1
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Mikata Y, Akedo M, Hamamoto E, Yoshida S, Shoji S, Ohsedo Y, Matsuo T, Storr T, Funahashi Y. Structural and electrochemical properties of mononuclear copper(II) complexes with pentadentate ethylenediamine-based ligands with pyridine/quinoline/isoquinoline/quinoxaline binding sites. Dalton Trans 2024. [PMID: 39344499 DOI: 10.1039/d4dt02363c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/01/2024]
Abstract
N-Monosubstituted ethylenediamine derivatives with three methylene-tethered aromatic groups ((ArCH2)2NCH2CH2N(R)CH2Ar (R-ArArAr), where Ar = 2-pyridyl, 2-quinolyl, 1- and 3-isoquinolyl and 2-quinoxalyl; R = methyl, benzyl and phenyl) were utilized as pentadentate ligands for copper(II) complexation. Fifteen mononuclear copper(II) complexes were synthesized and exhibit differences in cyclic voltammetry, absorption spectroscopy and solid state geometries, depending on the aromatic group (Ar) and the substituent on the aliphatic nitrogen atom (R) of the ligand. Compared with the pyridine and isoquinoline complexes, the quinoline and quinoxaline derivatives exhibit distinct Cu(II)/Cu(I) redox potentials and d-d transition absorption wavelengths. Similarly, the phenyl derivatives are different from their methyl and benzyl counterparts. These characteristic trends are discussed in relation to the square-pyramidal/trigonal-bipyramidal structure of the complexes which is perturbed by the location of quinoline moieties in the penta- or hexacoordinate complexes with Jahn-Teller distortion. In addition, the results are compared to the copper(II) complexes with pyridine/quinoline mixed ligands, Ph-Ar1Ar2Ar3 ((Ar1CH2)(Ar2CH2)NCH2CH2N(Ph)CH2Ar3).
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Affiliation(s)
- Yuji Mikata
- Laboratory for Molecular & Functional Design, Department of Engineering, Nara Women's University, Nara 630-8506, Japan.
- Cooperative Major in Human Centered Engineering, Nara Women's University, Nara 630-8506, Japan
- Department of Chemistry, Biology, and Environmental Science, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
- KYOUSEI Science Center, Nara Women's University, Nara 630-8506, Japan
| | - Miyu Akedo
- Cooperative Major in Human Centered Engineering, Nara Women's University, Nara 630-8506, Japan
| | - Erina Hamamoto
- Department of Chemistry, Biology, and Environmental Science, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
| | - Shoko Yoshida
- Department of Chemistry, Biology, and Environmental Science, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
| | - Sunao Shoji
- Laboratory for Molecular & Functional Design, Department of Engineering, Nara Women's University, Nara 630-8506, Japan.
- Cooperative Major in Human Centered Engineering, Nara Women's University, Nara 630-8506, Japan
| | - Yutaka Ohsedo
- Cooperative Major in Human Centered Engineering, Nara Women's University, Nara 630-8506, Japan
| | - Takashi Matsuo
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology (NAIST), Takayama, Ikoma, Nara 630-0192, Japan
| | - Tim Storr
- Department of Chemistry, Simon Fraser University, Burnaby, BC, V5A-1S6, Canada
| | - Yasuhiro Funahashi
- Department of Chemistry, Graduate School of Science, Osaka University, Machikaneyama, Toyonaka, Osaka 560-0043, Japan
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2
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Török P, Lakk-Bogáth D, Unjaroen D, Browne WR, Kaizer J. Effect of monodentate heterocycle co-ligands on the μ-1,2-peroxo-diiron(III) mediated aldehyde deformylation reactions. J Inorg Biochem 2024; 258:112620. [PMID: 38824901 DOI: 10.1016/j.jinorgbio.2024.112620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 05/17/2024] [Accepted: 05/25/2024] [Indexed: 06/04/2024]
Abstract
Peroxo-diiron(III) species are present in the active sites of many metalloenzymes that carry out challenging organic transformations. The reactivity of these species is influenced by various factors, such as the structure and topology of the supporting ligands, the identity of the axial and equatorial co-ligands, and the oxidation states of the metal ion(s). In this study, we aim to diversify the importance of equatorial ligands in controlling the reactivity of peroxo-diiron(III) species. As a model compound, we chose the previously published and fully characterized [(PBI)2(CH3CN)FeIII(μ-O2)FeIII(CH3CN)(PBI)2]4+ complex, where the steric effect of the four PBI ligands is minimal, so the labile CH3CN molecules easily can be replaced by different monodentate co-ligands (substituted pyridines and N-donor heterocyclic compounds). Thus, their effect on the electronic and spectral properties of peroxo-divas(III) intermediates could be easily investigated. The relationship between structure and reactivity was also investigated in the stoichiometric deformylation of PPA mediated by peroxo-diiron(III) complexes. It was found that the deformylation rates are influenced by the Lewis acidity and redox properties of the metal centers, and showed a linear correlation with the FeIII/FeII redox potentials (in the range of 197 to 415 mV).
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Affiliation(s)
- Patrik Török
- Research Group of Bioorganic and Biocoordination Chemistry, Universtiy of Pannonia, 8201 Veszprém, Hungary
| | - Dóra Lakk-Bogáth
- Research Group of Bioorganic and Biocoordination Chemistry, Universtiy of Pannonia, 8201 Veszprém, Hungary
| | - Duenpen Unjaroen
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| | - Wesley R Browne
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands.
| | - József Kaizer
- Research Group of Bioorganic and Biocoordination Chemistry, Universtiy of Pannonia, 8201 Veszprém, Hungary.
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3
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Török P, Kaizer J. Effect of Substituted Pyridine Co-Ligands and (Diacetoxyiodo)benzene Oxidants on the Fe(III)-OIPh-Mediated Triphenylmethane Hydroxylation Reaction. Molecules 2024; 29:3842. [PMID: 39202921 PMCID: PMC11357111 DOI: 10.3390/molecules29163842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2024] [Revised: 08/09/2024] [Accepted: 08/12/2024] [Indexed: 09/03/2024] Open
Abstract
Iodosilarene derivatives (PhIO, PhI(OAc)2) constitute an important class of oxygen atom transfer reagents in organic synthesis and are often used together with iron-based catalysts. Since the factors controlling the ability of iron centers to catalyze alkane hydroxylation are not yet fully understood, the aim of this report is to develop bioinspired non-heme iron catalysts in combination with PhI(OAc)2, which are suitable for performing C-H activation. Overall, this study provides insight into the iron-based ([FeII(PBI)3(CF3SO3)2] (1), where PBI = 2-(2-pyridyl)benzimidazole) catalytic and stoichiometric hydroxylation of triphenylmethane using PhI(OAc)2, highlighting the importance of reaction conditions including the effect of the co-ligands (para-substituted pyridines) and oxidants (para-substituted iodosylbenzene diacetates) on product yields and reaction kinetics. A number of mechanistic studies have been carried out on the mechanism of triphenylmethane hydroxylation, including C-H activation, supporting the reactive intermediate, and investigating the effects of equatorial co-ligands and coordinated oxidants. Strong evidence for the electrophilic nature of the reaction was observed based on competitive experiments, which included a Hammett correlation between the relative reaction rate (logkrel) and the σp (4R-Py and 4R'-PhI(OAc)2) parameters in both stoichiometric (ρ = +0.87 and +0.92) and catalytic (ρ = +0.97 and +0.77) reactions. The presence of [(PBI)2(4R-Py)FeIIIOIPh-4R']3+ intermediates, as well as the effect of co-ligands and coordinated oxidants, was supported by their spectral (UV-visible) and redox properties. It has been proven that the electrophilic nature of iron(III)-iodozilarene complexes is crucial in the oxidation reaction of triphenylmethane. The hydroxylation rates showed a linear correlation with the FeIII/FeII redox potentials (in the range of -350 mV and -524 mV), which suggests that the Lewis acidity and redox properties of the metal centers greatly influence the reactivity of the reactive intermediates.
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Affiliation(s)
| | - József Kaizer
- Research Group of Bioorganic and Biocoordination Chemistry, University of Pannonia, H-8201 Veszprém, Hungary;
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4
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Rice DB, Wong D, Weyhermüller T, Neese F, DeBeer S. The spin-forbidden transition in iron(IV)-oxo catalysts relevant to two-state reactivity. SCIENCE ADVANCES 2024; 10:eado1603. [PMID: 38941457 PMCID: PMC11212722 DOI: 10.1126/sciadv.ado1603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 05/23/2024] [Indexed: 06/30/2024]
Abstract
Quintet oxoiron(IV) intermediates are often invoked in nonheme iron enzymes capable of performing selective oxidation, while most well-characterized synthetic model oxoiron(IV) complexes have a triplet ground state. These differing spin states lead to the proposal of a two-state reactivity model, where the complexes cross from the triplet to an excited quintet state. However, the energy of this quintet state has never been measured experimentally. Here, magnetic circular dichroism is used to assign the singlet and triplet excited states in a series of triplet oxoiron(IV) complexes. These transition energies are used to determine the energies of the quintet state via constrained fitting of 2p3d resonant inelastic x-ray scattering. This allowed for a direct correlation between the quintet energies and substrate C─H oxidation rates.
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Affiliation(s)
- Derek B. Rice
- Max Planck Institute for Chemical Energy Conversion, D-45470 Mülheim an der Ruhr, Germany
| | - Deniz Wong
- Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
| | - Thomas Weyhermüller
- Max Planck Institute for Chemical Energy Conversion, D-45470 Mülheim an der Ruhr, Germany
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim an der Ruhr, Germany
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, D-45470 Mülheim an der Ruhr, Germany
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5
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Fagnano A, Frateloreto F, Paoloni R, Sappino C, Lanzalunga O, Costas M, Di Stefano S, Olivo G. Proximity Effects on the Reactivity of a Nonheme Iron (IV) Oxo Complex in C-H Oxidation. Angew Chem Int Ed Engl 2024; 63:e202401694. [PMID: 38478739 DOI: 10.1002/anie.202401694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Indexed: 04/05/2024]
Abstract
Precise control of substrate positioning and orientation (its proximity to the reactive unit) is often invoked to rationalize the superior enzymatic reaction rates and selectivities when compared to synthetic models. Artificial nonheme iron (IV) oxo (Fe(IV)=O) complexes react with C(sp3)-H bonds via a biomimetic Hydrogen Atom Transfer/Hydroxyl Rebound mechanism, but rates, site-selectivity and even hydroxyl rebound efficiency (ligand rebound versus substrate radical diffusion) are smaller than in oxygenases. Herein, we quantitatively analyze how substrate binding modulates nonheme Fe(IV)=O reactivity by comparing rates and outcomes of C-H oxidation by a pair of Fe(IV)=O complexes that share the same first coordination sphere but only one contains a crown ether receptor that recognizes the substrate. Substrate binding makes the reaction intramolecular, exhibiting Michaelis-Menten kinetics and increased reaction rates. In addition, C-H oxidation occurs with high site selectivity for remote sites. Analysis of Effective Molarity reveals that the system operates at its maximal theoretical capability for the oxidation of these remote sites. Remarkably, substrate positioning also affects Hydroxyl Rebound, whose efficiency only increases on the sites placed in proximity by recognition. Overall, these observations provide evidence that supramolecular control of substrate positioning can effectively modulate the reactivity of oxygenases and its models.
