1
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Misawa-Suzuki T, Nagao H. Ru(IV)-Ru(IV) complexes having the doubly oxido-bridged core with a bridging carbonato or hydrogencarbonato ligand. Dalton Trans 2023; 52:2863-2871. [PMID: 36762568 DOI: 10.1039/d2dt04080h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Ru(IV)-Ru(IV) complexes having the doubly oxido-bridged diamond core with a bridging carbonato or hydrogencarbonato ligand, [{RuIV(ebpma)}2(μ-O)2(μ-O2CO(H)m)]Xn (ebpma; ethylbis(2-pyridylmethyl)amine, m = 0; [IV,IV]X2 (X = PF6, ClO4), m = 1; [IV,IV_1H](ClO4)3), were isolated via the oxidation of the corresponding carbonato-bridged Ru(III)-Ru(IV) complex ([III,IV]+), and "[IV,IV](ClO4)2 and [IV,IV_1H](ClO4)3" were structurally characterized. The electrochemical and spectroscopic properties of [IV,IV]2+ and [IV,IV_1H]3+ were investigated both in organic solvents and aqueous solutions. The reactivity toward organic solvents having (a) methyl group(s) and reactions with organic substrates were studied as well. This should be the first time when systematic comparisons of the Ru(IV)-Ru(IV) species and corresponding Ru(III)-Ru(IV) complexes in the same tridentate ligand system were made.
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Affiliation(s)
- Tomoyo Misawa-Suzuki
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioicho Chiyoda-ku, Tokyo 102-8554, Japan.
| | - Hirotaka Nagao
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioicho Chiyoda-ku, Tokyo 102-8554, Japan.
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2
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Bio-Inspired Iron Pentadentate Complexes as Dioxygen Activators in the Oxidation of Cyclohexene and Limonene. Molecules 2023; 28:molecules28052240. [PMID: 36903486 PMCID: PMC10004738 DOI: 10.3390/molecules28052240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 02/24/2023] [Accepted: 02/25/2023] [Indexed: 03/04/2023] Open
Abstract
The use of dioxygen as an oxidant in fine chemicals production is an emerging problem in chemistry for environmental and economical reasons. In acetonitrile, the [(N4Py)FeII]2+ complex, [N4Py-N,N-bis(2-pyridylmethyl)-N-(bis-2-pyridylmethyl)amine] in the presence of the substrate activates dioxygen for the oxygenation of cyclohexene and limonene. Cyclohexane is oxidized mainly to 2-cyclohexen-1-one, and 2-cyclohexen-1-ol, cyclohexene oxide is formed in much smaller amounts. Limonene gives as the main products limonene oxide, carvone, and carveol. Perillaldehyde and perillyl alcohol are also present in the products but to a lesser extent. The investigated system is twice as efficient as the [(bpy)2FeII]2+/O2/cyclohexene system and comparable to the [(bpy)2MnII]2+/O2/limonene system. Using cyclic voltammetry, it has been shown that, when the catalyst, dioxgen, and substrate are present simultaneously in the reaction mixture, the iron(IV) oxo adduct [(N4Py)FeIV=O]2+ is formed, which is the oxidative species. This observation is supported by DFT calculations.
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3
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Xie J, Xie J, Miller CJ, Waite TD. Enhanced Direct Electron Transfer Mediated Contaminant Degradation by Fe(IV) Using a Carbon Black-Supported Fe(III)-TAML Suspension Electrode System. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:2557-2565. [PMID: 36725204 DOI: 10.1021/acs.est.2c08467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Iron complexes of tetra-amido macrocyclic ligands (Fe-TAML) are recognized to be effective catalysts for the degradation of a wide range of organic contaminants in homogeneous conditions with the high valent Fe(IV) and Fe(V) species generated on activation of the Fe-TAML complex by hydrogen peroxide (H2O2) recognized to be powerful oxidants. Electrochemical activation of Fe-TAML would appear an attractive alternative to H2O2 activation, especially if the Fe-TAML complex could be attached to the anode, as this would enable formation of high valent iron species at the anode and, importantly, retention of the valuable Fe-TAML complex within the reaction system. In this work, we affix Fe-TAML to the surface of carbon black particles and apply this "suspension anode" process to oxidize selected target compounds via generation of high valent iron species. We show that the overpotential for Fe(IV) formation is 0.17 V lower than the potential required to generate Fe(IV) electrochemically in homogeneous solution and also show that the stability of the Fe(IV) species is enhanced considerably compared to the homogeneous Fe-TAML case. Application of the carbon black-supported Fe-TAML suspension anode reactor to degradation of oxalate and hydroquinone with an initial pH value of 3 resulted in oxidation rate constants that were up to three times higher than could be achieved by anodic oxidation in the absence of Fe-TAML and at energy consumptions per order of removal substantially lower than could be achieved by alternate technologies.
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Affiliation(s)
- Jiangzhou Xie
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW2052, Australia
- UNSW Centre for Transformational Environmental Technologies, Yixing, Jiangsu Province, 214206, P.R. China
| | - Jieli Xie
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW2052, Australia
| | - Christopher J Miller
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW2052, Australia
| | - T David Waite
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW2052, Australia
- UNSW Centre for Transformational Environmental Technologies, Yixing, Jiangsu Province, 214206, P.R. China
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4
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Maldonado-Domínguez M, Srnec M. H-Atom Abstraction Reactivity through the Lens of Asynchronicity and Frustration with Their Counteracting Effects on Barriers. Inorg Chem 2022; 61:18811-18822. [DOI: 10.1021/acs.inorgchem.2c03269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Mauricio Maldonado-Domínguez
- J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, Prague 8 18223, Czech Republic
| | - Martin Srnec
- J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, Prague 8 18223, Czech Republic
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5
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Gogoi G, Baruah MJ, Biswas S, Hoque N, Lee S, Park YB, Saikia L, Bania KK. CuO-Fe(III)-Zeolite-Y as efficient catalyst for oxidative alcohol-amine coupling reactions. MOLECULAR CATALYSIS 2022. [DOI: 10.1016/j.mcat.2022.112458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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6
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Panda C, Doyle LM, Gericke R, McDonald AR. Rapid Iron(III)-Fluoride-Mediated Hydrogen Atom Transfer. Angew Chem Int Ed Engl 2021; 60:26281-26286. [PMID: 34582619 PMCID: PMC9298026 DOI: 10.1002/anie.202112683] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Indexed: 01/08/2023]
Abstract
We anticipate high-valent metal-fluoride species will be highly effective hydrogen atom transfer (HAT) oxidants because of the magnitude of the H-F bond (in the product) that drives HAT oxidation. We prepared a dimeric FeIII (F)-F-FeIII (F) complex (1) by reacting [FeII (NCCH3 )2 (TPA)](ClO4 )2 (TPA=tris(2-pyridylmethyl)amine) with difluoro(phenyl)-λ3 -iodane (difluoroiodobenzene). 1 was a sluggish oxidant, however, it was readily activated by reaction with Lewis or Brønsted acids to yield a monomeric [FeIII (TPA)(F)(X)]+ complex (2) where X=F/OTf. 1 and 2 were characterized using NMR, EPR, UV/Vis, and FT-IR spectroscopies and mass spectrometry. 2 was a remarkably reactive FeIII reagent for oxidative C-H activation, demonstrating reaction rates for hydrocarbon HAT comparable to the most reactive FeIII and FeIV oxidants.
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Affiliation(s)
- Chakadola Panda
- School of ChemistryTrinity College DublinThe University of Dublin, College GreenDublin 2Ireland
| | - Lorna M. Doyle
- School of ChemistryTrinity College DublinThe University of Dublin, College GreenDublin 2Ireland
| | - Robert Gericke
- School of ChemistryTrinity College DublinThe University of Dublin, College GreenDublin 2Ireland
- Current address: Helmholtz-Zentrum Dresden-Rossendorf e. V.Institute of Resource EcologyBautzner Landstrasse 40001328DresdenGermany
| | - Aidan R. McDonald
- School of ChemistryTrinity College DublinThe University of Dublin, College GreenDublin 2Ireland
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7
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Panda C, Doyle LM, Gericke R, McDonald AR. Rapid Iron(III)−Fluoride‐Mediated Hydrogen Atom Transfer. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202112683] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Chakadola Panda
- School of Chemistry Trinity College Dublin The University of Dublin, College Green Dublin 2 Ireland
| | - Lorna M. Doyle
- School of Chemistry Trinity College Dublin The University of Dublin, College Green Dublin 2 Ireland
| | - Robert Gericke
- School of Chemistry Trinity College Dublin The University of Dublin, College Green Dublin 2 Ireland
- Current address: Helmholtz-Zentrum Dresden-Rossendorf e. V. Institute of Resource Ecology Bautzner Landstrasse 400 01328 Dresden Germany
| | - Aidan R. McDonald
- School of Chemistry Trinity College Dublin The University of Dublin, College Green Dublin 2 Ireland
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8
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‘Oxygen-Consuming Complexes’–Catalytic Effects of Iron–Salen Complexes with Dioxygen. Catalysts 2021. [DOI: 10.3390/catal11121462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
[(salen)FeIII]+MeCN complex is a useful catalyst for cyclohexene oxidation with dioxygen. As the main products, ketone and alcohol are formed. In acetonitrile, [(salen)FeII]MeCN is rapidly oxidized by dioxygen, forming iron(III) species. Voltammetric electroreduction of the [(salen)FeIII]+MeCN complex in the presence of dioxygen causes the increase in current observed, which indicates the existence of a catalytic effect. Further transformations of the oxygen-activated iron(III) salen complex generate an effective catalyst. Based on the catalytic and electrochemical results, as well as DFT calculations, possible forms of active species in c-C6H10 oxidation have been proposed.
