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Thomas J, Mokkawes T, Senft L, Dey A, Gordon JB, Ivanovic-Burmazovic I, de Visser SP, Goldberg DP. Axial Ligation Impedes Proton-Coupled Electron-Transfer Reactivity of a Synthetic Compound-I Analogue. J Am Chem Soc 2024; 146:12338-12354. [PMID: 38669456 DOI: 10.1021/jacs.3c08950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2024]
Abstract
The nature of the axial ligand in high-valent iron-oxo heme enzyme intermediates and related synthetic catalysts is a critical structural element for controlling proton-coupled electron-transfer (PCET) reactivity of these species. Herein, we describe the generation and characterization of three new 6-coordinate, iron(IV)-oxo porphyrinoid-π-cation-radical complexes and report their PCET reactivity together with a previously published 5-coordinate analogue, FeIV(O)(TBP8Cz+•) (TBP8Cz = octakis(p-tert-butylphenyl)corrolazinato3-) (2) (Cho, K. A high-valent iron-oxo corrolazine activates C-H bonds via hydrogen-atom transfer. J. Am. Chem. Soc. 2012, 134, 7392-7399). The new complexes FeIV(O)(TBP8Cz+•)(L) (L = 1-methyl imidazole (1-MeIm) (4a), 4-dimethylaminopyridine (DMAP) (4b), cyanide (CN-)(4c)) can be generated from either oxidation of the ferric precursors or by addition of L to the Compound-I (Cpd-I) analogue at low temperatures. These complexes were characterized by UV-vis, electron paramagnetic resonance (EPR), and Mössbauer spectroscopies, and cryospray ionization mass spectrometry (CSI-MS). Kinetic studies using 4-OMe-TEMPOH as a test substrate indicate that coordination of a sixth axial ligand dramatically lowers the PCET reactivity of the Cpd-I analogue (rates up to 7000 times slower). Extensive density functional theory (DFT) calculations together with the experimental data show that the trend in reactivity with the axial ligands does not correlate with the thermodynamic driving force for these reactions or the calculated strengths of the O-H bonds being formed in the FeIV(O-H) products, pointing to non-Bell-Evans-Polanyi behavior. However, the PCET reactivity does follow a trend with the bracketed reduction potential of Cpd-I analogues and calculated electron affinities. The combined data suggest a concerted mechanism (a concerted proton electron transfer (CPET)) and an asynchronous movement of the electron/proton pair in the transition state.
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Affiliation(s)
- Jithin Thomas
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Thirakorn Mokkawes
- The Manchester Institute of Biotechnology and Department of Chemical Engineering, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Laura Senft
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr., 5-13, Haus D, 81377 München, Germany
| | - Aniruddha Dey
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Jesse B Gordon
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Ivana Ivanovic-Burmazovic
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr., 5-13, Haus D, 81377 München, Germany
| | - Sam P de Visser
- The Manchester Institute of Biotechnology and Department of Chemical Engineering, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - David P Goldberg
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
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2
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Engbers S, Guo Y, Klein JEMN. A Porphyrin Iron(III) π-Dication Species and its Relevance in Catalyst Design for the Umpolung of Nucleophiles. Angew Chem Int Ed Engl 2023; 62:e202313006. [PMID: 37751302 DOI: 10.1002/anie.202313006] [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: 09/03/2023] [Revised: 09/16/2023] [Accepted: 09/18/2023] [Indexed: 09/27/2023]
Abstract
Isoporphyrins have recently been identified as remarkable species capable of turning the nucleophile attached to the porphyrin ring into an electrophile, thereby providing umpolung of reactivity (Inorg. Chem. 2022, 61, 8105-8111). They are generated by nucleophilic attack on an iron(III) π-dication, a class of species that has received scant attention. Here, we explore the effect of the porphyrin meso-substituent and report a iron(III) π-dication bearing the meso-tetraphenylporphyrin (TPP) ligand. We provide an extensive study of the species by UV/Vis absorption, 2 H NMR, EPR, applied field Mössbauer, and resonance Raman spectroscopy. We further explore the system's highly dynamic and tunable properties and address the nature of the axial ligands as well as the conformation of the porphyrin ring. The insights presented are essential for the rational design of catalysts for the umpolung of nucleophiles. Such catalytic avenues could for example provide a novel method for electrophilic chlorinations. We further examine the importance of electronic tuning of the porphyrin by nature of the meso-substituent as a factor in catalyst design.
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Affiliation(s)
- Silène Engbers
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747 AG, Groningen (The, Netherlands
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Ave, Pittsburgh, Pennsylvania, 15213, United States
| | - Johannes E M N Klein
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747 AG, Groningen (The, Netherlands
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3
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Tahoun M, Engeser M, Svolacchia L, Sander PM, Müller CE. Molecular Taphonomy of Heme: Chemical Degradation of Hemin under Presumed Fossilization Conditions. Molecules 2023; 28:4887. [PMID: 37446548 DOI: 10.3390/molecules28134887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/16/2023] [Accepted: 06/18/2023] [Indexed: 07/15/2023] Open
Abstract
The metalloporphyrin heme acts as the oxygen-complexing prosthetic group of hemoglobin in blood. Heme has been noted to survive for many millions of years in fossils. Here, we investigate its stability and degradation under various conditions expected to occur during fossilization. Oxidative, reductive, aerobic, and anaerobic conditions were studied at neutral and alkaline pH values. Elevated temperatures were applied to accelerate degradation. High-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) identified four main degradation products. The vinyl residues are oxidized to formyl and further to carboxylate groups. In the presence of air or H2O2, cleavage of the tetrapyrrole ring occurs, and hematinic acid is formed. The highest stability of heme was observed under anaerobic reductive conditions (half-life 9.5 days), while the lowest stability was found in the presence of H2O2 (half-life 1 min). We confirmed that the iron cation plays a crucial role in degradation, since protoporphyrin IX, lacking iron, remained significantly more stable. Under anaerobic, reductive conditions, the above-mentioned degradation products were not observed, suggesting a different degradation pathway. To our knowledge, this is the first molecular taphonomy study on heme, which will be useful for understanding its fate during fossilization.
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Affiliation(s)
- Mariam Tahoun
- PharmaCenter Bonn & Pharmaceutical Institute, Department of Pharmaceutical & Medicinal Chemistry, University of Bonn, An der Immenburg 4, 53121 Bonn, Germany
| | - Marianne Engeser
- Kekulé Institute for Organic Chemistry and Biochemistry, University of Bonn, 53121 Bonn, Germany
| | - Luca Svolacchia
- PharmaCenter Bonn & Pharmaceutical Institute, Department of Pharmaceutical & Medicinal Chemistry, University of Bonn, An der Immenburg 4, 53121 Bonn, Germany
| | - Paul Martin Sander
- Section Paleontology, Institute of Geosciences, University of Bonn, 53115 Bonn, Germany
| | - Christa E Müller
- PharmaCenter Bonn & Pharmaceutical Institute, Department of Pharmaceutical & Medicinal Chemistry, University of Bonn, An der Immenburg 4, 53121 Bonn, Germany
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4
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Yanai K, Hada M, Fujii H. Electric field effect of positive and negative charges of substituents on electronic structure and reactivity of oxoiron(IV) porphyrin π-cation radical complex. J Inorg Biochem 2023; 244:112208. [PMID: 37037142 DOI: 10.1016/j.jinorgbio.2023.112208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 03/07/2023] [Accepted: 04/03/2023] [Indexed: 04/08/2023]
Abstract
Electric field effect by the positive and negative changes near the active site is an important factor for controlling the reactivity of metalloenzymes. Previously, we reported that the positive charge of the N-methyl-2-pyridinium cation increases the reactivity of oxoiron(IV) porphyrin π-cation radical complex (Compound I), due to the attractive Coulomb interaction with electrons in Compound I. To further investigate the electric field effect, we study here the effect of the negative charge of the sulfonate group on the electronic structure and reactivity using Compound I of meso-tetrakis(2,4,6-trimethyl-3-sulfonatophenyl)porphyrin (TMPS-I). Although Compound I has been known as a very unstable complex, TMPS-I is very stable in 0.1 M acetate buffer at pH = 6. The half-life of TMPS-I is estimated to be 6.9 × 103 s, which is the longest in Compound I previously reported. The redox potential of TMPS-I is estimated to be 0.76 V vs SCE in phosphate buffer, pH = 10. Kinetic analysis with stopped-flow technique indicates TMPS-I is less reactive than Compounds I reported previously. However, 1H NMR and EPR spectra of TMPS-I are very close to those of Compounds I reported previously. The DFT calculations show that the orbital energy of Compound I is drastically altered by the positive and negative charges on the meso-phenyl group, suggesting the electric field effect. The difference of the reactivity of Compound I can be rationalized with the change of the orbital energy caused by the intramolecular electric field effect of the positive and negative charges.
