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Wu Z, Zhang X, Gao L, Sun D, Zhao Y, Nam W, Wang Y. Elusive Active Intermediates and Reaction Mechanisms of ortho-/ ipso-Hydroxylation of Benzoic Acid by Hydrogen Peroxide Mediated by Bioinspired Iron(II) Catalysts. Inorg Chem 2023; 62:14261-14278. [PMID: 37604675 DOI: 10.1021/acs.inorgchem.3c01576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
Aromatic hydroxylation of benzoic acids (BzOH) to salicylates and phenolates is fundamentally interesting in industrial chemistry. However, key mechanistic uncertainties and dichotomies remain after decades of effort. Herein, the elusive mechanism of the competitive ortho-/ipso-hydroxylation of BzOH by H2O2 mediated by a nonheme iron(II) catalyst was comprehensively investigated using density functional theory calculations. Results revealed that the long-postulated FeV(O)(anti-BzO) oxidant is an FeIV(O)(anti-BzO•) species 2 (anti- and syn- are defined by the orientation of the carboxyl oxygen of BzO to the oxo), which rules out the noted two-oxidant mechanism proposed previously. We propose a new mechanism in which, following the formation of an FeV(O)(syn-BzO) species (3) and its electromer FeIV(O)(syn-BzO•) (3'), 3/3' either converts to salicylate and phenolate via intramolecular self-hydroxylation (route A) or acts as an oxidant to oxygenate another BzOH to generate the same products (route B). In route A, the rotation of the BzO group along the C-O bond forms 2, in which the BzO group is orientated by π-π stacking interactions. An electrophilic ipso-addition forms a phenolate by concomitant decarboxylation or an ortho-attack forms a cationic complex, which readily undergoes an NIH shift and a BzOH-assisted proton shift to form a salicylate. In route B, 3 oxidizes an additional BzOH molecule directed by hydrogen bonding and π-π stacking interactions. In both routes, selectivity is determined by the chemical property of the BzO ring. These mechanistic findings provide a clear mechanistic scenario and enrich the knowledge of hydroxylation of aromatic acids.
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Affiliation(s)
- Zhimin Wu
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China
- Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, Zhejiang, China
| | - Xuan Zhang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China
- Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, Zhejiang, China
| | - Lanping Gao
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China
- Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, Zhejiang, China
| | - Dongru Sun
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China
- Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, Zhejiang, China
| | - Yufen Zhao
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China
- Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, Zhejiang, China
| | - 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, China
| | - Yong Wang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China
- Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, Zhejiang, China
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Cao X, Song H, Li XX, Zhao Y, Qiao Q, Wang Y. Which is the real oxidant in the competitive ligand self-hydroxylation and substrate oxidation, a biomimetic iron(II)-hydroperoxo species or an oxo-iron(IV)-hydroxy one? Dalton Trans 2022; 51:7571-7580. [DOI: 10.1039/d2dt00797e] [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
Nonheme iron(II)-hydroperoxo species (FeII-(η2-OOH)) 1 and the concomitant oxo-iron(IV)-hydroxyl one 2 are proposed as the key intermediates of a large class of 2-oxoglutarate dependent dioxygenases (e.g., isopenicillin N synthase). Extensive...
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Rebilly JN, Herrero C, Sénéchal-David K, Guillot R, Inceoglu T, Maisonneuve H, Banse F. Second-sphere effects on H 2O 2 activation by non-heme Fe II complexes: role of a phenol group in the [H 2O 2]-dependent accumulation of Fe IVO vs. Fe IIIOOH. Chem Sci 2021; 12:15691-15699. [PMID: 35003600 PMCID: PMC8653992 DOI: 10.1039/d1sc03303d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 11/17/2021] [Indexed: 12/03/2022] Open
Abstract
Redox metalloenzymes achieve very selective oxidation reactions under mild conditions using O2 or H2O2 as oxidants and release harmless side-products like water. Their oxidation selectivity is intrinsically linked to the control of the oxidizing species generated during the catalytic cycle. To do so, a second coordination sphere is used in order to create a pull effect during the activation of O2 or H2O2, thus ensuring a heterolytic O-O bond cleavage. Herein, we report the synthesis and study of a new non-heme FeII complex bearing a pentaazadentate first coordination sphere and a pendant phenol group. Its reaction with H2O2 generates the classical FeIIIOOH species at high H2O2 loading. But at low H2O2 concentrations, an FeIVO species is generated instead. The formation of the latter is directly related to the presence of the 2nd sphere phenol group. Kinetic, variable temperature and labelling studies support the involvement of the attached phenol as a second coordination sphere moiety (weak acid) during H2O2 activation. Our results suggest a direct FeII → FeIVO conversion directed by the 2nd sphere phenol via the protonation of the distal O atom of the FeII/H2O2 adduct leading to a heterolytic O-O bond cleavage.
