1
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Luo J, Montag M, Milstein D. Metal-Ligand Cooperation with Thiols as Transient Cooperative Ligands: Acceleration and Inhibition Effects in (De)Hydrogenation Reactions. Acc Chem Res 2024; 57:1709-1721. [PMID: 38833580 PMCID: PMC11191399 DOI: 10.1021/acs.accounts.4c00198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 05/13/2024] [Accepted: 05/15/2024] [Indexed: 06/06/2024]
Abstract
ConspectusOver the past two decades, we have developed a series of pincer-type transition metal complexes capable of activating strong covalent bonds through a mode of reactivity known as metal-ligand cooperation (MLC). In such systems, an incoming substrate molecule simultaneously interacts with both the metal center and ligand backbone, with one part of the molecule reacting at the metal center and another part at the ligand. The majority of these complexes feature pincer ligands with a pyridine core, and undergo MLC through reversible dearomatization/aromatization of this pyridine moiety. This MLC platform has enabled us to perform a variety of catalytic dehydrogenation, hydrogenation, and related reactions, with high efficiency and selectivity under relatively mild conditions.In a typical catalytic complex that operates through MLC, the cooperative ligand remains coordinated to the metal center throughout the entire catalytic process, and this complex is the only catalytic species involved in the reaction. As part of our ongoing efforts to develop new catalytic systems featuring MLC, we have recently introduced the concept of transient cooperative ligand (TCL), i.e., a ligand that is capable of MLC when coordinated to a metal center, but the coordination of which is reversible rather than permanent. We have thus far employed thiol(ate)s as TCLs, in conjunction with an acridanide-based ruthenium(II)-pincer catalyst, and this has resulted in remarkable acceleration and inhibition effects in various hydrogenation and dehydrogenation reactions. A cooperative thiol(ate) ligand can be installed in situ by the simple addition of an appropriate thiol in an amount equivalent to the catalyst, and this has been repeatedly shown to enable efficient bond activation by MLC without the need for other additives, such as base. The use of an ancillary thiol ligand that is not fixed to the pincer backbone allows the catalytic system to benefit from a high degree of tunability, easily implemented by varying the added thiol. Importantly, thiols are coordinatively labile enough under typical catalytic conditions to leave a meaningful portion of the catalyst in its original unsaturated form, thereby allowing it to carry out its own characteristic catalytic activity. This generates two coexisting catalyst populations─one that contains a thiol(ate) ligand and another that does not─and this may lead to different catalytic outcomes, namely, enhancement of the original catalytic activity, inhibition of this activity, or the occurrence of diverging reactivities within the same catalytic reaction mixture. These thiol effects have enabled us to achieve a series of unique transformations, such as thiol-accelerated base-free aqueous methanol reforming, controlled stereodivergent semihydrogenation of alkynes using thiol as a reversible catalyst inhibitor, and hydrogenative perdeuteration of C═C bonds without using D2, enabled by a combination of thiol-induced acceleration and inhibition. We have also successfully realized the unprecedented formation of thioesters through dehydrogenative coupling of alcohols and thiols, as well as the hydrogenation of organosulfur compounds, wherein the cooperative thiol serves as a reactant or product. In this Account, we present an overview of the TCL concept and its various applications using thiols.
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Affiliation(s)
- Jie Luo
- Department of Molecular Chemistry
and Materials Science, Weizmann Institute
of Science, Rehovot 7610001, Israel
| | - Michael Montag
- Department of Molecular Chemistry
and Materials Science, Weizmann Institute
of Science, Rehovot 7610001, Israel
| | - David Milstein
- Department of Molecular Chemistry
and Materials Science, Weizmann Institute
of Science, Rehovot 7610001, Israel
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2
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Ekanger LA, Shah RK, Porowski ME, Ziolkowski Z, Calello A. Spectroscopic, electrochemical, and kinetic trends in Fe(III)-thiolate disproportionation near physiologic pH. J Biol Inorg Chem 2024; 29:291-301. [PMID: 38722396 PMCID: PMC11111527 DOI: 10.1007/s00775-024-02051-3] [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: 08/17/2023] [Accepted: 02/01/2024] [Indexed: 05/24/2024]
Abstract
In addition to its primary oxygen-atom-transfer function, cysteamine dioxygenase (ADO) exhibits a relatively understudied anaerobic disproportionation reaction (ADO-Fe(III)-SR → ADO-Fe(II) + ½ RSSR) with its native substrates. Inspired by ADO disproportionation reactivity, we employ [Fe(tacn)Cl3] (tacn = 1,4,7-triazacyclononane) as a precursor for generating Fe(III)-thiolate model complexes in buffered aqueous media. A series of Fe(III)-thiolate model complexes are generated in situ using aqueous [Fe(tacn)Cl3] and thiol-containing ligands cysteamine, penicillamine, mercaptopropionate, cysteine, cysteine methyl ester, N-acetylcysteine, and N-acetylcysteine methyl ester. We observe trends in UV-Vis and electron paramagnetic resonance (EPR) spectra, disproportionation rate constants, and cathodic peak potentials as a function of thiol ligand. These trends will be useful in rationalizing substrate-dependent Fe(III)-thiolate disproportionation reactions in metalloenzymes.
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Affiliation(s)
- Levi A Ekanger
- Department of Chemistry, The College of New Jersey, Ewing, NJ, 08628, USA.
| | - Ruhi K Shah
- Department of Chemistry, The College of New Jersey, Ewing, NJ, 08628, USA
| | - Matthew E Porowski
- Department of Chemistry, The College of New Jersey, Ewing, NJ, 08628, USA
| | - Zach Ziolkowski
- Department of Chemistry, The College of New Jersey, Ewing, NJ, 08628, USA
| | - Alana Calello
- Department of Chemistry, The College of New Jersey, Ewing, NJ, 08628, USA
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3
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Battistella B, Iffland-Mühlhaus L, Schütze M, Cula B, Kuhlmann U, Dau H, Hildebrandt P, Lohmiller T, Mebs S, Apfel UP, Ray K. Evidence of Sulfur Non-Innocence in [Co II (dithiacyclam)] 2+ -Mediated Catalytic Oxygen Reduction Reactions. Angew Chem Int Ed Engl 2023; 62:e202214074. [PMID: 36378951 PMCID: PMC10108118 DOI: 10.1002/anie.202214074] [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: 09/23/2022] [Revised: 11/10/2022] [Accepted: 11/14/2022] [Indexed: 11/16/2022]
Abstract
In many metalloenzymes, sulfur-containing ligands participate in catalytic processes, mainly via the involvement in electron transfer reactions. In a biomimetic approach, we now demonstrate the implication of S-ligation in cobalt mediated oxygen reduction reactions (ORR). A comparative study between the catalytic ORR capabilities of the four-nitrogen bound [Co(cyclam)]2+ (1; cyclam=1,5,8,11-tetraaza-cyclotetradecane) and the S-containing analog [Co(S2 N2 -cyclam)]2+ (2; S2 N2 -cyclam=1,8-dithia-5,11-diaza-cyclotetradecane) reveals improved catalytic performance once the chalcogen is introduced in the Co coordination sphere. Trapping and characterization of the intermediates formed upon dioxygen activation at the CoII centers in 1 and 2 point to the involvement of sulfur in the O2 reduction process as the key for the improved catalytic ORR capabilities of 2.
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Affiliation(s)
- Beatrice Battistella
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Linda Iffland-Mühlhaus
- Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, Universitätsstraße 150, 44780, Bochum, Germany
| | - Maximillian Schütze
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Beatrice Cula
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Uwe Kuhlmann
- Institut für Chemie, Fakultät II, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Holger Dau
- Institut für Physik, Freie Universität zu Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Peter Hildebrandt
- Institut für Chemie, Fakultät II, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Thomas Lohmiller
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany.,EPR4Energy Joint Lab, Department Spins in Energy Conversion and Quantum Information Science, Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 16, 12489, Berlin, Germany
| | - Stefan Mebs
- Institut für Physik, Freie Universität zu Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Ulf-Peter Apfel
- Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, Universitätsstraße 150, 44780, Bochum, Germany.,Department for Electrosynthesis, Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT, Osterfelder Str. 3, 46047, Oberhausen, Germany
| | - Kallol Ray
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
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4
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Hern M, Foley R, Bacsa J, Wallen CM. Binding polyprotic small molecules with second-sphere hydrogen bonds. J COORD CHEM 2022. [DOI: 10.1080/00958972.2022.2119850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
- Morgan Hern
- Department of Chemistry and Fermentation Sciences, Appalachian State University, Boone, NC, USA
| | - Rebecca Foley
- Department of Chemistry and Fermentation Sciences, Appalachian State University, Boone, NC, USA
| | - John Bacsa
- Department of Chemistry, Emory University, Atlanta, GA, USA
| | - Christian M. Wallen
- Department of Chemistry and Fermentation Sciences, Appalachian State University, Boone, NC, USA
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5
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Dedushko MA, Greiner MB, Downing AN, Coggins M, Kovacs JA. Electronic Structure and Reactivity of Dioxygen-Derived Aliphatic Thiolate-Ligated Fe-Peroxo and Fe(IV) Oxo Compounds. J Am Chem Soc 2022; 144:8515-8528. [PMID: 35522532 DOI: 10.1021/jacs.1c07656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Herein, we examine the electronic and geometric structural properties of O2-derived aliphatic thiolate-ligated Fe-peroxo, Fe-hydroxo, and Fe(IV) oxo compounds. The latter cleaves strong C-H bonds (96 kcal mol-1) on par with the valine C-H bond cleaved by isopencillin N synthase (IPNS). Stopped-flow kinetics studies indicate that the barrier to O2 binding to [FeII(SMe2N4(tren))]+ (3) is extremely low (Ea = 36(2) kJ mol-1), as theoretically predicted for IPNS. Dioxygen binding to 3 is shown to be reversible, and a superoxo intermediate, [FeIII(SMe2N4(tren))(O2)]+ (6), forms in the first 25 ms of the reaction at -40 °C prior to the rate-determining (Ea = 46(2) kJ mol-1) formation of peroxo-bridged [(SMe2N4(tren))Fe(III)]2(μ-O2)2+ (7). A log(kobs) vs log([Fe]) plot for the formation of 7 is consistent with the second-order dependence on iron, and H2O2 assays are consistent with a 2:1 ratio of Fe/H2O2. Peroxo 7 is shown to convert to ferric-hydroxo [FeIII(SMe2N(tren))(OH)]+ (9, g⊥ = 2.24, g∥ = 1.96), the identity of which was determined via its independent synthesis. Rates of the conversion 7 → 9 are shown to be dependent on the X-H bond strength of the H-atom donor, with a kH/kD = 4 when CD3OD is used in place of CH3OH as a solvent. A crystallographically characterized cis thiolate-ligated high-valent iron oxo, [FeIV(O)(SMe2N4(tren))]+ (11), is shown to form en route to hydroxo 9. Electronic structure calculations were shown to be consistent with 11 being an S = 1 Fe(IV)═O with an unusually high νFe-O stretching frequency at 918 cm-1 in line with the extremely short Fe-O bond (1.603(7) Å).