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Affiliation(s)
- Kanae Yanai
- Department of Chemistry, Biology, and Environmental Sciences, Graduate School of Humanities and Sciences, Nara Women's University, Nara 630-8506, Japan
| | - Masahiko Hada
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Hachioji 192-0397, Japan
| | - Hiroshi Fujii
- Department of Chemistry, Biology, and Environmental Sciences, Graduate School of Humanities and Sciences, Nara Women's University, Nara 630-8506, Japan.
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5
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Katogi Y, Okamoto A, Hada M, Fujii H. Characterization and Reactivity of an Incredibly Reactive Intermediate in the Protonation Reaction of Dioxo-Manganese(V) Porphyrin with Acid. ACS Catal 2023. [DOI: 10.1021/acscatal.2c06122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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6
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Karuppasamy P. Selective Oxidation of L-Methionine, L-Ethionine, N-Acetyl-L-Methionine, L-Buthionine Catalyzed by [FeIII-Salen]Cl Complexes: A Spectral, Kinetic, and Electrochemical Study. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2022. [DOI: 10.1134/s0036024421150127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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7
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Ishimizu Y, Ma Z, Hada M, Fujii H. Rate-Limiting Step of Epoxidation Reaction of the Oxoiron(IV) Porphyrin π-Cation Radical Complex: Electron Transfer Coupled Bond Formation Mechanism. Inorg Chem 2021; 60:17687-17698. [PMID: 34775756 DOI: 10.1021/acs.inorgchem.1c02287] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Epoxidation reactions catalyzed by high-valent metal-oxo species are key reactions in various biological and chemical processes. Because the redox potentials of alkenes are higher than those of most high-valent metal-oxo species, the electron transfer (ET) from the alkene to the high-valent metal-oxo species in the epoxidation reaction is endergonic and must be coupled with another exergonic process. To reveal the mechanism of the ET, we performed a Marcus plot analysis for the epoxidation reaction of the oxoiron(IV) porphyrin π-cation radical complex (compound I) with alkene. The Marcus plots can be simulated with a linear line with the gradient of 0.50 when the redox potential of compound I varies and 0.07 when the redox potential of alkene varies. These results indicate that the ET process is involved in the rate-limiting step and coupled with the following O-C bond formation process: ET coupled bond formation mechanism. The DFT calculations support this conclusion and disclose the details of the mechanism. As the alkene comes close to the oxo ligand, the energy of the highest occupied molecular orbital (HOMO) of the alkene increases and the energy for the ET becomes small enough to allow the ET. Finally, the ET occurs from the HOMO of the alkene to the porphyrin π-radical orbital. The shift of one electron from the HOMO of the alkene by the ET simultaneously results in the O-C half bond formation between the oxo ligand and the alkene. The ET process itself is still endergonic and reversible, but the bond formation coupled with the ET changes the overall process to exergonic and irreversible. We also discuss the similarity with the aromatic hydroxylation reaction and the relevance to the epoxidation reactions of other metal-oxo complexes and peracid.
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Affiliation(s)
- Yuri Ishimizu
- Department of Chemistry, Graduate School of Humanities and Sciences, Nara Women's University, Kitauoyanishi, Nara 630-8506, Japan
| | - Zhifeng Ma
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, 1-1 Minamiosawa, Hachioji 192-0397, Japan
| | - Masahiko Hada
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, 1-1 Minamiosawa, Hachioji 192-0397, Japan
| | - Hiroshi Fujii
- Department of Chemistry, Graduate School of Humanities and Sciences, Nara Women's University, Kitauoyanishi, Nara 630-8506, Japan
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8
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Guo M, Zhang J, Zhang L, Lee YM, Fukuzumi S, Nam W. Enthalpy-Entropy Compensation Effect in Oxidation Reactions by Manganese(IV)-Oxo Porphyrins and Nonheme Iron(IV)-Oxo Models. J Am Chem Soc 2021; 143:18559-18570. [PMID: 34723505 DOI: 10.1021/jacs.1c08198] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
"Enthalpy-Entropy Compensation Effect" (EECE) is ubiquitous in chemical reactions; however, such an EECE has been rarely explored in biomimetic oxidation reactions. In this study, six manganese(IV)-oxo complexes bearing electron-rich and -deficient porphyrins are synthesized and investigated in various oxidation reactions, such as hydrogen atom transfer (HAT), oxygen atom transfer (OAT), and electron-transfer (ET) reactions. First, all of the six Mn(IV)-oxo porphyrins are highly reactive in the HAT, OAT, and ET reactions. Interestingly, we have observed a reversed reactivity in the HAT and OAT reactions by the electron-rich and -deficient Mn(IV)-oxo porphyrins, depending on reaction temperatures, but not in the ET reactions; the electron-rich Mn(IV)-oxo porphyrins are more reactive than the electron-deficient Mn(IV)-oxo porphyrins at high temperature (e.g., 0 °C), whereas at low temperature (e.g., -60 °C), the electron-deficient Mn(IV)-oxo porphyrins are more reactive than the electron-rich Mn(IV)-oxo porphyrins. Such a reversed reactivity between the electron-rich and -deficient Mn(IV)-oxo porphyrins depending on reaction temperatures is rationalized with EECE; that is, the lower is the activation enthalpy, the more negative is the activation entropy, and vice versa. Interestingly, a unified linear correlation between the activation enthalpies and the activation entropies is observed in the HAT and OAT reactions of the Mn(IV)-oxo porphyrins. Moreover, from the previously reported HAT reactions of nonheme Fe(IV)-oxo complexes, a linear correlation between the activation enthalpies and the activation entropies is also observed. To the best of our knowledge, we report the first detailed mechanistic study of EECE in the oxidation reactions by synthetic high-valent metal-oxo complexes.
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Affiliation(s)
- Mian Guo
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea.,College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, PR China
| | - Jisheng Zhang
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Lina Zhang
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Yong-Min Lee
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Shunichi Fukuzumi
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea.,Faculty of Science and Engineering, Meijo University, Nagoya, Aichi 468-8502, Japan
| | - Wonwoo Nam
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea.,School of Chemistry and Chemical Engineering, University of Jinan, Jinan, 250022, PR China
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9
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Oakley K, Sterling K, Shearer J, Kim E. Controlled Protonation of [2Fe-2S] Leading to MitoNEET Analogues and Concurrent Cluster Modification. Inorg Chem 2021; 60:16074-16078. [PMID: 34672568 DOI: 10.1021/acs.inorgchem.1c02622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
MitoNEET, a key regulatory protein in mitochondrial energy metabolism, exhibits a uniquely ligated [2Fe-2S] cluster with one histidine and three cysteines. This unique cluster has been postulated to sense the redox environment and release Fe-S cofactors under acidic pH. Reported herein is a synthetic system that shows how [2Fe-2S] clusters react with protons and rearrange their coordination geometry. The low-temperature stable, site-differentiated clusters [Fe2S2(SPh)3(CF3COO)]2- and [Fe2S2(SPh)3(py)]- have been prepared via controlled protonation below -35 °C and characterized by NMR, UV-vis, and X-ray absorption spectroscopy. Both complexes exhibit anodically shifted redox potentials compared to [Fe2S2(SPh)4]2- and convert to [Fe4S4(SPh)4]2- upon warming to room temperature. The current study provides insight into how mitoNEET releases its [2Fe-2S] in response to highly tuned acidic conditions, the chemistry of which may have further implications in Fe-S biogenesis.