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Affiliation(s)
- Alessandro Fagnano
- 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
| | - Roberta Paoloni
- 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
| | - Carla Sappino
- 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
| | - Miquel Costas
- QBIS-Cat, Institut de Química Computacional i Catàlisi (IQCC), Departament de Quimica, Universitat de Girona Campus Montilivi, 17071, Girona, Catalonia, Spain
| | - 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
| | - 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
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6
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Gong Z, Wang L, Xu Y, Xie D, Qi X, Nam W, Guo M. Enhanced Reactivities of Iron(IV)-Oxo Porphyrin Species in Oxidation Reactions Promoted by Intramolecular Hydrogen-Bonding. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2310333. [PMID: 38477431 PMCID: PMC11109629 DOI: 10.1002/advs.202310333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 02/19/2024] [Indexed: 03/14/2024]
Abstract
High-valent iron-oxo species are one of the common intermediates in both biological and biomimetic catalytic oxidation reactions. Recently, hydrogen-bonding (H-bonding) has been proved to be critical in determining the selectivity and reactivity. However, few examples have been established for mechanistic insights into the H-bonding effect. Moreover, intramolecular H-bonding effect on both C-H activation and oxygen atom transfer (OAT) reactions in synthetic porphyrin model system has not been investigated yet. In this study, a series of heme-containing iron(IV)-oxo porphyrin species with or without intramolecular H-bonding are synthesized and characterized. Kinetic studies revealed that intramolecular H-bonding can significantly enhance the reactivity of iron(IV)-oxo species in OAT, C-H activation, and electron-transfer reactions. This unprecedented unified H-bonding effect is elucidated by theoretical calculations, which showed that intramolecular H-bonding interactions lower the energy of the anti-bonding orbital of iron(IV)-oxo porphyrin species, resulting in the enhanced reactivities in oxidation reactions irrespective of the reaction type. To the best of the knowledge, this is the first extensive investigation on the intramolecular H-bonding effect in heme system. The results show that H-bonding interactions have a unified effect with iron(IV)-oxo porphyrin species in all three investigated reactions.
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Affiliation(s)
- Zhe Gong
- College of Chemistry and Molecular SciencesWuhan UniversityWuhanHubei430072P. R. China
| | - Liwei Wang
- College of Chemistry and Molecular SciencesWuhan UniversityWuhanHubei430072P. R. China
| | - Yiran Xu
- College of Chemistry and Molecular SciencesWuhan UniversityWuhanHubei430072P. R. China
| | - Duanfeng Xie
- College of Chemistry and Molecular SciencesWuhan UniversityWuhanHubei430072P. R. China
| | - Xiaotian Qi
- College of Chemistry and Molecular SciencesWuhan UniversityWuhanHubei430072P. R. China
| | - Wonwoo Nam
- Department of Chemistry and Nano ScienceEwha Womans UniversitySeoul03760South Korea
| | - Mian Guo
- College of Chemistry and Molecular SciencesWuhan UniversityWuhanHubei430072P. R. China
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7
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Singh P, Massie AA, Denler MC, Lee Y, Mayfield JR, Lomax MJA, Singh R, Nordlander E, Jackson TA. C-H Bond Oxidation by Mn IV-Oxo Complexes: Hydrogen-Atom Tunneling and Multistate Reactivity. Inorg Chem 2024; 63:7754-7769. [PMID: 38625043 DOI: 10.1021/acs.inorgchem.4c00186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
The reactivity of six MnIV-oxo complexes in C-H bond oxidation has been examined using a combination of kinetic experiments and computational methods. Variable-temperature studies of the oxidation of 9,10-dihydroanthracene (DHA) and ethylbenzene by these MnIV-oxo complexes yielded activation parameters suitable for evaluating electronic structure computations. Complementary kinetic experiments of the oxidation of deuterated DHA provided evidence for hydrogen-atom tunneling in C-H bond oxidation for all MnIV-oxo complexes. These results are in accordance with the Bell model, where tunneling occurs near the top of the transition-state barrier. Density functional theory (DFT) and DLPNO-CCSD(T1) computations were performed for three of the six MnIV-oxo complexes to probe a previously predicted multistate reactivity model. The DFT computations predicted a thermal crossing from the 4B1 ground state to a 4E state along the C-H bond oxidation reaction coordinate. DLPNO-CCSD(T1) calculations further confirm that the 4E transition state offers a lower energy barrier, reinforcing the multistate reactivity model for these complexes. We discuss how this multistate model can be reconciled with recent computations that revealed that the kinetics of C-H bond oxidation by this set of MnIV-oxo complexes can be well-predicted on the basis of the thermodynamic driving force for these reactions.
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Affiliation(s)
- Priya Singh
- The University of Kansas, Department of Chemistry and Center for Environmentally Beneficial Catalysis, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Allyssa A Massie
- The University of Kansas, Department of Chemistry and Center for Environmentally Beneficial Catalysis, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Melissa C Denler
- The University of Kansas, Department of Chemistry and Center for Environmentally Beneficial Catalysis, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Yuri Lee
- The University of Kansas, Department of Chemistry and Center for Environmentally Beneficial Catalysis, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Jaycee R Mayfield
- The University of Kansas, Department of Chemistry and Center for Environmentally Beneficial Catalysis, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Markell J A Lomax
- The University of Kansas, Department of Chemistry and Center for Environmentally Beneficial Catalysis, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Reena Singh
- Lund University, Chemical Physics, Department of Chemistry, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Ebbe Nordlander
- Lund University, Chemical Physics, Department of Chemistry, P.O. 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, Kansas 66045, United States
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8
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Keshari K, Santra A, Velasco L, Sauvan M, Kaur S, Ugale AD, Munshi S, Marco JF, Moonshiram D, Paria S. Functional Model of Compound II of Cytochrome P450: Spectroscopic Characterization and Reactivity Studies of a Fe IV-OH Complex. JACS AU 2024; 4:1142-1154. [PMID: 38559734 PMCID: PMC10976569 DOI: 10.1021/jacsau.3c00844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 02/12/2024] [Accepted: 02/26/2024] [Indexed: 04/04/2024]
Abstract
Herein, we show that the reaction of a mononuclear FeIII(OH) complex (1) with N-tosyliminobenzyliodinane (PhINTs) resulted in the formation of a FeIV(OH) species (3). The obtained complex 3 was characterized by an array of spectroscopic techniques and represented a rare example of a synthetic FeIV(OH) complex. The reaction of 1 with the one-electron oxidizing agent was reported to form a ligand-oxidized FeIII(OH) complex (2). 3 revealed a one-electron reduction potential of -0.22 V vs Fc+/Fc at -15 °C, which was 150 mV anodically shifted than 2 (Ered = -0.37 V vs Fc+/Fc at -15 °C), inferring 3 to be more oxidizing than 2. 3 reacted spontaneously with (4-OMe-C6H4)3C• to form (4-OMe-C6H4)3C(OH) through rebound of the OH group and displayed significantly faster reactivity than 2. Further, activation of the hydrocarbon C-H and the phenolic O-H bond by 2 and 3 was compared and showed that 3 is a stronger oxidant than 2. A detailed kinetic study established the occurrence of a concerted proton-electron transfer/hydrogen atom transfer reaction of 3. Studying one-electron reduction of 2 and 3 using decamethylferrocene (Fc*) revealed a higher ket of 3 than 2. The study established that the primary coordination sphere around Fe and the redox state of the metal center is very crucial in controlling the reactivity of high-valent Fe-OH complexes. Further, a FeIII(OMe) complex (4) was synthesized and thoroughly characterized, including X-ray structure determination. The reaction of 4 with PhINTs resulted in the formation of a FeIV(OMe) species (5), revealing the presence of two FeIV species with isomer shifts of -0.11 mm/s and = 0.17 mm/s in the Mössbauer spectrum and showed FeIV/FeIII potential at -0.36 V vs Fc+/Fc couple in acetonitrile at -15 °C. The reactivity studies of 5 were investigated and compared with the FeIV(OH) complex (3).
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Affiliation(s)
- Kritika Keshari
- Department
of Chemistry, Indian Institute of Technology
Delhi, Hauz Khas, New Delhi 110016, India
| | - Aakash Santra
- Department
of Chemistry, Indian Institute of Technology
Delhi, Hauz Khas, New Delhi 110016, India
| | - Lucía Velasco
- Instituto
de Ciencia de Materiales de Madrid, Consejo
Superior de Investigaciones Científicas, Sor Juana Inés de la Cruz, 3, Madrid 28049, Spain
| | - Maxime Sauvan
- Instituto
de Ciencia de Materiales de Madrid, Consejo
Superior de Investigaciones Científicas, Sor Juana Inés de la Cruz, 3, Madrid 28049, Spain
| | - Simarjeet Kaur
- Department
of Chemistry, Indian Institute of Technology
Delhi, Hauz Khas, New Delhi 110016, India
| | - Ashok D. Ugale
- Instituto
de Ciencia de Materiales de Madrid, Consejo
Superior de Investigaciones Científicas, Sor Juana Inés de la Cruz, 3, Madrid 28049, Spain
| | - Sandip Munshi
- School
of Chemical Science, Indian Association
for the Cultivation of Science, Raja S C Mulliick Road, Kolkata 700032, India
| | - J. F. Marco
- Instituto
de Quimica Fisica Blas Cabrera, Consejo
Superior de Investigaciones Científicas, C. de Serrano, 119, Serrano, Madrid 28006, Spain
| | - Dooshaye Moonshiram
- Instituto
de Ciencia de Materiales de Madrid, Consejo
Superior de Investigaciones Científicas, Sor Juana Inés de la Cruz, 3, Madrid 28049, Spain
| | - Sayantan Paria
- Department
of Chemistry, Indian Institute of Technology
Delhi, Hauz Khas, New Delhi 110016, India
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9
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Rasheed W, Pal N, Aboelenen AM, Banerjee S, Oloo WN, Klein JEMN, Fan R, Xiong J, Guo Y, Que L. NMR and Mössbauer Studies Reveal a Temperature-Dependent Switch from S = 1 to 2 in a Nonheme Oxoiron(IV) Complex with Faster C-H Bond Cleavage Rates. J Am Chem Soc 2024; 146:3796-3804. [PMID: 38299607 PMCID: PMC11238627 DOI: 10.1021/jacs.3c10694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
S = 2 FeIV═O centers generated in the active sites of nonheme iron oxygenases cleave substrate C-H bonds at rates significantly faster than most known synthetic FeIV═O complexes. Unlike the majority of the latter, which are S = 1 complexes, [FeIV(O)(tris(2-quinolylmethyl)amine)(MeCN)]2+ (3) is a rare example of a synthetic S = 2 FeIV═O complex that cleaves C-H bonds 1000-fold faster than the related [FeIV(O)(tris(pyridyl-2-methyl)amine)(MeCN)]2+ complex (0). To rationalize this significant difference, a systematic comparison of properties has been carried out on 0 and 3 as well as related complexes 1 and 2 with mixed pyridine (Py)/quinoline (Q) ligation. Interestingly, 2 with a 2-Q-1-Py donor combination cleaves C-H bonds at 233 K with rates approaching those of 3, even though Mössbauer analysis reveals 2 to be S = 1 at 4 K. At 233 K however, 2 becomes S = 2, as shown by its 1H NMR spectrum. These results demonstrate a unique temperature-dependent spin-state transition from triplet to quintet in oxoiron(IV) chemistry that gives rise to the high C-H bond cleaving reactivity observed for 2.