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Affiliation(s)
- Maksym A Dedushko
- Department of Chemistry, University of Washington, Campus Box 351700, Seattle, Washington 98195-1700, United States
| | - Maria B Greiner
- Department of Chemistry, University of Washington, Campus Box 351700, Seattle, Washington 98195-1700, United States
| | - Alexandra N Downing
- Department of Chemistry, University of Washington, Campus Box 351700, Seattle, Washington 98195-1700, United States
| | - Michael Coggins
- Department of Chemistry, University of Washington, Campus Box 351700, Seattle, Washington 98195-1700, United States
| | - Julie A Kovacs
- Department of Chemistry, University of Washington, Campus Box 351700, Seattle, Washington 98195-1700, United States
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6
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Jesse KA, Anferov SW, Collins KA, Valdez-Moreira JA, Czaikowski ME, Filatov AS, Anderson JS. Direct Aerobic Generation of a Ferric Hydroperoxo Intermediate Via a Preorganized Secondary Coordination Sphere. J Am Chem Soc 2021; 143:18121-18130. [PMID: 34698493 PMCID: PMC8569801 DOI: 10.1021/jacs.1c06911] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Indexed: 01/19/2023]
Abstract
Enzymes exert control over the reactivity of metal centers with precise tuning of the secondary coordination sphere of active sites. One particularly elegant illustration of this principle is in the controlled delivery of proton and electron equivalents in order to activate abundant but kinetically inert oxidants such as O2 for oxidative chemistry. Chemists have drawn inspiration from biology in designing molecular systems where the secondary coordination sphere can shuttle protons or electrons to substrates. However, a biomimetic activation of O2 requires the transfer of both protons and electrons, and molecular systems where ancillary ligands are designed to provide both of these equivalents are comparatively rare. Here, we report the use of a dihydrazonopyrrole (DHP) ligand complexed to Fe to perform exactly such a biomimetic activation of O2. In the presence of O2, this complex directly generates a high spin Fe(III)-hydroperoxo intermediate which features a DHP• ligand radical via ligand-based transfer of an H atom. This system displays oxidative reactivity and ultimately releases hydrogen peroxide, providing insight on how secondary coordination sphere interactions influence the evolution of oxidizing intermediates in Fe-mediated aerobic oxidations.
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Affiliation(s)
- Kate A. Jesse
- Department
of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Sophie W. Anferov
- Department
of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Kelsey A. Collins
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | | | - Maia E. Czaikowski
- Department
of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Alexander S. Filatov
- Department
of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - John S. Anderson
- Department
of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
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7
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Ekanayake DM, Pham D, Probst AL, Miller JR, Popescu CV, Fiedler AT. Electronic structures and spectroscopic signatures of diiron intermediates generated by O 2 activation of nonheme iron(II)-thiolate complexes. Dalton Trans 2021; 50:14432-14443. [PMID: 34570147 PMCID: PMC8721859 DOI: 10.1039/d1dt02286e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The activation of O2 at thiolate-ligated iron(II) sites is essential to the function of numerous metalloenzymes and synthetic catalysts. Iron-thiolate bonds in the active sites of nonheme iron enzymes arise from either coordination of an endogenous cysteinate residue or binding of a deprotonated thiol-containing substrate. Examples of the latter include sulfoxide synthases, such as EgtB and OvoA, that utilize O2 to catalyze tandem S-C bond formation and S-oxygenation steps in thiohistidine biosyntheses. We recently reported the preparation of two mononuclear nonheme iron-thiolate complexes (1 and 2) that serve as structural active-site models of substrate-bound EgtB and OvoA (Dalton Trans. 2020, 49, 17745-17757). These models feature monodentate thiolate ligands and tripodal N4 ligands with mixed pyridyl/imidazolyl donors. Here, we describe the reactivity of 1 and 2 with O2 at low temperatures to give metastable intermediates (3 and 4, respectively). Characterization with multiple spectroscopic techniques (UV-vis absorption, NMR, variable-field and -temperature Mössbauer, and resonance Raman) revealed that these intermediates are thiolate-ligated iron(III) dimers with a bridging oxo ligand derived from the four-electron reduction of O2. Structural models of 3 and 4 consistent with the experimental data were generated via density functional theory (DFT) calculations. The combined experimental and computational results illuminate the geometric and electronic origins of the unique spectral features of diiron(III)-μ-oxo complexes with thiolate ligands, and the spectroscopic signatures of 3 and 4 are compared to those of closely-related diiron(III)-μ-peroxo species. Collectively, these results will assist in the identification of intermediates that appear on the O2 reaction landscapes of iron-thiolate species in both biological and synthetic environments.
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Affiliation(s)
| | - Dao Pham
- Department of Chemistry, The College of Arts and Sciences, University of St. Thomas, St. Paul, Minnesota 55105, USA.
| | - Andrew L Probst
- Department of Chemistry, The College of Arts and Sciences, University of St. Thomas, St. Paul, Minnesota 55105, USA.
| | - Joshua R Miller
- Department of Chemistry, University of Wisconsin - Madison, Madison, Wisconsin 53706, USA
| | - Codrina V Popescu
- Department of Chemistry, The College of Arts and Sciences, University of St. Thomas, St. Paul, Minnesota 55105, USA.
| | - Adam T Fiedler
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53233, USA.
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8
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Toledo S, Yan Poon PC, Gleaves M, Rees J, Rogers DM, Kaminsky W, Kovacs JA. Increasing reactivity by incorporating π-acceptor ligands into coordinatively unsaturated thiolate-ligated iron(II) complexes. Inorganica Chim Acta 2021; 524. [PMID: 34305163 DOI: 10.1016/j.ica.2021.120422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Reported herein is the structural, spectroscopic, redox, and reactivity properties of a series of iron complexes containing both a π-donating thiolate, and π-accepting N-heterocycles in the coordination sphere, in which we systematically vary the substituents on the N-heterocycle, the size of the N-heterocycle, and the linker between the imine nitrogen and tertiary amine nitrogen. In contrast to our primary amine/thiolate-ligated Fe(II) complex, [FeII(SMe2N4(tren))]+ (1), the Fe(II) complexes reported herein are intensely colored, allowing us to visually monitor reactivity. Ferrous complexes with R = H substituents in the 6-position of the pyridines, [FeII(SMe2N4(6-H-DPPN)]+ (6) and [FeII(SMe2N4(6-H-DPEN))(MeOH)]+ (8-MeOH) are shown to readily bind neutral ligands, and all of the Fe(II) complexes are shown to bind anionic ligands regardless of steric congestion. This reactivity is in contrast to 1 and is attributed to an increased metal ion Lewis acidity assessed via aniodic redox potentials, Ep,a, caused by the π-acid ligands. Thermodynamic parameters (ΔH, ΔS) for neutral ligand binding were obtained from T-dependent equilibrium constants. All but the most sterically congested complex, [FeII(SMe2N4(6-Me-DPPN)]+ (5), react with O2. In contrast to our Mn(II)-analogues, dioxygen intermediates are not observed. Rates of formation of the final mono oxo-bridged products were assessed via kinetics and shown to be inversely dependent on redox potentials, Ep,a, consistent with a mechanism involving electron transfer.