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9
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Fukuzumi S, Lee Y, Nam W. Deuterium kinetic isotope effects as redox mechanistic criterions. B KOREAN CHEM SOC 2021. [DOI: 10.1002/bkcs.12417] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Shunichi Fukuzumi
- Department of Chemistry and Nano Science Ewha Womans University Seoul Korea
- Faculty of Science and Engineering Meijo University Nagoya Aichi Japan
| | - Yong‐Min Lee
- Department of Chemistry and Nano Science Ewha Womans University Seoul Korea
- Research Institute for Basic Sciences Ewha Womans University Seoul Korea
| | - Wonwoo Nam
- Department of Chemistry and Nano Science Ewha Womans University Seoul Korea
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10
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Nesterova OV, Vassilyeva OY, Skelton BW, Bieńko A, Pombeiro AJL, Nesterov DS. A novel o-vanillin Fe(III) complex catalytically active in C-H oxidation: exploring the magnetic exchange interactions and spectroscopic properties with different DFT functionals. Dalton Trans 2021; 50:14782-14796. [PMID: 34595485 DOI: 10.1039/d1dt02366g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The novel complex [FeIIICl(L)2(H2O)] (1) was synthesized by interaction of iron(III) chloride with ethanol solution of o-vanillin (HL) and characterized by IR, UV/Vis spectroscopy, thermogravimetry and single crystal X-ray diffraction analysis. The molecules of 1 in the solid state are joined into supramolecular dimeric units, where a set of strong hydrogen bonds predefines the structure of the dimer according to the "key-lock" principle. From the Hirshfield surface analysis the contribution of π⋯π stacking to the overall stabilization of the dimer was found to be negligible. Broken symmetry DFT calculations suggested the presence of long-range antiferromagnetic interactions (J = -0.12 cm-1 for H = -JS1S2 formalism) occurring through the Fe-O⋯O-Fe pathway, as evidenced by the studies of the model dimers where the water molecules were substituted by acetonitrile and acetone ones. The benchmark studies using a set of literature examples and various DFT functionals revealed the hybrid-GGA B3LYP as the best one for prediction of FeIII⋯FeIII antiferromagnetic exchange couplings of small magnitude. Magnetic susceptibility measurements confirmed antiferromagnetic coupling between the metal atoms in 1 with a coupling constant of -0.35 cm-1. Catalytic studies demonstrated that 1 acts as an efficient catalyst in the oxidation of cyclohexane with hydrogen peroxide in the presence of nitric acid promoter and under mild conditions (yield up to 37% based on the substrate), while tert-butylhydroperoxide (TBHP) and m-chloroperoxybenzoic acid (m-CPBA) as oxidants exhibit less efficiency. Combined UV/TDDFT studies evidence the structural rearrangement of 1 in acetonitrile with the formation of [FeIIICl(L)2(CH3CN)] species. The TDDFT benchmark using nine common DFT functionals and two model compounds (o-vanillin and [FeIII(H2O)6]3+ ion) support the hybrid meta-GGA M06-2X functional as the one most correctly predicting the excited state structure for the Fe(III) complexes, under the conditions studied.
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Affiliation(s)
- Oksana V Nesterova
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
| | - Olga Yu Vassilyeva
- Department of Chemistry, Taras Shevchenko National University of Kyiv, 64/13 Volodymyrska str., Kyiv 01601, Ukraine.
| | - Brian W Skelton
- School of Molecular Sciences, M310, University of Western Australia, Perth, WA 6009, Australia
| | - Alina Bieńko
- Faculty of Chemistry, University of Wroclaw, F. Joliot-Curie 14, Wroclaw 50-383, Poland
| | - Armando J L Pombeiro
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal. .,Peoples' Friendship University of Russia (RUDN University), Research Institute of Chemistry, 6 Miklukho-Maklaya st, Moscow 117198, Russia
| | - Dmytro S Nesterov
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
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11
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Di Berto Mancini M, Del Gelsomino A, Di Stefano S, Frateloreto F, Lapi A, Lanzalunga O, Olivo G, Sajeva S. Change of Selectivity in C-H Functionalization Promoted by Nonheme Iron(IV)-oxo Complexes by the Effect of the N-hydroxyphthalimide HAT Mediator. ACS OMEGA 2021; 6:26428-26438. [PMID: 34661000 PMCID: PMC8515612 DOI: 10.1021/acsomega.1c03679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
A kinetic analysis of the hydrogen atom transfer (HAT) reactions from a series of organic compounds to the iron(IV)-oxo complex [(N4Py)FeIV(O)]2+ and to the phthalimide N-oxyl radical (PINO) has been carried out. The results indicate that a higher activating effect of α-heteroatoms toward the HAT from C-H bonds is observed with the more electrophilic PINO radical. When the N-hydroxy precursor of PINO, N-hydroxyphthalimide (NHPI), is used as a HAT mediator in the oxidation promoted by [(N4Py)FeIV(O)]2+, significant differences in terms of selectivity have been found. Product studies of the competitive oxidations of primary and secondary aliphatic alcohols (1-decanol, cyclopentanol, and cyclohexanol) with alkylaromatics (ethylbenzene and diphenylmethane) demonstrated that it is possible to modify the selectivity of the oxidations promoted by [(N4Py)FeIV(O)]2+ in the presence of NHPI. In fact, alkylaromatic substrates are more reactive in the absence of the mediator while alcohols are preferably oxidized in the presence of NHPI.
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Affiliation(s)
- Marika Di Berto Mancini
- Dipartimento
di Chimica and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione
Meccanismi di Reazione, c/o Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro, 5, I-00185 Rome, Italy
| | - Andrea Del Gelsomino
- Dipartimento
di Chimica and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione
Meccanismi di Reazione, c/o Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro, 5, I-00185 Rome, Italy
| | - Stefano Di Stefano
- Dipartimento
di Chimica and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione
Meccanismi di Reazione, c/o Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro, 5, I-00185 Rome, Italy
| | - Federico Frateloreto
- Dipartimento
di Chimica and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione
Meccanismi di Reazione, c/o Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro, 5, I-00185 Rome, Italy
| | - Andrea Lapi
- Dipartimento
di Chimica and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione
Meccanismi di Reazione, c/o Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro, 5, I-00185 Rome, Italy
| | - Osvaldo Lanzalunga
- Dipartimento
di Chimica and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione
Meccanismi di Reazione, c/o Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro, 5, I-00185 Rome, Italy
- CIRCC
Interuniversity Consortium Chemical Reactivity and Catalysis, Via Celso Ulpiani 27, 70126 Bari, Italy
| | - Giorgio Olivo
- Dipartimento
di Chimica and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione
Meccanismi di Reazione, c/o Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro, 5, I-00185 Rome, Italy
| | - Stefano Sajeva
- Dipartimento
di Chimica and Istituto CNR per i Sistemi Biologici (ISB-CNR), Sezione
Meccanismi di Reazione, c/o Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro, 5, I-00185 Rome, Italy
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12
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Rydel-Ciszek K. The most reactive iron and manganese complexes with N-pentadentate ligands for dioxygen activation—synthesis, characteristics, applications. REACTION KINETICS MECHANISMS AND CATALYSIS 2021. [PMCID: PMC8204929 DOI: 10.1007/s11144-021-02008-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The iron and manganese complexes that activate oxygen atom play multiple role in technologically relevant reactions as well as in biological transformations, in which exist in different redox states. Among them, high-valent oxo intermediate seems to be the most important one. Iron, and/or manganese-based processes have found application in many areas, starting from catalysis and sustainable technologies, through DNA oxidative cleavage, to new substances useful in chemotherapeutic drugs. This review is not only the latest detailed list of uses of homogeneous N-pentadentate iron and manganese catalysts for syntheses of valuable molecules with huge applications in green technologies, but also a kind of "a cookbook", collecting "recipes" for the discussed complexes, in which the sources necessary to obtain a full characterization of the compounds are presented. Following the catalytic activity of metalloenzymes, and taking into account the ubiquity of iron and manganese salts, which in combination with properly designed ligands may show similarity to natural systems, the discussed complexes can find application as new anti-cancer drugs. Also, owing to ability of oxygen atom to exchange in reaction with H2O, they can be successfully applied in photodriven reactions of water oxidation, as well as in chemically regenerated fuel cells as a redox catalyst.
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Affiliation(s)
- Katarzyna Rydel-Ciszek
- Department of Physical Chemistry, Faculty of Chemistry, Rzeszów University of Technology, al. Powstańców Warszawy 6, P.O. Box 85, 35-959 Rzeszów, Poland
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13
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Gericke R, Doyle LM, Farquhar ER, McDonald AR. Oxo-Free Hydrocarbon Oxidation by an Iron(III)-Isoporphyrin Complex. Inorg Chem 2020; 59:13952-13961. [PMID: 32955871 DOI: 10.1021/acs.inorgchem.0c01618] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Metal-halides that perform proton coupled electron-transfer (PCET) oxidation are an important new class of high-valent oxidant. In investigating metal-dihalides, we reacted [FeIII(Cl)(T(OMe)PP)] (1, T(OMe)PP = meso-tetra(4-methoxyphenyl)porphyrinyl) with (dichloroiodo)benzene. An FeIII-meso-chloro-isoporphyrin complex [FeIII(Cl)2(T(OMe)PP-Cl)] (2) was obtained. 2 was characterized by electronic absorption, 1H NMR, EPR, and X-ray absorption spectroscopies and mass spectrometry with support from computational analyses. 2 was reacted with a series of hydrocarbon substrates. The measured kinetic data exhibited a nonlinear behavior, whereby the oxidation followed a hydrogen-atom-transfer (HAT) PCET mechanism. The meso-chlorine atom was identified as the HAT agent. In one case, a halogenated product was identified by mass spectrometry. Our findings demonstrate that oxo-free hydrocarbon oxidation with heme systems is possible and show the potential for iron-dihalides in oxidative hydrocarbon halogenation.
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Affiliation(s)
- Robert Gericke
- School of Chemistry, College Green, Trinity College Dublin, The University of Dublin, Dublin 2 D02 PN40, Ireland
| | - Lorna M Doyle
- School of Chemistry, College Green, Trinity College Dublin, The University of Dublin, Dublin 2 D02 PN40, Ireland
| | - Erik R Farquhar
- National Synchrotron Light Source II, Brookhaven National Laboratory, Case Western Reserve University Center for Synchrotron Biosciences, Upton, New York 11973, United States
| | - Aidan R McDonald
- School of Chemistry, College Green, Trinity College Dublin, The University of Dublin, Dublin 2 D02 PN40, Ireland
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Mondal P, McDonald AR. Phenol Oxidation by a Nickel(III)-Fluoride Complex: Exploring the Influence of the Proton Accepting Ligand in PCET Oxidation. Chemistry 2020; 26:10083-10089. [PMID: 32567726 DOI: 10.1002/chem.202002135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/15/2020] [Indexed: 11/05/2022]
Abstract
In order to gain insight into the influence of the H+ -accepting terminal ligand in high-valent oxidant mediated proton coupled electron transfer (PCET) reactions, the reactivity of a high valent nickel-fluoride complex [NiIII (F)(L)] (2, L=N,N'-(2,6-dimethylphenyl)-2,6-pyridinecarboxamidate) with substituted phenols was explored. Analysis of kinetic data from these reactions (Evans-Polanyi, Hammett, and Marcus plots, and KIE measurements) and the formed products show that 2 reacted with electron rich phenols through a hydrogen atom transfer (HAT, or concerted PCET) mechanism and with electron poor phenols through a stepwise proton transfer/electron transfer (PT/ET) reaction mechanism. The analogous complexes [NiIII (Z)(L)] (Z=Cl, OCO2 H, O2 CCH3 , ONO2 ) reacted with all phenols through a HAT mechanism. We explore the reason for a change in mechanism with the highly basic fluoride ligand in 2. Complex 2 was also found to react one to two orders of magnitude faster than the corresponding analogous [NiIII (Z)(L)] complexes. This was ascribed to a high bond dissociation free energy value associated with H-F (135 kcal mol-1 ), which is postulated to be the product formed from PCET oxidation by 2 and is believed to be the driving force for the reaction. Our findings show that high-valent metal-fluoride complexes represent a class of highly reactive PCET oxidants.