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Affiliation(s)
- Waqas Rasheed
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Nabhendu Pal
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Ahmed M Aboelenen
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Saikat Banerjee
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Williamson N Oloo
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Johannes E M N Klein
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Ruixi Fan
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Jin Xiong
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Lawrence Que
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
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10
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Lakk-Bogáth D, Pintarics D, Török P, Kaizer J. Influence of Equatorial Co-Ligands on the Reactivity of LFe IIIOIPh. Molecules 2023; 29:58. [PMID: 38202641 PMCID: PMC10779584 DOI: 10.3390/molecules29010058] [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: 12/06/2023] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 01/12/2024] Open
Abstract
Previous biomimetic studies clearly proved that equatorial ligands significantly influence the redox potential and thus the stability/reactivity of biologically important oxoiron intermediates; however, no such studies were performed on FeIIIOIPh species. In this study, the influence of substituted pyridine co-ligands on the reactivity of iron(III)-iodosylbenzene adduct has been investigated in sulfoxidation and epoxidation reactions. Selective oxidation of thioanisole, cis-cyclooctene, and cis- and trans-stilbene in the presence of a catalytic amount of [FeII(PBI)3](OTf)2 with PhI(OAc)2 provide products in good to excellent yields through an FeIIIOIPh intermediate depending on the co-ligand (4R-Py) used. Several mechanistic studies were performed to gain more insight into the mechanism of oxygen atom transfer (OAT) reactions to support the reactive intermediate and investigate the effect of the equatorial co-ligands. Based on competitive experiments, including a linear free-energy relationship between the relative reaction rates (logkrel) and the σp (4R-Py) parameters, strong evidence has been observed for the electrophilic character of the reactive species. The presence of the [(PBI)2(4R-Py)FeIIIOIPh]3+ intermediates and the effect of the co-ligands was also supported by UV-visible measurements, including the color change from red to green and the hypsochromic shifts in the presence of co-ligands. This is another indication that the title iron(III)-iodosylbenzene adduct is able to oxygenate sulfides and alkenes before it is transformed into the oxoiron form by cleavage of the O-I bond.
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Affiliation(s)
| | | | | | - József Kaizer
- Research Group of Bioorganic and Biocoordination Chemistry, University of Pannonia, H-8201 Veszprém, Hungary; (D.L.-B.); (D.P.); (P.T.)
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11
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Li Y, Singh R, Sinha A, Lisensky GC, Haukka M, Nilsson J, Yiga S, Demeshko S, Gross SJ, Dechert S, Gonzalez A, Farias G, Wendt OF, Meyer F, Nordlander E. Nonheme Fe IV═O Complexes Supported by Four Pentadentate Ligands: Reactivity toward H- and O- Atom Transfer Processes. Inorg Chem 2023; 62:18338-18356. [PMID: 37913548 PMCID: PMC10647104 DOI: 10.1021/acs.inorgchem.3c02526] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 10/06/2023] [Accepted: 10/11/2023] [Indexed: 11/03/2023]
Abstract
Four new pentadentate N5-donor ligands, [N-(1-methyl-2-imidazolyl)methyl-N-(2-pyridyl)-methyl-N-(bis-2-pyridylmethyl)-amine] (L1), [N-bis(1-methyl-2-imidazolyl)methyl-N-(bis-2-pyridylmethyl)amine] (L2), (N-(isoquinolin-3-ylmethyl)-1,1-di(pyridin-2-yl)-N-(pyridin-2-ylmethyl)methanamine (L3), and N,N-bis(isoquinolin-3-ylmethyl)-1,1-di(pyridin-2-yl)methanamine (L4), have been synthesized based on the N4Py ligand framework, where one or two pyridyl arms of the N4Py parent are replaced by (N-methyl)imidazolyl or N-(isoquinolin-3-ylmethyl) moieties. Using these four pentadentate ligands, the mononuclear complexes [FeII(CH3CN)(L1)]2+ (1a), [FeII(CH3CN)(L2)]2+ (2a), [FeII(CH3CN)(L3)]2+ (3a), and [FeII(CH3CN)(L4)]2+ (4a) have been synthesized and characterized. The half-wave potentials (E1/2) of the complexes become more positive in the order: 2a < 1a < 4a ≤ 3a ≤ [Fe(N4Py)(CH3CN)]2+. The order of redox potentials correlates well with the Fe-Namine distances observed by crystallography, which are 2a > 1a ≥ 4a > 3a ≥ [Fe(N4Py)(CH3CN)]2+. The corresponding ferryl complexes [FeIV(O)(L1)]2+ (1b), [FeIV(O)(L2)]2+ (2b), [FeIV(O)(L3)]2+ (3b), and [FeIV(O)(L4)]2+ (4b) were prepared by the reaction of the ferrous complexes with isopropyl 2-iodoxybenzoate (IBX ester) in acetonitrile. The greenish complexes 3b and 4b were also isolated in the solid state by the reaction of the ferrous complexes in CH3CN with ceric ammonium nitrate in water. Mössbauer spectroscopy and magnetic measurements (using superconducting quantum interference device) show that the four complexes 1b, 2b, 3b, and 4b are low-spin (S = 1) FeIV═O complexes. UV/vis spectra of the four FeIV═O complexes in acetonitrile show typical long-wavelength absorptions of around 700 nm, which are expected for FeIV═O complexes with N4Py-type ligands. The wavelengths of these absorptions decrease in the following order: 721 nm (2b) > 706 nm (1b) > 696 nm (4b) > 695 nm (3b) = 695 nm ([FeIV(O) (N4Py)]2+), indicating that the replacement of the pyridyl arms with (N-methyl) imidazolyl moieties makes L1 and L2 exert weaker ligand fields than the parent N4Py ligand, while the ligand field strengths of L3 and L4 are similar to the N4Py parent despite the replacement of the pyridyl arms with N-(isoquinolin-3-ylmethyl) moieties. Consequently, complexes 1b and 2b tend to be less stable than the parent [FeIV(O)(N4Py)]2+ complex: the half-life sequence at room temperature is 1.67 h (2b) < 16 h (1b) < 45 h (4b) < 63 h (3b) ≈ 60 h ([FeIV(O)(N4Py)]2+). Compared to the parent complex, 1b and 2b exhibit enhanced reactivity in both the oxidation of thioanisole in the oxygen atom transfer (OAT) reaction and the oxygenation of C-H bonds of aromatic and aliphatic substrates, presumed to occur via an oxygen rebound process. Furthermore, the second-order rate constants for hydrogen atom transfer (HAT) reactions affected by the ferryl complexes can be directly related to the C-H bond dissociation energies of a range of substrates that have been studied. Using either IBX ester or H2O2 as an oxidant, all four new FeII complexes display good performance in catalytic reactions involving both HAT and OAT reactions.
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Affiliation(s)
- Yong Li
- Chemical
Physics, Department of Chemistry, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Reena Singh
- Chemical
Physics, Department of Chemistry, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Arup Sinha
- Chemical
Physics, Department of Chemistry, Lund University, Box 124, Lund SE-221 00, Sweden
| | - George C. Lisensky
- Department
of Chemistry, Beloit College, 700 College Street, Beloit, Wisconsin 53511, United States
| | - Matti Haukka
- Department
of Chemistry, University of Jyväskylä, P.O. Box-35, Jyväskylä FI-40014, Finland
| | - Justin Nilsson
- Chemical
Physics, Department of Chemistry, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Solomon Yiga
- Centre
for Analysis and Synthesis, Department of Chemistry, Lund University, P.O. Box 124, Lund SE-22100, Sweden
| | - Serhiy Demeshko
- Georg-August
Universität Göttingen, Institut
für Anorganische Chemie, Tammanstrasse 4, Göttingen D-37077, Germany
| | - Sophie Jana Gross
- Georg-August
Universität Göttingen, Institut
für Anorganische Chemie, Tammanstrasse 4, Göttingen D-37077, Germany
| | - Sebastian Dechert
- Georg-August
Universität Göttingen, Institut
für Anorganische Chemie, Tammanstrasse 4, Göttingen D-37077, Germany
| | - Ana Gonzalez
- MAX IV Laboratory, Lund University, P.O.
Box 118, Lund SE-221 00, Sweden
| | - Giliandro Farias
- Department
of Chemistry, Federal University of Santa
Catarina, Florianópolis 88040900, Santa Catarina, Brazil
| | - Ola F. Wendt
- Centre
for Analysis and Synthesis, Department of Chemistry, Lund University, P.O. Box 124, Lund SE-22100, Sweden
| | - Franc Meyer
- Georg-August
Universität Göttingen, Institut
für Anorganische Chemie, Tammanstrasse 4, Göttingen D-37077, Germany
| | - Ebbe Nordlander
- Chemical
Physics, Department of Chemistry, Lund University, Box 124, Lund SE-221 00, Sweden
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12
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Singh P, Lee Y, Mayfield JR, Singh R, Denler MC, Jones SD, Day VW, Nordlander E, Jackson TA. Enhanced Understanding of Structure-Function Relationships for Oxomanganese(IV) Complexes. Inorg Chem 2023; 62:18357-18374. [PMID: 37314463 DOI: 10.1021/acs.inorgchem.3c00600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
A series of manganese(II) and oxomanganese(IV) complexes supported by neutral, pentadentate ligands with varied equatorial ligand-field strength (N3pyQ, N2py2I, and N4pyMe2) were synthesized and then characterized using structural and spectroscopic methods. On the basis of electronic absorption spectroscopy, the [MnIV(O)(N4pyMe2)]2+ complex has the weakest equatorial ligand field among a set of similar MnIV-oxo species. In contrast, [MnIV(O)(N2py2I)]2+ shows the strongest equatorial ligand-field strength for this same series. We examined the influence of these changes in electronic structure on the reactivity of the oxomanganese(IV) complexes using hydrocarbons and thioanisole as substrates. The [MnIV(O)(N3pyQ)]2+ complex, which contains one quinoline and three pyridine donors in the equatorial plane, ranks among the fastest MnIV-oxo complexes in C-H bond and thioanisole oxidation. While a weak equatorial ligand field has been associated with high reactivity, the [MnIV(O)(N4pyMe2)]2+ complex is only a modest oxidant. Buried volume plots suggest that steric factors dampen the reactivity of this complex. Trends in reactivity were examined using density functional theory (DFT)-computed bond dissociation free energies (BDFEs) of the MnIIIO-H and MnIV ═ O bonds. We observe an excellent correlation between MnIV═O BDFEs and rates of thioanisole oxidation, but more scatter is observed between hydrocarbon oxidation rates and the MnIIIO-H BDFEs.
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Affiliation(s)
- Priya Singh
- The University of Kansas, Department of Chemistry and Center for Environmentally Beneficial Catalysis, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Yuri Lee
- The University of Kansas, Department of Chemistry and Center for Environmentally Beneficial Catalysis, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Jaycee R Mayfield
- The University of Kansas, Department of Chemistry and Center for Environmentally Beneficial Catalysis, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Reena Singh
- Lund University, Chemical Physics, Department of Chemistry, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Melissa C Denler
- The University of Kansas, Department of Chemistry and Center for Environmentally Beneficial Catalysis, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Shannon D Jones
- The University of Kansas, Department of Chemistry and Center for Environmentally Beneficial Catalysis, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Victor W Day
- The University of Kansas, Department of Chemistry and Center for Environmentally Beneficial Catalysis, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Ebbe Nordlander
- Lund University, Chemical Physics, Department of Chemistry, P.O. 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, Kansas 66045, United States
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13
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Claveau EE, Sader S, Jackson BA, Khan SN, Miliordos E. Transition metal oxide complexes as molecular catalysts for selective methane to methanol transformation: any prospects or time to retire? Phys Chem Chem Phys 2023; 25:5313-5326. [PMID: 36723253 DOI: 10.1039/d2cp05480a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Transition metal oxides have been extensively used in the literature for the conversion of methane to methanol. Despite the progress made over the past decades, no method with satisfactory performance or economic viability has been detected. The main bottleneck is that the produced methanol oxidizes further due to its weaker C-H bond than that of methane. Every improvement in the efficiency of a catalyst to activate methane leads to reduction of the selectivity towards methanol. Is it therefore prudent to keep studying (both theoretically and experimentally) metal oxides as catalysts for the quantitative conversion of methane to methanol? This perspective focuses on molecular metal oxide complexes and suggests strategies to bypass the current bottlenecks with higher weight on the computational chemistry side. We first discuss the electronic structure of metal oxides, followed by assessing the role of the ligands in the reactivity of the catalysts. For better selectivity, we propose that metal oxide anionic complexes should be explored further, while hydrophylic cavities in the vicinity of the metal oxide can perturb the transition-state structure for methanol increasing appreciably the activation barrier for methanol. We also emphasize that computational studies should target the activation reaction of methanol (and not only methane), the study of complete catalytic cycles (including the recombination and oxidation steps), and the use of molecular oxygen as an oxidant. The titled chemical conversion is an excellent challenge for theory and we believe that computational studies should lead the field in the future. It is finally shown that bottom-up approaches offer a systematic way for exploration of the chemical space and should still be applied in parallel with the recently popular machine learning techniques. To answer the question of the title, we believe that metal oxides should still be considered provided that we change our focus and perform more systematic investigations on the activation of methanol.