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Affiliation(s)
- Santiago Toledo
- The Department of Chemistry, University of Washington, Box 351700 Seattle, WA 98195-1700, United States
| | - Penny Chaau Yan Poon
- The Department of Chemistry, University of Washington, Box 351700 Seattle, WA 98195-1700, United States
| | - Morgan Gleaves
- The Department of Chemistry, University of Washington, Box 351700 Seattle, WA 98195-1700, United States
| | - Julian Rees
- The Department of Chemistry, University of Washington, Box 351700 Seattle, WA 98195-1700, United States
| | - Dylan M Rogers
- The Department of Chemistry, University of Washington, Box 351700 Seattle, WA 98195-1700, United States
| | - Werner Kaminsky
- The Department of Chemistry, University of Washington, Box 351700 Seattle, WA 98195-1700, United States
| | - Julie A Kovacs
- The Department of Chemistry, University of Washington, Box 351700 Seattle, WA 98195-1700, United States
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9
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Dedushko MA, Pikul JH, Kovacs JA. Superoxide Oxidation by a Thiolate-Ligated Iron Complex and Anion Inhibition. Inorg Chem 2021; 60:7250-7261. [PMID: 33900756 DOI: 10.1021/acs.inorgchem.1c00336] [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
Superoxide (O2•-) is a toxic radical, generated via the adventitious reduction of dioxygen (O2), which has been implicated in a number of human disease states. Nonheme iron enzymes, superoxide reductase (SOR) and superoxide dismutase (SOD), detoxify O2•- via reduction to afford H2O2 and disproportionation to afford O2 and H2O2, respectively. The former contains a thiolate in the coordination sphere, which has been proposed to prevent O2•- oxidation to O2. The work described herein shows that, in contrast to this, oxidized thiolate-ligated [FeIII(SMe2N4(tren)(THF)]2+ (1ox-THF) is capable of oxidizing O2•- to O2. Coordinating anions, Cl- and OAc-, are shown to inhibit dioxygen evolution, implicating an inner-sphere mechanism. Previously we showed that the reduced thiolate-ligated [FeII(SMe2N4(tren))]+ (1) is capable of reducing O2•- via a proton-dependent inner-sphere mechanism involving a transient Fe(III)-OOH intermediate. A transient ferric-superoxo intermediate, [FeIII(SMe2N4(tren))(O2)]+ (3), is detected by electronic absorption spectroscopy at -130 °C in the reaction between 1ox-THF and KO2 and shown to evolve O2 upon slight warming to -115 °C. The DFT calculated O-O (1.306 Å) and Fe-O (1.943 Å) bond lengths of 3 are typical of ferric-superoxo complexes, and the time-dependent DFT calculated electronic absorption spectrum of 3 reproduces the experimental spectrum. The electronic structure of 3 is shown to consist of two antiferromagnetically coupled (Jcalc = -180 cm-1) unpaired electrons, one in a superoxo π*(O-O) orbital and the other in an antibonding π*(Fe(dyz)-S(py)) orbital.
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Affiliation(s)
- Maksym A Dedushko
- The Department of Chemistry, University of Washington: Box 351700, Seattle, Washington 98195-1700, United States
| | - Jessica H Pikul
- The Department of Chemistry, University of Washington: Box 351700, Seattle, Washington 98195-1700, United States
| | - Julie A Kovacs
- The Department of Chemistry, University of Washington: Box 351700, Seattle, Washington 98195-1700, United States
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10
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Downing AN, Coggins MK, Poon PCY, Kovacs JA. Influence of Thiolate versus Alkoxide Ligands on the Stability of Crystallographically Characterized Mn(III)-Alkylperoxo Complexes. J Am Chem Soc 2021; 143:6104-6113. [PMID: 33851827 DOI: 10.1021/jacs.0c13001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The work described herein demonstrates the exquisite control that the inner coordination sphere of metalloenzymes and transition-metal complexes can have on reactivity. We report one of few crystallographically characterized Mn-peroxo complexes and show that the tight correlations between metrical and spectroscopic parameters, established previously by our group for thiolate-ligated RS-Mn(III)-OOR complexes, can be extended to include an alkoxide-ligated RO-Mn(III)-OOR complex. We show that the alkoxide-ligated RO-Mn(III)-OOR complex is an order of magnitude more stable (t1/2298 K = 6730 s, kobs298 K = 1.03 × 10-4 s-1) than its thiolate-ligated RS-Mn(III)-OOR derivative (t1/2293 K = 249 s, k1293 K = 2.78 × 10-3 s-1). Electronic structure calculations provide insight regarding these differences in stability. The highest occupied orbital of the thiolate-ligated derivative possesses significant sulfur character and π-backdonation from the thiolate competes with π-backdonation from the peroxo π*(O-O). DFT-calculated Mulliken charges show that the Mn ion Lewis acidity of alkoxide-ligated RO-Mn(III)-OOR (+0.451) is greater than that of thiolate-ligated RS-Mn(III)-OOR (+0.306), thereby facilitating π-backdonation from the antibonding peroxo π*(O-O) orbital and increasing its stability. This helps to explain why the photosynthetic oxygen-evolving Mn complex, which catalyzes O-O bond formation as opposed to cleavage, incorporates O- and/or N-ligands as opposed to cysS-ligands.
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Affiliation(s)
- Alexandra N Downing
- The Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Michael K Coggins
- The Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Penny Chaau Yan Poon
- The Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Julie A Kovacs
- The Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
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11
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Liu J, Song H, Wang T, Jia J, Tong QX, Tung CH, Wang W. Iron-Catalyzed Regiodivergent Hydrostannation of Alkynes: Intermediacy of Fe(IV)-H versus Fe(II)-Vinylidene. J Am Chem Soc 2020; 143:409-419. [PMID: 33371677 DOI: 10.1021/jacs.0c11448] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We report an iron system, Cp*Fe(1,2-R2PC6H4X), which controls the Markovnikov and anti-Markovnikov hydrostannation of alkynes by tuning the ionic metal-heteroatom bonds (Fe-X) reactivity. The sequential addition of nBu3SnH to the iron-amido catalyst (1, X = HN-, R = Ph) affords a distannyl Fe(IV)-H species responsible for syn-addition of the Sn-H bond across the C≡C bond to produce branched α-vinylstannanes. Activation of the C(sp)-H bond of alkynes by an iron-aryloxide catalyst (2, X = O-, R = Cy) affords an iron(II) vinylidene intermediate, allowing for gem-addition of the Sn-H to the terminal-carbon producing β-vinylstannanes. These catalytic reactions exhibit excellent regioselectivity and broad functional group compatibility and enable the large-scale synthesis of diverse vinylstannanes. Many new reactions have been established based on such a synthetic Fe-X platform to demonstrate that the initial step of the catalysis is conveniently controlled by the activation of either the tin hydride or the alkyne substrate.
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Affiliation(s)
- Jianguo Liu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Heng Song
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Tianlin Wang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Jiong Jia
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Qing-Xiao Tong
- Department of Chemistry, Shantou University, Shantou 515063, China
| | - Chen-Ho Tung
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Wenguang Wang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.,College of Chemistry, Beijing Normal University, Beijing 100875, China
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12
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Gennari M, Duboc C. Bio-inspired, Multifunctional Metal-Thiolate Motif: From Electron Transfer to Sulfur Reactivity and Small-Molecule Activation. Acc Chem Res 2020; 53:2753-2761. [PMID: 33074643 DOI: 10.1021/acs.accounts.0c00555] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Sulfur-rich metalloproteins and metalloenzymes, containing strongly covalent metal-thiolate (cysteinate) or metal-sulfide bonds in their active site, are ubiquitous in nature. The metal-sulfur motif is a highly versatile tool involved in various biological processes: (i) metal storage, transport, and detoxification; (ii) electron transfer; (iii) activation of the sulfur atom to promote different types of S-based reactions including S-alkylation, S-oxygenation, S-nitrosylation, or disulfide or thiyl radicals formation; (iv) activation of small earth-abundant molecules (such as water, dioxygen, superoxide radical anion, carbon oxides, nitrous oxide, and dinitrogen).This Account describes our investigations carried out during the past 10 years on bio-inspired and biomimetic low-nuclearity complexes containing metal-thiolate bonds. The general objective of these structural, spectroscopic, electrochemical, and catalytic studies was to determine structure-properties-function correlations useful to (i) understanding the peculiar features or the mechanism of the mimicked natural systems and/or (ii) reproducing enzymatic reactivities for specific catalytic applications.By employing a unique highly preorganized N2S2-donor ligand with two thiolate functions, in combination with different first-row transition metals (Mn, Fe, Co, Ni, Cu, Zn, or V), we got access to a series of bio-inspired sulfur-rich complexes displaying a widespread spectrum of structures, properties, and functions. We isolated a dicopper(I) complex that, for the first time, mimicked concomitantly the key structural, spectroscopic, and redox features of the biological CuA center, a highly efficient electron transfer agent involved in the respiratory enzyme cytochrome c oxidase. In the field of sulfur activation, we explored (i) sulfur methylation promoted by a Zn-dithiolate complex that mimics Zn-dependent thiolate alkylation proteins and shows different selectivity compared to the Ni and Co congeners and (ii) a series of Co, Fe, and Mn complexes as the first copper-free systems able to promote thiolate/disulfide interconversion mediated by (de)coordination of halides. Concerning metal-centered reactivity, we investigated two families of metal-thiolate catalysts for small-molecule activation, especially relevant in the fields of sustainable fuel production and energy conversion: (i) two isostructural Mn and Fe dinuclear complexes that activate and reduce dioxygen selectively, either to hydrogen peroxide or water as a function of the experimental conditions; (ii) a family of dinuclear MFe (M = Ni or Fe) hydrogenase mimics active for catalytic H2 evolution both in organic solution and on modified electrodes in water.This Account thus illustrates how the versatility of thiolate ligation can support selected functions for transition metal complexes, depending on the nature of the metal, the nuclearity of the complex, the presence and type of co-ligands, the second coordination sphere effects, and the experimental conditions.