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Affiliation(s)
- Kady Oakley
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Kevin Sterling
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Jason Shearer
- Department of Chemistry, Trinity University, San Antonio, Texas 78212, United States
| | - Eunsuk Kim
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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10
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Suzuki Y, Hada M, Fujii H. Synthesis, characterization, and reactivity of oxoiron(IV) porphyrin π-cation radical complexes bearing cationic N-methyl-2-pyridinium group. J Inorg Biochem 2021; 223:111542. [PMID: 34293682 DOI: 10.1016/j.jinorgbio.2021.111542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/22/2021] [Accepted: 07/11/2021] [Indexed: 11/30/2022]
Abstract
Electronic charge near the active site is an important factor for controlling the reactivity of metalloenzymes. Here, to investigate the effect of the cationic charge near the heme in heme proteins, we synthesized new iron porphyrin complexes (1 and 2) having cationic 3-methyl-N-methyl-2-pyrdinium group and N-methyl-2-pyridinium group at one of the four meso-positions, respectively. The N-methyl-2-pyridinium groups could be introduced by Stille coupling used palladium catalysts. Oxoiron(IV) porphyrin π-cation radical complexes (Compound I) of 1 (1-CompI) and 2 (2-CompI) are soluble in most organic solvents, allowing direct comparison of their electronic structure and reactivity with Compound I of tetramesitylporphyrin (3-CompI) and tetrakis-(2,6-dichlorophenyl)porphyrin (4-CompI) under the same conditions. Spectroscopic data for 1-CompI are close to those for 3-CompI, but the redox potential for 1-CompI is close to that of 4-CompI. Kinetic analysis of the epoxidation reactions shows that 1-CompI and 2-CompI are (~250-fold) more reactive than 3-CompI, and comparable to 4-CompI. DFT calculations allow to propose that the positive shift of the redox potential and the enhanced reactivity of 1-CompI and 2-CompI is induced by the intramolecular electric field effect of N-methyl-2-pyridinium cation, not by the electron-withdrawing effect.
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Affiliation(s)
- Yuna Suzuki
- Department of Chemistry, Biology, and Environmental Sciences, Graduate School of Humanities and Sciences, Nara Women's University, Nara 630-8506, Japan
| | - Masahiko Hada
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Hachioji 192-0397, Japan
| | - Hiroshi Fujii
- Department of Chemistry, Biology, and Environmental Sciences, Graduate School of Humanities and Sciences, Nara Women's University, Nara 630-8506, Japan.
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11
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12
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Karuppasamy P, Thiruppathi D, Ganesan M, Rajendran T, Rajagopal S, Sivasubramanian VK, Rajapandian V. Electrocatalytic Oxidation of L-Cysteine, L-Methionine, and Methionine–Glycine Using [Oxoiron(IV)–Salen] Ion Immobilized Glassy Carbon Electrode. Electrocatalysis (N Y) 2021. [DOI: 10.1007/s12678-021-00652-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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13
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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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14
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Fukui N, Ueno K, Hada M, Fujii H. meso-Substitution Activates Oxoiron(IV) Porphyrin π-Cation Radical Complex More Than Pyrrole-β-Substitution for Atom Transfer Reaction. Inorg Chem 2021; 60:3207-3217. [DOI: 10.1021/acs.inorgchem.0c03548] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nami Fukui
- Department of Chemistry, Graduate School of Humanities and Sciences, Nara Women’s University, Kitauoyanishi, Nara 630-8506, Japan
| | - Kanako Ueno
- Department of Chemistry, Graduate School of Humanities and Sciences, Nara Women’s University, Kitauoyanishi, Nara 630-8506, Japan
| | - Masahiko Hada
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, 1-1 Minamiosawa, Hachioji 192-0397, Japan
| | - Hiroshi Fujii
- Department of Chemistry, Graduate School of Humanities and Sciences, Nara Women’s University, Kitauoyanishi, Nara 630-8506, Japan
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15
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Ali HS, Henchman RH, de Visser SP. Lignin Biodegradation by a Cytochrome P450 Enzyme: A Computational Study into Syringol Activation by GcoA. Chemistry 2020; 26:13093-13102. [PMID: 32613677 PMCID: PMC7590115 DOI: 10.1002/chem.202002203] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Indexed: 12/12/2022]
Abstract
A recently characterized cytochrome P450 isozyme GcoA activates lignin components through a selective O-demethylation or alternatively an acetal formation reaction. These are important reactions in biotechnology and, because lignin is readily available; it being the main component in plant cell walls. In this work we present a density functional theory study on a large active site model of GcoA to investigate syringol activation by an iron(IV)-oxo heme cation radical oxidant (Compound I) leading to hemiacetal and acetal products. Several substrate-binding positions were tested and full energy landscapes calculated. The study shows that substrate positioning determines the product distributions. Thus, with the phenol group pointing away from the heme, an O-demethylation is predicted, whereas an initial hydrogen-atom abstraction of the weak phenolic O-H group would trigger a pathway leading to ring-closure to form acetal products. Predictions on how to engineer P450 GcoA to get more selective product distributions are given.
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Affiliation(s)
- Hafiz Saqib Ali
- Manchester Institute of BiotechnologyThe University of Manchester131 Princess StreetManchesterM1 7DNUnited Kingdom
- Department of ChemistryThe University of ManchesterOxford RoadManchesterM13 9PLUnited Kingdom
| | - Richard H. Henchman
- Manchester Institute of BiotechnologyThe University of Manchester131 Princess StreetManchesterM1 7DNUnited Kingdom
- Department of ChemistryThe University of ManchesterOxford RoadManchesterM13 9PLUnited Kingdom
| | - Sam P. de Visser
- Manchester Institute of BiotechnologyThe University of Manchester131 Princess StreetManchesterM1 7DNUnited Kingdom
- Department of Chemical Engineering and Analytical ScienceThe University of ManchesterOxford RoadManchesterM13 9PLUnited Kingdom
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16
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Noel J, Kostopoulos N, Achaibou C, Fave C, Anxolabéhère‐Mallart E, Kanoufi F. Probing the Activity of Iron Peroxo Porphyrin Intermediates in the Reaction Layer during the Electrochemical Reductive Activation of O
2. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202004977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - Nikolaos Kostopoulos
- Université de Paris, Laboratoire d'Electrochimie MoléculaireCNRS 75006 Paris France
| | - Célia Achaibou
- Université de Paris, Laboratoire d'Electrochimie MoléculaireCNRS 75006 Paris France
| | - Claire Fave
- Université de Paris, Laboratoire d'Electrochimie MoléculaireCNRS 75006 Paris France
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17
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Noel JM, Kostopoulos N, Achaibou C, Fave C, Anxolabéhère-Mallart E, Kanoufi F. Probing the Activity of Iron Peroxo Porphyrin Intermediates in the Reaction Layer during the Electrochemical Reductive Activation of O 2. Angew Chem Int Ed Engl 2020; 59:16376-16380. [PMID: 32543058 DOI: 10.1002/anie.202004977] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Indexed: 02/02/2023]
Abstract
Herein we report the first example of using scanning electrochemical microscopy (SECM) to quantitatively analyze O2 reductive activation in organic media catalyzed by three different Fe porphyrins. For each porphyrin, SECM can provide in one single experiment the redox potential of various intermediates, the association constant of FeII with O2 , and the pKa of the FeIII (OOH- )/ FeIII (OO2- ) couple. The results obtained can contribute to a further understanding of the parameters controlling the catalytic efficiency of the Fe porphyrin towards O2 activation and reduction.
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Affiliation(s)
| | - Nikolaos Kostopoulos
- Université de Paris, Laboratoire d'Electrochimie Moléculaire, CNRS, 75006, Paris, France
| | - Célia Achaibou
- Université de Paris, Laboratoire d'Electrochimie Moléculaire, CNRS, 75006, Paris, France
| | - Claire Fave
- Université de Paris, Laboratoire d'Electrochimie Moléculaire, CNRS, 75006, Paris, France
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Nishikawa K, Honda Y, Fujii H. Spectroscopic Evidence for Acid-Catalyzed Disproportionation Reaction of Oxoiron(IV) Porphyrin to Oxoiron(IV) Porphyrin π-Cation Radical and Iron(III) Porphyrin. J Am Chem Soc 2020; 142:4980-4984. [PMID: 32118413 DOI: 10.1021/jacs.9b13503] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The disproportionation reaction of oxoiron(IV) porphyrin complex (II) to oxoiron(IV) porphyrin π-cation radical complex (I) and iron(III) porphyrin complex (III) have been proposed in various reactions. However, there have been no report that clarifies the disproportionation reaction spectroscopically. Here, we show direct evidence for the disproportionation reaction of II with absorption, 2H NMR, and EPR spectroscopy. Kinetic study of the disproportionation reaction with stopped flow technique can be analyzed as the second-order reaction for the concentration of proton and the first-order for the concentration of II. These results allow us to propose the mechanism of the disproportionation reaction, involving the sequential addition of two protons to the oxo ligand of II, to give an iron(III) porphyrin π-cation radical species, which reacts with another II to afford I and III.