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Affiliation(s)
- Emily E Claveau
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
| | - Safaa Sader
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
| | - Benjamin A Jackson
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
| | - Shahriar N Khan
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
| | - Evangelos Miliordos
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
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14
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Dantignana V, Pérez‐Segura MC, Besalú‐Sala P, Delgado‐Pinar E, Martínez‐Camarena Á, Serrano‐Plana J, Álvarez‐Núñez A, Castillo CE, García‐España E, Luis JM, Basallote MG, Costas M, Company A. Characterization of a Ferryl Flip in Electronically Tuned Nonheme Complexes. Consequences in Hydrogen Atom Transfer Reactivity. Angew Chem Int Ed Engl 2023; 62:e202211361. [PMID: 36305539 PMCID: PMC10107328 DOI: 10.1002/anie.202211361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Indexed: 12/04/2022]
Abstract
Two oxoiron(IV) isomers (R 2a and R 2b) of general formula [FeIV (O)(R PyNMe3 )(CH3 CN)]2+ are obtained by reaction of their iron(II) precursor with NBu4 IO4 . The two isomers differ in the position of the oxo ligand, cis and trans to the pyridine donor. The mechanism of isomerization between R 2a and R 2b has been determined by kinetic and computational analyses uncovering an unprecedented path for interconversion of geometrical oxoiron(IV) isomers. The activity of the two oxoiron(IV) isomers in hydrogen atom transfer (HAT) reactions shows that R 2a reacts one order of magnitude faster than R 2b, which is explained by a repulsive noncovalent interaction between the ligand and the substrate in R 2b. Interestingly, the electronic properties of the R substituent in the ligand pyridine ring do not have a significant effect on reaction rates. Overall, the intrinsic structural aspects of each isomer define their relative HAT reactivity, overcoming changes in electronic properties of the ligand.
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Affiliation(s)
- Valeria Dantignana
- Institut de Química Computacional i Catàlisi (IQCC)Departament de Química, Universitat de GironaC/Mª Aurèlia Capmany 6917003GironaCataloniaSpain
| | - M. Carmen Pérez‐Segura
- Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química InorgánicaFacultad de Ciencias, Instituto de Biomoléculas (INBIO)Universidad de CádizPuerto Real11510CádizSpain
| | - Pau Besalú‐Sala
- Institut de Química Computacional i Catàlisi (IQCC)Departament de Química, Universitat de GironaC/Mª Aurèlia Capmany 6917003GironaCataloniaSpain
| | - Estefanía Delgado‐Pinar
- Departamento de Química InorgánicaInstituto de Ciencia Molecular (ICMol)Universidad de ValenciaC/Catedrático José Beltrán, Paterna46980Valencia 2Spain
| | - Álvaro Martínez‐Camarena
- Departamento de Química InorgánicaInstituto de Ciencia Molecular (ICMol)Universidad de ValenciaC/Catedrático José Beltrán, Paterna46980Valencia 2Spain
| | - Joan Serrano‐Plana
- Institut de Química Computacional i Catàlisi (IQCC)Departament de Química, Universitat de GironaC/Mª Aurèlia Capmany 6917003GironaCataloniaSpain
| | - Andrea Álvarez‐Núñez
- Institut de Química Computacional i Catàlisi (IQCC)Departament de Química, Universitat de GironaC/Mª Aurèlia Capmany 6917003GironaCataloniaSpain
| | - Carmen E. Castillo
- Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química InorgánicaFacultad de Ciencias, Instituto de Biomoléculas (INBIO)Universidad de CádizPuerto Real11510CádizSpain
| | - Enrique García‐España
- Departamento de Química InorgánicaInstituto de Ciencia Molecular (ICMol)Universidad de ValenciaC/Catedrático José Beltrán, Paterna46980Valencia 2Spain
| | - Josep M. Luis
- Institut de Química Computacional i Catàlisi (IQCC)Departament de Química, Universitat de GironaC/Mª Aurèlia Capmany 6917003GironaCataloniaSpain
| | - Manuel G. Basallote
- Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química InorgánicaFacultad de Ciencias, Instituto de Biomoléculas (INBIO)Universidad de CádizPuerto Real11510CádizSpain
| | - Miquel Costas
- Institut de Química Computacional i Catàlisi (IQCC)Departament de Química, Universitat de GironaC/Mª Aurèlia Capmany 6917003GironaCataloniaSpain
| | - Anna Company
- Institut de Química Computacional i Catàlisi (IQCC)Departament de Química, Universitat de GironaC/Mª Aurèlia Capmany 6917003GironaCataloniaSpain
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15
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Wu P, Gu Y, Liao L, Wu Y, Jin J, Wang Z, Zhou J, Shaik S, Wang B. Coordination Switch Drives Selective C−S Bond Formation by the Non‐Heme Sulfoxide Synthases**. Angew Chem Int Ed Engl 2022; 61:e202214235. [DOI: 10.1002/anie.202214235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Indexed: 11/16/2022]
Affiliation(s)
- Peng Wu
- State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering School of Chemistry and Chemical Engineering Ningxia University Yinchuan 750021 China
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry College of Chemistry and Chemical Engineering Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM) Xiamen University Xiamen 361005 China
| | - Yang Gu
- Shenzhen Key Laboratory for the Intelligent Microbial Manufacturing of Medicine Shenzhen Institute of Synthetic Biology Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen 518055 China
| | - Langxing Liao
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry College of Chemistry and Chemical Engineering Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM) Xiamen University Xiamen 361005 China
| | - Yanfei Wu
- Shenzhen Key Laboratory for the Intelligent Microbial Manufacturing of Medicine Shenzhen Institute of Synthetic Biology Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen 518055 China
| | - Jiaoyu Jin
- Shenzhen Key Laboratory for the Intelligent Microbial Manufacturing of Medicine Shenzhen Institute of Synthetic Biology Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen 518055 China
| | - Zhanfeng Wang
- Center for Advanced Materials Research Beijing Normal University Zhuhai 519087 China
| | - Jiahai Zhou
- Shenzhen Key Laboratory for the Intelligent Microbial Manufacturing of Medicine Shenzhen Institute of Synthetic Biology Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen 518055 China
| | - Sason Shaik
- Institute of Chemistry The Hebrew University of Jerusalem Jerusalem 9190401 Israel
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry College of Chemistry and Chemical Engineering Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM) Xiamen University Xiamen 361005 China
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16
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Field MJ, Oyala PH, Green MT. 17O Electron Nuclear Double Resonance Analysis of Compound I: Inverse Correlation between Oxygen Spin Population and Electron Donation. J Am Chem Soc 2022; 144:19272-19283. [PMID: 36240444 DOI: 10.1021/jacs.2c05459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although the activation of inert C-H bonds by metal-oxo complexes has been widely studied, important questions remain, particularly regarding the role of oxygen spin population (i.e., unpaired electrons on the oxo ligand) in facilitating C-H bond cleavage. In order to shed light on this issue, we have utilized 17O electron nuclear double resonance spectroscopy to measure the oxygen spin populations of three compound I intermediates in heme enzymes with different reactivities toward C-H bonds: chloroperoxidase, cytochrome P450, and a selenolate (selenocysteinyl)-ligated cytochrome P450. The experimental data suggest an inverse correlation between oxygen spin population and electron donation from the axial ligand. We have explored the implications of this result using a Hückel-type molecular orbital model and constrained density functional theory calculations. These investigations have allowed us to examine the relationship between oxygen spin population, oxygen charge, electron donation from the axial ligand, and reactivity.
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Affiliation(s)
- Mackenzie J Field
- Department of Chemistry and Department of Molecular Biology and Biochemistry, University of California, Irvine, California92697, United States
| | - Paul H Oyala
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California91125, United States
| | - Michael T Green
- Department of Chemistry and Department of Molecular Biology and Biochemistry, University of California, Irvine, California92697, United States
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17
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Cutsail GE, Banerjee R, Rice DB, McCubbin Stepanic O, Lipscomb JD, DeBeer S. Determination of the iron(IV) local spin states of the Q intermediate of soluble methane monooxygenase by Kβ X-ray emission spectroscopy. J Biol Inorg Chem 2022; 27:573-582. [PMID: 35988092 PMCID: PMC9470658 DOI: 10.1007/s00775-022-01953-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 08/07/2022] [Indexed: 11/29/2022]
Abstract
Soluble methane monooxygenase (sMMO) facilitates the conversion of methane to methanol at a non-heme FeIV2 intermediate MMOHQ, which is formed in the active site of the sMMO hydroxylase component (MMOH) during the catalytic cycle. Other biological systems also employ high-valent FeIV sites in catalysis; however, MMOHQ is unique as Nature’s only identified FeIV2 intermediate. Previous 57Fe Mössbauer spectroscopic studies have shown that MMOHQ employs antiferromagnetic coupling of the two FeIV sites to yield a diamagnetic cluster. Unfortunately, this lack of net spin prevents the determination of the local spin state (Sloc) of each of the irons by most spectroscopic techniques. Here, we use Fe Kβ X-ray emission spectroscopy (XES) to characterize the local spin states of the key intermediates of the sMMO catalytic cycle, including MMOHQ trapped by rapid-freeze-quench techniques. A pure XES spectrum of MMOHQ is obtained by subtraction of the contributions from other reaction cycle intermediates with the aid of Mössbauer quantification. Comparisons of the MMOHQ spectrum with those of known Sloc = 1 and Sloc = 2 FeIV sites in chemical and biological models reveal that MMOHQ possesses Sloc = 2 iron sites. This experimental determination of the local spin state will help guide future computational and mechanistic studies of sMMO catalysis.
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Affiliation(s)
- George E Cutsail
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470, Mülheim an der Ruhr, Germany.
- Institute of Inorganic Chemistry, University of Duisburg-Essen, Universitätsstrasse 5-7, 45117, Essen, Germany.
| | - Rahul Banerjee
- Department of Biochemistry Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Derek B Rice
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470, Mülheim an der Ruhr, Germany
| | - Olivia McCubbin Stepanic
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470, Mülheim an der Ruhr, Germany
| | - John D Lipscomb
- Department of Biochemistry Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470, Mülheim an der Ruhr, Germany.