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Affiliation(s)
- Prasenjit Mondal
- School of Chemistry, Trinity College Dublin, The University of Dublin, College Green, Dublin, 2, Ireland
| | - Aidan R McDonald
- School of Chemistry, Trinity College Dublin, The University of Dublin, College Green, Dublin, 2, Ireland
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15
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Fujisaki H, Ishizuka T, Shimoyama Y, Kotani H, Shiota Y, Yoshizawa K, Kojima T. Selective catalytic 2e --oxidation of organic substrates by an Fe II complex having an N-heterocyclic carbene ligand in water. Chem Commun (Camb) 2020; 56:9783-9786. [PMID: 32716434 DOI: 10.1039/d0cc03289a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An FeII complex, 1, having a pentadentate ligand with an NHC moiety catalyzes substrate oxidation to afford 2e--oxidized products with high selectivity by suppression of overoxidation in water. A Bell-Evance-Polanyi plot for the substrate oxidation catalyzed by 1 exhibited an inflection point around 86 kcal mol-1, indicating strong C-H abstraction ability of the reactive species derived from 1.
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Affiliation(s)
- Hiroto Fujisaki
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan.
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Mondal P, Lovisari M, Twamley B, McDonald AR. Fast Hydrocarbon Oxidation by a High‐Valent Nickel–Fluoride Complex. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202004639] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Prasenjit Mondal
- School of Chemistry Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
| | - Marta Lovisari
- School of Chemistry Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
| | - Brendan Twamley
- School of Chemistry Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
| | - Aidan R. McDonald
- School of Chemistry Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
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17
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Mondal P, Lovisari M, Twamley B, McDonald AR. Fast Hydrocarbon Oxidation by a High‐Valent Nickel–Fluoride Complex. Angew Chem Int Ed Engl 2020; 59:13044-13050. [DOI: 10.1002/anie.202004639] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Indexed: 11/11/2022]
Affiliation(s)
- Prasenjit Mondal
- School of Chemistry Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
| | - Marta Lovisari
- School of Chemistry Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
| | - Brendan Twamley
- School of Chemistry Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
| | - Aidan R. McDonald
- School of Chemistry Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
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18
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Jiang D, Hu W, Chen M, Fu Z, Su A, Yang B, Mao F, Zhang C, Liu Y, Yin D. Visible-Light-Triggered Quantitative Oxidation of 9,10-Dihydroanthracene to Anthraquinone by O 2 under Mild Conditions. CHEMSUSCHEM 2020; 13:1785-1792. [PMID: 31944592 DOI: 10.1002/cssc.201903549] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 01/15/2020] [Indexed: 06/10/2023]
Abstract
The development of mild and efficient processes for the selective oxygenation of organic compounds by molecular oxygen (O2 ) is key for the synthesis of oxygenates. This paper discloses an atom-efficient synthesis protocol for the photo-oxygenation of 9,10-dihydroanthracene (DHA) by O2 to anthraquinone (AQ), which could achieve quantitative AQ yield (100 %) without any extra catalysts or additives under ambient temperature and pressure. A yield of 86.4 % AQ was obtained even in an air atmosphere. Furthermore, this protocol showed good compatibility for the photo-oxidation of several other compounds with similar structures to DHA. From a series of control experiments, free-radical quenching, and electron paramagnetic resonance spin-trapping results, the photo-oxygenation of DHA was probably initiated by its photoexcited state DHA*, and the latter could activate O2 to a superoxide anion radical (O2 .- ) through the transfer of its electron. Subsequently, this photo-oxidation was gradually dominated by the oxygenated product AQ as an active photocatalyst obtained from the oxidation of DHA by O2 .- , and was accelerated with the rapid accumulation of AQ. The present photo-oxidation protocol is a good example of selective oxygenation based on the photoexcited substrate self-activated O2 , which complies well with green chemistry ideals.
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Affiliation(s)
- Dabo Jiang
- National and Local Joint Engineering Laboratory for New Petro-chemical Materials and Fine Utilization of Resources, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan, 410081, P.R. China
| | - Wenwei Hu
- National and Local Joint Engineering Laboratory for New Petro-chemical Materials and Fine Utilization of Resources, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan, 410081, P.R. China
| | - Mengke Chen
- National and Local Joint Engineering Laboratory for New Petro-chemical Materials and Fine Utilization of Resources, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan, 410081, P.R. China
| | - Zaihui Fu
- National and Local Joint Engineering Laboratory for New Petro-chemical Materials and Fine Utilization of Resources, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan, 410081, P.R. China
| | - Anqun Su
- National and Local Joint Engineering Laboratory for New Petro-chemical Materials and Fine Utilization of Resources, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan, 410081, P.R. China
| | - Bo Yang
- National and Local Joint Engineering Laboratory for New Petro-chemical Materials and Fine Utilization of Resources, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan, 410081, P.R. China
| | - Feng Mao
- National and Local Joint Engineering Laboratory for New Petro-chemical Materials and Fine Utilization of Resources, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan, 410081, P.R. China
| | - Chao Zhang
- National and Local Joint Engineering Laboratory for New Petro-chemical Materials and Fine Utilization of Resources, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan, 410081, P.R. China
| | - Yachun Liu
- National and Local Joint Engineering Laboratory for New Petro-chemical Materials and Fine Utilization of Resources, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan, 410081, P.R. China
| | - Dulin Yin
- National and Local Joint Engineering Laboratory for New Petro-chemical Materials and Fine Utilization of Resources, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan, 410081, P.R. China
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19
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Sen A, Vyas N, Pandey B, Jaccob M, Rajaraman G. Mechanistic Insights on the Formation of High‐Valent Mn
III/IV
=O Species Using Oxygen as Oxidant: A Theoretical Perspective. Isr J Chem 2020. [DOI: 10.1002/ijch.201900142] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Asmita Sen
- Department of Chemistry Indian Institute of Technology Bombay Mumbai 400076 India
| | - Nidhi Vyas
- Department of Chemistry Indian Institute of Technology Bombay Mumbai 400076 India
- School of Biotechnology Jawaharlal Nehru University New Delhi 110067 India
| | - Bhawana Pandey
- Department of Chemistry Indian Institute of Technology Bombay Mumbai 400076 India
| | - Madhavan Jaccob
- Department of Chemistry Indian Institute of Technology Bombay Mumbai 400076 India
- Department of chemistry Loyola College Chennai 600 034
| | - Gopalan Rajaraman
- Department of Chemistry Indian Institute of Technology Bombay Mumbai 400076 India
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20
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Massie AA, Denler MC, Singh R, Sinha A, Nordlander E, Jackson TA. Structural Characterization of a Series of N5-Ligated Mn IV -Oxo Species. Chemistry 2020; 26:900-912. [PMID: 31693757 PMCID: PMC7388070 DOI: 10.1002/chem.201904434] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/23/2019] [Indexed: 11/05/2022]
Abstract
Analysis of extended X-ray absorption fine structure (EXAFS) data for the MnIV -oxo complexes [MnIV (O)(DMM N4py)]2+ , [MnIV (O)(2pyN2B)]2+ , and [MnIV (O)(2pyN2Q)]2+ (DMM N4py=N,N-bis(4-methoxy-3,5-dimethyl-2-pyridylmethyl)-N-bis(2-pyridyl)methylamine; 2pyN2B=(N-bis(1-methyl-2-benzimidazolyl)methyl-N-(bis-2-pyridylmethyl)amine, and 2pyN2Q=N,N-bis(2-pyridyl)-N,N-bis(2-quinolylmethyl)methanamine) afforded Mn=O and Mn-N bond lengths. The Mn=O distances for [MnIV (O)(DMM N4py)]2+ and [MnIV (O)(2pyN2B)]2+ are 1.72 and 1.70 Å, respectively. In contrast, the Mn=O distance for [MnIV (O)(2pyN2Q)]2+ was significantly longer (1.76 Å). We attribute this long distance to sample heterogeneity, which is reasonable given the reduced stability of [MnIV (O)(2pyN2Q)]2+ . The Mn=O distances for [MnIV (O)(DMM N4py)]2+ and [MnIV (O)(2pyN2B)]2+ could only be well-reproduced using DFT-derived models that included strong hydrogen-bonds between second-sphere solvent 2,2,2-trifluoroethanol molecules and the oxo ligand. These results suggest an important role for the 2,2,2-trifluoroethanol solvent in stabilizing MnIV -oxo adducts. The DFT methods were extended to investigate the structure of the putative [MnIV (O)(N4py)]2+ ⋅(HOTf)2 adduct. These computations suggest that a MnIV -hydroxo species is most consistent with the available experimental data.
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Affiliation(s)
- Allyssa A. Massie
- The University of Kansas, Department of Chemistry and Center for Environmentally Beneficial Catalysis, 1567 Irving Hill Road, Lawrence, KS 66045, USA
| | - Melissa C. Denler
- The University of Kansas, Department of Chemistry and Center for Environmentally Beneficial Catalysis, 1567 Irving Hill Road, Lawrence, KS 66045, USA
| | - Reena Singh
- Lund University, Chemical Physics, Department of Chemistry, Box 124, SE-221 00 Lund, Sweden
| | - Arup Sinha
- Lund University, Chemical Physics, Department of Chemistry, Box 124, SE-221 00 Lund, Sweden
- Department of Chemistry, School of Advanced Science, Vellore Institute of Technology, Vellore - 632014 Tamil Nadu, India
| | - Ebbe Nordlander
- Lund University, Chemical Physics, Department of Chemistry, Box 124, SE-221 00 Lund, Sweden
| | - Timothy A. Jackson
- The University of Kansas, Department of Chemistry and Center for Environmentally Beneficial Catalysis, 1567 Irving Hill Road, Lawrence, KS 66045, USA
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21
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Dantignana V, Serrano-Plana J, Draksharapu A, Magallón C, Banerjee S, Fan R, Gamba I, Guo Y, Que L, Costas M, Company A. Spectroscopic and Reactivity Comparisons between Nonheme Oxoiron(IV) and Oxoiron(V) Species Bearing the Same Ancillary Ligand. J Am Chem Soc 2019; 141:15078-15091. [PMID: 31469954 DOI: 10.1021/jacs.9b05758] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This work directly compares the spectroscopic and reactivity properties of an oxoiron(IV) and an oxoiron(V) complex that are supported by the same neutral tetradentate N-based PyNMe3 ligand. A complete spectroscopic characterization of the oxoiron(IV) species (2) reveals that this compound exists as a mixture of two isomers. The reactivity of the thermodynamically more stable oxoiron(IV) isomer (2b) is directly compared to that exhibited by the previously reported 1e--oxidized analogue [FeV(O)(OAc)(PyNMe3)]2+ (3). Our data indicates that 2b is 4 to 5 orders of magnitude slower than 3 in hydrogen atom transfer (HAT) from C-H bonds. The origin of this huge difference lies in the strength of the O-H bond formed after HAT by the oxoiron unit, the O-H bond derived from 3 being about 20 kcal·mol-1 stronger than that from 2b. The estimated bond strength of the FeIVO-H bond of 100 kcal·mol-1 is very close to the reported values for highly active synthetic models of compound I of cytochrome P450. In addition, this comparative study provides direct experimental evidence that the lifetime of the carbon-centered radical that forms after the initial HAT by the high valent oxoiron complex depends on the oxidation state of the nascent Fe-OH complex. Complex 2b generates long-lived carbon-centered radicals that freely diffuse in solution, while 3 generates short-lived caged radicals that rapidly form product C-OH bonds, so only 3 engages in stereoretentive hydroxylation reactions. Thus, the oxidation state of the iron center modulates not only the rate of HAT but also the rate of ligand rebound.