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Affiliation(s)
- Kana Nishikawa
- Department of Chemistry, Biology, and Environmental Science, Graduate School of Humanities and Sciences, Nara Women's University, Nara 630-8506, Japan
| | - Yuki Honda
- Department of Chemistry, Biology, and Environmental Science, Graduate School of Humanities and Sciences, Nara Women's University, Nara 630-8506, Japan
| | - Hiroshi Fujii
- Department of Chemistry, Biology, and Environmental Science, Graduate School of Humanities and Sciences, Nara Women's University, Nara 630-8506, Japan
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19
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Ambient O2 is a switch between [1-electron/1-radical] vs. [2–electron] oxidative catalytic path in Fe-Phthalocyanines. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Fukui N, Li XX, Nam W, Fukuzumi S, Fujii H. Small Reorganization Energy for Ligand-Centered Electron-Transfer Reduction of Compound I to Compound II in a Heme Model Study. Inorg Chem 2019; 58:8263-8266. [DOI: 10.1021/acs.inorgchem.9b01051] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Nami Fukui
- Department of Chemistry, Graduate School of Humanities and Sciences, Nara Women’s University, Nara 650-8506, Japan
| | - Xiao-Xi Li
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Wonwoo Nam
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
| | - Shunichi Fukuzumi
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Korea
- Faculty of Science and Engineering, Meijo University, SENTAN, Japan Science and Technology Agency, Nagoya, Aichi 468-0073, Japan
| | - Hiroshi Fujii
- Department of Chemistry, Graduate School of Humanities and Sciences, Nara Women’s University, Nara 650-8506, Japan
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21
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Ehudin MA, Gee LB, Sabuncu S, Braun A, Moënne-Loccoz P, Hedman B, Hodgson KO, Solomon EI, Karlin KD. Tuning the Geometric and Electronic Structure of Synthetic High-Valent Heme Iron(IV)-Oxo Models in the Presence of a Lewis Acid and Various Axial Ligands. J Am Chem Soc 2019; 141:5942-5960. [PMID: 30860832 DOI: 10.1021/jacs.9b00795] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
High-valent ferryl species (e.g., (Por)FeIV═O, Cmpd-II) are observed or proposed key oxidizing intermediates in the catalytic cycles of heme-containing enzymes (P-450s, peroxidases, catalases, and cytochrome c oxidase) involved in biological respiration and oxidative metabolism. Herein, various axially ligated iron(IV)-oxo complexes were prepared to examine the influence of the identity of the base. These were generated by addition of various axial ligands (1,5-dicyclohexylimidazole (DCHIm), a tethered-imidazole system, and sodium derivatives of 3,5-dimethoxyphenolate and imidazolate). Characterization was carried out via UV-vis, electron paramagnetic resonance (EPR), 57Fe Mössbauer, Fe X-ray absorption (XAS), and 54/57Fe resonance Raman (rR) spectroscopies to confirm their formation and compare the axial ligand perturbation on the electronic and geometric structures of these heme iron(IV)-oxo species. Mössbauer studies confirmed that the axially ligated derivatives were iron(IV) and six-coordinate complexes. XAS and 54/57Fe rR data correlated with slight elongation of the iron-oxo bond with increasing donation from the axial ligands. The first reported synthetic H-bonded iron(IV)-oxo heme systems were made in the presence of the protic Lewis acid, 2,6-lutidinium triflate (LutH+), with (or without) DCHIm. Mössbauer, rR, and XAS spectroscopic data indicated the formation of molecular Lewis acid ferryl adducts (rather than full protonation). The reduction potentials of these novel Lewis acid adducts were bracketed through addition of outer-sphere reductants. The oxidizing capabilities of the ferryl species with or without Lewis acid vary drastically; addition of LutH+ to F8Cmpd-II (F8 = tetrakis(2,6-difluorophenyl)porphyrinate) increased its reduction potential by more than 890 mV, experimentally confirming that H-bonding interactions can increase the reactivity of ferryl species.
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Affiliation(s)
- Melanie A Ehudin
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Leland B Gee
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
| | - Sinan Sabuncu
- Department of Biochemistry & Molecular Biology , Oregon Health & Science University , Portland , Oregon 97239-3098 , United States
| | - Augustin Braun
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
| | - Pierre Moënne-Loccoz
- Department of Biochemistry & Molecular Biology , Oregon Health & Science University , Portland , Oregon 97239-3098 , United States
| | - Britt Hedman
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , United States
| | - Keith O Hodgson
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States.,Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , United States
| | - Edward I Solomon
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States.,Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , United States
| | - Kenneth D Karlin
- Department of Chemistry , Johns Hopkins University , Baltimore , Maryland 21218 , United States
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22
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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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23
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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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24
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Adam SM, Wijeratne GB, Rogler PJ, Diaz DE, Quist DA, Liu JJ, Karlin KD. Synthetic Fe/Cu Complexes: Toward Understanding Heme-Copper Oxidase Structure and Function. Chem Rev 2018; 118:10840-11022. [PMID: 30372042 PMCID: PMC6360144 DOI: 10.1021/acs.chemrev.8b00074] [Citation(s) in RCA: 132] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Heme-copper oxidases (HCOs) are terminal enzymes on the mitochondrial or bacterial respiratory electron transport chain, which utilize a unique heterobinuclear active site to catalyze the 4H+/4e- reduction of dioxygen to water. This process involves a proton-coupled electron transfer (PCET) from a tyrosine (phenolic) residue and additional redox events coupled to transmembrane proton pumping and ATP synthesis. Given that HCOs are large, complex, membrane-bound enzymes, bioinspired synthetic model chemistry is a promising approach to better understand heme-Cu-mediated dioxygen reduction, including the details of proton and electron movements. This review encompasses important aspects of heme-O2 and copper-O2 (bio)chemistries as they relate to the design and interpretation of small molecule model systems and provides perspectives from fundamental coordination chemistry, which can be applied to the understanding of HCO activity. We focus on recent advancements from studies of heme-Cu models, evaluating experimental and computational results, which highlight important fundamental structure-function relationships. Finally, we provide an outlook for future potential contributions from synthetic inorganic chemistry and discuss their implications with relevance to biological O2-reduction.
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Affiliation(s)
- Suzanne M. Adam
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Gayan B. Wijeratne
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Patrick J. Rogler
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Daniel E. Diaz
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - David A. Quist
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Jeffrey J. Liu
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Kenneth D. Karlin
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
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25
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Ahmad S, Gautam R, Singhal A, Chauhan S. Significant effect of 5,10,15,20-meso-tetraarylporphyrinatoiron(III) chloride/triflate and acidic/neutral/basic imidazolium ionic liquids in catalytic oxidation of phenols. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.03.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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26
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Yokota S, Fujii H. Critical Factors in Determining the Heterolytic versus Homolytic Bond Cleavage of Terminal Oxidants by Iron(III) Porphyrin Complexes. J Am Chem Soc 2018; 140:5127-5137. [PMID: 29575900 DOI: 10.1021/jacs.7b13037] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Heterolytic versus homolytic cleavage of the metal-bound terminal oxidant is the key for determining the nature of reactive intermediates in metalloenzymes and metal catalyzed oxygenation reactions. Here, we study the bond cleavage process of hypochlorite by iron(III) porphyrin complexes having 4-methoxy-2,6-dimethylphenyl (1), 2,4,6-trimethylphenyl (2), 4-fluoro-2,6-dimethylphenyl (3), 2-chloro-6-methylphenyl (4), 2,6-dichlorophenyl (5), and 2,4,6-trichlorophenyl (6) groups at the meso position. Oxoiron(IV) porphyrin π-cation radical complexes (CompI) are characterized from the reactions of 1-4 with tetra- n-butylammonium hypochlorite (TBA-OCl) in dichloromethane at -80 °C, while oxoiron(IV) porphyrin complexes (CompII) are characterized for 5 and 6 under the same conditions. For all of 1-6, we find the formation of an epoxidation product in good yields from the catalytic reactions with TBA-OCl, suggesting heterolytic cleavages of the O-Cl bonds. CompI of 5 and 6 are reduced to the corresponding CompII by both chloride and hypochlorite, while CompI of 1-4 are not. The reduction reactions with hypochlorite are much faster than those with chloride. These results provide a mechanism where the O-Cl bond of the iron-bound hypochlorite is cleaved heterolytically to form CompI for all of 1-6, but the subsequent reduction reaction with remaining hypochlorite affords CompII for 5 and 6. The E(OCl•/OCl-) value is the boundary to discriminate the identity of the final product: CompI or CompII. Thermodynamic analysis based on the redox potential is successfully applied for explaining the bond cleavage processes of the hypochlorite, hydroperoxide, and tert-butyl peroxide complexes.