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Affiliation(s)
- Marcello Gennari
- UMR CNRS 5250, Département de Chimie Moléculaire, Univ. Grenoble Alpes, 38000 Grenoble, France
| | - Carole Duboc
- UMR CNRS 5250, Département de Chimie Moléculaire, Univ. Grenoble Alpes, 38000 Grenoble, France
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13
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Oh H, Ching WM, Kim J, Lee WZ, Hong S. Hydrogen Bond-Enabled Heterolytic and Homolytic Peroxide Activation within Nonheme Copper(II)-Alkylperoxo Complexes. Inorg Chem 2019; 58:12964-12974. [DOI: 10.1021/acs.inorgchem.9b01898] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Hana Oh
- Department of Chemistry, Sookmyung Women’s University, Seoul 04310, Korea
| | - Wei-Min Ching
- Department of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan
- Instrumental Center, National Taiwan Normal University, Taipei 11677, Taiwan
| | - Jin Kim
- Western Seoul Centre, Korea Basic Science Institute, Seoul 03759, Republic of Korea
| | - Way-Zen Lee
- Department of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Seungwoo Hong
- Department of Chemistry, Sookmyung Women’s University, Seoul 04310, Korea
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14
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Yan Poon PC, Dedushko MA, Sun X, Yang G, Toledo S, Hayes EC, Johansen A, Piquette MC, Rees JA, Stoll S, Rybak-Akimova E, Kovacs JA. How Metal Ion Lewis Acidity and Steric Properties Influence the Barrier to Dioxygen Binding, Peroxo O-O Bond Cleavage, and Reactivity. J Am Chem Soc 2019; 141:15046-15057. [PMID: 31480847 DOI: 10.1021/jacs.9b04729] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Herein we quantitatively investigate how metal ion Lewis acidity and steric properties influence the kinetics and thermodynamics of dioxygen binding versus release from structurally analogous Mn-O2 complexes, as well as the barrier to Mn peroxo O-O bond cleavage, and the reactivity of Mn oxo intermediates. Previously we demonstrated that the steric and electronic properties of MnIII-OOR complexes containing N-heterocyclic (NAr) ligand scaffolds can have a dramatic influence on alkylperoxo O-O bond lengths and the barrier to alkylperoxo O-O bond cleavage. Herein, we examine the dioxygen reactivity of a new MnII complex containing a more electron-rich, less sterically demanding NAr ligand scaffold, and compare it with previously reported MnII complexes. Dioxygen binding is shown to be reversible with complexes containing the more electron-rich metal ions. The kinetic barrier to O2 binding and peroxo O-O bond cleavage is shown to correlate with redox potentials, as well as the steric properties of the supporting NAr ligands. The reaction landscape for the dioxygen chemistry of the more electron-rich complexes is shown to be relatively flat. A total of four intermediates, including a superoxo and peroxo species, are observed with the most electron-rich complex. Two new intermediates are shown to form following the peroxo, which are capable of cleaving strong X-H bonds. In the absence of a sacrificial H atom donor, solvent, or ligand, serves as a source of H atoms. With TEMPOH as sacrificial H atom donor, a deuterium isotope effect is observed (kH/kD = 3.5), implicating a hydrogen atom transfer (HAT) mechanism. With 1,4-cyclohexadiene, 0.5 equiv of benzene is produced prior to the formation of an EPR detected MnIIIMnIV bimetallic species, and 0.5 equiv after its formation.
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Affiliation(s)
- Penny Chaau Yan Poon
- Department of Chemistry , University of Washington , Campus Box 351700 , Seattle , Washington 98195-1700 , United States
| | - Maksym A Dedushko
- Department of Chemistry , University of Washington , Campus Box 351700 , Seattle , Washington 98195-1700 , United States
| | - Xianru Sun
- Department of Chemistry , Tufts University , 62 Talbot Avenue , Medford , Massachusetts 02155 , United States
| | - Guang Yang
- Department of Chemistry , Tufts University , 62 Talbot Avenue , Medford , Massachusetts 02155 , United States
| | - Santiago Toledo
- The Department of Chemistry , St. Edward's University , 3001 South Congress , Austin , Texas 78704-6489 , United States
| | - Ellen C Hayes
- Department of Chemistry , University of Washington , Campus Box 351700 , Seattle , Washington 98195-1700 , United States
| | - Audra Johansen
- Department of Chemistry , University of Washington , Campus Box 351700 , Seattle , Washington 98195-1700 , United States
| | - Marc C Piquette
- Department of Chemistry , Tufts University , 62 Talbot Avenue , Medford , Massachusetts 02155 , United States
| | - Julian A Rees
- Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Stefan Stoll
- Department of Chemistry , University of Washington , Campus Box 351700 , Seattle , Washington 98195-1700 , United States
| | - Elena Rybak-Akimova
- Department of Chemistry , Tufts University , 62 Talbot Avenue , Medford , Massachusetts 02155 , United States
| | - Julie A Kovacs
- Department of Chemistry , University of Washington , Campus Box 351700 , Seattle , Washington 98195-1700 , United States
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15
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Dedushko MA, Schweitzer D, Blakely MN, Swartz RD, Kaminsky W, Kovacs JA. Geometric and electronic structure of a crystallographically characterized thiolate-ligated binuclear peroxo-bridged cobalt(III) complex. J Biol Inorg Chem 2019; 24:919-926. [PMID: 31342141 PMCID: PMC6948190 DOI: 10.1007/s00775-019-01686-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 07/11/2019] [Indexed: 10/26/2022]
Abstract
In order to shed light on metal-dependent mechanisms for O-O bond cleavage, and its microscopic reverse, we compare herein the electronic and geometric structures of O2-derived binuclear Co(III)- and Mn(III)-peroxo compounds. Binuclear metal peroxo complexes are proposed to form as intermediates during Mn-promoted photosynthetic H2O oxidation, and a Co-containing artificial leaf inspired by nature's photosynthetic H2O oxidation catalyst. Crystallographic characterization of an extremely activated peroxo is made possible by working with substitution-inert, low-spin Co(III). Density functional theory (DFT) calculations show that the frontier orbitals of the Co(III)-peroxo compound differ noticeably from the analogous Mn(III)-peroxo compound. The highest occupied molecular orbital (HOMO) associated with the Co(III)-peroxo is more localized on the peroxo in an antibonding π*(O-O) orbital, whereas the HOMO of the structurally analogous Mn(III)-peroxo is delocalized over both the metal d-orbitals and peroxo π*(O-O) orbital. With low-spin d6 Co(III), filled t2g orbitals prevent π-back-donation from the doubly occupied antibonding π*(O-O) orbital onto the metal ion. This is not the case with high-spin d4 Mn(III), since these orbitals are half-filled. This weakens the peroxo O-O bond of the former relative to the latter.
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Affiliation(s)
- Maksym A Dedushko
- The Department of Chemistry, University of Washington, Box 351700, Seattle, WA, 98195-1700, USA
| | - Dirk Schweitzer
- The Department of Chemistry, University of Washington, Box 351700, Seattle, WA, 98195-1700, USA
| | - Maike N Blakely
- The Department of Chemistry, University of Washington, Box 351700, Seattle, WA, 98195-1700, USA
| | - Rodney D Swartz
- The Department of Chemistry, University of Washington, Box 351700, Seattle, WA, 98195-1700, USA
| | - Werner Kaminsky
- The Department of Chemistry, University of Washington, Box 351700, Seattle, WA, 98195-1700, USA
| | - Julie A Kovacs
- The Department of Chemistry, University of Washington, Box 351700, Seattle, WA, 98195-1700, USA.
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16
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Horch M. Rational redox tuning of transition metal sites: learning from superoxide reductase. Chem Commun (Camb) 2019; 55:9148-9151. [PMID: 31304493 DOI: 10.1039/c9cc04004h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using superoxide reductase as a model system, a computational approach reveals how histidine tautomerism tunes the redox properties of metalloenzymes to enable their catalytic function. Inspired by these experimentally inaccessible insights, non-canonical histidine congeners are introduced as new versatile tools for the rational engineering of biological transition metal sites.
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Affiliation(s)
- Marius Horch
- Department of Chemistry and York Biomedical Research Institute, University of York, Heslington, York, YO10 5DD, UK.