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Affiliation(s)
- Valeria Dantignana
- Institut de Química Computacional i Catàlisi (IQCC), Departament de Química , Universitat de Girona , C/M. Aurèlia Capmany 69 , 17003 Girona , Catalonia , Spain
| | - Joan Serrano-Plana
- Institut de Química Computacional i Catàlisi (IQCC), Departament de Química , Universitat de Girona , C/M. Aurèlia Capmany 69 , 17003 Girona , Catalonia , Spain
| | - Apparao Draksharapu
- Department of Chemistry and Center for Metals in Biocatalysis , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Carla Magallón
- Institut de Química Computacional i Catàlisi (IQCC), Departament de Química , Universitat de Girona , C/M. Aurèlia Capmany 69 , 17003 Girona , Catalonia , Spain
| | - Saikat Banerjee
- Department of Chemistry and Center for Metals in Biocatalysis , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Ruixi Fan
- Department of Chemistry , Carnegie Mellon University , 4400 Fifth Avenue , Pittsburgh , Pennsylvania 15213 , United States
| | - Ilaria Gamba
- Institut de Química Computacional i Catàlisi (IQCC), Departament de Química , Universitat de Girona , C/M. Aurèlia Capmany 69 , 17003 Girona , Catalonia , Spain
| | - Yisong Guo
- Department of Chemistry , Carnegie Mellon University , 4400 Fifth Avenue , Pittsburgh , Pennsylvania 15213 , United States
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Miquel Costas
- Institut de Química Computacional i Catàlisi (IQCC), Departament de Química , Universitat de Girona , C/M. Aurèlia Capmany 69 , 17003 Girona , Catalonia , Spain
| | - Anna Company
- Institut de Química Computacional i Catàlisi (IQCC), Departament de Química , Universitat de Girona , C/M. Aurèlia Capmany 69 , 17003 Girona , Catalonia , Spain
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22
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Gu C, Nie X, Jiang J, Chen Z, Dong Y, Zhang X, Liu J, Yu Z, Zhu Z, Liu J, Liu X, Shao Y. Mechanistic Study of Oxygen Reduction at Liquid/Liquid Interfaces by Hybrid Ultramicroelectrodes and Mass Spectrometry. J Am Chem Soc 2019; 141:13212-13221. [PMID: 31353892 DOI: 10.1021/jacs.9b06299] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Proton-coupled electron transfer (PCET) reactions at various interfaces (liquid/membrane, solid/electrolyte, liquid/liquid) lie at the heart of many processes in biology and chemistry. Mechanistic study can provide profound understanding of PCET and rational design of new systems. However, most mechanisms of PCET reactions at a liquid/liquid interface have been proposed based on electrochemical and spectroscopic data, which lack direct evidence for possible intermediates. Moreover, a liquid/liquid interface as one type of soft interface is dynamic, making the investigation of interfacial reactions very challenging. Herein a novel electrochemistry method coupled to mass spectrometry (EC-MS) was introduced for in situ study of the oxygen reduction reaction (ORR) by ferrocene (Fc) under catalysis from cobalt tetraphenylporphine (CoTPP) at liquid/liquid interfaces. The key units are two types of gel hybrid ultramicroelectrodes (agar-gel/organic hybrid ultramicroelectrodes and water/PVC-gel hybrid ultramicroelectrodes), which were made based on dual micro- or nanopipettes. A solidified liquid/liquid interface can be formed at the tip of these pipettes, and it serves as both an electrochemical cell and a nanospray emitter for mass spectrometry. We demonstrated that the solidified L/L interfaces were very similar to typical L/L interfaces. Key CoTPP intermediates of the ORR at the liquid/liquid interfaces were identified for the first time, and the four-electron oxygen reduction pathway predominated, which provides valuable insights into the mechanism of the ORR. Theoretical simulation has further supported the possibility of formation of intermediates. This type of platform is promising for in situ tracking and identifying intermediates to study complicated reactions at liquid/liquid interfaces or other soft interfaces.
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Affiliation(s)
- Chaoyue Gu
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China
| | - Xin Nie
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China
| | - Jiezhang Jiang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China
| | - Zifei Chen
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China
| | - Yifan Dong
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China
| | - Xin Zhang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China
| | - Junjie Liu
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China
| | - Zhengyou Yu
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China
| | - Zhiwei Zhu
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China
| | - Jian Liu
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China
| | - Xiaoyun Liu
- Department of Microbiology, School of Basic Medical Sciences , Peking University Health Science Center , Beijing 100191 , China
| | - Yuanhua Shao
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China
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23
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Ehudin MA, Gee LB, Sabuncu S, Braun A, Moenne-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 PMCID: PMC6611672 DOI: 10.1021/jacs.9b00795] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [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 Moenne-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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24
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Chang WC, Liu P, Guo Y. Mechanistic Elucidation of Two Catalytically Versatile Iron(II)- and α-Ketoglutarate-Dependent Enzymes: Cases Beyond Hydroxylation. COMMENT INORG CHEM 2018. [DOI: 10.1080/02603594.2018.1509856] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Wei-chen Chang
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, USA
| | - Pinghua Liu
- Department of Chemistry, Boston University, Boston, Massachusetts, USA
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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25
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Structural characterization of a non-heme iron active site in zeolites that hydroxylates methane. Proc Natl Acad Sci U S A 2018; 115:4565-4570. [PMID: 29610304 DOI: 10.1073/pnas.1721717115] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Iron-containing zeolites exhibit unprecedented reactivity in the low-temperature hydroxylation of methane to form methanol. Reactivity occurs at a mononuclear ferrous active site, α-Fe(II), that is activated by N2O to form the reactive intermediate α-O. This has been defined as an Fe(IV)=O species. Using nuclear resonance vibrational spectroscopy coupled to X-ray absorption spectroscopy, we probe the bonding interaction between the iron center, its zeolite lattice-derived ligands, and the reactive oxygen. α-O is found to contain an unusually strong Fe(IV)=O bond resulting from a constrained coordination geometry enforced by the zeolite lattice. Density functional theory calculations clarify how the experimentally determined geometric structure of the active site leads to an electronic structure that is highly activated to perform H-atom abstraction.
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26
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Tse CW, Liu Y, Wai-Shan Chow T, Ma C, Yip WP, Chang XY, Low KH, Huang JS, Che CM. cis-Oxoruthenium complexes supported by chiral tetradentate amine (N 4) ligands for hydrocarbon oxidations. Chem Sci 2018; 9:2803-2816. [PMID: 29780453 PMCID: PMC5943683 DOI: 10.1039/c7sc05224c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 02/01/2018] [Indexed: 12/31/2022] Open
Abstract
We report the first examples of ruthenium complexes cis-[(N4)RuIIICl2]+ and cis-[(N4)RuII(OH2)2]2+ supported by chiral tetradentate amine ligands (N4), together with a high-valent cis-dioxo complex cis-[(N4)RuVI(O)2]2+ supported by the chiral N4 ligand mcp (mcp = N,N'-dimethyl-N,N'-bis(pyridin-2-ylmethyl)cyclohexane-1,2-diamine). The X-ray crystal structures of cis-[(mcp)RuIIICl2](ClO4) (1a), cis-[(Me2mcp)RuIIICl2]ClO4 (2a) and cis-[(pdp)RuIIICl2](ClO4) (3a) (Me2mcp = N,N'-dimethyl-N,N'-bis((6-methylpyridin-2-yl)methyl)cyclohexane-1,2-diamine, pdp = 1,1'-bis(pyridin-2-ylmethyl)-2,2'-bipyrrolidine)) show that the ligands coordinate to the ruthenium centre in a cis-α configuration. In aqueous solutions, proton-coupled electron-transfer redox couples were observed for cis-[(mcp)RuIII(O2CCF3)2]ClO4 (1b) and cis-[(pdp)RuIII(O3SCF3)2]CF3SO3 (3c'). Electrochemical analyses showed that the chemically/electrochemically generated cis-[(mcp)RuVI(O)2]2+ and cis-[(pdp)RuVI(O)2]2+ complexes are strong oxidants with E° = 1.11-1.13 V vs. SCE (at pH 1) and strong H-atom abstractors with DO-H = 90.1-90.8 kcal mol-1. The reaction of 1b or its (R,R)-mcp counterpart with excess (NH4)2[CeIV(NO3)6] (CAN) in aqueous medium afforded cis-[(mcp)RuVI(O)2](ClO4)2 (1e) or cis-[((R,R)-mcp)RuVI(O)2](ClO4)2 (1e*), respectively, a strong oxidant with E(RuVI/V) = 0.78 V (vs. Ag/AgNO3) in acetonitrile solution. Complex 1e oxidized various hydrocarbons, including cyclohexane, in acetonitrile at room temperature, affording alcohols and/or ketones in up to 66% yield. Stoichiometric oxidations of alkenes by 1e or 1e* in t BuOH/H2O (5 : 1 v/v) afforded diols and aldehydes in combined yields of up to 98%, with moderate enantioselectivity obtained for the reaction using 1e*. The cis-[(pdp)RuII(OH2)2]2+ (3c)-catalysed oxidation of saturated C-H bonds, including those of ethane and propane, with CAN as terminal oxidant was also demonstrated.