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Affiliation(s)
- Sawako Yokota
- Department of Chemistry, Graduate School of Humanities and Sciences , Nara Women's University , Kitauoyanishi , Nara 630-8506 , Japan
| | - Hiroshi Fujii
- Department of Chemistry, Graduate School of Humanities and Sciences , Nara Women's University , Kitauoyanishi , Nara 630-8506 , Japan
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27
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Huang X, Groves JT. Oxygen Activation and Radical Transformations in Heme Proteins and Metalloporphyrins. Chem Rev 2018; 118:2491-2553. [PMID: 29286645 PMCID: PMC5855008 DOI: 10.1021/acs.chemrev.7b00373] [Citation(s) in RCA: 582] [Impact Index Per Article: 97.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Indexed: 12/20/2022]
Abstract
As a result of the adaptation of life to an aerobic environment, nature has evolved a panoply of metalloproteins for oxidative metabolism and protection against reactive oxygen species. Despite the diverse structures and functions of these proteins, they share common mechanistic grounds. An open-shell transition metal like iron or copper is employed to interact with O2 and its derived intermediates such as hydrogen peroxide to afford a variety of metal-oxygen intermediates. These reactive intermediates, including metal-superoxo, -(hydro)peroxo, and high-valent metal-oxo species, are the basis for the various biological functions of O2-utilizing metalloproteins. Collectively, these processes are called oxygen activation. Much of our understanding of the reactivity of these reactive intermediates has come from the study of heme-containing proteins and related metalloporphyrin compounds. These studies not only have deepened our understanding of various functions of heme proteins, such as O2 storage and transport, degradation of reactive oxygen species, redox signaling, and biological oxygenation, etc., but also have driven the development of bioinorganic chemistry and biomimetic catalysis. In this review, we survey the range of O2 activation processes mediated by heme proteins and model compounds with a focus on recent progress in the characterization and reactivity of important iron-oxygen intermediates. Representative reactions initiated by these reactive intermediates as well as some context from prior decades will also be presented. We will discuss the fundamental mechanistic features of these transformations and delineate the underlying structural and electronic factors that contribute to the spectrum of reactivities that has been observed in nature as well as those that have been invented using these paradigms. Given the recent developments in biocatalysis for non-natural chemistries and the renaissance of radical chemistry in organic synthesis, we envision that new enzymatic and synthetic transformations will emerge based on the radical processes mediated by metalloproteins and their synthetic analogs.
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Affiliation(s)
- Xiongyi Huang
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department
of Chemistry, California Institute of Technology, Pasadena, California 91125, United States
| | - John T. Groves
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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28
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Baglia RA, Zaragoza JPT, Goldberg DP. Biomimetic Reactivity of Oxygen-Derived Manganese and Iron Porphyrinoid Complexes. Chem Rev 2017; 117:13320-13352. [PMID: 28991451 PMCID: PMC6058703 DOI: 10.1021/acs.chemrev.7b00180] [Citation(s) in RCA: 204] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Heme proteins utilize the heme cofactor, an iron porphyrin, to perform a diverse range of reactions including dioxygen binding and transport, electron transfer, and oxidation/oxygenations. These reactions share several key metalloporphyrin intermediates, typically derived from dioxygen and its congeners such as hydrogen peroxide. These species are composed of metal-dioxygen, metal-superoxo, metal-peroxo, and metal-oxo adducts. A wide variety of synthetic metalloporphyrinoid complexes have been synthesized to generate and stabilize these intermediates. These complexes have been studied to determine the spectroscopic features, structures, and reactivities of such species in controlled and well-defined environments. In this Review, we summarize recent findings on the reactivity of these species with common porphyrinoid scaffolds employed for biomimetic studies. The proposed mechanisms of action are emphasized. This Review is organized by structural type of metal-oxygen intermediate and broken into subsections based on the metal (manganese and iron) and porphyrinoid ligand (porphyrin, corrole, and corrolazine).
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Affiliation(s)
- Regina A. Baglia
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Jan Paulo T. Zaragoza
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - David P. Goldberg
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
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29
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Tsudaka T, Kotani H, Ohkubo K, Nakagawa T, Tkachenko NV, Lemmetyinen H, Fukuzumi S. Photoinduced Electron Transfer in 9-Substituted 10-Methylacridinium Ions. Chemistry 2016; 23:1306-1317. [DOI: 10.1002/chem.201604527] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Indexed: 01/05/2023]
Affiliation(s)
- Takeshi Tsudaka
- Department of Material and Life Science Graduate School of Engineering; Osaka University and SENTAN, Japan Science and Technology Agency (JST), Suita; Osaka 565-0871 Japan
| | - Hiroaki Kotani
- Department of Chemistry, Graduate School of Pure and Applied Sciences; University of Tsukuba; 1-1-1 Tennoudai, Tsukuba Ibaraki 305-8571 Japan
| | - Kei Ohkubo
- Department of Material and Life Science Graduate School of Engineering; Osaka University and SENTAN, Japan Science and Technology Agency (JST), Suita; Osaka 565-0871 Japan
- Department of Chemistry and Nano Science; Ewha Womans University; Seoul 120-750 Korea
- Division of Innovative Research for Drug Design, Institute of Academic Initiatives; Osaka University, Suita; Osaka 565-0871 Japan
| | - Tatsuo Nakagawa
- Unisoku Co. Ltd, SENTAN, Japan Science and Technology Agency (JST); Hirakata Osaka 573-0131 Japan
| | - Nikolai V. Tkachenko
- Institute of Materials Chemistry; Tampere University of Technology; P.O. Box 541 33101 Tampere Finland
| | - Helge Lemmetyinen
- Institute of Materials Chemistry; Tampere University of Technology; P.O. Box 541 33101 Tampere Finland
| | - Shunichi Fukuzumi
- Department of Chemistry and Nano Science; Ewha Womans University; Seoul 120-750 Korea
- Faculty of Science and Technology; Meijo University, SENTAN, Japan Science and Technology Agency (JST), Nagoya; Aichi 468-8502 Japan
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30
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Yang T, Quesne MG, Neu HM, Cantú Reinhard FG, Goldberg DP, de Visser SP. Singlet versus Triplet Reactivity in an Mn(V)-Oxo Species: Testing Theoretical Predictions Against Experimental Evidence. J Am Chem Soc 2016; 138:12375-86. [PMID: 27545752 PMCID: PMC5228574 DOI: 10.1021/jacs.6b05027] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Discerning the factors that control the reactivity of high-valent metal-oxo species is critical to both an understanding of metalloenzyme reactivity and related transition metal catalysts. Computational studies have suggested that an excited higher spin state in a number of metal-oxo species can provide a lower energy barrier for oxidation reactions, leading to the conclusion that this unobserved higher spin state complex should be considered as the active oxidant. However, testing these computational predictions by experiment is difficult and has rarely been accomplished. Herein, we describe a detailed computational study on the role of spin state in the reactivity of a high-valent manganese(V)-oxo complex with para-Z-substituted thioanisoles and utilize experimental evidence to distinguish between the theoretical results. The calculations show an unusual change in mechanism occurs for the dominant singlet spin state that correlates with the electron-donating property of the para-Z substituent, while this change is not observed on the triplet spin state. Minimum energy crossing point calculations predict small spin-orbit coupling constants making the spin state change from low spin to high spin unlikely. The trends in reactivity for the para-Z-substituted thioanisole derivatives provide an experimental measure for the spin state reactivity in manganese-oxo corrolazine complexes. Hence, the calculations show that the V-shaped Hammett plot is reproduced by the singlet surface but not by the triplet state trend. The substituent effect is explained with valence bond models, which confirm a change from an electrophilic to a nucleophilic mechanism through a change of substituent.