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18
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Hansen HB, Krzystek J, Telser J, Swain A, Rajaraman G, Wadepohl H, Enders M. Solid-State Conformational Isomerism Lacking a Gas-Phase Energy Barrier: Its Structural, Spectroscopic, and Theoretical Identification in an Organochromium(III) Complex. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Helge-Boj Hansen
- Institute of Inorganic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - J. Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Joshua Telser
- Department of Biological, Physical, and Health Sciences, Roosevelt University, Chicago, Illinois 60605, United States
| | - Abinash Swain
- Institute of Inorganic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Hubert Wadepohl
- Institute of Inorganic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Markus Enders
- Institute of Inorganic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
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19
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Munshi S, Sinha A, Yiga S, Banerjee S, Singh R, Hossain MK, Haukka M, Valiati AF, Huelsmann RD, Martendal E, Peralta R, Xavier F, Wendt OF, Paine TK, Nordlander E. Hydrogen-atom and oxygen-atom transfer reactivities of iron(IV)-oxo complexes of quinoline-substituted pentadentate ligands. Dalton Trans 2022; 51:870-884. [PMID: 34994361 DOI: 10.1039/d1dt03381f] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A series of iron(II) complexes with the general formula [FeII(L2-Qn)(L)]n+ (n = 1, L = F-, Cl-; n = 2, L = NCMe, H2O) have been isolated and characterized. The X-ray crystallographic data reveals that metal-ligand bond distances vary with varying ligand field strengths of the sixth ligand. While the complexes with fluoride, chloride and water as axial ligand are high spin, the acetonitrile-coordinated complex is in a mixed spin state. The steric bulk of the quinoline moieties forces the axial ligands to deviate from the Fe-Naxial axis. A higher deviation/tilt is noted for the high spin complexes, while the acetonitrile coordinated complex displays least deviation. This deviation from linearity is slightly less in the analogous low-spin iron(II) complex [FeII(L1-Qn)(NCMe)]2+ of the related asymmetric ligand L1-Qn due to the presence of only one sterically demanding quinoline moiety. The two iron(II)-acetonitrile complexes [FeII(L2-Qn)(NCMe)]2+ and [FeII(L1-Qn)(NCMe)]2+ generate the corresponding iron(IV)-oxo species with higher thermal stability of the species supported by the L1-Qn ligand. The crystallographic and spectroscopic data for [FeIV(O)(L1-Qn)](ClO4)2 bear resemblance to other crystallographically characterized S = 1 iron(IV)-oxo complexes. The hydrogen atom transfer (HAT) and oxygen atom transfer (OAT) reactivities of both the iron(IV)-oxo complexes were investigated, and a Box-Behnken multivariate optimization of the parameters for catalytic oxidation of cyclohexane by [FeII(L2-Qn)(NCMe)]2+ using hydrogen peroxide as the terminal oxidant is presented. An increase in the average Fe-N bond length in [FeII(L1-Qn)(NCMe)]2+ is also manifested in higher HAT and OAT rates relative to the other reported complexes of ligands based on the N4Py framework. The results reported here confirm that the steric influence of the ligand environment is of critical importance for the reactivity of iron(IV)-oxo complexes, but additional electronic factors must influence the reactivity of iron-oxo complexes of N4Py derivatives.
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Affiliation(s)
- Sandip Munshi
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Kolkata, India.
| | - Arup Sinha
- Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-221 00 Lund, Sweden. .,Department of Chemistry, School of Advanced Science, Vellore Institute of Technology, Vellore, India
| | - Solomon Yiga
- Center for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-221 00 Lund, Sweden. .,Department of Chemistry, Makerere University, P. O. Box 7062, Kampala, Uganda
| | - Sridhar Banerjee
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Kolkata, India.
| | - Reena Singh
- Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-221 00 Lund, Sweden.
| | - Md Kamal Hossain
- Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-221 00 Lund, Sweden.
| | - Matti Haukka
- Department of Chemistry, University of Jyväskylä, Box 35, FI-400 14, Jyväskylä, Finland
| | - Andrei Felipe Valiati
- Department of Chemistry, LABINC, Universidade Federal de Santa Catarina (UFSC), 88040-900 Florianopolis, Santa Catarina, Brazil
| | - Ricardo Dagnoni Huelsmann
- Department of Chemistry, Center for Technological Sciences, Universidade do Estado de Santa Catarina (UDESC), 89219-710 Joinville, Santa Catarina, Brazil
| | - Edmar Martendal
- Department of Chemistry, Center for Technological Sciences, Universidade do Estado de Santa Catarina (UDESC), 89219-710 Joinville, Santa Catarina, Brazil
| | - Rosely Peralta
- Department of Chemistry, LABINC, Universidade Federal de Santa Catarina (UFSC), 88040-900 Florianopolis, Santa Catarina, Brazil
| | - Fernando Xavier
- Department of Chemistry, Center for Technological Sciences, Universidade do Estado de Santa Catarina (UDESC), 89219-710 Joinville, Santa Catarina, Brazil
| | - Ola F Wendt
- Center for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-221 00 Lund, Sweden.
| | - Tapan K Paine
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Kolkata, India.
| | - Ebbe Nordlander
- Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-221 00 Lund, Sweden.
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20
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Gordon JB, Albert T, Dey A, Sabuncu S, Siegler MA, Bill E, Moënne-Loccoz P, Goldberg DP. A Reactive, Photogenerated High-Spin ( S = 2) Fe IV(O) Complex via O 2 Activation. J Am Chem Soc 2021; 143:21637-21647. [PMID: 34913683 PMCID: PMC9109941 DOI: 10.1021/jacs.1c10051] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Addition of dioxygen at low temperature to the non-heme ferrous complex FeII(Me3TACN)((OSiPh2)2O) (1) in 2-MeTHF produces a peroxo-bridged diferric complex Fe2III(μ-O2)(Me3TACN)2((OSiPh2)2O)2 (2), which was characterized by UV-vis, resonance Raman, and variable field Mössbauer spectroscopies. Illumination of a frozen solution of 2 in THF with white light leads to homolytic O-O bond cleavage and generation of a FeIV(O) complex 4 (ν(Fe=O) = 818 cm-1; δ = 0.22 mm s-1, ΔEQ = 0.23 mm s-1). Variable field Mössbauer spectroscopy measurements show that 4 is a rare example of a high-spin S = 2 FeIV(O) complex and the first synthetic example to be generated directly from O2. Complex 4 is highly reactive, as expected for a high-spin ferryl, and decays rapidly in fluid solution at cryogenic temperatures. This decay process in 2-MeTHF involves C-H cleavage of the solvent. However, the controlled photolysis of 2 in situ with visible light and excess phenol substrate leads to competitive phenol oxidation, via the proposed transient generation of 4 as the active oxidant.
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Affiliation(s)
- Jesse B. Gordon
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
| | - Therese Albert
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Aniruddha Dey
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
| | - Sinan Sabuncu
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Maxime A. Siegler
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
| | - Eckhard Bill
- Department of Inorganic Spectroscopy / Joint Workspace, Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34−36, 45470 Mülheim-an-der-Ruhr, Germany,Corresponding Author: , ,
| | - Pierre Moënne-Loccoz
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon 97239, USA,Corresponding Author: , ,
| | - David P. Goldberg
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA,Corresponding Author: , ,
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21
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Khan SN, Miliordos E. Electronic Structure of RhO 2+, Its Ammoniated Complexes (NH 3) 1-5RhO 2+, and Mechanistic Exploration of CH 4 Activation by Them. Inorg Chem 2021; 60:16111-16119. [PMID: 34637614 DOI: 10.1021/acs.inorgchem.1c01447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
High-level electronic structure calculations are initially performed to investigate the electronic structure of RhO2+. The construction of potential energy curves for the ground and low-lying excited states allowed the calculation of spectroscopic constants, including harmonic and anharmonic vibrational frequencies, bond lengths, spin-orbit constants, and excitation energies. The equilibrium electronic configurations were used for the interpretation of the chemical bonding. We further monitored how the Rh-O bonding scheme changes with the gradual addition of ammonia ligands. The nature of this bond remains unaffected up to four ammonia ligands but adopts a different electronic configuration in the pseudo-octahedral geometry of (NH3)5RhO2+. This has consequences in the activation mechanism of the C-H bond of methane by these complexes, especially (NH3)4RhO2+. We show that the [2 + 2] mechanism in the (NH3)4RhO2+ case has a very low energy barrier comparable to that of a radical mechanism. We also demonstrate that methane can coordinate to the metal in a similar fashion to ammonia and that knowledge of the electronic structure of the pure ammonia complexes provides qualitative insights into the optimal reaction mechanism.
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Affiliation(s)
- Shahriar N Khan
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849-5312, United States
| | - Evangelos Miliordos
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849-5312, United States
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22
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Claveau EE, Miliordos E. Electronic structure of the dicationic first row transition metal oxides. Phys Chem Chem Phys 2021; 23:21172-21182. [PMID: 34528643 DOI: 10.1039/d1cp02492b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Multi-reference electronic structure calculations combined with large basis sets are performed to investigate the electronic structure of the ground and low-lying electronic states of the MO2+ diatomic species with M = Ti-Cu. These systems have shown high efficiency in the activation of the C-H of saturated hydrocarbons. This study is the first systematic and accurate work for these systems and our results and discussion provides insights into the reactivity and stability of MO2+ units. We find that they can be divided in three groups. The early transition metals (Ti, V, Cr) have very stable and well separated oxo (M4+O2-) character ground states, the middle transition metals (Mn, Fe) have oxyl (M3+O˙-) ground states with low-lying oxo excited states, and the late transition metals (Co, Ni, Cu) have well separated oxyl states. The reported spectroscopic constants will aid future experimental investigations, which are sparse in the literature. Periodic trends for the bond lengths, energetics, excitation energies, and wavefunction composition are discussed in detail. Complete basis set limit results indicate the high accuracy of the quintuple-ζ basis sets.
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Affiliation(s)
- Emily E Claveau
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
| | - Evangelos Miliordos
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
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23
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Shteinman AA, Mitra M. Nonheme mono- and dinuclear iron complexes in bio-inspired C H and C C bond hydroxylation reactions: Mechanistic insight. Inorganica Chim Acta 2021. [DOI: 10.1016/j.ica.2021.120388] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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24
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Mukherjee G, Satpathy JK, Bagha UK, Mubarak MQE, Sastri CV, de Visser SP. Inspiration from Nature: Influence of Engineered Ligand Scaffolds and Auxiliary Factors on the Reactivity of Biomimetic Oxidants. ACS Catal 2021. [DOI: 10.1021/acscatal.1c01993] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Gourab Mukherjee
- Department of Chemistry, Indian Institute of Technology Guwahati, 781039, Assam, India
| | - Jagnyesh K. Satpathy
- Department of Chemistry, Indian Institute of Technology Guwahati, 781039, Assam, India
| | - Umesh K. Bagha
- Department of Chemistry, Indian Institute of Technology Guwahati, 781039, Assam, India
| | - M. Qadri E. Mubarak
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
- Fakulti Sains dan Teknologi, Universiti Sains Islam Malaysia, Bandar Baru Nilai, 71800 Nilai, Negeri Sembilan Malaysia
| | - Chivukula V. Sastri
- Department of Chemistry, Indian Institute of Technology Guwahati, 781039, Assam, India
| | - Sam P. de Visser
- Department of Chemistry, Indian Institute of Technology Guwahati, 781039, Assam, India
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
- Department of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
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25
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Biswas JP, Ansari M, Paik A, Sasmal S, Paul S, Rana S, Rajaraman G, Maiti D. Effect of the Ligand Backbone on the Reactivity and Mechanistic Paradigm of Non‐Heme Iron(IV)‐Oxo during Olefin Epoxidation. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102484] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Jyoti Prasad Biswas
- Department of Chemistry Indian Institute of Technology Bombay Powai Mumbai 400076 India
| | - Mursaleem Ansari
- Department of Chemistry Indian Institute of Technology Bombay Powai Mumbai 400076 India
| | - Aniruddha Paik
- Department of Chemistry University of North Bengal Raja Rammohunpur Darjeeling West Bengal, Pin 734013 India
| | - Sheuli Sasmal
- Department of Chemistry Indian Institute of Technology Bombay Powai Mumbai 400076 India
| | - Sabarni Paul
- Department of Chemistry University of North Bengal Raja Rammohunpur Darjeeling West Bengal, Pin 734013 India
| | - Sujoy Rana
- Department of Chemistry University of North Bengal Raja Rammohunpur Darjeeling West Bengal, Pin 734013 India
| | - Gopalan Rajaraman
- Department of Chemistry Indian Institute of Technology Bombay Powai Mumbai 400076 India
| | - Debabrata Maiti
- Department of Chemistry Indian Institute of Technology Bombay Powai Mumbai 400076 India
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26
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Biswas JP, Ansari M, Paik A, Sasmal S, Paul S, Rana S, Rajaraman G, Maiti D. Effect of the Ligand Backbone on the Reactivity and Mechanistic Paradigm of Non-Heme Iron(IV)-Oxo during Olefin Epoxidation. Angew Chem Int Ed Engl 2021; 60:14030-14039. [PMID: 33836110 DOI: 10.1002/anie.202102484] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Indexed: 01/08/2023]
Abstract
The oxygen atom transfer (OAT) reactivity of the non-heme [FeIV (2PyN2Q)(O)]2+ (2) containing the sterically bulky quinoline-pyridine pentadentate ligand (2PyN2Q) has been thoroughly studied with different olefins. The ferryl-oxo complex 2 shows excellent OAT reactivity during epoxidations. The steric encumbrance and electronic effect of the ligand influence the mechanistic shuttle between OAT pathway I and isomerization pathway II (during the reaction stereo pure olefins), resulting in a mixture of cis-trans epoxide products. In contrast, the sterically less hindered and electronically different [FeIV (N4Py)(O)]2+ (1) provides only cis-stilbene epoxide. A Hammett study suggests the role of dominant inductive electronic along with minor resonance effect during electron transfer from olefin to 2 in the rate-limiting step. Additionally, a computational study supports the involvement of stepwise pathways during olefin epoxidation. The ferryl bend due to the bulkier ligand incorporation leads to destabilization of both d z 2 and d x 2 - y 2 orbitals, leading to a very small quintet-triplet gap and enhanced reactivity for 2 compared to 1. Thus, the present study unveils the role of steric and electronic effects of the ligand towards mechanistic modification during olefin epoxidation.