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Affiliation(s)
- Jean-Noël Rebilly
- Université Paris-Saclay, CNRS, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) 91405 Orsay Cedex France
| | - Christian Herrero
- Université Paris-Saclay, CNRS, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) 91405 Orsay Cedex France
| | - Katell Sénéchal-David
- Université Paris-Saclay, CNRS, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) 91405 Orsay Cedex France
| | - Régis Guillot
- Université Paris-Saclay, CNRS, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) 91405 Orsay Cedex France
| | - Tanya Inceoglu
- Université Paris-Saclay, CNRS, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) 91405 Orsay Cedex France
| | - Hélène Maisonneuve
- Université Paris-Saclay, CNRS, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) 91405 Orsay Cedex France
| | - Frédéric Banse
- Université Paris-Saclay, CNRS, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) 91405 Orsay Cedex France
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Yeh CG, Hörner G, Visser SP. Computational Study on O–O Bond Formation on a Mononuclear Non‐Heme Iron Center. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000321] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Chieh‐Chih George Yeh
- Manchester Institute of Biotechnology and Department of Chemical Engineering and Analytical Science The University of Manchester 131 Princess Street M1 7DN Manchester UK
| | - Gerald Hörner
- Institut für Anorganische Chemie IV / NW I Universität Bayreuth Universitätsstraße 30 95440 Bayreuth Germany
| | - Sam P. Visser
- Manchester Institute of Biotechnology and Department of Chemical Engineering and Analytical Science The University of Manchester 131 Princess Street M1 7DN Manchester UK
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Rebilly J, Zhang W, Herrero C, Dridi H, Sénéchal‐David K, Guillot R, Banse F. Hydroxylation of Aromatics by H
2
O
2
Catalyzed by Mononuclear Non‐heme Iron Complexes: Role of Triazole Hemilability in Substrate‐Induced Bifurcation of the H
2
O
2
Activation Mechanism. Chemistry 2019; 26:659-668. [DOI: 10.1002/chem.201903239] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Indexed: 12/31/2022]
Affiliation(s)
- Jean‐Noël Rebilly
- Institut de Chimie Moléculaire et des Matériaux d'OrsayUniversité Paris-Sud, Université Paris-Saclay 91405 Orsay cedex France
| | - Wenli Zhang
- Institut de Chimie Moléculaire et des Matériaux d'OrsayUniversité Paris-Sud, Université Paris-Saclay 91405 Orsay cedex France
| | - Christian Herrero
- Institut de Chimie Moléculaire et des Matériaux d'OrsayUniversité Paris-Sud, Université Paris-Saclay 91405 Orsay cedex France
| | - Hachem Dridi
- Institut de Chimie Moléculaire et des Matériaux d'OrsayUniversité Paris-Sud, Université Paris-Saclay 91405 Orsay cedex France
| | - Katell Sénéchal‐David
- Institut de Chimie Moléculaire et des Matériaux d'OrsayUniversité Paris-Sud, Université Paris-Saclay 91405 Orsay cedex France
| | - Régis Guillot
- Institut de Chimie Moléculaire et des Matériaux d'OrsayUniversité Paris-Sud, Université Paris-Saclay 91405 Orsay cedex France
| | - Frédéric Banse
- Institut de Chimie Moléculaire et des Matériaux d'OrsayUniversité Paris-Sud, Université Paris-Saclay 91405 Orsay cedex France
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Xu S, Draksharapu A, Rasheed W, Que L. Acid pKa Dependence in O–O Bond Heterolysis of a Nonheme FeIII–OOH Intermediate To Form a Potent FeV═O Oxidant with Heme Compound I-Like Reactivity. J Am Chem Soc 2019; 141:16093-16107. [DOI: 10.1021/jacs.9b08442] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Shuangning Xu
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Apparao Draksharapu
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Waqas Rasheed
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
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Sénéchal-David K, Buron C, Ségaud N, Rebilly JN, Dos Santos A, Farjon J, Guillot R, Herrero C, Inceoglu T, Banse F. Non-Heme Fe II Diastereomeric Complexes Bearing a Hexadentate Ligand: Unexpected Consequences for the Spin State and Catalytic Oxidation Properties. Chemistry 2019; 25:12405-12411. [PMID: 31276256 DOI: 10.1002/chem.201902423] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/03/2019] [Indexed: 12/12/2022]
Abstract
The reactivity and selectivity of non-heme FeII complexes as oxidation catalysts can be substantially modified by alteration of the ligand backbone or introduction of various substituents. In comparison with the hexadentate ligand N,N,N',N'-tetrakis(pyridin-2-ylmethyl)ethane-1,2-diamine (TPEN), N,N'-bis[1-(pyridin-2-yl)ethyl]-N,N'-bis(pyridin-2-ylmethyl)ethane-1,2-diamine (2Me L6 2 ) has a methyl group on two of the four picolyl positions. FeII complexation by 2Me L6 2 yields two diastereomeric complexes with very similar structures, which only differ in the axial/equatorial positions occupied by the methylated pyridyl groups. In solution, these two isomers exhibit different magnetic behaviors. Whereas one isomer exhibits temperature-dependent spin-state conversion between the S=0 and S=2 states, the other is more reluctant towards this spin-state equilibrium and is essentially diamagnetic at room temperature. Their catalytic properties for the oxidation of anisole by H2 O2 are very different and correlate with their magnetic properties, which reflect their lability/inertness. These different properties most likely depend on the different steric constraints of the methylated pyridyl groups in the two complexes.