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17
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Wang L, Gennari M, Cantú Reinhard FG, Gutiérrez J, Morozan A, Philouze C, Demeshko S, Artero V, Meyer F, de Visser SP, Duboc C. A Non-Heme Diiron Complex for (Electro)catalytic Reduction of Dioxygen: Tuning the Selectivity through Electron Delivery. J Am Chem Soc 2019; 141:8244-8253. [DOI: 10.1021/jacs.9b02011] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Lianke Wang
- Université Grenoble Alpes, CNRS UMR 5250, DCM, F-38000 Grenoble, France
| | - Marcello Gennari
- Université Grenoble Alpes, CNRS UMR 5250, DCM, F-38000 Grenoble, France
| | - Fabián G. Cantú Reinhard
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Javier Gutiérrez
- Université Grenoble Alpes, CNRS UMR 5250, DCM, F-38000 Grenoble, France
| | - Adina Morozan
- Université Grenoble Alpes, CNRS, CEA, Laboratoire de Chimie et
Biologie des Métaux, F-38000 Grenoble, France
| | | | - Serhiy Demeshko
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Vincent Artero
- Université Grenoble Alpes, CNRS, CEA, Laboratoire de Chimie et
Biologie des Métaux, F-38000 Grenoble, France
| | - Franc Meyer
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Sam P. de Visser
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Carole Duboc
- Université Grenoble Alpes, CNRS UMR 5250, DCM, F-38000 Grenoble, France
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18
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Thapa K, Paul P, Bhattacharya S. A group of diphosphine-thiosemicarbazone complexes of palladium: Efficient precursors for catalytic C C and C N coupling reactions. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2018.10.053] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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19
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Blakely MN, Dedushko MA, Yan Poon PC, Villar-Acevedo G, Kovacs JA. Formation of a Reactive, Alkyl Thiolate-Ligated Fe III-Superoxo Intermediate Derived from Dioxygen. J Am Chem Soc 2019; 141:1867-1870. [PMID: 30661357 DOI: 10.1021/jacs.8b12670] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Herein, we describe an alkyl thiolate-ligated iron complex that reacts with dioxygen to form an unprecedented example of an iron superoxo (O2•-) intermediate, [FeIII(S2Me2N3(Pr,Pr))(O2)] (4), which is capable of cleaving strong C-H bonds. A cysteinate-ligated iron superoxo intermediate is proposed to play a key role in the biosynthesis of β-lactam antibiotics by isopenicillin N-synthase (IPNS). Superoxo 4 converts to a metastable putative Fe(III)-OOH intermediate, at rates that are dependent on the C-H bond strength of the H atom donor, with a kinetic isotope effect ( kH/ kD = 4.8) comparable to that of IPNS ( kH/ kD = 5.6). The bond dissociation energy of the C-H bonds cleaved by 4 (92 kcal/mol) is comparable to C-H bonds cleaved by IPNS (93 kcal/mol). Both the calculated and experimental electronic absorption spectra of 4 are comparable to those of the putative IPNS superoxo intermediate, and are shown to involve RS- → Fe-O2•- and O2•- → Fe charge transfer transitions. The π-back-donation by the electron-rich alkyl thiolate presumably facilitates this reactivity by increasing the basicity of the distal oxygen. The frontier orbitals of 4 are shown to consist of two strongly coupled unpaired electrons of opposite spin, one in a superoxo π*(O-O) orbital, and the other in an Fe(d xy) orbital.
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Affiliation(s)
- Maike N Blakely
- Department of Chemistry , University of Washington , Campus Box 351700 , Seattle , Washington 98195 , United States
| | - Maksym A Dedushko
- Department of Chemistry , University of Washington , Campus Box 351700 , Seattle , Washington 98195 , United States
| | - Penny Chaau Yan Poon
- Department of Chemistry , University of Washington , Campus Box 351700 , Seattle , Washington 98195 , United States
| | - Gloria Villar-Acevedo
- Department of Chemistry , University of Washington , Campus Box 351700 , Seattle , Washington 98195 , United States
| | - Julie A Kovacs
- Department of Chemistry , University of Washington , Campus Box 351700 , Seattle , Washington 98195 , United States
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20
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Jiang F, Siegler MA, Bouwman E. The Reactivity of Fe
II
and Co
II
Disulfide Compounds with Dihydrogen Peroxide. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201800962] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Feng Jiang
- Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University P.O. Box 9502 2300 RA Leiden The Netherlands
| | - Maxime A. Siegler
- Department of Chemistry Gorlaeus Laboratories Johns Hopkins University 3400 N. Charles Street 21218 Baltimore Maryland United States
| | - Elisabeth Bouwman
- Leiden Institute of Chemistry Gorlaeus Laboratories Leiden University P.O. Box 9502 2300 RA Leiden The Netherlands
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21
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Yu X, Pang M, Zhang S, Hu X, Tung CH, Wang W. Terminal Thiolate-Dominated H/D Exchanges and H2 Release: Diiron Thiol–Hydride. J Am Chem Soc 2018; 140:11454-11463. [DOI: 10.1021/jacs.8b06996] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Xin Yu
- Key Lab of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, No. 27 South Shanda Road, Jinan, 250100, P. R. China
| | - Maofu Pang
- Key Lab of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, No. 27 South Shanda Road, Jinan, 250100, P. R. China
| | - Shengnan Zhang
- Key Lab of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, No. 27 South Shanda Road, Jinan, 250100, P. R. China
| | - Xinlong Hu
- Key Lab of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, No. 27 South Shanda Road, Jinan, 250100, P. R. China
| | - Chen-Ho Tung
- Key Lab of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, No. 27 South Shanda Road, Jinan, 250100, P. R. China
| | - Wenguang Wang
- Key Lab of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, No. 27 South Shanda Road, Jinan, 250100, P. R. China
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22
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Enriquez Garcia A, Jalilehvand F. Aerobic reactions of antitumor active dirhodium(II) tetraacetate Rh 2(CH 3COO) 4 with glutathione. J Biol Inorg Chem 2018; 23:231-239. [PMID: 29214420 PMCID: PMC5816706 DOI: 10.1007/s00775-017-1524-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 11/29/2017] [Indexed: 12/27/2022]
Abstract
The aerobic reaction between glutathione (H3A) and dirhodium(II) tetraacetate, Rh2(AcO)4 (AcO- = CH3COO-), in aqueous solution (pH 7.4) breaks up the direct RhII-RhII bond and its carboxylate framework, as evidenced by UV-Vis spectroscopy. After purifying the reaction product using size exclusion chromatography, electrospray ionization mass spectrometry (ESI-MS) of the solution showed binuclear [Formula: see text] and [Formula: see text] ions. Evaporation yielded a solid compound, [Formula: see text], for which Rh K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy revealed ~ 2 Rh-O (2.08 ± 0.02 Å) and ~ 4 Rh-S (2.33 ± 0.02 Å) bond distances around each RhIII center, and the RhIII··RhIII distance 3.11 ± 0.02 Å, close to that in dirhodium(III) complexes with three bridging thiolates connecting [Formula: see text] units. The 13C CPMAS NMR spectrum of the RhIII-glutathione complex showed a change ∆δ C > 6 ppm in the chemical shift of the COO- signal, indicating some carboxylate coordination to the Rh(III) ions. This study shows that under aerobic conditions glutathione enables oxidation of Rh2(AcO)4 and thus reduces its antitumor efficiency. The reaction of Rh2(AcO)4 with glutathione was investigated by ESI-MS, UV-Vis, 13C NMR and X-ray absorption spectroscopy, revealing that glutathione breaks down the carboxylate framework enabling oxidization of the [Formula: see text] core to Rh(III) dimeric units, bridged by three thiolates.
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Affiliation(s)
- Alejandra Enriquez Garcia
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
| | - Farideh Jalilehvand
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.
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23
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Leipzig BK, Rees JA, Kowalska JK, Theisen RM, Kavčič M, Poon PCY, Kaminsky W, DeBeer S, Bill E, Kovacs JA. How Do Ring Size and π-Donating Thiolate Ligands Affect Redox-Active, α-Imino-N-heterocycle Ligand Activation? Inorg Chem 2018; 57:1935-1949. [PMID: 29411979 PMCID: PMC8312276 DOI: 10.1021/acs.inorgchem.7b02748] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Considerable effort has been devoted to the development of first-row transition-metal catalysts containing redox-active imino-pyridine ligands that are capable of storing multiple reducing equivalents. This property allows abundant and inexpensive first-row transition metals, which favor sequential one-electron redox processes, to function as competent catalysts in the concerted two-electron reduction of substrates. Herein we report the syntheses and characterization of a series of iron complexes that contain both π-donating thiolate and π-accepting (α-imino)-N-heterocycle redox-active ligands, with progressively larger N-heterocycle rings (imidazole, pyridine, and quinoline). A cooperative interaction between these complementary redox-active ligands is shown to dictate the properties of these complexes. Unusually intense charge-transfer (CT) bands, and intraligand metrical parameters, reminiscent of a reduced (α-imino)-N-heterocycle ligand (L•-), initially suggested that the electron-donating thiolate had reduced the N-heterocycle. Sulfur K-edge X-ray absorption spectroscopic (XAS) data, however, provides evidence for direct communication, via backbonding, between the thiolate sulfur and the formally orthogonal (α-imino)-N-heterocycle ligand π*-orbitals. DFT calculations provide evidence for extensive delocalization of bonds over the sulfur, iron, and (α-imino)-N-heterocycle, and TD-DFT shows that the intense optical CT bands involve transitions between a mixed Fe/S donor, and (α-imino)-N-heterocycle π*-acceptor orbital. The energies and intensities of the optical and S K-edge pre-edge XAS transitions are shown to correlate with N-heterocycle ring size, as do the redox potentials. When the thiolate is replaced with a thioether, or when the low-spin S = 0 Fe(II) is replaced with a high-spin S = 3/2 Co(II), the N-heterocycle ligand metrical parameters and electronic structure do not change relative to the neutral L0 ligand. With respect to the development of future catalysts containing redox-active ligands, the energy cost of storing reducing equivalents is shown to be lowest when a quinoline, as opposed to imidazole or pyridine, is incorporated into the ligand backbone of the corresponding Fe complex.