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Affiliation(s)
- Jyoti Prasad Biswas
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Mursaleem Ansari
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Aniruddha Paik
- Department of Chemistry, University of North Bengal, Raja Rammohunpur, Darjeeling, West Bengal, Pin, 734013, India
| | - Sheuli Sasmal
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Sabarni Paul
- Department of Chemistry, University of North Bengal, Raja Rammohunpur, Darjeeling, West Bengal, Pin, 734013, India
| | - Sujoy Rana
- Department of Chemistry, University of North Bengal, Raja Rammohunpur, Darjeeling, West Bengal, Pin, 734013, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Debabrata Maiti
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
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27
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Liu J, Wu P, Yan S, Li Y, Cao Z, Wang B. Spin-Regulated Inner-Sphere Electron Transfer Enables Efficient O—O Bond Activation in Nonheme Diiron Monooxygenase MIOX. ACS Catal 2021. [DOI: 10.1021/acscatal.1c00898] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Jia Liu
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| | - Peng Wu
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| | - Shengheng Yan
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| | - Yuanyuan Li
- College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, China
| | - Zexing Cao
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| | - Binju Wang
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
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28
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Sader S, Miliordos E. Methane to Methanol Conversion Facilitated by Anionic Transition Metal Centers: The Case of Fe, Ni, Pd, and Pt. J Phys Chem A 2021; 125:2364-2373. [PMID: 33710883 DOI: 10.1021/acs.jpca.0c10577] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Density functional theory and high-level ab initio electronic structure calculations are performed to study the mechanism of the partial oxidation of methane to methanol facilitated by the titled anionic transition metal atoms. The energy landscape for the overall reaction M- + N2O + CH4 → M- + N2 + CH3OH (M = Fe, Ni, Pd, Pt) is constructed for different reaction pathways for all four metals. The comparison with earlier experimental and theoretical results for cationic centers demonstrates the better performance of the metal anions. The main advantage is that anionic centers interact weakly with the produced methanol. This fact facilitates the fast removal of methanol from the catalytic center and prevents the overoxidation of methane. Moreover, a moderate or high energy barrier for the M- + CH4 → HMCH3- reaction step is observed, which protects the metal center from deactivation. Future work should focus on the identification of proper ligands, which stabilize the negative charge on the metal (electronic factors) and prevent the formation of the global CH3MOH- minimum (steric factors). Finally, a composite electronic structure method (combining size extensive coupled clusters approaches and accurate multireference configuration interaction) is proposed for computationally demanding systems and is applied to Fe-.
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Affiliation(s)
- Safaa Sader
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, United States
| | - Evangelos Miliordos
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, United States
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29
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Kannan N, Patil AR, Sinha A. Direct C-H bond halogenation and pseudohalogenation of hydrocarbons mediated by high-valent 3d metal-oxo species. Dalton Trans 2020; 49:14344-14360. [PMID: 33057538 DOI: 10.1039/d0dt02533j] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Late-stage direct functionalization of the C-H bond is synthetically desirable. Metalloenzymes having metal-oxo active sites are well known to selectively catalyze hydroxylation and halogenation reactions with high efficiency. This review highlights the recent developments in the field of direct C-H halogenation and pseudohalogenation reactions catalyzed by the functional models of metalloenzymes.
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Affiliation(s)
- Neppoliyan Kannan
- Department of Chemistry, School of Advanced Science, Vellore Institute of Technology, Vellore-632014, Tamil Nadu, India.
| | - Akshay R Patil
- Department of Chemistry, School of Advanced Science, Vellore Institute of Technology, Vellore-632014, Tamil Nadu, India.
| | - Arup Sinha
- Department of Chemistry, School of Advanced Science, Vellore Institute of Technology, Vellore-632014, Tamil Nadu, India.
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30
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Ansari M, Senthilnathan D, Rajaraman G. Deciphering the origin of million-fold reactivity observed for the open core diiron [HO-Fe III-O-Fe IV[double bond, length as m-dash]O] 2+ species towards C-H bond activation: role of spin-states, spin-coupling, and spin-cooperation. Chem Sci 2020; 11:10669-10687. [PMID: 33209248 PMCID: PMC7654192 DOI: 10.1039/d0sc02624g] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 06/16/2020] [Indexed: 01/26/2023] Open
Abstract
High-valent metal-oxo species have been characterised as key intermediates in both heme and non-heme enzymes that are found to perform efficient aliphatic hydroxylation, epoxidation, halogenation, and dehydrogenation reactions. Several biomimetic model complexes have been synthesised over the years to mimic both the structure and function of metalloenzymes. The diamond-core [Fe2(μ-O)2] is one of the celebrated models in this context as this has been proposed as the catalytically active species in soluble methane monooxygenase enzymes (sMMO), which perform the challenging chemical conversion of methane to methanol at ease. In this context, a report of open core [HO(L)FeIII-O-FeIV(O)(L)]2+ (1) gains attention as this activates C-H bonds a million-fold faster compared to the diamond-core structure and has the dual catalytic ability to perform hydroxylation as well as desaturation with organic substrates. In this study, we have employed density functional methods to probe the origin of the very high reactivity observed for this complex and also to shed light on how this complex performs efficient hydroxylation and desaturation of alkanes. By modelling fifteen possible spin-states for 1 that could potentially participate in the reaction mechanism, our calculations reveal a doublet ground state for 1 arising from antiferromagnetic coupling between the quartet FeIV centre and the sextet FeIII centre, which regulates the reactivity of this species. The unusual stabilisation of the high-spin ground state for FeIV[double bond, length as m-dash]O is due to the strong overlap of with the orbital, reducing the antibonding interactions via spin-cooperation. The electronic structure features computed for 1 are consistent with experiments offering confidence in the methodology chosen. Further, we have probed various mechanistic pathways for the C-H bond activation as well as -OH rebound/desaturation of alkanes. An extremely small barrier height computed for the first hydrogen atom abstraction by the terminal FeIV[double bond, length as m-dash]O unit was found to be responsible for the million-fold activation observed in the experiments. The barrier height computed for -OH rebound by the FeIII-OH unit is also smaller suggesting a facile hydroxylation of organic substrates by 1. A strong spin-cooperation between the two iron centres also reduces the barrier for second hydrogen atom abstraction, thus making the desaturation pathway competitive. Both the spin-state as well as spin-coupling between the two metal centres play a crucial role in dictating the reactivity for species 1. By exploring various mechanistic pathways, our study unveils the fact that the bridged μ-oxo group is a poor electrophile for both C-H activation as well for -OH rebound. As more and more evidence is gathered in recent years for the open core geometry of sMMO enzymes, the idea of enhancing the reactivity via an open-core motif has far-reaching consequences.
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Affiliation(s)
- Mursaleem Ansari
- Department of Chemistry , Indian Institute of Technology Bombay , Mumbai 400076 , India .
| | - Dhurairajan Senthilnathan
- Center for Computational Chemistry , CRD , PRIST University , Vallam , Thanjavur , Tamilnadu 613403 , India
| | - Gopalan Rajaraman
- Department of Chemistry , Indian Institute of Technology Bombay , Mumbai 400076 , India .
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31
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Kumar R, Pandey B, Sen A, Ansari M, Sharma S, Rajaraman G. Role of oxidation state, ferryl-oxygen, and ligand architecture on the reactivity of popular high-valent FeIV=O species: A theoretical perspective. Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2020.213397] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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32
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Mayfield JR, Grotemeyer EN, Jackson TA. Concerted proton-electron transfer reactions of manganese-hydroxo and manganese-oxo complexes. Chem Commun (Camb) 2020; 56:9238-9255. [PMID: 32578605 PMCID: PMC7429365 DOI: 10.1039/d0cc01201g] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The enzymes manganese superoxide dismutase and manganese lipoxygenase use MnIII-hydroxo centres to mediate proton-coupled electron transfer (PCET) reactions with substrate. As manganese is earth-abundant and inexpensive, manganese catalysts are of interest for synthetic applications. Recent years have seen exciting reports of enantioselective C-H bond oxidation by Mn catalysts supported by aminopyridyl ligands. Such catalysts offer economic and environmentally-friendly alternatives to conventional reagents and catalysts. Mechanistic studies of synthetic catalysts highlight the role of Mn-oxo motifs in attacking substrate C-H bonds, presumably by a concerted proton-electron transfer (CPET) step. (CPET is a sub-class of PCET, where the proton and electron are transferred in the same step.) Knowledge of geometric and electronic influences for CPET reactions of Mn-hydroxo and Mn-oxo adducts enhances our understanding of biological and synthetic manganese centers and informs the design of new catalysts. In this Feature article, we describe kinetic, spectroscopic, and computational studies of MnIII-hydroxo and MnIV-oxo complexes that provide insight into the basis for the CPET reactivity of these species. Systematic perturbations of the ligand environment around MnIII-hydroxo and MnIV-oxo motifs permit elucidation of structure-activity relationships. For MnIII-hydroxo centers, electron-deficient ligands enhance oxidative reactivity. However, ligand perturbations have competing consequences, as changes in the MnIII/II potential, which represents the electron-transfer component for CPET, is offset by compensating changes in the pKa of the MnII-aqua product, which represents the proton-transfer component for CPET. For MnIV-oxo systems, a multi-state reactivity model inspired the development of significantly more reactive complexes. Weakened equatorial donation to the MnIV-oxo unit results in large rate enhancements for C-H bond oxidation and oxygen-atom transfer reactions. These results demonstrate that the local coordination environment can be rationally changed to enhance reactivity of MnIII-hydroxo and MnIV-oxo adducts.
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Affiliation(s)
- Jaycee R Mayfield
- Department of Chemistry and Center for Environmentally Beneficial Catalysis, University of Kansas, Lawrence, KS 66045, USA.
