oxido unit. Experimentally, studies confirmed that H-bonds and LAII s can interact directly with the oxido ligand in FeIV-oxido complexes, which weakens the Fe═O bond and has an impact on the electronic structure. We found that relatively large vibrational changes in the Fe-oxido unit correlate with small structural changes that could be difficult to measure, especially within a protein active site. Our work demonstrates the important role of noncovalent interactions on the properties of metal complexes, and that these interactions need to be considered when developing effective oxidants.
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Affiliation(s)
- Victoria F Oswald
- Department of Chemistry, 1102 Natural Sciences II, University of California at Irvine, Irvine, California 92697, United States
| | - Justin L Lee
- Department of Chemistry, 1102 Natural Sciences II, University of California at Irvine, Irvine, California 92697, United States
| | - Saborni Biswas
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Andrew C Weitz
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Kaustuv Mittra
- Department of Molecular Biosciences and Biochemistry, University of California at Irvine, Irvine, California 92697, United States
| | - Ruixi Fan
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Jikun Li
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Jiyong Zhao
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Michael Y Hu
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Esen E Alp
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Emile L Bominaar
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Michael T Green
- Department of Chemistry, 1102 Natural Sciences II, University of California at Irvine, Irvine, California 92697, United States.,Department of Molecular Biosciences and Biochemistry, University of California at Irvine, Irvine, California 92697, United States
| | - Michael P Hendrich
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - A S Borovik
- Department of Chemistry, 1102 Natural Sciences II, University of California at Irvine, Irvine, California 92697, United States
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35
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Hüppe HM, Keisers K, Fink F, Mürtz SD, Hoffmann A, Iffland L, Apfel U, Herres‐Pawlis S. Catalytically Active Iron(IV)oxo Species Based on a Bis(pyridinyl)phenanthrolinylmethane. Isr J Chem 2020. [DOI: 10.1002/ijch.202000009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Henrika M. Hüppe
- Institute of Inorganic Chemistry RWTH Aachen University Landoltweg 1a 52074 Aachen Germany
| | - Kristina Keisers
- Institute of Inorganic Chemistry RWTH Aachen University Landoltweg 1a 52074 Aachen Germany
| | - Fabian Fink
- Institute of Inorganic Chemistry RWTH Aachen University Landoltweg 1a 52074 Aachen Germany
| | - Sonja D. Mürtz
- Institute of Inorganic Chemistry RWTH Aachen University Landoltweg 1a 52074 Aachen Germany
| | - Alexander Hoffmann
- Institute of Inorganic Chemistry RWTH Aachen University Landoltweg 1a 52074 Aachen Germany
| | - Linda Iffland
- Inorganic Chemistry I Ruhr-Universität Bochum Universitätsstraße 150 44801 Bochum Germany
| | - Ulf‐Peter Apfel
- Inorganic Chemistry I Ruhr-Universität Bochum Universitätsstraße 150 44801 Bochum Germany
- Fraunhofer UMSICHT Osterfelder Straße 3 46047 Oberhausen Germany
| | - Sonja Herres‐Pawlis
- Institute of Inorganic Chemistry RWTH Aachen University Landoltweg 1a 52074 Aachen Germany
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36
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The oxidation of cyclo-olefin by the S = 2 ground-state complex [Fe IV(O)(TQA)(NCMe)] 2. J Biol Inorg Chem 2020; 25:371-382. [PMID: 32133579 DOI: 10.1007/s00775-020-01768-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 02/16/2020] [Indexed: 10/24/2022]
Abstract
Density functional theory calculation is used to investigate the oxidation of cyclo-olefin (cyclobutene, cyclopentene, cyclohexene, cycloheptene, and cyclo-octene) by the complex [FeIV(O)(TQA)(NCMe)]2+, which has S = 2 ground state, and the effect of electronic factors and steric hindrance on reaction barriers. Our results suggest that the oxo-iron(IV) complex can oxidise C-H and C = C bonds via a single-state mechanism, and two different ways of electron transport exist. The energy barriers initially decrease with increasing substrate size, and the trend then reverses. Comparison of the energy barrier in different systems reveals that except for the reaction between [FeIV(O)(TQA)(NCMe)]2+ and cycloheptene, oxo-iron(IV) complexes prefer epoxidation to hydroxylation. However, the hydroxylated product is more stable than the corresponding epoxidated product. This result indicates that the products of epoxidation tend to decompose first. The energy barrier of hydroxylation and epoxidation originates from the balance of orbital interaction and Pauli repulsion from the equatorial ligand and protons on the approaching substrate. In this regard, we calculate the weak interaction between two fragments (oxo-iron complex and substrates) using the independent gradient model and drawn the corresponding 3D isosurface representations of reactants.