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Affiliation(s)
- Chun-Wai Tse
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China . .,HKU Shenzhen Institute of Research and Innovation , Shenzhen , Guangdong 518053 , China
| | - Yungen Liu
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China . .,Department of Chemistry , Southern University of Science of Technology , Shenzhen , Guangdong 518055 , China
| | - Toby Wai-Shan Chow
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Chaoqun Ma
- Department of Chemistry , Southern University of Science of Technology , Shenzhen , Guangdong 518055 , China
| | - Wing-Ping Yip
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Xiao-Yong Chang
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Kam-Hung Low
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Jie-Sheng Huang
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Chi-Ming Che
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China . .,HKU Shenzhen Institute of Research and Innovation , Shenzhen , Guangdong 518053 , China.,Department of Chemistry , Southern University of Science of Technology , Shenzhen , Guangdong 518055 , China
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27
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Mondal P, Pirovano P, Das A, Farquhar ER, McDonald AR. Hydrogen Atom Transfer by a High-Valent Nickel-Chloride Complex. J Am Chem Soc 2018; 140:1834-1841. [DOI: 10.1021/jacs.7b11953] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Prasenjit Mondal
- School
of Chemistry and CRANN/AMBER Nanoscience Institute, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, Ireland
| | - Paolo Pirovano
- School
of Chemistry and CRANN/AMBER Nanoscience Institute, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, Ireland
| | - Ankita Das
- School
of Chemistry and CRANN/AMBER Nanoscience Institute, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, Ireland
| | - Erik R. Farquhar
- Case
Western Reserve University Center for Synchrotron Biosciences, National Synchrotron Light Source II, Brookhaven National Laboratory II, Upton, New York 11973, United States
| | - Aidan R. McDonald
- School
of Chemistry and CRANN/AMBER Nanoscience Institute, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, Ireland
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28
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de Sousa DP, Miller CJ, Chang Y, Waite TD, McKenzie CJ. Electrochemically Generated cis-Carboxylato-Coordinated Iron(IV) Oxo Acid-Base Congeners as Promiscuous Oxidants of Water Pollutants. Inorg Chem 2017; 56:14936-14947. [PMID: 29039183 DOI: 10.1021/acs.inorgchem.7b02208] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The nonheme iron(IV) oxo complex [FeIV(O)(tpenaH)]2+ and its conjugate base [FeIV(O)(tpena)]+ [tpena- = N,N,N'-tris(2-pyridylmethyl)ethylenediamine-N'-acetate] have been prepared electrochemically in water by bulk electrolysis of solutions prepared from [FeIII2(μ-O)(tpenaH)2](ClO4)4 at potentials over 1.3 V (vs NHE) using inexpensive and commercially available carbon-based electrodes. Once generated, these iron(IV) oxo complexes persist at room temperature for minutes to half an hour over a wide range of pH values. They are capable of rapidly decomposing aliphatic and aromatic alcohols, alkanes, formic acid, phenols, and the xanthene dye rhodamine B. The oxidation of formic acid to carbon dioxide demonstrates the capacity for total mineralization of organic compounds. A radical hydrogen-atom-abstraction mechanism is proposed with a reactivity profile for the series that is reminiscent of oxidations by the hydroxyl radical. Facile regeneration of [FeIV(O)(tpenaH)]2+/ [FeIV(O)(tpena)]+ and catalytic turnover in the oxidation of cyclohexanol under continuous electrolysis demonstrates the potential of the application of [FeIII(tpena)]2+ as an electrocatalyst. The promiscuity of the electrochemically generated iron(IV) oxo complexes, in terms of the broad range of substrates examined, represents an important step toward the goal of cost-effective electrocatalytic water purification.
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Affiliation(s)
- David P de Sousa
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark , Campusvej 55, 5320 Odense, Denmark
| | - Christopher J Miller
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Yingyue Chang
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales , Sydney, New South Wales 2052, Australia
| | - T David Waite
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Christine J McKenzie
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark , Campusvej 55, 5320 Odense, Denmark
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29
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Collins TJ, Ryabov AD. Targeting of High-Valent Iron-TAML Activators at Hydrocarbons and Beyond. Chem Rev 2017; 117:9140-9162. [PMID: 28488444 DOI: 10.1021/acs.chemrev.7b00034] [Citation(s) in RCA: 121] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
TAML activators of peroxides are iron(III) complexes. The ligation by four deprotonated amide nitrogens in macrocyclic motifs is the signature of TAMLs where the macrocyclic structures vary considerably. TAML activators are exceptional functional replicas of the peroxidases and cytochrome P450 oxidizing enzymes. In water, they catalyze peroxide oxidation of a broad spectrum of compounds, many of which are micropollutants, compounds that produce undesired effects at low concentrations-as with the enzymes, peroxide is typically activated with near-quantitative efficiency. In nonaqueous solvents such as organic nitriles, the prototype TAML activator gave the structurally authenticated reactive iron(V)oxo units (FeVO), wherein the iron atom is two oxidation equivalents above the FeIII resting state. The iron(V) state can be achieved through the intermediacy of iron(IV) species, which are usually μ-oxo-bridged dimers (FeIVFeIV), and this allows for the reactivity of this potent reactive intermediate to be studied in stoichiometric processes. The present review is primarily focused at the mechanistic features of the oxidation by FeVO of hydrocarbons including cyclohexane. The main topic is preceded by a description of mechanisms of oxidation of thioanisoles by FeVO, because the associated studies provide valuable insight into the ability of FeVO to oxidize organic molecules. The review is opened by a summary of the interconversions between FeIII, FeIVFeIV, and FeVO species, since this information is crucial for interpreting the kinetic data. The highest reactivity in both reaction classes described belongs to FeVO. The resting state FeIII is unreactive oxidatively. Intermediate reactivity is typically found for FeIVFeIV; therefore, kinetic features for these species in interchange and oxidation processes are also reviewed. Examples of using TAML activators for C-H bond cleavage applied to fine organic synthesis conclude the review.
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Affiliation(s)
- Terrence J Collins
- Department of Chemistry, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Alexander D Ryabov
- Department of Chemistry, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
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30
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Pattanayak S, Jasniewski AJ, Rana A, Draksharapu A, Singh KK, Weitz A, Hendrich M, Que L, Dey A, Sen Gupta S. Spectroscopic and Reactivity Comparisons of a Pair of bTAML Complexes with Fe V═O and Fe IV═O Units. Inorg Chem 2017; 56:6352-6361. [PMID: 28481521 DOI: 10.1021/acs.inorgchem.7b00448] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In this report we compare the geometric and electronic structures and reactivities of [FeV(O)]- and [FeIV(O)]2- species supported by the same ancillary nonheme biuret tetraamido macrocyclic ligand (bTAML). Resonance Raman studies show that the Fe═O vibration of the [FeIV(O)]2- complex 2 is at 798 cm-1, compared to 862 cm-1 for the corresponding [FeV(O)]- species 3, a 64 cm-1 frequency difference reasonably reproduced by density functional theory calculations. These values are, respectively, the lowest and the highest frequencies observed thus far for nonheme high-valent Fe═O complexes. Extended X-ray absorption fine structure analysis of 3 reveals an Fe═O bond length of 1.59 Å, which is 0.05 Å shorter than that found in complex 2. The redox potentials of 2 and 3 are 0.44 V (measured at pH 12) and 1.19 V (measured at pH 7) versus normal hydrogen electrode, respectively, corresponding to the [FeIV(O)]2-/[FeIII(OH)]2- and [FeV(O)]-/[FeIV(O)]2- couples. Consistent with its higher potential (even after correcting for the pH difference), 3 oxidizes benzyl alcohol at pH 7 with a second-order rate constant that is 2500-fold bigger than that for 2 at pH 12. Furthermore, 2 exhibits a classical kinteic isotope effect (KIE) of 3 in the oxidation of benzyl alcohol to benzaldehyde versus a nonclassical KIE of 12 for 3, emphasizing the reactivity differences between 2 and 3.
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Affiliation(s)
- Santanu Pattanayak
- Chemical Engineering Division, CSIR-National Chemical Laboratory , Pune 411008, India
| | - Andrew J Jasniewski
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota , 207 Pleasant Street Southeast, Minneapolis, Minnesota 55455, United States
| | - Atanu Rana
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science , Kolkata 700032, India
| | - Apparao Draksharapu
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota , 207 Pleasant Street Southeast, Minneapolis, Minnesota 55455, United States
| | - Kundan K Singh
- Chemical Engineering Division, CSIR-National Chemical Laboratory , Pune 411008, India
| | - Andrew Weitz
- Department of Chemistry, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Michael Hendrich
- Department of Chemistry, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota , 207 Pleasant Street Southeast, Minneapolis, Minnesota 55455, United States
| | - Abhishek Dey
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science , Kolkata 700032, India
| | - Sayam Sen Gupta
- Department of Chemical Sciences, Indian Institute of Science Education and Research-Kolkata , Mohanpur, West Bengal 741246, India
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31
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Shen LQ, Kundu S, Collins TJ, Bominaar EL. Analysis of Hydrogen Atom Abstraction from Ethylbenzene by an FeVO(TAML) Complex. Inorg Chem 2017; 56:4347-4356. [DOI: 10.1021/acs.inorgchem.6b02796] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Longzhu Q. Shen
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Soumen Kundu
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Terrence J. Collins
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Emile L. Bominaar
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
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32
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Gao H, Groves JT. Fast Hydrogen Atom Abstraction by a Hydroxo Iron(III) Porphyrazine. J Am Chem Soc 2017; 139:3938-3941. [PMID: 28245648 DOI: 10.1021/jacs.6b13091] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
A reactive hydroxoferric porphyrazine complex, [(PyPz)FeIII(OH) (OH2)]4+ (1, PyPz = tetramethyl-2,3-pyridino porphyrazine), has been prepared via one-electron oxidation of the corresponding ferrous species [(PyPz)FeII(OH2)2]4+ (2). Electrochemical analysis revealed a pH-dependent and remarkably high FeIII-OH/FeII-OH2 reduction potential of 680 mV vs Ag/AgCl at pH 5.2. Nernstian behavior from pH 2 to pH 8 indicates a one-proton, one-electron interconversion throughout that range. The O-H bond dissociation energy of the FeII-OH2 complex was estimated to be 84 kcal mol-1. Accordingly, 1 reacts rapidly with a panel of substrates via C-H hydrogen atom transfer (HAT), reducing 1 to [(PyPz)FeII(OH2)2]4+ (2). The second-order rate constant for the reaction of [(PyPz)FeIII(OH) (OH2)]4+ with xanthene was 2.22 × 103 M-1 s-1, 5-6 orders of magnitude faster than other reported FeIII-OH complexes and faster than many ferryl complexes.
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Affiliation(s)
- Hongxin Gao
- 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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33
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Indefinitely stable iron(IV) cage complexes formed in water by air oxidation. Nat Commun 2017; 8:14099. [PMID: 28102364 PMCID: PMC5253674 DOI: 10.1038/ncomms14099] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 11/28/2016] [Indexed: 01/04/2023] Open
Abstract
In nature, iron, the fourth most abundant element of the Earth's crust, occurs in its stable forms either as the native metal or in its compounds in the +2 or +3 (low-valent) oxidation states. High-valent iron (+4, +5, +6) compounds are not formed spontaneously at ambient conditions, and the ones obtained synthetically appear to be unstable in polar organic solvents, especially aqueous solutions, and this is what limits their studies and use. Here we describe unprecedented iron(IV) hexahydrazide clathrochelate complexes that are assembled in alkaline aqueous media from iron(III) salts, oxalodihydrazide and formaldehyde in the course of a metal-templated reaction accompanied by air oxidation. The complexes can exist indefinitely at ambient conditions without any sign of decomposition in water, nonaqueous solutions and in the solid state. We anticipate that our findings may open a way to aqueous solution and polynuclear high-valent iron chemistry that remains underexplored and presents an important challenge.