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Affiliation(s)
- Tzuhsiung Yang
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Matthew G. Quesne
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Heather M. Neu
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Fabián G. Cantú Reinhard
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - David P. Goldberg
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Sam P. de Visser
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
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31
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Joslin EE, Zaragoza JPT, Baglia RA, Siegler MA, Goldberg DP. The Influence of Peripheral Substituent Modification on P(V), Mn(III), and Mn(V)(O) Corrolazines: X-ray Crystallography, Electrochemical and Spectroscopic Properties, and HAT and OAT Reactivities. Inorg Chem 2016; 55:8646-60. [PMID: 27529361 DOI: 10.1021/acs.inorgchem.6b01219] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The influence of remote peripheral substitution on the physicochemical properties and reactivity of phosphorus and manganese corrolazine (Cz) complexes was examined. The substitution of p-MeO for p-t-Bu groups on the eight phenyl substituents of the β-carbon atoms of the Cz ring led to changes in UV-vis transitions and redox potentials for each of the complexes. The oxygen atom transfer (OAT) and hydrogen atom transfer (HAT) reactivity of the Mn(V)(O) complexes was also influenced by p-MeO substitution. The OAT reactivity of Mn(V)(O)(MeOP8Cz) (MeOP8Cz = octakis(p-methoxyphenyl)corrolazinato(3-)) with triarylphosphine (PAr3) substrates led to second-order rate constants from 10.2(5) to 3.1(2) × 10(4) M(-1) s(-1). These rates of OAT are slower than those seen for Mn(V)(O)(TBP8Cz) (TBP8Cz = octakis(p-tert-butylphenyl)corrolazinato(3-)). A Hammett study involving para-substituted PAr3 substrates reveals a Hammett ρ-value for Mn(V)(O)(MeOP8Cz) that is more negative than that observed for Mn(V)(O)(TBP8Cz), consistent with a less electrophilic Mn center. The HAT reactivity of Mn(V)(O)(MeOP8Cz) with C-H substrates was examined and revealed second-order rate constants from 6.8(5) × 10(-5) to 1.70(2) × 10(-1) M(-1) s(-1). The rate constants varied with the C-H bond strength of the substrate. Slightly faster HAT rates with C-H substrates were observed with Mn(V)(O)(MeOP8Cz) compared to Mn(V)(O)(TBP8Cz), indicating that the basicity of the putative [Mn(IV)(O)](-) intermediate likely compensates for the more negative redox potential in the driving force for HAT. In addition, the complete, large-scale synthesis of the para-phenyl-substituted porphyrazines RP8PzH2 (R = p-tert-butylphenyl (TB), p-methoxyphenyl (MeO), and p-isopropylphenyl) and corrolazines RP8CzH3 (TBP8CzH3 and MeOP8CzH3) is presented. The crystal structures of the monoprotonated, metal-free corrolazine [(TBP8CzH3)(H)](+)[BArF](-), P(V)(OMe)2(MeOP8Cz), and Mn(III)(MeOP8Cz)(MeOH) are presented. This work provides the first insights into the influence of electronic substituent effects on the corrolazine periphery.
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Affiliation(s)
- Evan E Joslin
- Department of Chemistry, The Johns Hopkins University , 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Jan Paulo T Zaragoza
- Department of Chemistry, The Johns Hopkins University , 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Regina A Baglia
- Department of Chemistry, The Johns Hopkins University , 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Maxime A Siegler
- Department of Chemistry, The Johns Hopkins University , 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - David P Goldberg
- Department of Chemistry, The Johns Hopkins University , 3400 North Charles Street, Baltimore, Maryland 21218, United States
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32
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Asaka M, Fujii H. Participation of Electron Transfer Process in Rate-Limiting Step of Aromatic Hydroxylation Reactions by Compound I Models of Heme Enzymes. J Am Chem Soc 2016; 138:8048-51. [PMID: 27327623 DOI: 10.1021/jacs.6b03223] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Hydroxylation reactions of aromatic rings are key reactions in various biological and chemical processes. In spite of their significance, no consensus mechanism has been established. Here we performed Marcus plot analysis for aromatic hydroxylation reactions with oxoiron(IV) porphyrin π-cation radical complexes (compound I). Although many recent studies support the mechanism involving direct electrophilic attack of compound I, the slopes of the Marcus plots indicate a significant contribution of an electron transfer process in the rate-limiting step, leading us to propose a new reaction mechanism in which the electron transfer process between an aromatic compound and compound I is in equilibrium in a solvent cage and coupled with the subsequent bond formation process.
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Affiliation(s)
- Maaya Asaka
- Department of Chemistry, Graduate School of Humanities and Sciences, Nara Women's University , Kitauoyanishi, Nara 630-8506, Japan
| | - Hiroshi Fujii
- Department of Chemistry, Graduate School of Humanities and Sciences, Nara Women's University , Kitauoyanishi, Nara 630-8506, Japan
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33
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Quesne MG, Senthilnathan D, Singh D, Kumar D, Maldivi P, Sorokin AB, de Visser SP. Origin of the Enhanced Reactivity of μ-Nitrido-Bridged Diiron(IV)-Oxo Porphyrinoid Complexes over Cytochrome P450 Compound I. ACS Catal 2016. [DOI: 10.1021/acscatal.5b02720] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Matthew G. Quesne
- Manchester
Institute of Biotechnology and School of Chemical Engineering and
Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Dhurairajan Senthilnathan
- Univ. Grenoble Alpes, INAC-SCIB, Reconnaissance
Ionique et Chimie de Coordination, F-38000 Grenoble, France
- Center for
Computational Chemistry, CRD, PRIST University, Vallam, Thanjavur, Tamilnadu 613403, India
| | - Devendra Singh
- Department
of Applied Physics, Babasaheb Bhimrao Ambedkar University, School for Physical Sciences, Vidya Vihar, Rae Bareilly Road, Lucknow, Uttar Pradesh 226025, India
| | - Devesh Kumar
- Department
of Applied Physics, Babasaheb Bhimrao Ambedkar University, School for Physical Sciences, Vidya Vihar, Rae Bareilly Road, Lucknow, Uttar Pradesh 226025, India
| | - Pascale Maldivi
- Univ. Grenoble Alpes, INAC-SCIB, Reconnaissance
Ionique et Chimie de Coordination, F-38000 Grenoble, France
- CEA, INAC-SCIB, F-38000 Grenoble, France
| | - Alexander B. Sorokin
- Institut
de Recherches sur la Catalyse et l’Environnement de Lyon (IRCELYON),
UMR 5256, CNRS-Université Lyon 1, 2, av. A. Einstein, 69626 Villeurbanne, France
| | - Sam P. de Visser
- Manchester
Institute of Biotechnology and School of Chemical Engineering and
Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
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34
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Oszajca M, Franke A, Brindell M, Stochel G, van Eldik R. Redox cycling in the activation of peroxides by iron porphyrin and manganese complexes. ‘Catching’ catalytic active intermediates. Coord Chem Rev 2016. [DOI: 10.1016/j.ccr.2015.01.013] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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35
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İşci Ü, Faponle AS, Afanasiev P, Albrieux F, Briois V, Ahsen V, Dumoulin F, Sorokin AB, de Visser SP. Site-selective formation of an iron(iv)-oxo species at the more electron-rich iron atom of heteroleptic μ-nitrido diiron phthalocyanines. Chem Sci 2015; 6:5063-5075. [PMID: 30155008 PMCID: PMC6088558 DOI: 10.1039/c5sc01811k] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 06/16/2015] [Indexed: 11/21/2022] Open
Abstract
A combination of MS and computation on μ-nitrido bridged diiron complexes reveals H2O2 binding to the complex and generates an oxidant capable of oxidizing methane.
Iron(iv)–oxo species have been identified as the active intermediates in key enzymatic processes, and their catalytic properties are strongly affected by the equatorial and axial ligands bound to the metal, but details of these effects are still unresolved. In our aim to create better and more efficient oxidants of H-atom abstraction reactions, we have investigated a unique heteroleptic diiron phthalocyanine complex. We propose a novel intramolecular approach to determine the structural features that govern the catalytic activity of iron(iv)–oxo sites. Heteroleptic μ-nitrido diiron phthalocyanine complexes having an unsubstituted phthalocyanine (Pc1) and a phthalocyanine ligand substituted with electron-withdrawing alkylsulfonyl groups (PcSO2R) were prepared and characterized. A reaction with terminal oxidants gives two isomeric iron(iv)–oxo and iron(iii)–hydroperoxo species with abundances dependent on the equatorial ligand. Cryospray ionization mass spectrometry (CSI-MS) characterized both hydroperoxo and diiron oxo species in the presence of H2O2. When m-CPBA was used as the oxidant, the formation of diiron oxo species (PcSO2R)FeNFe(Pc1)
Created by potrace 1.16, written by Peter Selinger 2001-2019
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O was also evidenced. Sufficient amounts of these transient species were trapped in the quadrupole region of the mass-spectrometer and underwent a CID-MS/MS fragmentation. Analyses of fragmentation patterns indicated a preferential formation of hydroperoxo and oxo moieties at more electron-rich iron sites of both heteroleptic μ-nitrido complexes. DFT calculations show that both isomers are close in energy. However, the analysis of the iron(iii)–hydroperoxo bond strength reveals major differences for the (Pc1)FeN(PcSO2R)FeIIIOOH system as compared to (PcSO2R)FeN(Pc1)FeIIIOOH system, and, hence binding of a terminal oxidant will be preferentially on more electron-rich sides. Subsequent kinetics studies showed that these oxidants are able to even oxidize methane to formic acid efficiently.