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37
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Comba P, Faltermeier D, Krieg S, Martin B, Rajaraman G. Spin state and reactivity of iron(iv)oxido complexes with tetradentate bispidine ligands. Dalton Trans 2020; 49:2888-2894. [DOI: 10.1039/c9dt04578c] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The iron(iv)oxido complex [(bispidine)FeIVO(Cl)]+is shown by experiment and high-level DLPNO-CCSD(T) quantum-chemical calculations to be an extremely short-lived and very reactive intermediate-spin (S= 1) species.
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Affiliation(s)
- Peter Comba
- Universität Heidelberg
- Anorganisch-Chemisches Institut
- D-69120 Heidelberg
- Germany
- Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR)
| | - Dieter Faltermeier
- Universität Heidelberg
- Anorganisch-Chemisches Institut
- D-69120 Heidelberg
- Germany
- Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR)
| | - Saskia Krieg
- Universität Heidelberg
- Anorganisch-Chemisches Institut
- D-69120 Heidelberg
- Germany
| | - Bodo Martin
- Universität Heidelberg
- Anorganisch-Chemisches Institut
- D-69120 Heidelberg
- Germany
- Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR)
| | - Gopalan Rajaraman
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai-400076
- India
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38
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Mondal S, Naik PK, Adha JK, Kar S. Synthesis, characterization, and reactivities of high valent metal–corrole (M = Cr, Mn, and Fe) complexes. Coord Chem Rev 2019. [DOI: 10.1016/j.ccr.2019.213043] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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39
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Iovan DA, Jia S, Chang CJ. Inorganic Chemistry Approaches to Activity-Based Sensing: From Metal Sensors to Bioorthogonal Metal Chemistry. Inorg Chem 2019; 58:13546-13560. [PMID: 31185541 PMCID: PMC8544879 DOI: 10.1021/acs.inorgchem.9b01221] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The complex network of chemical processes that sustain life motivates the development of new synthetic tools to decipher biological mechanisms of action at a molecular level. In this context, fluorescent and related optical probes have emerged as useful chemical reagents for monitoring small-molecule and metal signals in biological systems, enabling visualization of dynamic cellular events with spatial and temporal resolution. In particular, metals occupy a central role in this field as analytes in their own right, while also being leveraged for their unique biocompatible reactivity with small-molecule substrates. This Viewpoint highlights the use of inorganic chemistry principles to develop activity-based sensing platforms mediated by metal reactivity, spanning indicators for metal detection to metal-based reagents for bioorthogonal tracking, and manipulation of small and large biomolecules, illustrating the privileged roles of metals at the interface of chemistry and biology.
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Affiliation(s)
- Diana A. Iovan
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Howard Hughes Medical Institute, University of California, Berkeley, California 94720, United States
| | - Shang Jia
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Christopher J. Chang
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, United States
- Howard Hughes Medical Institute, University of California, Berkeley, California 94720, United States
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40
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Mukherjee G, Alili A, Barman P, Kumar D, Sastri CV, de Visser SP. Interplay Between Steric and Electronic Effects: A Joint Spectroscopy and Computational Study of Nonheme Iron(IV)-Oxo Complexes. Chemistry 2019; 25:5086-5098. [PMID: 30720909 DOI: 10.1002/chem.201806430] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Indexed: 01/05/2023]
Abstract
Iron is an essential element in nonheme enzymes that plays a crucial role in many vital oxidative transformations and metabolic reactions in the human body. Many of those reactions are regio- and stereospecific and it is believed that the selectivity is guided by second-coordination sphere effects in the protein. Here, results are shown of a few engineered biomimetic ligand frameworks based on the N4Py (N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine) scaffold and the second-coordination sphere effects are studied. For the first time, selective substitutions in the ligand framework have been shown to tune the catalytic properties of the iron(IV)-oxo complexes by regulating the steric and electronic factors. In particular, a better positioning of the oxidant and substrate in the rate-determining transition state lowers the reaction barriers. Therefore, an optimum balance between steric and electronic factors mediates the ideal positioning of oxidant and substrate in the rate-determining transition state that affects the reactivity of high-valent reaction intermediates.