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34
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Gao J, Jiang F, Zhai G. Ultra-High Molecular Weight Alpha-Amino Poly(Methyl Methacrylate) with High Tgthrough Emulsion Polymerization by Using Transition Metal Cation-Tertiary Amine Pairs as a Mono-Centered Initiator. MACROMOL REACT ENG 2016. [DOI: 10.1002/mren.201500067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jie Gao
- Department of Materials Chemistry; College of Science and Engineering; Changzhou University; Changzhou 213164 China
| | - Fengchi Jiang
- Department of Materials Chemistry; College of Science and Engineering; Changzhou University; Changzhou 213164 China
| | - Guangqun Zhai
- Department of Materials Chemistry; College of Science and Engineering; Changzhou University; Changzhou 213164 China
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35
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Pirovano P, Farquhar ER, Swart M, McDonald AR. Tuning the Reactivity of Terminal Nickel(III)-Oxygen Adducts for C-H Bond Activation. J Am Chem Soc 2016; 138:14362-14370. [PMID: 27739688 DOI: 10.1021/jacs.6b08406] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two metastable NiIII complexes, [NiIII(OAc)(L)] and [NiIII(ONO2)(L)] (L = N,N'-(2,6-dimethylphenyl)-2,6-pyridinedicarboxamidate, OAc = acetate), were prepared, adding to the previously prepared [NiIII(OCO2H)(L)], with the purpose of probing the properties of terminal late-transition metal oxidants. These high-valent oxidants were prepared by the one-electron oxidation of their NiII precursors ([NiII(OAc)(L)]- and [NiII(ONO2)(L)]-) with tris(4-bromophenyl)ammoniumyl hexachloroantimonate. Fascinatingly, the reaction between any [NiII(X)(L)]- and NaOCl/acetic acid (AcOH) or cerium ammonium nitrate ((NH4)2[CeIV(NO3)6], CAN), yielded [NiIII(OAc)(L)] and [NiIII(ONO2)(L)], respectively. An array of spectroscopic characterizations (electronic absorption, electron paramagnetic resonance, X-ray absorption spectroscopies), electrochemical methods, and computational predictions (density functional theory) have been used to determine the structural, electronic, and magnetic properties of these highly reactive metastable oxidants. The NiIII-oxidants proved competent in the oxidation of phenols (weak O-H bonds) and a series of hydrocarbon substrates (some with strong C-H bonds). Kinetic investigation of the reactions with di-tert-butylphenols showed a 15-fold enhanced reaction rate for [NiIII(ONO2)(L)] compared to [NiIII(OCO2H)(L)] and [NiIII(OAc)(L)], demonstrating the effect of electron-deficiency of the O-ligand on oxidizing power. The oxidation of a series of hydrocarbons by [NiIII(OAc)(L)] was further examined. A linear correlation between the rate constant and the bond dissociation energy of the C-H bonds in the substrates was indicative of a hydrogen atom transfer mechanism. The reaction rate with dihydroanthracene (k2 = 8.1 M-1 s-1) compared favorably with the most reactive high-valent metal-oxidants, and showcases the exceptional reactivity of late transition metal-oxygen adducts.
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Affiliation(s)
- Paolo Pirovano
- School of Chemistry and CRANN/AMBER Nanoscience Institute, Trinity College Dublin, The University of Dublin , College Green, Dublin 2, Ireland
| | - Erik R Farquhar
- Case Western Reserve University Center for Synchrotron Biosciences, National Synchrotron Light Source II, Brookhaven National Laboratory , Upton, New York 11973, United States
| | - Marcel Swart
- ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain.,Institut de Química Computacional i Catàlisi, Facultat de Ciències, Universitat de Girona , Campus Montilivi, 17003 Girona, Spain
| | - Aidan R McDonald
- School of Chemistry and CRANN/AMBER Nanoscience Institute, Trinity College Dublin, The University of Dublin , College Green, Dublin 2, Ireland
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36
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Mousavi MPS, Saba SA, Anderson EL, Hillmyer MA, Bühlmann P. Avoiding Errors in Electrochemical Measurements: Effect of Frit Material on the Performance of Reference Electrodes with Porous Frit Junctions. Anal Chem 2016; 88:8706-13. [DOI: 10.1021/acs.analchem.6b02025] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Maral P. S. Mousavi
- Department of Chemistry and ‡Department of
Chemical Engineering and Materials
Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Stacey A. Saba
- Department of Chemistry and ‡Department of
Chemical Engineering and Materials
Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Evan L. Anderson
- Department of Chemistry and ‡Department of
Chemical Engineering and Materials
Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Marc A. Hillmyer
- Department of Chemistry and ‡Department of
Chemical Engineering and Materials
Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Philippe Bühlmann
- Department of Chemistry and ‡Department of
Chemical Engineering and Materials
Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
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37
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Comba P, Fukuzumi S, Koke C, Martin B, Löhr AM, Straub J. A Bispidine Iron(IV)-Oxo Complex in the Entatic State. Angew Chem Int Ed Engl 2016; 55:11129-33. [PMID: 27466945 DOI: 10.1002/anie.201605099] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 06/30/2016] [Indexed: 11/10/2022]
Abstract
For a series of Fe(IV) =O complexes with tetra- and pentadentate bispidine ligands, the correlation of their redox potentials with reactivity, involving a variety of substrates for alkane hydroxylation (HAT), alkene epoxidation, and phosphine and thioether oxidation (OAT) are reported. The redox potentials span approximately 350 mV and the reaction rates over 8 orders of magnitude. From the experimental data and in comparison with published studies it emerges that electron transfer and the driving force are of major importance, and this is also supported by the DFT-based computational analysis. The striking difference of reactivity of two isomeric systems with pentadentate bispidines is found to be due to a destabilization of the S=1 ground state of one of the ferryl isomers, and this is supported by the experimentally determined redox potentials and published stability constants with a series of first-row transition metal ions with these two isomeric ligands.
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Affiliation(s)
- Peter Comba
- Universität Heidelberg, Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270, 69120, Heidelberg, Germany.
| | - Shunichi Fukuzumi
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 120-750, Korea. .,Faculty of Science and Engineering, Meijo University, Nagoya, Aichi, 468-8502, Japan.
| | - Carsten Koke
- Universität Heidelberg, Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270, 69120, Heidelberg, Germany
| | - Bodo Martin
- Universität Heidelberg, Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270, 69120, Heidelberg, Germany
| | - Anna-Maria Löhr
- Universität Heidelberg, Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270, 69120, Heidelberg, Germany
| | - Johannes Straub
- Universität Heidelberg, Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270, 69120, Heidelberg, Germany
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38
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Comba P, Fukuzumi S, Koke C, Martin B, Löhr AM, Straub J. A Bispidine Iron(IV)-Oxo Complex in the Entatic State. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201605099] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Peter Comba
- Universität Heidelberg; Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270; 69120 Heidelberg Germany
| | - Shunichi Fukuzumi
- Department of Chemistry and Nano Science; Ewha Womans University; Seoul 120-750 Korea
- Faculty of Science and Engineering; Meijo University; Nagoya Aichi 468-8502 Japan
| | - Carsten Koke
- Universität Heidelberg; Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270; 69120 Heidelberg Germany
| | - Bodo Martin
- Universität Heidelberg; Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270; 69120 Heidelberg Germany
| | - Anna-Maria Löhr
- Universität Heidelberg; Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270; 69120 Heidelberg Germany
| | - Johannes Straub
- Universität Heidelberg; Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270; 69120 Heidelberg Germany
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39
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Mitome H, Ishizuka T, Kotani H, Shiota Y, Yoshizawa K, Kojima T. Mechanistic Insights into C–H Oxidations by Ruthenium(III)-Pterin Complexes: Impact of Basicity of the Pterin Ligand and Electron Acceptability of the Metal Center on the Transition States. J Am Chem Soc 2016; 138:9508-20. [DOI: 10.1021/jacs.6b03785] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hiroumi Mitome
- Department
of Chemistry, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan
| | - Tomoya Ishizuka
- Department
of Chemistry, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan
| | - Hiroaki Kotani
- Department
of Chemistry, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan
| | - Yoshihito Shiota
- Institute
for Materials Chemistry and Engineering, Kyushu University, Motooka, Nishi-Ku, Fukuoka 819-0395, Japan
| | - Kazunari Yoshizawa
- Institute
for Materials Chemistry and Engineering, Kyushu University, Motooka, Nishi-Ku, Fukuoka 819-0395, Japan
| | - Takahiko Kojima
- Department
of Chemistry, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan
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40
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Barbieri A, De Carlo Chimienti R, Del Giacco T, Di Stefano S, Lanzalunga O, Lapi A, Mazzonna M, Olivo G, Salamone M. Oxidation of Aryl Diphenylmethyl Sulfides Promoted by a Nonheme Iron(IV)-Oxo Complex: Evidence for an Electron Transfer-Oxygen Transfer Mechanism. J Org Chem 2016; 81:2513-20. [PMID: 26886491 DOI: 10.1021/acs.joc.6b00099] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The oxidation of a series of aryl diphenylmethyl sulfides (4-X-C6H4SCH(C6H5)2, where X = OCH3 (1), X = CH3 (2), X = H (3), and X = CF3 (4)) promoted by the nonheme iron(IV)-oxo complex [(N4Py)Fe(IV)═O](2+) occurs by an electron transfer-oxygen transfer (ET-OT) mechanism as supported by the observation of products (diphenylmethanol, benzophenone, and diaryl disulfides) deriving from α-C-S and α-C-H fragmentation of radical cations 1(+•)-4(+•), formed besides the S-oxidation products (aryl diphenylmethyl sulfoxides). The fragmentation/S-oxidation product ratios regularly increase through a decrease in the electron-donating power of the aryl substituents, that is, by increasing the fragmentation rate constants of the radical cations as indicated by a laser flash photolysis (LFP) study of the photochemical oxidation of 1-4 carried out in the presence of N-methoxyphenanthridinium hexafluorophosphate (MeOP(+)PF6(-)).
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Affiliation(s)
- Alessia Barbieri
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza" , P. le A. Moro 5, 00185 Rome, Italy
| | - Rosemilia De Carlo Chimienti
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza" , P. le A. Moro 5, 00185 Rome, Italy
| | - Tiziana Del Giacco
- Dipartimento di Chimica, Biologia e Biotecnologie and Centro di Eccellenza Materiali Innovativi Nanostrutturati, Università di Perugia , Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Stefano Di Stefano
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza" , P. le A. Moro 5, 00185 Rome, Italy
| | - Osvaldo Lanzalunga
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza" , P. le A. Moro 5, 00185 Rome, Italy
| | - Andrea Lapi
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza" , P. le A. Moro 5, 00185 Rome, Italy
| | - Marco Mazzonna
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza" , P. le A. Moro 5, 00185 Rome, Italy
| | - Giorgio Olivo
- Dipartimento di Chimica and Istituto CNR di Metodologie Chimiche-IMC, Sezione Meccanismi di Reazione c/o Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza" , P. le A. Moro 5, 00185 Rome, Italy
| | - Michela Salamone
- Dipartimento di Scienze e Tecnologie Chimiche, Università "Tor Vergata" , Via della Ricerca Scientifica 1, I-00133 Rome, Italy
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41
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Ishizuka T, Kotani H, Kojima T. Characteristics and reactivity of ruthenium–oxo complexes. Dalton Trans 2016; 45:16727-16750. [DOI: 10.1039/c6dt03024f] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this perspective, we have surveyed the synthetic procedure, characteristics, and reactivity of high-valent ruthenium–oxo complexes.