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Affiliation(s)
- Benjamin K. Leipzig
- The Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Julian A. Rees
- The Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Joanna K. Kowalska
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34–36, D–45470 Mülheim an der Ruhr, Germany
| | - Roslyn M. Theisen
- The Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | | | | | - Werner Kaminsky
- The Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34–36, D–45470 Mülheim an der Ruhr, Germany
| | - Eckhard Bill
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34–36, D–45470 Mülheim an der Ruhr, Germany
| | - Julie A. Kovacs
- The Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
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24
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Jiang L, Huang C, Wang B, Guo H, Sun Q, Xia F, Xu G, Xia Q. Enhanced heat tolerance in transgenic silkworm via overexpression of Pyrococcus furiosus superoxide reductase. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 92:40-44. [PMID: 29170068 DOI: 10.1016/j.ibmb.2017.11.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 10/27/2017] [Accepted: 11/20/2017] [Indexed: 06/07/2023]
Abstract
Heat shock causes a serious harm to organisms by accelerating the production of reactive oxygen species (ROS). Pyrococcus furiosus superoxide reductase (PfSOR) is an enzyme that efficiently detoxifies ROS. In order to generate a silkworm strain with high heat tolerance for sericulture, we synthesized an artificial DNA sequence encoding PfSOR based on the codon bias of Bombyx mori. PfSOR was successfully overexpressed in transgenic silkworm (named A4SOR) and BmE cells, as determined by RT-PCR and western blot analyses. An SOR activity assay confirmed that the expressed enzyme was functional in A4SOR. After exposure to a temperature of 35 °C for 44 h, the mortality rate was about 30% lower in transgenic A4SOR than in non-transgenic silkworms. Moreover, transgene expression had no apparent effect on economic characteristics of silkworms. The heat tolerance of silkworm was thus enhanced by expressing an archaeal SOR; this can be useful for sericulture in regions where the average temperature exceeds the optimal environmental temperature for B. mori of 25 °C.
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Affiliation(s)
- Liang Jiang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, PR China
| | - Chunlin Huang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, PR China
| | - Bingbing Wang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, PR China
| | - Huizhen Guo
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, PR China
| | - Qiang Sun
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, PR China
| | - Fei Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, PR China
| | - Guowen Xu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, PR China
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, PR China.
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25
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Gallagher AT, Lee JY, Kathiresan V, Anderson JS, Hoffman BM, Harris TD. A structurally-characterized peroxomanganese(iv) porphyrin from reversible O 2 binding within a metal-organic framework. Chem Sci 2017; 9:1596-1603. [PMID: 29675204 PMCID: PMC5890324 DOI: 10.1039/c7sc03739b] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 12/13/2017] [Indexed: 11/22/2022] Open
Abstract
Within a MOF, a side-on peroxomanganese(iv) porphyrin has been isolated and comprehensively examined.
The role of peroxometal species as reactive intermediates in myriad biological processes has motivated the synthesis and study of analogous molecular model complexes. Peroxomanganese(iv) porphyrin complexes are of particular interest, owing to their potential ability to form from reversible O2 binding, yet have been exceedingly difficult to isolate and characterize in molecular form. Alternatively, immobilization of metalloporphyrin sites within a metal–organic framework (MOF) can enable the study of interactions between low-coordinate metal centers and gaseous substrates, without interference from bimolecular reactions and axial ligation by solvent molecules. Here, we employ this approach to isolate the first rigorously four-coordinate manganese(ii) porphyrin complex and examine its reactivity with O2 using infrared spectroscopy, single-crystal X-ray diffraction, EPR spectroscopy, and O2 adsorption analysis. X-ray diffraction experiments reveal for the first time a peroxomanganese(iv) porphyrin species, which exhibits a side-on, η2 binding mode. Infrared and EPR spectroscopic data confirm the formulation of a peroxomanganese(iv) electronic structure, and show that O2 binding is reversible at ambient temperature, in contrast to what has been observed in molecular form. Finally, O2 gas adsorption measurements are employed to quantify the enthalpy of O2 binding as hads = –49.6(8) kJ mol–1. This enthalpy is considerably higher than in the corresponding Fe- and Co-based MOFs, and is found to increase with increasing reductive capacity of the MII/III redox couple.
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Affiliation(s)
- Audrey T Gallagher
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , IL 60208-3113 , USA .
| | - Jung Yoon Lee
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , IL 60208-3113 , USA .
| | - Venkatesan Kathiresan
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , IL 60208-3113 , USA .
| | - John S Anderson
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , IL 60208-3113 , USA .
| | - Brian M Hoffman
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , IL 60208-3113 , USA .
| | - T David Harris
- Department of Chemistry , Northwestern University , 2145 Sheridan Road , Evanston , IL 60208-3113 , USA .
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26
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Lee CM, Wu WY, Chiang MH, Bohle DS, Lee GH. Generation of a Mn(IV)–Peroxo or Mn(III)–Oxo–Mn(III) Species upon Oxygenation of Mono- and Binuclear Thiolate-Ligated Mn(II) Complexes. Inorg Chem 2017; 56:10559-10569. [DOI: 10.1021/acs.inorgchem.7b01513] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chien-Ming Lee
- Department of Applied
Science, National Taitung University, Taitung 950, Taiwan
| | - Wun-Yan Wu
- Department of Applied
Science, National Taitung University, Taitung 950, Taiwan
| | | | - D. Scott Bohle
- Department
of Chemistry, McGill University, Montreal, Quebec H3A 0B8, Canada
| | - Gene-Hsiang Lee
- Instrumentation
Center, National Taiwan University, Taipei 107, Taiwan
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27
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Steiner RA, Dzul SP, Stemmler TL, Harrop TC. Synthesis and Speciation-Dependent Properties of a Multimetallic Model Complex of NiSOD That Exhibits Unique Hydrogen-Bonding. Inorg Chem 2017; 56:2849-2862. [PMID: 28212040 DOI: 10.1021/acs.inorgchem.6b02997] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The complex Na3[{NiII(nmp)}3S3BTAalk)] (1) (nmp2- = deprotonated form of N-(2-mercaptoethyl)picolinamide; H3S3BTAalk = N1,N3,N5-tris(2-mercaptoethyl)benzene-1,3,5-tricarboxamide, where H = dissociable protons), supported by the thiolate-benzenetricarboxamide scaffold (S3BTAalk), has been synthesized as a trimetallic model of nickel-containing superoxide dismutase (NiSOD). X-ray absorption spectroscopy (XAS) and 1H NMR measurements on 1 indicate that the NiII centers are square-planar with N2S2 coordination, and Ni-N and Ni-S distances of 1.95 and 2.16 Å, respectively. Additional evidence from IR indicates the presence of H-bonds in 1 from the approximately -200 cm-1 shift in νNH from free ligand. The presence of H-bonds allows for speciation that is temperature-, concentration-, and solvent-dependent. In unbuffered water and at low temperature, a dimeric complex (1A; λ = 410 nm) that aggregates through intermolecular NH···O═C bonds of BTA units is observed. Dissolution of 1 in pH 7.4 buffer or in unbuffered water at temperatures above 50 °C results in monomeric complex (1M; λ = 367 nm) linked through intramolecular NH···S bonds. DFT computations indicate a low energy barrier between 1A and 1M with nearly identical frontier MOs and Ni-ligand metrics. Notably, 1A and 1M exhibit remarkable stability in protic solvents such as MeOH and H2O, in stark contrast to monometallic [NiII(nmp)(SR)]- complexes. The reactivity of 1 with excess O2, H2O2, and O2•- is species-dependent. IR and UV-vis reveal that 1A in MeOH reacts with excess O2 to yield an S-bound sulfinate, but does not react with O2•-. In contrast, 1M is stable to O2 in pH 7.4 buffer, but reacts with O2•- to yield a putative [NiII(nmp)(O2)]- complex from release of the BTA-thiolate based on EPR.
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Affiliation(s)
- Ramsey A Steiner
- Department of Chemistry and Center for Metalloenzyme Studies, The University of Georgia , 140 Cedar St, Athens, Georgia 30602, United States
| | - Stephen P Dzul
- Departments of Pharmaceutical Sciences, and Biochemistry and Molecular Biology, Wayne State University , Detroit, Michigan 48201, United States
| | - Timothy L Stemmler
- Departments of Pharmaceutical Sciences, and Biochemistry and Molecular Biology, Wayne State University , Detroit, Michigan 48201, United States
| | - Todd C Harrop
- Department of Chemistry and Center for Metalloenzyme Studies, The University of Georgia , 140 Cedar St, Athens, Georgia 30602, United States
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28
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Creutz SE, Peters JC. Exploring secondary-sphere interactions in Fe-N x H y complexes relevant to N 2 fixation. Chem Sci 2017; 8:2321-2328. [PMID: 28451336 PMCID: PMC5363375 DOI: 10.1039/c6sc04805f] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 12/07/2016] [Indexed: 12/11/2022] Open
Abstract
Hydrogen bonding and other types of secondary-sphere interactions are ubiquitous in metalloenzyme active sites and are critical to the transformations they mediate. Exploiting secondary sphere interactions in synthetic catalysts to study the role(s) they might play in biological systems, and to develop increasingly efficient catalysts, is an important challenge. Whereas model studies in this broad context are increasingly abundant, as yet there has been relatively little progress in the area of synthetic catalysts for nitrogen fixation that incorporate secondary sphere design elements. Herein we present our first study of Fe-N x H y complexes supported by new tris(phosphine)silyl ligands, abbreviated as [SiPNMe3] and [SiPiPr2PNMe], that incorporate remote tertiary amine hydrogen-bond acceptors within a tertiary phosphine/amine 6-membered ring. These remote amine sites facilitate hydrogen-bonding interactions via a boat conformation of the 6-membered ring when certain nitrogenous substrates (e.g., NH3 and N2H4) are coordinated to the apical site of a trigonal bipyramidal iron complex, and adopt a chair conformation when no H-bonding is possible (e.g., N2). Countercation binding at the cyclic amine is also observed for anionic {Fe-N2}- complexes. Reactivity studies in the presence of proton/electron sources show that the incorporated amine functionality leads to rapid generation of catalytically inactive Fe-H species, thereby substantiating a hydride termination pathway that we have previously proposed deactivates catalysts of the type [EPR3]FeN2 (E = Si, C).