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Affiliation(s)
- Gourab Mukherjee
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India
| | - Aligulu Alili
- The Manchester Institute of Biotechnology and School of Chemical, Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Prasenjit Barman
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India
| | - Devesh Kumar
- Department of Applied Physics, Babasaheb Bhimrao Ambedkar University, School for Physical Sciences, Vidya Vihar, Rae Bareilly Road, Lucknow, 226025, UP, India
| | - Chivukula V Sastri
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India
| | - Sam P de Visser
- The Manchester Institute of Biotechnology and School of Chemical, Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
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41
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Iron(III)–salen ion catalyzed s-oxidation of l-cysteine and s-alkyl-l-cysteines by H2O2: Spectral, kinetic and electrochemical study. Polyhedron 2019. [DOI: 10.1016/j.poly.2018.11.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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42
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Guo M, Corona T, Ray K, Nam W. Heme and Nonheme High-Valent Iron and Manganese Oxo Cores in Biological and Abiological Oxidation Reactions. ACS CENTRAL SCIENCE 2019; 5:13-28. [PMID: 30693322 PMCID: PMC6346628 DOI: 10.1021/acscentsci.8b00698] [Citation(s) in RCA: 226] [Impact Index Per Article: 45.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Indexed: 05/23/2023]
Abstract
Utilization of O2 as an abundant and environmentally benign oxidant is of great interest in the design of bioinspired synthetic catalytic oxidation systems. Metalloenzymes activate O2 by employing earth-abundant metals and exhibit diverse reactivities in oxidation reactions, including epoxidation of olefins, functionalization of alkane C-H bonds, arene hydroxylation, and syn-dihydroxylation of arenes. Metal-oxo species are proposed as reactive intermediates in these reactions. A number of biomimetic metal-oxo complexes have been synthesized in recent years by activating O2 or using artificial oxidants at iron and manganese centers supported on heme or nonheme-type ligand environments. Detailed reactivity studies together with spectroscopy and theory have helped us understand how the reactivities of these metal-oxygen intermediates are controlled by the electronic and steric properties of the metal centers. These studies have provided important insights into biological reactions, which have contributed to the design of biologically inspired oxidation catalysts containing earth-abundant metals like iron and manganese. In this Outlook article, we survey a few examples of these advances with particular emphasis in each case on the interplay of catalyst design and our understanding of metalloenzyme structure and function.
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Affiliation(s)
- Mian Guo
- Department
of Chemistry and Nano Science, Ewha Womans
University, Seoul 03760, Korea
| | - Teresa Corona
- Department
of Chemistry, Humboldt-Universität
zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Kallol Ray
- Department
of Chemistry, Humboldt-Universität
zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Wonwoo Nam
- Department
of Chemistry and Nano Science, Ewha Womans
University, Seoul 03760, Korea
- State
Key Laboratory for Oxo Synthesis and Selective Oxidation, Center for
Excellence in Molecular Synthesis, Suzhou
Research Institute of LICP, Lanzhou Institute of Chemical Physics
(LICP), Chinese Academy of Sciences, Lanzhou, 730000, P. R.
China
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43
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Singh R, Ganguly G, Malinkin SO, Demeshko S, Meyer F, Nordlander E, Paine TK. A Mononuclear Nonheme Iron(IV)-Oxo Complex of a Substituted N4Py Ligand: Effect of Ligand Field on Oxygen Atom Transfer and C–H Bond Cleavage Reactivity. Inorg Chem 2019; 58:1862-1876. [DOI: 10.1021/acs.inorgchem.8b02577] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Reena Singh
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Gaurab Ganguly
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Sergey O. Malinkin
- Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-22100 Lund, Sweden
| | - Serhiy Demeshko
- Universität
Göttingen, Institut für Anorganische Chemie, Tammanstrasse 4, D-37077 Göttingen, Germany
| | - Franc Meyer
- Universität
Göttingen, Institut für Anorganische Chemie, Tammanstrasse 4, D-37077 Göttingen, Germany
| | - Ebbe Nordlander
- Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-22100 Lund, Sweden
| | - Tapan Kanti Paine
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
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44
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Harmalkar DS, Santosh G, Shetgaonkar SB, Sankaralingam M, Dhuri SN. A putative heme manganese(v)-oxo species in the C–H activation and epoxidation reactions in an aqueous buffer. NEW J CHEM 2019. [DOI: 10.1039/c9nj01381d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Synthesis and reactivity studies of manganese(v)-oxo species in the C–H activation of alkyl hydrocarbons and epoxidation of cyclohexene in aqueous conditions are investigated.