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Affiliation(s)
| | - Hiroaki Kotani
- Department of Chemistry
- University of Tsukuba
- Tsukuba
- Japan
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42
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Wijeratne GB, Day VW, Jackson TA. O-H bond oxidation by a monomeric Mn(III)-OMe complex. Dalton Trans 2015; 44:3295-306. [PMID: 25597362 DOI: 10.1039/c4dt03546a] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Manganese-containing, mid-valent oxidants (Mn(III)-OR) that mediate proton-coupled electron-transfer (PCET) reactions are central to a variety of crucial enzymatic processes. The Mn-dependent enzyme lipoxygenase is such an example, where a Mn(III)-OH unit activates fatty acid substrates for peroxidation by an initial PCET. This present work describes the quantitative generation of the Mn(III)-OMe complex, [Mn(III)(OMe)(dpaq)](+) (dpaq = 2-[bis(pyridin-2-ylmethyl)]amino-N-quinolin-8-yl-acetamidate) via dioxygen activation by [Mn(II)(dpaq)](+) in methanol at 25 °C. The X-ray diffraction structure of [Mn(III)(OMe)(dpaq)](+) exhibits a Mn-OMe group, with a Mn-O distance of 1.825(4) Å, that is trans to the amide functionality of the dpaq ligand. The [Mn(III)(OMe)(dpaq)](+) complex is quite stable in solution, with a half-life of 26 days in MeCN at 25 °C. [Mn(III)(OMe)(dpaq)](+) can activate phenolic O-H bonds with bond dissociation free energies (BDFEs) of less than 79 kcal mol(-1) and reacts with the weak O-H bond of TEMPOH (TEMPOH = 2,2'-6,6'-tetramethylpiperidine-1-ol) with a hydrogen/deuterium kinetic isotope effect (H/D KIE) of 1.8 in MeCN at 25 °C. This isotope effect, together with other experimental evidence, is suggestive of a concerted proton-electron transfer (CPET) mechanism for O-H bond oxidation by [Mn(III)(OMe)(dpaq)](+). A kinetic and thermodynamic comparison of the O-H bond oxidation reactivity of [Mn(III)(OMe)(dpaq)](+) to other M(III)-OR oxidants is presented as an aid to gain more insight into the PCET reactivity of mid-valent oxidants. In contrast to high-valent counterparts, the limited examples of M(III)-OR oxidants exhibit smaller H/D KIEs and show weaker dependence of their oxidation rates on the driving force of the PCET reaction with O-H bonds.
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Affiliation(s)
- Gayan B Wijeratne
- Department of Chemistry and Center for Environmentally Beneficial Catalysis, University of Kansas, 1251 Wescoe Hall Drive, Lawrence, KS 66045, USA.
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Shahbazi-Raz F, Amani V, Noruzi EB, Safari N, Boča R, Titiš J, Notash B. Synthesis, characterization, electrochemical and magnetic study of mixed ligand mono iron and O-methoxy bridged diiron complexes. Inorganica Chim Acta 2015. [DOI: 10.1016/j.ica.2015.07.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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44
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To WP, Wai-Shan Chow T, Tse CW, Guan X, Huang JS, Che CM. Water oxidation catalysed by iron complex of N, N'-dimethyl-2,11-diaza[3,3](2,6)pyridinophane. Spectroscopy of iron-oxo intermediates and density functional theory calculations. Chem Sci 2015; 6:5891-5903. [PMID: 29861914 PMCID: PMC5950833 DOI: 10.1039/c5sc01680k] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 06/23/2015] [Indexed: 12/19/2022] Open
Abstract
The macrocyclic [FeIII(L1)Cl2]+ (1, L1 = N,N'-dimethyl-2,11-diaza[3,3](2,6)pyridinophane) complex is an active catalyst for the oxidation of water to oxygen using [NH4]2[CeIV(NO3)6] (CAN), NaIO4, or Oxone as the oxidant. The mechanism of 1-catalysed water oxidation was examined by spectroscopic methods and by 18O-labelling experiments, revealing that FeIV 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 O and/or FeV 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 O species are likely to be involved in the reaction. The redox behaviour of 1 and these high-valent Fe 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 O species of L1 has been examined by both cyclic voltammetry and density functional theory (DFT) calculations. In aqueous solutions, the cyclic voltammograms of 1 at different pH show a pH-dependent reversible couple (E1/2 = +0.46 V vs. SCE at pH 1) and an irreversible anodic wave (Epa = +1.18 V vs. SCE at pH 1) assigned to the FeIII/FeII couple and the FeIII to FeIV oxidation, respectively. DFT calculations showed that the E value of the half reaction involving [FeV(L1)(O)(OH)]2+/[FeIV(L1)(O)(OH2)]2+ is +1.42 V vs. SCE at pH 1. Using CAN as the oxidant at pH 1, the formation of an FeIV 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 O reaction intermediate was suggested by ESI-MS and UV-vis absorption spectroscopic measurements, and the rate of oxygen evolution was linearly dependent on the concentrations of both 1 and CAN. Using NaIO4 or Oxone as the oxidant at pH 1, the rate of oxygen evolution was linearly dependent on the concentration of 1, and a reactive FeV 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 O species with formula [FeV(L1)(O)2]+ generated by oxidation with NaIO4 or Oxone was suggested by ESI-MS measurements. DFT calculations revealed that [FeV(L1)(O)2]+ is capable of oxidizing water to oxygen with a reaction barrier of 15.7 kcal mol-1.
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Affiliation(s)
- Wai-Pong To
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China . ;
| | - Toby Wai-Shan Chow
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China . ;
| | - Chun-Wai Tse
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China . ;
| | - Xiangguo Guan
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China . ;
| | - Jie-Sheng Huang
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China . ;
| | - Chi-Ming Che
- Department of Chemistry and State Key Laboratory of Synthetic Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China . ; .,HKU Shenzhen Institute of Research and Innovation , Shenzhen 518053 , China
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45
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Brines LM, Coggins MK, Poon PCY, Toledo S, Kaminsky W, Kirk ML, Kovacs JA. Water-soluble Fe(II)-H2O complex with a weak O-H bond transfers a hydrogen atom via an observable monomeric Fe(III)-OH. J Am Chem Soc 2015; 137:2253-64. [PMID: 25611075 DOI: 10.1021/ja5068405] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Understanding the metal ion properties that favor O-H bond formation versus cleavage should facilitate the development of catalysts tailored to promote a specific reaction, e.g., C-H activation or H2O oxidation. The first step in H2O oxidation involves the endothermic cleavage of a strong O-H bond (BDFE = 122.7 kcal/mol), promoted by binding the H2O to a metal ion, and by coupling electron transfer to proton transfer (PCET). This study focuses on details regarding how a metal ion's electronic structure and ligand environment can tune the energetics of M(HO-H) bond cleavage. The synthesis and characterization of an Fe(II)-H2O complex, 1, that undergoes PCET in H2O to afford a rare example of a monomeric Fe(III)-OH, 7, is described. High-spin 7 is also reproducibly generated via the addition of H2O to {[Fe(III)(O(Me2)N4(tren))]2-(μ-O)}(2+) (8). The O-H bond BDFE of Fe(II)-H2O (1) (68.6 kcal/mol) is calculated using linear fits to its Pourbaix diagram and shown to be 54.1 kcal/mol less than that of H2O and 10.9 kcal/mol less than that of [Fe(II)(H2O)6](2+). The O-H bond of 1 is noticeably weaker than the majority of reported M(n+)(HxO-H) (M = Mn, Fe; n+ = 2+, 3+; x = 0, 1) complexes. Consistent with their relative BDFEs, Fe(II)-H2O (1) is found to donate a H atom to TEMPO(•), whereas the majority of previously reported M(n+)-O(H) complexes, including [Mn(III)(S(Me2)N4(tren))(OH)](+) (2), have been shown to abstract H atoms from TEMPOH. Factors responsible for the weaker O-H bond of 1, such as differences in the electron-donating properties of the ligand, metal ion Lewis acidity, and electronic structure, are discussed.
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Affiliation(s)
- Lisa M Brines
- Department of Chemistry, University of Washington , Campus Box 351700, Seattle, Washington 98195-1700, United States
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46
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Dhar D, Tolman WB. Hydrogen atom abstraction from hydrocarbons by a copper(III)-hydroxide complex. J Am Chem Soc 2015; 137:1322-9. [PMID: 25581555 PMCID: PMC4311965 DOI: 10.1021/ja512014z] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Indexed: 12/17/2022]
Abstract
With the aim of understanding the basis for the high rate of hydrogen atom abstraction (HAT) from dihydroanthracene (DHA) by the complex LCuOH (1; L = N,N'-bis(2,6-diisopropylphenyl)-2,6-pyridinedicarboxamide), the bond dissociation enthalpy of the reaction product LCu(H2O) (2) was determined through measurement of its pK(a) and E(1/2) in THF solution. In so doing, an equilibrium between 2 and LCu(THF) was characterized by UV-vis and EPR spectroscopy and cyclic voltammetry (CV). A high pK(a) of 18.8 ± 1.8 and a low E(1/2) of -0.074 V vs Fc/Fc(+) in THF combined to yield an O-H BDE for 2 of 90 ± 3 kcal mol(-1) that is large relative to values for most transition metal oxo/hydroxo complexes. By taking advantage of the increased stability of 1 observed in 1,2-difluorobenzene (DFB) solvent, the kinetics of the reactions of 1 with a range of substrates with varying BDE values for their C-H bonds were measured. The oxidizing power of 1 was revealed through the accelerated decay of 1 in the presence of the substrates, including THF (BDE = 92 kcal mol(-1)) and cyclohexane (BDE = 99 kcal mol(-1)). CV experiments in THF solvent showed that 1 reacted with THF via rate-determining attack at the THF C-H(D) bonds with a kinetic isotope effect of 10.2. Analysis of the kinetic and thermodynamic data provides new insights into the basis for the high reactivity of 1 and the possible involvement of species like 1 in oxidation catalysis.