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Affiliation(s)
- Ümit İşci
- Gebze Technical University , Department of Chemistry , P.O. Box 141, Gebze , 41400 Kocaeli , Turkey .
| | - Abayomi S Faponle
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science , The University of Manchester , 131 Princess Street , Manchester M1 7DN , UK .
| | - Pavel Afanasiev
- Institut de Recherches sur la Catalyse et l'Environnement de Lyon (IRCELYON) , UMR 5256 , CNRS-Université Lyon 1 , 2, av. A. Einstein , 69626 Villeurbanne Cedex , France .
| | - Florian Albrieux
- Centre Commun de Spectrométrie de Masse UMR 5246 , CNRS-Université Claude Bernard Lyon 1 , Université de Lyon , Bâtiment Curien , 43, bd du 11 Novembre , 69622 Villeurbanne Cedex , France
| | - Valérie Briois
- Synchrotron Soleil , L'orme des merisiers, St-Aubin , 91192 Gif-sur-Yvette , France
| | - Vefa Ahsen
- Gebze Technical University , Department of Chemistry , P.O. Box 141, Gebze , 41400 Kocaeli , Turkey .
| | - Fabienne Dumoulin
- Gebze Technical University , Department of Chemistry , P.O. Box 141, Gebze , 41400 Kocaeli , Turkey .
| | - Alexander B Sorokin
- Institut de Recherches sur la Catalyse et l'Environnement de Lyon (IRCELYON) , UMR 5256 , CNRS-Université Lyon 1 , 2, av. A. Einstein , 69626 Villeurbanne Cedex , France .
| | - Sam P de Visser
- 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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36
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Boaz NC, Bell SR, Groves JT. Ferryl protonation in oxoiron(IV) porphyrins and its role in oxygen transfer. J Am Chem Soc 2015; 137:2875-85. [PMID: 25651467 PMCID: PMC4363944 DOI: 10.1021/ja508759t] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Ferryl porphyrins, P-Fe(IV)═O, are central reactive intermediates in the catalytic cycles of numerous heme proteins and a variety of model systems. There has been considerable interest in elucidating factors, such as terminal oxo basicity, that may control ferryl reactivity. Here, the sulfonated, water-soluble ferryl porphyrin complexes tetramesitylporphyrin, oxoFe(IV)TMPS (FeTMPS-II), its 2,6-dichlorophenyl analogue, oxoFe(IV)TDClPS (FeTDClPS-II), and two other analogues are shown to be protonated under turnover conditions to produce the corresponding bis-aqua-iron(III) porphyrin cation radicals. The results reveal a novel internal electromeric equilibrium, P-Fe(IV)═O ⇆ P(+)-Fe(III)(OH2)2. Reversible pKa values in the range of 4-6.3 have been measured for this process by pH-jump, UV-vis spectroscopy. Ferryl protonation has important ramifications for C-H bond cleavage reactions mediated by oxoiron(IV) porphyrin cation radicals in protic media. Both solvent O-H and substrate C-H deuterium kinetic isotope effects are observed for these reactions, indicating that hydrocarbon oxidation by these oxoiron(IV) porphyrin cation radicals occurs via a solvent proton-coupled hydrogen atom transfer from the substrate that has not been previously described. The effective FeO-H bond dissociation energies for FeTMPS-II and FeTDClPS-II were estimated from similar kinetic reactivities of the corresponding oxoFe(IV)TMPS(+) and oxoFe(IV)TDClPS(+) species to be ∼92-94 kcal/mol. Similar values were calculated from the two-proton P(+)-Fe(III)(OH2)2 pKa(obs) and the porphyrin oxidation potentials, despite a 230 mV range for the iron porphyrins examined. Thus, the iron porphyrin with the lower ring oxidation potential has a compensating higher basicity of the ferryl oxygen. The solvent-derived proton adds significantly to the driving force for C-H bond scission.
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Affiliation(s)
- Nicholas C. Boaz
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Seth R. Bell
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - John T. Groves
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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37
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Abstract
In order to address how diverse metalloprotein active sites, in particular those containing iron and copper, guide O₂binding and activation processes to perform diverse functions, studies of synthetic models of the active sites have been performed. These studies have led to deep, fundamental chemical insights into how O₂coordinates to mono- and multinuclear Fe and Cu centers and is reduced to superoxo, peroxo, hydroperoxo, and, after O-O bond scission, oxo species relevant to proposed intermediates in catalysis. Recent advances in understanding the various factors that influence the course of O₂activation by Fe and Cu complexes are surveyed, with an emphasis on evaluating the structure, bonding, and reactivity of intermediates involved. The discussion is guided by an overarching mechanistic paradigm, with differences in detail due to the involvement of disparate metal ions, nuclearities, geometries, and supporting ligands providing a rich tapestry of reaction pathways by which O₂is activated at Fe and Cu sites.
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38
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Ji L, Franke A, Brindell M, Oszajca M, Zahl A, van Eldik R. Combined experimental and theoretical study on the reactivity of compounds I and II in horseradish peroxidase biomimetics. Chemistry 2014; 20:14437-50. [PMID: 25220399 DOI: 10.1002/chem.201402347] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Indexed: 12/21/2022]
Abstract
For the exploration of the intrinsic reactivity of two key active species in the catalytic cycle of horseradish peroxidase (HRP), Compound I (HRP-I) and Compound II (HRP-II), we generated in situ [Fe(IV) O(TMP(+.) )(2-MeIm)](+) and [Fe(IV) O(TMP)(2-MeIm)](0) (TMP=5,10,15,20-tetramesitylporphyrin; 2-MeIm=2-methylimidazole) as biomimetics for HRP-I and HRP-II, respectively. Their catalytic activities in epoxidation, hydrogen abstraction, and heteroatom oxidation reactions were studied in acetonitrile at -15 °C by utilizing rapid-scan UV/Vis spectroscopy. Comparison of the second-order rate constants measured for the direct reactions of the HRP-I and HRP-II mimics with the selected substrates clearly confirmed the outstanding oxidizing capability of the HRP-I mimic, which is significantly higher than that of HRP-II. The experimental study was supported by computational modeling (DFT calculations) of the oxidation mechanism of the selected substrates with the involvement of quartet and doublet HRP-I mimics ((2,4) Cpd I) and the closed-shell triplet spin HRP-II model ((3) Cpd II) as oxidizing species. The significantly lower activation barriers calculated for the oxidation systems involving (2,4) Cpd I than those found for (3) Cpd II are in line with the much higher oxidizing efficiency of the HRP-I mimic proven in the experimental part of the study. In addition, the DFT calculations show that all three reaction types catalyzed by HRP-I occur on the doublet spin surface in an effectively concerted manner, whereas these reactions may proceed in a stepwise mechanism with the HRP-II mimic as oxidant. However, the high desaturation or oxygen rebound barriers during CH bond activation processes by the HRP-II mimic predict a sufficient lifetime for the substrate radical formed through hydrogen abstraction. Thus, the theoretical calculations suggest that the dissociation of the substrate radical may be a more favorable pathway than desaturation or oxygen rebound processes. Importantly, depending on the electronic nature of the oxidizing species, that is, (2,4) Cpd I or (3) Cpd II, an interesting region-selective conversion phenomenon between sulfoxidation and H-atom abstraction was revealed in the course of the oxidation reaction of dimethylsulfide. The combined experimental and theoretical study on the elucidation of the intrinsic reactivity patterns of the HRP-I and HRP-II mimics provides a valuable tool for evaluating the particular role of the HRP active species in biological systems.
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Affiliation(s)
- Li Ji
- Inorganic Chemistry, Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, Egerlandstrasse 1, 91058 Erlangen (Germany); College of Environmental and Resource Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou 310058 (China)
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Meininger DJ, Muzquiz N, Arman HD, Tonzetich ZJ. A convenient procedure for the synthesis of fluoro-iron(III) complexes of common synthetic porphyrinates. J PORPHYR PHTHALOCYA 2014. [DOI: 10.1142/s108842461450014x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We report here an improved method for the preparation of fluoro-iron(III) porphyrinate complexes. Treatment of [ Fe 2( P )2(μ- O )] (P = tetraphenylporphyrinate {TPP}, tetra-p-tolylporphyrinate {TTP}, or octaethylporphyrinate {OEP}) or [ Fe ( OH )( OH 2)( TMP )] (TMP = tetramesitylporphyrinate) with the commercially available fluorinating agent, Et 3 N ·3 HF , in dichloromethane affords the desired [ FeF ( P )] complexes in a straightforward fashion and in good yield while avoiding the use of aqueous hydrofluoric acid. All fluoro-iron(III) complexes have been completely characterized by a series of different spectroscopic techniques including cyclic voltammetry. Reaction of a representative complex, [ FeF ( OEP )], with various chloride reagents demonstrates that halide exchange with chloride is facile, but only proceeds at an appreciable rate in the presence of proton sources. Unexpectedly, treatment of [ FeF ( OEP )] with NOBF 4 did not to lead formation of an oxidized species, but rather to formation of the { Fe – NO }6 complex, [ Fe ( NO )( OEP )]( BF 4).