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Affiliation(s)
| | - G. Santosh
- School of Chemical Sciences
- Goa University
- Panaji
- India
- Divison of Chemistry
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45
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Chen L, Su XJ, Jurss JW. Selective Alkane C–H Bond Oxidation Catalyzed by a Non-Heme Iron Complex Featuring a Robust Tetradentate Ligand. Organometallics 2018. [DOI: 10.1021/acs.organomet.8b00611] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lizhu Chen
- Department of Chemistry and Biochemistry, University of Mississippi, University, Mississippi 38677, United States
| | - Xiao-Jun Su
- Department of Chemistry and Biochemistry, University of Mississippi, University, Mississippi 38677, United States
| | - Jonah W. Jurss
- Department of Chemistry and Biochemistry, University of Mississippi, University, Mississippi 38677, United States
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46
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Cyclic Voltammetric DNA Binding Investigations on Some Anticancer Potential Metal Complexes: a Review. Appl Biochem Biotechnol 2018; 186:1090-1110. [DOI: 10.1007/s12010-018-2818-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 06/10/2018] [Indexed: 12/27/2022]
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47
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Lyakin OY, Zima AM, Tkachenko NV, Bryliakov KP, Talsi EP. Direct Evaluation of the Reactivity of Nonheme Iron(V)–Oxo Intermediates toward Arenes. ACS Catal 2018. [DOI: 10.1021/acscatal.8b00661] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Oleg Y. Lyakin
- Boreskov Institute of Catalysis, Pr. Lavrentieva 5, Novosibirsk 630090, Russian Federation
- Novosibirsk State University, Pirogova 2, Novosibirsk 630090, Russian Federation
| | - Alexandra M. Zima
- Boreskov Institute of Catalysis, Pr. Lavrentieva 5, Novosibirsk 630090, Russian Federation
- Novosibirsk State University, Pirogova 2, Novosibirsk 630090, Russian Federation
| | - Nikolay V. Tkachenko
- Boreskov Institute of Catalysis, Pr. Lavrentieva 5, Novosibirsk 630090, Russian Federation
- Novosibirsk State University, Pirogova 2, Novosibirsk 630090, Russian Federation
| | - Konstantin P. Bryliakov
- Boreskov Institute of Catalysis, Pr. Lavrentieva 5, Novosibirsk 630090, Russian Federation
- Novosibirsk State University, Pirogova 2, Novosibirsk 630090, Russian Federation
| | - Evgenii P. Talsi
- Boreskov Institute of Catalysis, Pr. Lavrentieva 5, Novosibirsk 630090, Russian Federation
- Novosibirsk State University, Pirogova 2, Novosibirsk 630090, Russian Federation
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48
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Sizing up a supercharged ferryl. Proc Natl Acad Sci U S A 2018; 115:4532-4534. [PMID: 29666275 DOI: 10.1073/pnas.1804490115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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49
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Kirkland JK, Khan SN, Casale B, Miliordos E, Vogiatzis KD. Ligand field effects on the ground and excited states of reactive FeO2+ species. Phys Chem Chem Phys 2018; 20:28786-28795. [DOI: 10.1039/c8cp05372c] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Multiconfigurational quantum chemical calculations on bare and representative ligated iron oxide dicationic species suggest that weak ligand fields promote more reactive channels, whereas strong ligand fields stabilize the less reactive iron-oxo structure.
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Affiliation(s)
| | - Shahriar N. Khan
- Department of Chemistry and Biochemistry
- Auburn University
- Auburn
- USA
| | - Bryan Casale
- Department of Chemistry
- University of Tennessee
- Knoxville
- USA
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50
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de Ruiter G, Carsch KM, Takase MK, Agapie T. Selectivity of C-H versus C-F Bond Oxygenation by Homo- and Heterometallic Fe 4 , Fe 3 Mn, and Mn 4 Clusters. Chemistry 2017; 23:10744-10748. [PMID: 28658508 PMCID: PMC5659184 DOI: 10.1002/chem.201702302] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Indexed: 02/03/2023]
Abstract
A series of tetranuclear [LM3 (HFArPz)3 OM'][OTf]2 (M, M'=Fe or Mn) clusters that displays 3-(2-fluorophenyl)pyrazolate (HFArPz) as bridging ligand is reported. With these complexes, manganese was demonstrated to facilitate C(sp2 )-F bond oxygenation via a putative terminal metal-oxo species. Moreover, the presence of both ortho C(sp2 )-H and C(sp2 )-F bonds in proximity of the apical metal center provided an opportunity to investigate the selectivity of intramolecular C(sp2 )-X bond oxygenation (X=H or F) in these isostructural compounds. With iron as the apical metal center, (M'=Fe) C(sp2 )-F bond oxygenation occur almost exclusively, whereas with manganese (M'=Mn), the opposite reactivity is preferred.
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Affiliation(s)
- Graham de Ruiter
- Department of Chemistry and Chemical Engineering, California Institute of Technology; MC 127-72, Pasadena, California, 91125, USA
| | - Kurtis M Carsch
- Department of Chemistry and Chemical Engineering, California Institute of Technology; MC 127-72, Pasadena, California, 91125, USA
| | - Michael K Takase
- Department of Chemistry and Chemical Engineering, California Institute of Technology; MC 127-72, Pasadena, California, 91125, USA
| | - Theodor Agapie
- Department of Chemistry and Chemical Engineering, California Institute of Technology; MC 127-72, Pasadena, California, 91125, USA
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