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Affiliation(s)
- Debanjan Dhar
- Department of Chemistry and
Center for Metals in Biocatalysis, University
of Minnesota, 207 Pleasant
Street SE, Minneapolis, Minnesota 55455, United States
| | - William B. Tolman
- 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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47
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Ségaud N, Anxolabéhère-Mallart E, Sénéchal-David K, Acosta-Rueda L, Robert M, Banse F. Electrochemical study of a nonheme Fe(ii) complex in the presence of dioxygen. Insights into the reductive activation of O 2 at Fe(ii) centers. Chem Sci 2015; 6:639-647. [PMID: 28936313 PMCID: PMC5588783 DOI: 10.1039/c4sc01891e] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 09/16/2014] [Indexed: 01/15/2023] Open
Abstract
Recent efforts to model the reactivity of iron oxygenases have led to the generation of nonheme FeIII(OOH) and FeIV(O) intermediates from FeII complexes and O2 but using different cofactors. This diversity emphasizes the rich chemistry of nonheme Fe(ii) complexes with dioxygen. We report an original mechanistic study of the reaction of [(TPEN)FeII]2+ with O2 carried out by cyclic voltammetry. From this FeII precursor, reaction intermediates such as [(TPEN)FeIV(O)]2+, [(TPEN)FeIII(OOH)]2+ and [(TPEN)FeIII(OO)]+ have been chemically generated in high yield, and characterized electrochemically. These electrochemical data have been used to analyse and perform simulation of the cyclic voltammograms of [(TPEN)FeII]2+ in the presence of O2. Thus, several important mechanistic informations on this reaction have been obtained. An unfavourable chemical equilibrium between O2 and the FeII complex occurs that leads to the FeIII-peroxo complex upon reduction, similarly to heme enzymes such as P450. However, unlike in heme systems, further reduction of this latter intermediate does not result in O-O bond cleavage.
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Affiliation(s)
- Nathalie Ségaud
- Institut de Chimie Moléculaire et des Matériaux d'Orsay , UMR CNRS 8182 , Université Paris Sud , F-91405 Orsay Cedex , France .
| | - Elodie Anxolabéhère-Mallart
- Laboratoire d'Electrochimie Moléculaire , Université Paris Diderot , Sorbonne Paris Cité , F-75205 PARIS CEDEX 13 , France .
| | - Katell Sénéchal-David
- Institut de Chimie Moléculaire et des Matériaux d'Orsay , UMR CNRS 8182 , Université Paris Sud , F-91405 Orsay Cedex , France .
| | - Laura Acosta-Rueda
- Institut de Chimie Moléculaire et des Matériaux d'Orsay , UMR CNRS 8182 , Université Paris Sud , F-91405 Orsay Cedex , France .
| | - Marc Robert
- Laboratoire d'Electrochimie Moléculaire , Université Paris Diderot , Sorbonne Paris Cité , F-75205 PARIS CEDEX 13 , France .
| | - Frédéric Banse
- Institut de Chimie Moléculaire et des Matériaux d'Orsay , UMR CNRS 8182 , Université Paris Sud , F-91405 Orsay Cedex , France .
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48
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Barbieri A, De Gennaro M, Di Stefano S, Lanzalunga O, Lapi A, Mazzonna M, Olivo G, Ticconi B. Isotope effect profiles in the N-demethylation of N,N-dimethylanilines: a key to determine the pKa of nonheme Fe(iii)–OH complexes. Chem Commun (Camb) 2015; 51:5032-5. [DOI: 10.1039/c5cc00411j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
pKa of [(N4Py)FeIII–OH]2+ is obtained from the kinetic isotope effect profiles in the N-demethylation of N,N-dimethylanilines promoted by [(N4Py)FeIVO]2+.
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Affiliation(s)
- Alessia Barbieri
- Dipartimento di Chimica
- Sapienza Università di Roma and Istituto CNR di Metodologie Chimiche (IMC-CNR)
- Sezione Meccanismi di Reazione
- c/o Dipartimento di Chimica
- Sapienza Università di Roma
| | - Martina De Gennaro
- Dipartimento di Chimica
- Sapienza Università di Roma and Istituto CNR di Metodologie Chimiche (IMC-CNR)
- Sezione Meccanismi di Reazione
- c/o Dipartimento di Chimica
- Sapienza Università di Roma
| | - Stefano Di Stefano
- Dipartimento di Chimica
- Sapienza Università di Roma and Istituto CNR di Metodologie Chimiche (IMC-CNR)
- Sezione Meccanismi di Reazione
- c/o Dipartimento di Chimica
- Sapienza Università di Roma
| | - Osvaldo Lanzalunga
- Dipartimento di Chimica
- Sapienza Università di Roma and Istituto CNR di Metodologie Chimiche (IMC-CNR)
- Sezione Meccanismi di Reazione
- c/o Dipartimento di Chimica
- Sapienza Università di Roma
| | - Andrea Lapi
- Dipartimento di Chimica
- Sapienza Università di Roma and Istituto CNR di Metodologie Chimiche (IMC-CNR)
- Sezione Meccanismi di Reazione
- c/o Dipartimento di Chimica
- Sapienza Università di Roma
| | - Marco Mazzonna
- Dipartimento di Chimica
- Sapienza Università di Roma and Istituto CNR di Metodologie Chimiche (IMC-CNR)
- Sezione Meccanismi di Reazione
- c/o Dipartimento di Chimica
- Sapienza Università di Roma
| | - Giorgio Olivo
- Dipartimento di Chimica
- Sapienza Università di Roma and Istituto CNR di Metodologie Chimiche (IMC-CNR)
- Sezione Meccanismi di Reazione
- c/o Dipartimento di Chimica
- Sapienza Università di Roma
| | - Barbara Ticconi
- Dipartimento di Chimica
- Sapienza Università di Roma and Istituto CNR di Metodologie Chimiche (IMC-CNR)
- Sezione Meccanismi di Reazione
- c/o Dipartimento di Chimica
- Sapienza Università di Roma
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49
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Kundu S, Thompson JVK, Shen LQ, Mills MR, Bominaar EL, Ryabov AD, Collins TJ. Activation parameters as mechanistic probes in the TAML iron(V)-oxo oxidations of hydrocarbons. Chemistry 2014; 21:1803-10. [PMID: 25410933 DOI: 10.1002/chem.201405024] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Indexed: 11/11/2022]
Abstract
The results of low-temperature investigations of the oxidations of 9,10-dihydroanthracene, cumene, ethylbenzene, [D10]ethylbenzene, cyclooctane, and cyclohexane by an iron(V)-oxo TAML complex (2; see Figure 1) are presented, including product identification and determination of the second-order rate constants k2 in the range 233-243 K and the activation parameters (ΔH(≠) and ΔS(≠)). Statistically normalized k2 values (log k2') correlate linearly with the C-H bond dissociation energies DC-H, but ΔH(≠) does not. The point for 9,10-dihydroanthracene for the ΔH(≠) vs. DC-H correlation lies markedly off a common straight line of best fit for all other hydrocarbons, suggesting it proceeds via an alternate mechanism than the rate-limiting C-H bond homolysis promoted by 2. Contribution from an electron-transfer pathway may be substantial for 9,10-dihydroanthracene. Low-temperature kinetic measurements with ethylbenzene and [D10]ethylbenzene reveal a kinetic isotope effect of 26, indicating tunneling. The tunnel effect is drastically reduced at 0 °C and above, although it is an important feature of the reactivity of TAML activators at lower temperatures. The diiron(IV) μ-oxo dimer that is often a common component of the reaction medium involving 2 also oxidizes 9,10-dihydroanthracene, although its reactivity is three orders of magnitude lower than that of 2.
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Affiliation(s)
- Soumen Kundu
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA, 15213 (USA)
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50
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Nam W, Lee YM, Fukuzumi S. Tuning reactivity and mechanism in oxidation reactions by mononuclear nonheme iron(IV)-oxo complexes. Acc Chem Res 2014; 47:1146-54. [PMID: 24524675 DOI: 10.1021/ar400258p] [Citation(s) in RCA: 383] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mononuclear nonheme iron enzymes generate high-valent iron(IV)-oxo intermediates that effect metabolically important oxidative transformations in the catalytic cycle of dioxygen activation. In 2003, researchers first spectroscopically characterized a mononuclear nonheme iron(IV)-oxo intermediate in the reaction of taurine: α-ketogultarate dioxygenase (TauD). This nonheme iron enzyme with an iron active center was coordinated to a 2-His-1- carboxylate facial triad motif. In the same year, researchers obtained the first crystal structure of a mononuclear nonheme iron(IV)-oxo complex bearing a macrocyclic supporting ligand, [(TMC)Fe(IV)(O)](2+) (TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecene), in studies that mimicked the biological enzymes. With these breakthrough results, many other studies have examined mononuclear nonheme iron(IV)-oxo intermediates trapped in enzymatic reactions or synthesized in biomimetic reactions. Over the past decade, researchers in the fields of biological, bioinorganic, and oxidation chemistry have extensively investigated the structure, spectroscopy, and reactivity of nonheme iron(IV)-oxo species, leading to a wealth of information from these enzymatic and biomimetic studies. This Account summarizes the reactivity and mechanisms of synthetic mononuclear nonheme iron(IV)-oxo complexes in oxidation reactions and examines factors that modulate their reactivities and change their reaction mechanisms. We focus on several reactions including the oxidation of organic and inorganic compounds, electron transfer, and oxygen atom exchange with water by synthetic mononuclear nonheme iron(IV)-oxo complexes. In addition, we recently observed that the C-H bond activation by nonheme iron(IV)-oxo and other nonheme metal(IV)-oxo complexes does not follow the H-atom abstraction/oxygen-rebound mechanism, which has been well-established in heme systems. The structural and electronic effects of supporting ligands on the oxidizing power of iron(IV)-oxo complexes are significant in these reactions. However, the difference in spin states between nonheme iron(IV)-oxo complexes with an octahedral geometry (with an S = 1 intermediate-spin state) or a trigonal bipyramidal (TBP) geometry (with an S = 2 high-spin state) does not lead to a significant change in reactivity in biomimetic systems. Thus, the importance of the high-spin state of iron(IV)-oxo species in nonheme iron enzymes remains unexplained. We also discuss how the axial and equatorial ligands and binding of redox-inactive metal ions and protons to the iron-oxo moiety influence the reactivities of the nonheme iron(IV)-oxo complexes. We emphasize how these changes can enhance the oxidizing power of nonheme metal(IV)-oxo complexes in oxygen atom transfer and electron-transfer reactions remarkably. This Account demonstrates great advancements in the understanding of the chemistry of mononuclear nonheme iron(IV)-oxo intermediates within the last 10 years.
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Affiliation(s)
- Wonwoo Nam
- Department
of Chemistry and Nano Science, Department of Bioinspired Science,
Center for Biomimetic Systems, Ewha Womans University, Seoul 120-750, Korea
| | - Yong-Min Lee
- Department
of Chemistry and Nano Science, Department of Bioinspired Science,
Center for Biomimetic Systems, Ewha Womans University, Seoul 120-750, Korea
| | - Shunichi Fukuzumi
- Department
of Chemistry and Nano Science, Department of Bioinspired Science,
Center for Biomimetic Systems, Ewha Womans University, Seoul 120-750, Korea
- Department
of Material and Life Science, Graduate School of Engineering, Osaka University, ALCA, Japan Science
and Technology Agency, Suita, Osaka 565-0871, Japan
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