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Coin G, Patra R, Rana S, Biswas JP, Dubourdeaux P, Clémancey M, de Visser SP, Maiti D, Maldivi P, Latour JM. Fe-Catalyzed Aziridination Is Governed by the Electron Affinity of the Active Imido-Iron Species. ACS Catal 2020. [DOI: 10.1021/acscatal.0c01427] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Guillaume Coin
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, LCBM, 38000 Grenoble, France
- Univ. Grenoble Alpes, CEA, CNRS, DCM, 38000 Grenoble, France
| | - Ranjan Patra
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, LCBM, 38000 Grenoble, France
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, DIESE, SYMMES, 38000 Grenoble, France
- Amity Institute of Click Chemistry Research & Studies (AICCRS), Amity University, Sector-125, Noida, India
| | - Sujoy Rana
- Department of Chemistry, University of North Bengal, Raja Rammohunpur, Darjeeling, West Bengal 734013, India
| | | | | | - Martin Clémancey
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, LCBM, 38000 Grenoble, France
| | - Sam P. de Visser
- Manchester Institute of Biotechnology and Department of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Debabrata Maiti
- Department of Chemistry, IIT Bombay, Powai, Mumbai 400076, India
| | - Pascale Maldivi
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, DIESE, SYMMES, 38000 Grenoble, France
| | - Jean-Marc Latour
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, LCBM, 38000 Grenoble, France
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Ramírez E, Hossain MK, Flores‐Alamo M, Haukka M, Nordlander E, Castillo I. Oxygen Transfer from Trimethylamine
N
‐Oxide to Cu
I
Complexes Supported by Pentanitrogen Ligands. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000488] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Erick Ramírez
- Instituto de Química Universidad Nacional Autónoma de México Circuito Exterior CU 04510 México México
| | - Md. Kamal Hossain
- Chemical Physics Center for Chemistry and Chemical Engineering Lund University Box 124 221 00 Lund Sweden
| | - Marcos Flores‐Alamo
- Facultad de Química División de Estudios de Posgrado Universidad Nacional Autónoma de México México 04510 México
| | - Matti Haukka
- Department of Chemistry University of Jyväskylä P.O. Box‐35 40014 Jyväskylä Finland
| | - Ebbe Nordlander
- Chemical Physics Center for Chemistry and Chemical Engineering Lund University Box 124 221 00 Lund Sweden
| | - Ivan Castillo
- Instituto de Química Universidad Nacional Autónoma de México Circuito Exterior CU 04510 México México
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35
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Catalytic and stoichiometric oxoiron(IV) assisted oxidation of hydrocynnamaldehyde under air. Polyhedron 2020. [DOI: 10.1016/j.poly.2020.114505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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36
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Bhattacharya S, Singh R, Paine TK. Effect of Ligand Fields on the Reactivity of O 2 -Activating Iron(II)-Benzilate Complexes of Neutral N5 Donor Ligands. Chem Asian J 2020; 15:1360-1368. [PMID: 32141712 DOI: 10.1002/asia.202000142] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 03/04/2020] [Indexed: 01/05/2023]
Abstract
Three new iron(II)-benzilate complexes [(N4Py)FeII (benzilate)]ClO4 (1), [(N4PyMe2 )FeII (benzilate)]ClO4 (2) and [(N4PyMe4 )FeII (benzilate)]ClO4 (3) of neutral pentadentate nitrogen donor ligands have been isolated and characterized to study their dioxygen reactivity. Single-crystal X-ray structures reveal a mononuclear six-coordinate iron(II) center in each case, where benzilate binds to the iron center in monodentate mode via one carboxylate oxygen. Introduction of methyl groups in the 6-positions of the pyridine rings makes the N4PyMe2 and N4PyMe4 ligand fields weaker compared to that of the parent N4Py ligand. All the complexes (1-3) react with dioxygen to decarboxylate the coordinated benzilate to benzophenone quantitatively. The decarboxylation is faster for the complex of the more sterically hindered ligand and follows the order 3>2>1. The complexes display oxygen atom transfer reactivity to thioanisole and also exhibit hydrogen atom transfer reactions with substrates containing weak C-H bonds. Based on interception studies with external substrates, labelling experiments and Hammett analysis, a nucleophilic iron(II)-hydroperoxo species is proposed to form upon two-electron reductive activation of dioxygen by each iron(II)-benzilate complex. The nucleophilic oxidants are converted to the corresponding electrophilic iron(IV)-oxo oxidant upon treatment with a protic acid. The high-spin iron(II)-benzilate complex with the weakest ligand field results in the formation of a more reactive iron-oxygen oxidant.
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Affiliation(s)
- Shrabanti Bhattacharya
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A&2B Raja S. C. Mullick Road, Jadavpur, Kolkata, 700032, India
| | - Reena Singh
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A&2B Raja S. C. Mullick Road, Jadavpur, Kolkata, 700032, India
| | - Tapan Kanti Paine
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A&2B Raja S. C. Mullick Road, Jadavpur, Kolkata, 700032, India
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37
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Park H, Lee D. Ligand Taxonomy for Bioinorganic Modeling of Dioxygen-Activating Non-Heme Iron Enzymes. Chemistry 2020; 26:5916-5926. [PMID: 31909506 DOI: 10.1002/chem.201904975] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 01/04/2020] [Indexed: 12/15/2022]
Abstract
Novel functions emerge from novel structures. To develop efficient catalytic systems for challenging chemical transformations, chemists often seek inspirations from enzymatic catalysis. A large number of iron complexes supported by nitrogen-rich multidentate ligands have thus been developed to mimic oxo-transfer reactivity of dioxygen-activating metalloenzymes. Such efforts have significantly advanced our understanding of the reaction mechanisms by trapping key intermediates and elucidating their geometric and electronic properties. Critical to the success of this biomimetic approach is the design and synthesis of elaborate ligand systems to balance the thermodynamic stability, structural adaptability, and chemical reactivity. In this Concept article, representative design strategies for biomimetic atom-transfer chemistry are discussed from the perspectives of "ligand builders". Emphasis is placed on how the primary coordination sphere is constructed, and how it can be elaborated further by rational design for desired functions.
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Affiliation(s)
- Hyunchang Park
- Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea
| | - Dongwhan Lee
- Department of Chemistry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea
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38
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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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Krzystek J, Schnegg A, Aliabadi A, Holldack K, Stoian SA, Ozarowski A, Hicks SD, Abu-Omar MM, Thomas KE, Ghosh A, Caulfield KP, Tonzetich ZJ, Telser J. Advanced Paramagnetic Resonance Studies on Manganese and Iron Corroles with a Formal d 4 Electron Count. Inorg Chem 2020; 59:1075-1090. [PMID: 31909979 DOI: 10.1021/acs.inorgchem.9b02635] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Metallocorroles wherein the metal ion is MnIII and formally FeIV are studied here using field- and frequency-domain electron paramagnetic resonance techniques. The MnIII corrole, Mn(tpfc) (tpfc = 5,10,15-tris(pentafluorophenyl)corrole trianion), exhibits the following S = 2 zero-field splitting (zfs) parameters: D = -2.67(1) cm-1, |E| = 0.023(5) cm-1. This result and those for other MnIII tetrapyrroles indicate that when D ≈ - 2.5 ± 0.5 cm-1 for 4- or 5-coordinate and D ≈ - 3.5 ± 0.5 cm-1 for 6-coordinate complexes, the ground state description is [MnIII(Cor3-)]0 or [MnIII(P2-)]+ (Cor = corrole, P = porphyrin). The situation for formally FeIV corroles is more complicated, and it has been shown that for Fe(Cor)X, when X = Ph (phenyl), the ground state is a spin triplet best described by [FeIV(Cor3-)]+, but when X = halide, the ground state corresponds to [FeIII(Cor•2-)]+, wherein an intermediate spin (S = 3/2) FeIII is antiferromagnetically coupled to a corrole radical dianion (S = 1/2) to also give an S = 1 ground state. These two valence isomers can be distinguished by their zfs parameters, as determined here for Fe(tpc)X, X = Ph, Cl (tpc = 5,10,15-triphenylcorrole trianion). The complex with axial phenyl gives D = 21.1(2) cm-1, while that with axial chloride gives D = 14.6(1) cm-1. The D value for Fe(tpc)Ph is in rough agreement with the range of values reported for other FeIV complexes. In contrast, the D value for Fe(tpc)Cl is inconsistent with an FeIV description and represents a different type of iron center. Computational studies corroborate the zfs for the two types of iron corrole complexes. Thus, the zfs of metallocorroles can be diagnostic as to the electronic structure of a formally high oxidation state metallocorrole, and by extension to metalloporphyrins, although such studies have yet to be performed.
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Affiliation(s)
- J Krzystek
- National High Magnetic Field Laboratory , Florida State University , Tallahassee , Florida 32310 , United States
| | - Alexander Schnegg
- EPR Research Group , Max Planck Institute for Chemical Energy Conversion , Stiftstraße 34-36 , D-45470 Mülheim Ruhr , Germany.,Berlin Joint EPR Laboratory , Helmholtz-Zentrum Berlin , Kekulestraße 5 , D-12489 Berlin , Germany
| | - Azar Aliabadi
- Berlin Joint EPR Laboratory , Helmholtz-Zentrum Berlin , Kekulestraße 5 , D-12489 Berlin , Germany
| | - Karsten Holldack
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung am Elektronenspeicherring BESSY II , Albert-Einstein-Straße 15 , D-12489 Berlin , Germany
| | - Sebastian A Stoian
- Department of Chemistry , University of Idaho , Moscow , Idaho 83844 , United States
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory , Florida State University , Tallahassee , Florida 32310 , United States
| | - Scott D Hicks
- Department of Chemistry , Purdue University , West Lafayette , Indiana 47907 , United States
| | - Mahdi M Abu-Omar
- Departments of Chemistry and Biochemistry , University of California , Santa Barbara , California 93106-9510 , United States
| | - Kolle E Thomas
- Department of Chemistry , UiT-The Arctic University of Norway , N-9037 Tromsø , Norway
| | - Abhik Ghosh
- Department of Chemistry , UiT-The Arctic University of Norway , N-9037 Tromsø , Norway
| | - Kenneth P Caulfield
- Department of Chemistry , University of Texas at San Antonio (UTSA) , One UTSA Circle , San Antonio , Texas 78249 , United States
| | - Zachary J Tonzetich
- Department of Chemistry , University of Texas at San Antonio (UTSA) , One UTSA Circle , San Antonio , Texas 78249 , United States
| | - Joshua Telser
- Department of Biological, Physical, and Health Sciences , Roosevelt University , Chicago , Illinois 60605 , United States
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40
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Mukherjee G, Reinhard FGC, Bagha UK, Sastri CV, de Visser SP. Sluggish reactivity by a nonheme iron(iv)-tosylimido complex as compared to its oxo analogue. Dalton Trans 2020; 49:5921-5931. [DOI: 10.1039/d0dt00018c] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A comparative spectroscopic and computational study of reactivity between ferryl-tosylimido and ferryl-oxo complexes of two biomimetic model systems. The Fe(iv)-tosylimido complex was found to be sluggish in comparison to its fellow oxo counterpart.