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Affiliation(s)
- Katell Sénéchal-David
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Univ. Paris-Sud, Univ. Paris-Saclay, CNRS, 91405, Orsay cedex, France
| | - Charlotte Buron
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Univ. Paris-Sud, Univ. Paris-Saclay, CNRS, 91405, Orsay cedex, France
| | - Nathalie Ségaud
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Univ. Paris-Sud, Univ. Paris-Saclay, CNRS, 91405, Orsay cedex, France.,Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland
| | - Jean-Noël Rebilly
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Univ. Paris-Sud, Univ. Paris-Saclay, CNRS, 91405, Orsay cedex, France
| | - Amandine Dos Santos
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Univ. Paris-Sud, Univ. Paris-Saclay, CNRS, 91405, Orsay cedex, France
| | - Jonathan Farjon
- CEISAM, Université de Nantes, CNRS, 2, chemin de la Houssinière, 44322, Nantes CEDEX 3, France
| | - Régis Guillot
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Univ. Paris-Sud, Univ. Paris-Saclay, CNRS, 91405, Orsay cedex, France
| | - Christian Herrero
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Univ. Paris-Sud, Univ. Paris-Saclay, CNRS, 91405, Orsay cedex, France
| | - Tanya Inceoglu
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Univ. Paris-Sud, Univ. Paris-Saclay, CNRS, 91405, Orsay cedex, France
| | - Frédéric Banse
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Univ. Paris-Sud, Univ. Paris-Saclay, CNRS, 91405, Orsay cedex, France
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8
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Cantú Reinhard FG, DuBois JL, de Visser SP. Catalytic Mechanism of Nogalamycin Monoxygenase: How Does Nature Synthesize Antibiotics without a Metal Cofactor? J Phys Chem B 2018; 122:10841-10854. [DOI: 10.1021/acs.jpcb.8b09648] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- 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, U.K
| | - Jennifer L. DuBois
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59715-3400, 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, U.K
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9
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A Comparative Review on the Catalytic Mechanism of Nonheme Iron Hydroxylases and Halogenases. Catalysts 2018. [DOI: 10.3390/catal8080314] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Enzymatic halogenation and haloperoxidation are unusual processes in biology; however, a range of halogenases and haloperoxidases exist that are able to transfer an aliphatic or aromatic C–H bond into C–Cl/C–Br. Haloperoxidases utilize hydrogen peroxide, and in a reaction with halides (Cl−/Br−), they react to form hypohalides (OCl−/OBr−) that subsequently react with substrate by halide transfer. There are three types of haloperoxidases, namely the iron-heme, nonheme vanadium, and flavin-dependent haloperoxidases that are reviewed here. In addition, there are the nonheme iron halogenases that show structural and functional similarity to the nonheme iron hydroxylases and form an iron(IV)-oxo active species from a reaction of molecular oxygen with α-ketoglutarate on an iron(II) center. They subsequently transfer a halide (Cl−/Br−) to an aliphatic C–H bond. We review the mechanism and function of nonheme iron halogenases and hydroxylases and show recent computational modelling studies of our group on the hectochlorin biosynthesis enzyme and prolyl-4-hydroxylase as examples of nonheme iron halogenases and hydroxylases. These studies have established the catalytic mechanism of these enzymes and show the importance of substrate and oxidant positioning on the stereo-, chemo- and regioselectivity of the reaction that takes place.