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Affiliation(s)
- Sidney E Creutz
- California Institute of Technology , Division , of Chemistry and Chemical Engineering , Pasadena , California 91125 , USA .
| | - Jonas C Peters
- California Institute of Technology , Division , of Chemistry and Chemical Engineering , Pasadena , California 91125 , USA .
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29
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Zhang F, Zhang J, Zhou X. Facile Construction of Yttrium Pentasulfides from Yttrium Alkyl Precursors: Synthesis, Mechanism, and Reactivity. Inorg Chem 2017; 56:2070-2077. [DOI: 10.1021/acs.inorgchem.6b02747] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Fangjun Zhang
- Department of Chemistry, Fudan University, Shanghai 200433, People’s Republic of China
| | - Jie Zhang
- Department of Chemistry, Fudan University, Shanghai 200433, People’s Republic of China
| | - Xigeng Zhou
- Department of Chemistry, Fudan University, Shanghai 200433, People’s Republic of China
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30
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Wu Y, Chang C, Wang C, Hsieh C, Horng Y. C=N Bond Activation and Hydration by an Iron(III) Complex with Asymmetric Sulfur Oxygenation. Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201601565] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yun‐Ru Wu
- Department of Chemistry National Changhua University of Education 50058 Changhua Taiwan
| | - Chia‐Ming Chang
- Department of Chemistry National Changhua University of Education 50058 Changhua Taiwan
| | - Chia‐Chi Wang
- Department of Chemistry National Changhua University of Education 50058 Changhua Taiwan
| | - Chang‐Chih Hsieh
- Department of Chemistry National Changhua University of Education 50058 Changhua Taiwan
| | - Yih‐Chern Horng
- Department of Chemistry National Changhua University of Education 50058 Changhua Taiwan
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31
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Fujikawa M, Kobayashi K, Tsutsui Y, Tanaka T, Kozawa T. Rational Tuning of Superoxide Sensitivity in SoxR, the [2Fe-2S] Transcription Factor: Implications of Species-Specific Lysine Residues. Biochemistry 2017; 56:403-410. [DOI: 10.1021/acs.biochem.6b01096] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Mayu Fujikawa
- The Institute of Scientific
and Industrial Research, Osaka University, Mihogaoka 8-1, Osaka, Ibaraki 567-0047, Japan
| | - Kazuo Kobayashi
- The Institute of Scientific
and Industrial Research, Osaka University, Mihogaoka 8-1, Osaka, Ibaraki 567-0047, Japan
| | - Yuko Tsutsui
- The Institute of Scientific
and Industrial Research, Osaka University, Mihogaoka 8-1, Osaka, Ibaraki 567-0047, Japan
| | - Takahiro Tanaka
- The Institute of Scientific
and Industrial Research, Osaka University, Mihogaoka 8-1, Osaka, Ibaraki 567-0047, Japan
| | - Takahiro Kozawa
- The Institute of Scientific
and Industrial Research, Osaka University, Mihogaoka 8-1, Osaka, Ibaraki 567-0047, Japan
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32
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Villar-Acevedo G, Lugo-Mas P, Blakely MN, Rees JA, Ganas AS, Hanada EM, Kaminsky W, Kovacs JA. Metal-Assisted Oxo Atom Addition to an Fe(III) Thiolate. J Am Chem Soc 2016; 139:119-129. [PMID: 28033001 DOI: 10.1021/jacs.6b03512] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cysteinate oxygenation is intimately tied to the function of both cysteine dioxygenases (CDOs) and nitrile hydratases (NHases), and yet the mechanisms by which sulfurs are oxidized by these enzymes are unknown, in part because intermediates have yet to be observed. Herein, we report a five-coordinate bis-thiolate ligated Fe(III) complex, [FeIII(S2Me2N3(Pr,Pr))]+ (2), that reacts with oxo atom donors (PhIO, IBX-ester, and H2O2) to afford a rare example of a singly oxygenated sulfenate, [FeIII(η2-SMe2O)(SMe2)N3(Pr,Pr)]+ (5), resembling both a proposed intermediate in the CDO catalytic cycle and the essential NHase Fe-S(O)Cys114 proposed to be intimately involved in nitrile hydrolysis. Comparison of the reactivity of 2 with that of a more electron-rich, crystallographically characterized derivative, [FeIIIS2Me2NMeN2amide(Pr,Pr)]- (8), shows that oxo atom donor reactivity correlates with the metal ion's ability to bind exogenous ligands. Density functional theory calculations suggest that the mechanism of S-oxygenation does not proceed via direct attack at the thiolate sulfurs; the average spin-density on the thiolate sulfurs is approximately the same for 2 and 8, and Mulliken charges on the sulfurs of 8 are roughly twice those of 2, implying that 8 should be more susceptible to sulfur oxidation. Carboxamide-ligated 8 is shown to be unreactive towards oxo atom donors, in contrast to imine-ligated 2. Azide (N3-) is shown to inhibit sulfur oxidation with 2, and a green intermediate is observed, which then slowly converts to sulfenate-ligated 5. This suggests that the mechanism of sulfur oxidation involves initial coordination of the oxo atom donor to the metal ion. Whether the green intermediate is an oxo atom donor adduct, Fe-O═I-Ph, or an Fe(V)═O remains to be determined.
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Affiliation(s)
- Gloria Villar-Acevedo
- The Department of Chemistry, University of Washington , Box 351700, Seattle, Washington 98195-1700, United States
| | - Priscilla Lugo-Mas
- The Department of Chemistry, University of Washington , Box 351700, Seattle, Washington 98195-1700, United States
| | - Maike N Blakely
- The Department of Chemistry, University of Washington , Box 351700, Seattle, Washington 98195-1700, United States
| | - Julian A Rees
- The Department of Chemistry, University of Washington , Box 351700, Seattle, Washington 98195-1700, United States
| | - Abbie S Ganas
- The Department of Chemistry, University of Washington , Box 351700, Seattle, Washington 98195-1700, United States
| | - Erin M Hanada
- The Department of Chemistry, University of Washington , Box 351700, Seattle, Washington 98195-1700, United States
| | - Werner Kaminsky
- The Department of Chemistry, University of Washington , Box 351700, Seattle, Washington 98195-1700, United States
| | - Julie A Kovacs
- The Department of Chemistry, University of Washington , Box 351700, Seattle, Washington 98195-1700, United States
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33
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Attia AAA, Cioloboc D, Lupan A, Silaghi-Dumitrescu R. Multiconfigurational and DFT analyses of the electromeric formulation and UV-vis absorption spectra of the superoxide adduct of ferrous superoxide reductase. J Inorg Biochem 2016; 165:49-53. [PMID: 27768962 DOI: 10.1016/j.jinorgbio.2016.09.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Revised: 09/14/2016] [Accepted: 09/29/2016] [Indexed: 11/29/2022]
Abstract
The putative initial adduct of ferrous superoxide reductase (SOR) with superoxide has been alternatively formulated as ferric-peroxo or ferrous-superoxo. The ~600-nm UV-vis absorption band proposed to be assigned to this adduct (either as sole intermediate in the SOR catalytic cycle, or as one of the two intermediates) has recently been interpreted as due to a ligand-to-metal charge transfer, involving thiolate and superoxide in a ferrous complex, contrary to an alternative assignment as a predominantly cysteine thiolate-to-ferric charge transfer in a ferric-peroxo electromer. In an attempt to clarify the electromeric formulation of this adduct, we report a computational study using a multiconfigurational complete active space self-consistent field (MC-CASSCF) wave function approach as well as modelling the UV-vis absorption spectra with time-dependent density functional theory (TD-DFT). The MC-CASSCF calculations disclose a weak interaction between iron and the dioxygenic ligand and a dominant configuration with an essentially ferrous-superoxo character. The computed UV-vis absorption spectra reveal a marked dependence on the choice of density functional - both in terms of location of bands and in terms of orbital contributors. For the main band in the visible region, besides the recently reported thiolate-to-superoxide charge transfer, a more salient, and less functional-dependent, feature is a thiolate-to-ferric iron charge transfer, consistent with a ferric-peroxo electromer. By contrast, the computed UV-vis spectra of a ferric-hydroperoxo SOR model match distinctly better (and with no qualitative dependence on the DFT methodology) the 600-nm band as due to a mainly thiolate-to-ferric character - supporting the assignment of the SOR "600-nm intermediate" as a S=5/2 ferric-hydroperoxo species.
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Affiliation(s)
- Amr A A Attia
- Department of Chemistry, Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Cluj-Napoca, Romania
| | - Daniela Cioloboc
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, United States
| | - Alexandru Lupan
- Department of Chemistry, Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Cluj-Napoca, Romania
| | - Radu Silaghi-Dumitrescu
- Department of Chemistry, Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Cluj-Napoca, Romania.