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Affiliation(s)
- Daniel J. Meininger
- Department of Chemistry, University of Texas at San Antonio (UTSA), One UTSA Circle, San Antonio, TX 78249, USA
| | - Nicanor Muzquiz
- Department of Chemistry, University of Texas at San Antonio (UTSA), One UTSA Circle, San Antonio, TX 78249, USA
| | - Hadi D. Arman
- Department of Chemistry, University of Texas at San Antonio (UTSA), One UTSA Circle, San Antonio, TX 78249, USA
| | - Zachary J. Tonzetich
- Department of Chemistry, University of Texas at San Antonio (UTSA), One UTSA Circle, San Antonio, TX 78249, USA
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40
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Castro L, Bühl M. Calculations of One-Electron Redox Potentials of Oxoiron(IV) Porphyrin Complexes. J Chem Theory Comput 2013; 10:243-51. [DOI: 10.1021/ct400975w] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Ludovic Castro
- School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9ST, Scotland, United Kingdom
| | - Michael Bühl
- School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9ST, Scotland, United Kingdom
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41
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Garcia-Bosch I, Sharma SK, Karlin KD. A selective stepwise heme oxygenase model system: an iron(IV)-oxo porphyrin π-cation radical leads to a verdoheme-type compound via an isoporphyrin intermediate. J Am Chem Soc 2013; 135:16248-51. [PMID: 24147457 DOI: 10.1021/ja405739m] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The selective oxidation of the α-position of two heme-Fe(III) tetraarylporphryinate complexes occurs when water(hydroxide) attacks their oxidized Cmpd I-type equivalents, high-valent Fe(IV)═O π-cation radical species ((P(+•))Fe(IV)═O). Stepwise intermediate formation occurs, as detected by UV-vis spectroscopic monitoring or mass spectrometric interrogation, being iron(III) isoporphyrins, iron(III) benzoyl-biliverdins, and the final verdoheme-like products. Heme oxygenase (HO) enzymes could proceed through heterolytic cleavage of an iron(III)-hydroperoxo intermediate to form a transient Cmpd I-type species.
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Affiliation(s)
- Isaac Garcia-Bosch
- Department of Chemistry, The Johns Hopkins University , Baltimore, Maryland 21218, United States
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42
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Kumar D, Latifi R, Kumar S, Rybak-Akimova EV, Sainna MA, de Visser SP. Rationalization of the Barrier Height for p-Z-styrene Epoxidation by Iron(IV)-Oxo Porphyrin Cation Radicals with Variable Axial Ligands. Inorg Chem 2013; 52:7968-79. [DOI: 10.1021/ic4005104] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Devesh Kumar
- Department of Applied Physics, School of Physical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar,
Rae Bareilly Road, Lucknow 226-025, India
| | - Reza Latifi
- Manchester Institute of Biotechnology and School
of Chemical Engineering and Analytical Science, University of Manchester, 131 Princess Street, Manchester M1 7DN,
U.K
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United
States
| | - Suresh Kumar
- Department of Applied Physics, School of Physical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar,
Rae Bareilly Road, Lucknow 226-025, India
| | | | - Mala A. Sainna
- Manchester Institute of Biotechnology and School
of Chemical Engineering and Analytical Science, University of Manchester, 131 Princess Street, Manchester M1 7DN,
U.K
| | - Sam P. de Visser
- Manchester Institute of Biotechnology and School
of Chemical Engineering and Analytical Science, University of Manchester, 131 Princess Street, Manchester M1 7DN,
U.K
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43
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Zhang R, He Q, Chatfield D, Wang X. Paramagnetic nuclear magnetic resonance relaxation and molecular mechanics studies of the chloroperoxidase-indole complex: insights into the mechanism of chloroperoxidase-catalyzed regioselective oxidation of indole. Biochemistry 2013; 52:3688-701. [PMID: 23634952 DOI: 10.1021/bi4002437] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To unravel the mechanism of chloroperoxidase (CPO)-catalyzed regioselective oxidation of indole, we studied the structure of the CPO-indole complex using nuclear magnetic resonance (NMR) relaxation measurements and computational techniques. The dissociation constant (KD) of the CPO-indole complex was calculated to be approximately 21 mM. The distances (r) between protons of indole and the heme iron calculated via NMR relaxation measurements and molecular docking revealed that the pyrrole ring of indole is oriented toward the heme with its 2-H pointing directly at the heme iron. Both KD and r values are independent of pH in the range of 3.0-6.5. The stability and structure of the CPO-indole complex are also independent of the concentration of chloride or iodide ion. Molecular docking suggests the formation of a hydrogen bond between the NH group of indole and the carboxyl O of Glu 183 in the binding of indole to CPO. Simulated annealing of the CPO-indole complex using r values from NMR experiments as distance restraints reveals that the van der Waals interactions were much stronger than the Coulomb interactions in the binding of indole to CPO, indicating that the association of indole with CPO is primarily governed by hydrophobic rather than electrostatic interactions. This work provides the first experimental and theoretical evidence of the long-sought mechanism that leads to the "unexpected" regioselectivity of the CPO-catalyzed oxidation of indole. The structure of the CPO-indole complex will serve as a lighthouse in guiding the design of CPO mutants with tailor-made activities for biotechnological applications.
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Affiliation(s)
- Rui Zhang
- Department of Chemistry and Biochemistry, Florida International University , Miami, Florida 33199, United States
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44
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Latifi R, Sainna MA, Rybak-Akimova EV, de Visser SP. Does Hydrogen-Bonding Donation to Manganese(IV)-Oxo and Iron(IV)-Oxo Oxidants Affect the Oxygen-Atom Transfer Ability? A Computational Study. Chemistry 2013; 19:4058-68. [DOI: 10.1002/chem.201202811] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2012] [Revised: 11/16/2012] [Indexed: 12/21/2022]
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45
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Zyska B, Schwalbe M. Synthesis of sterically hindered xanthene-modified iron corroles with catalase-like activity. Chem Commun (Camb) 2013; 49:3799-801. [DOI: 10.1039/c3cc40625c] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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46
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Intrinsic properties and reactivities of mononuclear nonheme iron–oxygen complexes bearing the tetramethylcyclam ligand. Coord Chem Rev 2013. [DOI: 10.1016/j.ccr.2012.06.002] [Citation(s) in RCA: 137] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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47
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Takahashi A, Yamaki D, Ikemura K, Kurahashi T, Ogura T, Hada M, Fujii H. Effect of the Axial Ligand on the Reactivity of the Oxoiron(IV) Porphyrin π-Cation Radical Complex: Higher Stabilization of the Product State Relative to the Reactant State. Inorg Chem 2012; 51:7296-305. [DOI: 10.1021/ic3006597] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Akihiro Takahashi
- Institute for Molecular
Science
and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Myodaiji, Okazaki 444-8787,
Japan
- Department of Functional
Molecular
Science, The Graduate University for Advanced Studies (SOKENDAI), Myodaiji, Okazaki 444-8787, Japan
| | - Daisuke Yamaki
- Department of Chemistry, Graduate
School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397,
Japan
| | - Kenichiro Ikemura
- Department of Life
Science and
Picobiology Institute, Graduate
School of Life Science, University of Hyogo, Koto, Kamigori, Ako, Hyogo 678-1297, Japan
| | - Takuya Kurahashi
- Institute for Molecular
Science
and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Myodaiji, Okazaki 444-8787,
Japan
- Department of Functional
Molecular
Science, The Graduate University for Advanced Studies (SOKENDAI), Myodaiji, Okazaki 444-8787, Japan
| | - Takashi Ogura
- Department of Life
Science and
Picobiology Institute, Graduate
School of Life Science, University of Hyogo, Koto, Kamigori, Ako, Hyogo 678-1297, Japan
| | - Masahiko Hada
- Department of Chemistry, Graduate
School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397,
Japan
| | - Hiroshi Fujii
- Institute for Molecular
Science
and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Myodaiji, Okazaki 444-8787,
Japan
- Department of Functional
Molecular
Science, The Graduate University for Advanced Studies (SOKENDAI), Myodaiji, Okazaki 444-8787, Japan
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48
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Yoon H, Morimoto Y, Lee YM, Nam W, Fukuzumi S. Electron-transfer properties of a nonheme manganese(iv)–oxo complex acting as a stronger one-electron oxidant than the iron(iv)–oxo analogue. Chem Commun (Camb) 2012; 48:11187-9. [DOI: 10.1039/c2cc36291k] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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