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10
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Cantú Reinhard FG, Barman P, Mukherjee G, Kumar J, Kumar D, Kumar D, Sastri CV, de Visser SP. Keto-Enol Tautomerization Triggers an Electrophilic Aldehyde Deformylation Reaction by a Nonheme Manganese(III)-Peroxo Complex. J Am Chem Soc 2017; 139:18328-18338. [PMID: 29148746 DOI: 10.1021/jacs.7b10033] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Oxygen atom transfer by high-valent enzymatic intermediates remains an enigma in chemical catalysis. In particular, manganese is an important first-row metal involved in key biochemical processes, including the biosynthesis of molecular oxygen (through the photosystem II complex) and biodegradation of toxic superoxide to hydrogen peroxide by superoxide dismutase. Biomimetic models of these biological systems have been developed to gain understanding on the structure and properties of short-lived intermediates but also with the aim to create environmentally benign oxidants. In this work, we report a combined spectroscopy, kinetics and computational study on aldehyde deformylation by two side-on manganese(III)-peroxo complexes with bispidine ligands. Both manganese(III)-peroxo complexes are characterized by UV-vis and mass spectrometry techniques, and their reactivity patterns with aldehydes was investigated. We find a novel mechanism for the reaction that is initiated by a hydrogen atom abstraction reaction, which enables a keto-enol tautomerization in the substrate. This is an essential step in the mechanism that makes an electrophilic attack on the olefin bond possible as the attack on the aldehyde carbonyl is too high in energy. Kinetics studies determine a large kinetic isotope effect for the replacement of the transferring hydrogen atom by deuterium, while replacing the transferring hydrogen atom by a methyl group makes the substrate inactive and hence confirm the hypothesized mechanism. Our new mechanism is confirmed with density functional theory modeling on the full mechanism and rationalized through valence bond and thermochemical cycles. Our unprecedented new mechanism may have relevance to biological and biomimetic chemistry processes in general and gives insight into the reactivity patterns of metal-peroxo and metal-hydroperoxo intermediates in general.
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Affiliation(s)
- Fabián G Cantú Reinhard
- The Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester , 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Prasenjit Barman
- Department of Chemistry, Indian Institute of Technology Guwahati 781039, Assam, India
| | - Gourab Mukherjee
- Department of Chemistry, Indian Institute of Technology Guwahati 781039, Assam, India
| | - Jitendra Kumar
- Department of Applied Physics, School for Physical Sciences, Babasaheb Bhimrao Ambedkar University , Lucknow 226025, UP, India
| | - Deep Kumar
- Department of Applied Physics, School for Physical Sciences, Babasaheb Bhimrao Ambedkar University , Lucknow 226025, UP, India
| | - Devesh Kumar
- Department of Applied Physics, School for Physical Sciences, Babasaheb Bhimrao Ambedkar University , Lucknow 226025, UP, India
| | - Chivukula V Sastri
- Department of Chemistry, Indian Institute of Technology 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, United Kingdom
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11
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Zhang J, Wei WJ, Lu X, Yang H, Chen Z, Liao RZ, Yin G. Nonredox Metal Ions Promoted Olefin Epoxidation by Iron(II) Complexes with H2O2: DFT Calculations Reveal Multiple Channels for Oxygen Transfer. Inorg Chem 2017; 56:15138-15149. [DOI: 10.1021/acs.inorgchem.7b02463] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Jisheng Zhang
- School of Chemistry and Chemical Engineering, Key laboratory
of Material Chemistry for Energy Conversion and Storage, Ministry
of Education, Hubei Key Laboratory of Material Chemistry and Service
Failure, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Wen-Jie Wei
- School of Chemistry and Chemical Engineering, Key laboratory
of Material Chemistry for Energy Conversion and Storage, Ministry
of Education, Hubei Key Laboratory of Material Chemistry and Service
Failure, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Xiaoyan Lu
- School of Chemistry and Chemical Engineering, Key laboratory
of Material Chemistry for Energy Conversion and Storage, Ministry
of Education, Hubei Key Laboratory of Material Chemistry and Service
Failure, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Hang Yang
- School of Chemistry and Chemical Engineering, Key laboratory
of Material Chemistry for Energy Conversion and Storage, Ministry
of Education, Hubei Key Laboratory of Material Chemistry and Service
Failure, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Zhuqi Chen
- School of Chemistry and Chemical Engineering, Key laboratory
of Material Chemistry for Energy Conversion and Storage, Ministry
of Education, Hubei Key Laboratory of Material Chemistry and Service
Failure, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Rong-Zhen Liao