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Affiliation(s)
- Gourab Mukherjee
- Department of Chemistry
- Indian Institute of Technology Guwahati
- India
| | - Fabián G. Cantú Reinhard
- The Manchester Institute of Biotechnology and Department of Chemical Engineering and Analytical Science
- The University of Manchester
- Manchester M1 7DN
- UK
| | | | | | - Sam P. de Visser
- The Manchester Institute of Biotechnology and Department of Chemical Engineering and Analytical Science
- The University of Manchester
- Manchester M1 7DN
- UK
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41
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Rice DB, Massie AA, Jackson TA. Experimental and Multireference ab Initio Investigations of Hydrogen-Atom-Transfer Reactivity of a Mononuclear MnIV-oxo Complex. Inorg Chem 2019; 58:13902-13916. [DOI: 10.1021/acs.inorgchem.9b01761] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Derek B. Rice
- Department of Chemistry and Center for Environmentally Beneficial Catalysis, The University of Kansas, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Allyssa A. Massie
- Department of Chemistry and Center for Environmentally Beneficial Catalysis, The University of Kansas, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Timothy A. Jackson
- Department of Chemistry and Center for Environmentally Beneficial Catalysis, The University of Kansas, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
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42
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Piquette MC, Kryatov SV, Rybak-Akimova EV. Kinetic Studies on the Oxoiron(IV) Complex with Tetradentate Aminopyridine Ligand PDP*: Restoration of Catalytic Activity by Reduction with H2O2. Inorg Chem 2019; 58:13382-13393. [DOI: 10.1021/acs.inorgchem.9b02269] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marc C. Piquette
- Department of Chemistry, Tufts University, 62 Talbot Avenue, Medford, Massachusetts 02155, United States
| | - Sergiy V. Kryatov
- Department of Chemistry, Tufts University, 62 Talbot Avenue, Medford, Massachusetts 02155, United States
| | - Elena V. Rybak-Akimova
- Department of Chemistry, Tufts University, 62 Talbot Avenue, Medford, Massachusetts 02155, United States
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43
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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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44
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Kara H, Gungor E, Coban MB, Acar Y. Crystal structure and magnetic characterizationof μ6–oxo bridged Hexanuclear Fe(III) complex. INORG CHEM COMMUN 2019. [DOI: 10.1016/j.inoche.2019.107466] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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45
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Banerjee S, Rasheed W, Fan R, Draksharapu A, Oloo WN, Guo Y, Que L. NMR Reveals That a Highly Reactive Nonheme Fe IV =O Complex Retains Its Six-Coordinate Geometry and S=1 State in Solution. Chemistry 2019; 25:9608-9613. [PMID: 31059593 DOI: 10.1002/chem.201902048] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Indexed: 01/08/2023]
Abstract
The [FeIV (O)(Me3 NTB)]2+ (Me3 NTB=tris[(1-methyl-benzimidazol-2-yl)methyl]amine) complex 1 has been shown by Mössbauer spectroscopy to have an S=1 ground state at 4 K, but is proposed to become an S=2 trigonal-bipyramidal species at higher temperatures based on a DFT model to rationalize its very high C-H bond-cleavage reactivity. In this work, 1 H NMR spectroscopy was used to determine that 1 does not have C3 -symmetry in solution and is not an S=2 species. Our results show that 1 is unique among nonheme FeIV =O complexes in retaining its S=1 spin state and high reactivity at 193 K, providing evidence that S=1 FeIV =O complexes can be as reactive as their S=2 counterparts. This result emphasizes the need to identify factors besides the ground spin state of the FeIV =O center to rationalize nonheme oxoiron(IV) reactivity.
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Affiliation(s)
- Saikat Banerjee
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Waqas Rasheed
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Ruixi Fan
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Apparao Draksharapu
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN, 55455, USA.,Current address: Southern Laboratories, Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Williamson N Oloo
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN, 55455, USA
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46
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Rasheed W, Fan R, Abelson CS, Peterson PO, Ching WM, Guo Y, Que L. Structural implications of the paramagnetically shifted NMR signals from pyridine H atoms on synthetic nonheme Fe IV=O complexes. J Biol Inorg Chem 2019; 24:533-545. [PMID: 31172289 DOI: 10.1007/s00775-019-01672-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 05/20/2019] [Indexed: 12/12/2022]
Abstract
Oxoiron(IV) motifs are found in important intermediates in many enzymatic cycles that involve oxidations. Over half of the reported synthetic nonheme oxoiron(IV) analogs incorporate heterocyclic donors, with a majority of them comprising pyridines. Herein, we report 1H-NMR studies of oxoiron(IV) complexes containing pyridines that are arranged in different configurations relative to the Fe = O unit and give rise to paramagnetically shifted resonances that differ by as much as 50 ppm. The strong dependence of 1H-NMR shifts on the different configurations and orientation of pyridines relative to the oxoiron(IV) unit demonstrates how unpaired electronic spin density of the iron center affects the chemical shifts of these protons.
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Affiliation(s)
- Waqas Rasheed
- Department of Chemistry and Center of Metals in Biocatalysis, University of Minnesota-Twin Cities, 207 Pleasant Street SE, Minneapolis, MN, 55455, USA
| | - Ruixi Fan
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Chase S Abelson
- Department of Chemistry and Center of Metals in Biocatalysis, University of Minnesota-Twin Cities, 207 Pleasant Street SE, Minneapolis, MN, 55455, USA
| | - Paul O Peterson
- Department of Chemistry and Center of Metals in Biocatalysis, University of Minnesota-Twin Cities, 207 Pleasant Street SE, Minneapolis, MN, 55455, USA
| | - Wei-Min Ching
- Department of Chemistry and Center of Metals in Biocatalysis, University of Minnesota-Twin Cities, 207 Pleasant Street SE, Minneapolis, MN, 55455, USA
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.
| | - Lawrence Que
- Department of Chemistry and Center of Metals in Biocatalysis, University of Minnesota-Twin Cities, 207 Pleasant Street SE, Minneapolis, MN, 55455, USA.
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Mukherjee G, Alili A, Barman P, Kumar D, Sastri CV, de Visser SP. Interplay Between Steric and Electronic Effects: A Joint Spectroscopy and Computational Study of Nonheme Iron(IV)-Oxo Complexes. Chemistry 2019; 25:5086-5098. [PMID: 30720909 DOI: 10.1002/chem.201806430] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Indexed: 01/05/2023]
Abstract
Iron is an essential element in nonheme enzymes that plays a crucial role in many vital oxidative transformations and metabolic reactions in the human body. Many of those reactions are regio- and stereospecific and it is believed that the selectivity is guided by second-coordination sphere effects in the protein. Here, results are shown of a few engineered biomimetic ligand frameworks based on the N4Py (N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine) scaffold and the second-coordination sphere effects are studied. For the first time, selective substitutions in the ligand framework have been shown to tune the catalytic properties of the iron(IV)-oxo complexes by regulating the steric and electronic factors. In particular, a better positioning of the oxidant and substrate in the rate-determining transition state lowers the reaction barriers. Therefore, an optimum balance between steric and electronic factors mediates the ideal positioning of oxidant and substrate in the rate-determining transition state that affects the reactivity of high-valent reaction intermediates.
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Affiliation(s)
- Gourab Mukherjee
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India
| | - Aligulu Alili
- The Manchester Institute of Biotechnology and School of Chemical, Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Prasenjit Barman
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India
| | - Devesh Kumar
- Department of Applied Physics, Babasaheb Bhimrao Ambedkar University, School for Physical Sciences, Vidya Vihar, Rae Bareilly Road, Lucknow, 226025, UP, India
| | - Chivukula V Sastri
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India
| | - Sam P de Visser
- The Manchester Institute of Biotechnology and School of Chemical, Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
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Singh R, Ganguly G, Malinkin SO, Demeshko S, Meyer F, Nordlander E, Paine TK. A Mononuclear Nonheme Iron(IV)-Oxo Complex of a Substituted N4Py Ligand: Effect of Ligand Field on Oxygen Atom Transfer and C–H Bond Cleavage Reactivity. Inorg Chem 2019; 58:1862-1876. [DOI: 10.1021/acs.inorgchem.8b02577] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Reena Singh
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Gaurab Ganguly
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Sergey O. Malinkin
- Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-22100 Lund, Sweden
| | - Serhiy Demeshko
- Universität
Göttingen, Institut für Anorganische Chemie, Tammanstrasse 4, D-37077 Göttingen, Germany
| | - Franc Meyer
- Universität
Göttingen, Institut für Anorganische Chemie, Tammanstrasse 4, D-37077 Göttingen, Germany
| | - Ebbe Nordlander
- Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-22100 Lund, Sweden
| | - Tapan Kanti Paine
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
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Denler MC, Massie AA, Singh R, Stewart-Jones E, Sinha A, Day VW, Nordlander E, Jackson TA. Mn IV-Oxo complex of a bis(benzimidazolyl)-containing N5 ligand reveals different reactivity trends for Mn IV-oxo than Fe IV-oxo species. Dalton Trans 2019; 48:5007-5021. [PMID: 30916103 DOI: 10.1039/c9dt00308h] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Using the pentadentate ligand (N-bis(1-methyl-2-benzimidazolyl)methyl-N-(bis-2-pyridylmethyl)amine, 2pyN2B), presenting two pyridyl and two (N-methyl)benzimidazolyl donor moieties in addition to a central tertiary amine, new MnII and MnIV-oxo complexes were generated and characterized. The [MnIV(O)(2pyN2B)]2+ complex showed spectroscopic signatures (i.e., electronic absorption band maxima and intensities, EPR signals, and Mn K-edge X-ray absorption edge and near-edge data) similar to those observed for other MnIV-oxo complexes with neutral, pentadentate N5 supporting ligands. The near-IR electronic absorption band maximum of [MnIV(O)(2pyN2B)]2+, as well as DFT-computed metric parameters, are consistent with the equatorial (N-methyl)benzimidazolyl ligands being stronger donors to the MnIV center than the pyridyl and quinolinyl ligands found in analogous MnIV-oxo complexes. The hydrogen- and oxygen-atom transfer reactivities of [MnIV(O)(2pyN2B)]2+ were assessed through reactions with hydrocarbons and thioanisole, respectively. When compared with related MnIV-oxo adducts, [MnIV(O)(2pyN2B)]2+ showed muted reactivity in hydrogen-atom transfer reactions with hydrocarbons. This result stands in contrast to observations for the analogous FeIV-oxo complexes, where [FeIV(O)(2pyN2B)]2+ was found to be one of the more reactive members of its class.
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Affiliation(s)
- Melissa C Denler
- 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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50
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Nehrkorn J, Veber SL, Zhukas LA, Novikov VV, Nelyubina YV, Voloshin YZ, Holldack K, Stoll S, Schnegg A. Determination of Large Zero-Field Splitting in High-Spin Co(I) Clathrochelates. Inorg Chem 2018; 57:15330-15340. [PMID: 30495930 DOI: 10.1021/acs.inorgchem.8b02670] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Joscha Nehrkorn
- Department of Chemistry, Institute for Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, D-20146 Hamburg, Germany
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
- Berlin Joint EPR Laboratory, Institut für Nanospektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Kekuléstr. 5, D-12489 Berlin, Germany
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Sergey L. Veber
- International Tomography Center, Siberian Branch of the Russian Academy of Sciences, Institutskaya str. 3a, 630090 Novosibirsk, Russia
- Novosibirsk State University, Pirogova str. 1, 630090 Novosibirsk, Russia
| | - Liudmila A. Zhukas
- International Tomography Center, Siberian Branch of the Russian Academy of Sciences, Institutskaya str. 3a, 630090 Novosibirsk, Russia
- Novosibirsk State University, Pirogova str. 1, 630090 Novosibirsk, Russia
| | - Valentin V. Novikov
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 119991 Moscow, Russia
| | - Yulia V. Nelyubina
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 119991 Moscow, Russia
| | - Yan Z. Voloshin
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 119991 Moscow, Russia
| | - Karsten Holldack
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Str. 15, D-12489 Berlin, Germany
| | - Stefan Stoll
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Alexander Schnegg
- Berlin Joint EPR Laboratory, Institut für Nanospektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Kekuléstr. 5, D-12489 Berlin, Germany
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany
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