- School of Chemistry and Chemical Engineering, Key laboratory
of Material Chemistry for Energy Conversion and Storage, Ministry
of Education, Hubei Key Laboratory of Material Chemistry and Service
Failure, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Guochuan Yin
- School of Chemistry and Chemical Engineering, Key laboratory
of Material Chemistry for Energy Conversion and Storage, Ministry
of Education, Hubei Key Laboratory of Material Chemistry and Service
Failure, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
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12
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Faponle AS, de Visser SP. The Role of Nonheme Transition Metal-Oxo, -Peroxo, and -Superoxo Intermediates in Enzyme Catalysis and Reactions of Bioinspired Complexes. ADVANCES IN INORGANIC CHEMISTRY 2017. [DOI: 10.1016/bs.adioch.2017.01.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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13
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Buron C, Groni S, Ségaud N, Mazerat S, Dragoe D, Fave C, Sénéchal-David K, Schöllhorn B, Banse F. Self-assembled monolayer formation of a (N 5)Fe(ii) complex on gold electrodes: electrochemical properties and coordination chemistry on a surface. Dalton Trans 2016; 45:19053-19061. [PMID: 27858029 DOI: 10.1039/c6dt03870k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A coordinatively unsaturated FeII complex bearing a pentadentate ligand (N,N',N'-tris(2-pyridyl-methyl)-1,2-diaminoethane) functionalized with a cyclic disulfide group has been prepared in order to graft reactive metal entities as self-assembled monolayers (SAMs) on gold electrodes. Prior to grafting, exogenous ligand exchange has been investigated by cyclic voltammetry (CV) in solution, showing that the nature of the first coordination sphere (N5)FeII-X (X = Cl-, OTf-, MeCN, acetone) can be tuned, thanks to the control of the chemical conditions. The FeII complex has been immobilized on gold electrodes by spontaneous (passive) adsorption as well as by an electro-assisted method. The resulting SAMs were characterised by XPS and AFM analyses. CV experiments implementing these SAMs as working electrodes showed that the first coordination sphere of the grafted FeII complex can be controlled by adjusting the chemical conditions, similarly to the studies in a homogeneous solution. Finally, the supported FeII complex proved to be reactive with superoxide generated at the electrode surface by reduction of dissolved dioxygen. Under the employed conditions, leaking of the metal complex was not observed.
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Affiliation(s)
- Charlotte Buron
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris Sud, Université Paris Saclay, CNRS, 91405, Orsay Cedex, France.
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14
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Rokob TA. Pathways for Arene Oxidation in Non-Heme Diiron Enzymes: Lessons from Computational Studies on Benzoyl Coenzyme A Epoxidase. J Am Chem Soc 2016; 138:14623-14638. [PMID: 27682344 DOI: 10.1021/jacs.6b06987] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oxygenation of aromatic rings using O2 is catalyzed by several non-heme carboxylate-bridged diiron enzymes. In order to provide a general mechanistic description for these reactions, computational studies were carried out at the ONIOM(B3LYP/BP86/Amber) level on the non-heme diiron enzyme benzoyl coenzyme A epoxidase, BoxB. The calculations revealed four possible pathways for attacking the aromatic ring: (a) electrophilic (2e-) attack by a bis(μ-oxo)-diiron(IV) species (Q pathway); (b) electrophilic (2e-) attack via the σ* orbital of a μ-η2:η2-peroxo-diiron(III) intermediate (Pσ* pathway); (c) radical (1e-) attack via the π*-orbital of a superoxo-diiron(II,III) species (Pπ* pathway); (d) radical (1e-) attack of a partially quenched bis(μ-oxo)-diiron(IV) intermediate (Q' pathway). The results allowed earlier work of de Visser on olefin epoxidation by diiron complexes and QM-cluster studies of Liao and Siegbahn on BoxB to be put into a broader perspective. Parallels with epoxidation using organic peracids were also examined. Specifically for the BoxB enzyme, the Q pathway was found to be the most preferred, but the corresponding bis(μ-oxo)-diiron(IV) species is significantly destabilized and not expected to be directly observable. Epoxidation via the Pσ* pathway represents an energetically somewhat higher lying alternative; possible strategies for experimental discrimination are discussed. The selectivity toward epoxidation is shown to stem from a combination of inherent electronic properties of the thioacyl substituent and enzymatic constraints. Possible implications of the results for toluene monooxygenases are considered as well.
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Affiliation(s)
- Tibor András Rokob
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences , Magyar Tudósok körútja 2, 1117 Budapest, Hungary
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