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34
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Abstract
CytP450s have a cysteine-bound heme cofactor that, in its as-isolated resting (oxidized) form, can be conclusively described as a ferric thiolate species. Unlike the native enzyme, most synthetic thiolate-bound ferric porphyrins are unstable in air unless the axial thiolate ligand is sterically protected. Spectroscopic investigations on a series of synthetic mimics of cytP450 indicate that a thiolate-bound ferric porphyrin coexists in organic solutions at room temperature (RT) with a thiyl-radical bound ferrous porphyrin, i.e., its valence tautomer. The ferric thiolate state is favored by greater enthalpy and is air stable. The ferrous thiyl state is favored by entropy, populates at RT, and degrades in air. These ground states can be reversibly interchanged at RT by the addition or removal of water to the apolar medium. It is concluded that hydrogen bonding and local electrostatics protect the resting oxidized cytP450 active site from degradation in air by stabilizing the ferric thiolate ground state in contrast to its synthetic analogs.
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35
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Kowalewska A, Nowacka M, Maniukiewicz W. Octa(3-mercaptopropyl)octasilsesquioxane – A reactive nanocube of unique self-assembled packing morphology. J Organomet Chem 2016. [DOI: 10.1016/j.jorganchem.2016.02.040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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36
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Das UK, Daifuku SL, Gorelsky SI, Korobkov I, Neidig ML, Le Roy JJ, Murugesu M, Baker RT. Mononuclear, Dinuclear, and Trinuclear Iron Complexes Featuring a New Monoanionic SNS Thiolate Ligand. Inorg Chem 2016; 55:987-97. [PMID: 26741465 DOI: 10.1021/acs.inorgchem.5b02833] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The new tridentate ligand, S(Me)N(H)S = 2-(2-methylthiophenyl)benzothiazolidine, prepared in a single step from commercial precursors in excellent yield, undergoes ring-opening on treatment with Fe(OTf)2 in the presence of base affording a trinuclear iron complex, [Fe3(μ2-S(Me)NS(-))4](OTf)2 (1) which is fully characterized by structural and spectroscopic methods. X-ray structural data reveal that 1 contains four S(Me)NS(-) ligands meridionally bound to two pseudooctahedral iron centers each bridged by two thiolates to a distorted tetrahedral central iron. The combined spectroscopic (UV-vis, Mössbauer, NMR), magnetic (solution and solid state), and computational (DFT) studies indicate that 1 includes a central, high-spin Fe(II) (S = 2) with two low-spin (S = 0) peripheral Fe(II) centers. Complex 1 reacts with excess PMePh2, CNxylyl (2,6-dimethylphenyl isocyanide), and P(OMe)3 in CH3CN to form diamagnetic, thiolate-bridged, dinuclear Fe(II) complexes {[Fe(μ-S(Me)NS(-))L2]2}(OTf)2 (2-4). These complexes are characterized by elemental analysis; (1)H NMR, IR, UV-vis, and Mössbauer spectroscopy; and single crystal X-ray diffraction. Interestingly, addition of excess P(OMe)3 to complex 1 in CH2Cl2 produces primarily the diamagnetic, mononuclear Fe(II) complex, {Fe(S(Me)NS(-))[P(OMe)3]3}(OTf) (5).
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Affiliation(s)
- Uttam K Das
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa , Ottawa, Ontario K1N 6N5, Canada
| | - Stephanie L Daifuku
- Department of Chemistry, University of Rochester , Rochester, New York 14627, United States
| | - Serge I Gorelsky
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa , Ottawa, Ontario K1N 6N5, Canada
| | - Ilia Korobkov
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa , Ottawa, Ontario K1N 6N5, Canada
| | - Michael L Neidig
- Department of Chemistry, University of Rochester , Rochester, New York 14627, United States
| | - Jennifer J Le Roy
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa , Ottawa, Ontario K1N 6N5, Canada
| | - Muralee Murugesu
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa , Ottawa, Ontario K1N 6N5, Canada
| | - R Tom Baker
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa , Ottawa, Ontario K1N 6N5, Canada
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37
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Kovacs JA. Tuning the Relative Stability and Reactivity of Manganese Dioxygen and Peroxo Intermediates via Systematic Ligand Modification. Acc Chem Res 2015; 48:2744-53. [PMID: 26335158 DOI: 10.1021/acs.accounts.5b00260] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Many fundamental processes of life depend on the chemical energy stored in the O–O bond of dioxygen (O2), the majority of which is derived from photosynthetic H2O oxidation. Key steps in these processes involve Mn-, Fe-, or Cu-promoted formation or cleavage of O–O and O–H bonds, the mechanisms of which are not fully understood, especially with Mn. Metal–peroxo and high-valent metal–oxo species are proposed to be involved as intermediates. The metal ion properties that favor O–O and O–H bond formation versus cleavage have yet to be systematically explored. Herein we examine the O2 reactivity of a series of structurally related Mn(II) complexes and show that several metastable intermediates are observed, the relative stabilities of which depend on subtle differences in ligand architecture. We show that in contrast to Fe and Cu complexes, O2 binds irreversibly to Mn(II). By crystallizing an entire series of the first reported examples of Mn(III)–OOR peroxos as well as an O2-derived binuclear trans-μ-1,2-bridged Mn(III)–peroxo with varying degrees of O–O bond activation, we demonstrate that there are distinct correlations between spectroscopic, structural, and reactivity properties. Rate-limiting O–O bond cleavage is shown to afford a reactive species capable of abstracting H atoms from 2,4-tBu2-PhOH or 1,4-cyclohexadiene, depending on the ligand substituents. The weakly coordinated N-heterocycle Mn···Npy,quino distance is shown to correlate with the peroxo O–O bond length and modulate the π overlap between the filled πv*(O–O) and Mn dxz orbitals. We also show that there is a strong correlation between the peroxo → Mn charge transfer (CT) band and the peroxo O–O bond length. The energy difference between the CT bands associated with the peroxos possessing the shortest and longest O–O bonds shows that these distances are spectroscopically distinguishable. We show that we can use this spectroscopic parameter to estimate the O–O bond length, and thus the degree of O–O bond activation, in intermediates for which there is no crystal structure, as long as the ligand environment is approximately the same.
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Affiliation(s)
- Julie A. Kovacs
- The Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
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38
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Rees JA, Martin-Diaconescu V, Kovacs JA, DeBeer S. X-ray Absorption and Emission Study of Dioxygen Activation by a Small-Molecule Manganese Complex. Inorg Chem 2015; 54:6410-22. [PMID: 26061165 PMCID: PMC4494871 DOI: 10.1021/acs.inorgchem.5b00699] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Manganese K-edge X-ray absorption (XAS) and Kβ emission (XES) spectroscopies were used to investigate the factors contributing to O-O bond activation in a small-molecule system. The recent structural characterization of a metastable peroxo-bridged dimeric Mn(III)2 complex derived from dioxygen has provided the first opportunity to obtain X-ray spectroscopic data on this type of species. Ground state and time-dependent density functional theory calculations have provided further insight into the nature of the transitions in XAS pre-edge and valence-to-core (VtC) XES spectral regions. An experimentally validated electronic structure description has also enabled the determination of structural and electronic factors that govern peroxo bond activation, and have allowed us to propose both a rationale for the metastability of this unique compound, as well as potential future ligand designs which may further promote or inhibit O-O bond scission. Finally, we have explored the potential of VtC XES as an element-selective probe of both the coordination mode and degree of activation of peroxomanganese adducts. The comparison of these results to a recent VtC XES study of iron-mediated dintrogen activation helps to illustrate the factors that may determine the success of this spectroscopic method for future studies of small-molecule activation at transition metal sites.
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Affiliation(s)
- Julian A. Rees
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, Mülheim an der Ruhr D-45470, Germany
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Vlad Martin-Diaconescu
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, Mülheim an der Ruhr D-45470, Germany
| | - Julie A. Kovacs
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Serena DeBeer
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, Mülheim an der Ruhr D-45470, Germany
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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39
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Gennari M, Brazzolotto D, Pécaut J, Cherrier MV, Pollock CJ, DeBeer S, Retegan M, Pantazis DA, Neese F, Rouzières M, Clérac R, Duboc C. Dioxygen Activation and Catalytic Reduction to Hydrogen Peroxide by a Thiolate-Bridged Dimanganese(II) Complex with a Pendant Thiol. J Am Chem Soc 2015; 137:8644-53. [DOI: 10.1021/jacs.5b04917] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Marcello Gennari
- CNRS
UMR 5250, DCM, Université Grenoble Alpes, F-38000 Grenoble, France
| | | | - Jacques Pécaut
- INAC-SCIB, Université Grenoble Alpes, F-38000 Grenoble, France
- Reconnaissance Ionique et Chimie de Coordination, CEA, INAC-SCIB, F-38000 Grenoble, France
| | - Mickael V. Cherrier
- Metalloproteins
Unit, Institut de Biologie Structurale Jean-Pierre Ebel, CEA, CNRS
UMR 5075, Université Grenoble Alpes, 41 rue Horowitz, 38027 Grenoble Cedex 1, France
- Université de Lyon, F-69622 Lyon, France
- Université Claude Bernard Lyon 1, F-69622 Villeurbanne, France
- CNRS,
UMR 5086 Bases Moléculaires et Structurales de Systèmes
Infectieux, Institut de Biologie et Chimie des Protéines, 7 Passage du Vercors, F-69367 Lyon, France
| | - Christopher J. Pollock
- Max-Planck-Institut für Chemische Energie Konversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Serena DeBeer
- Max-Planck-Institut für Chemische Energie Konversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
- Department
of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Marius Retegan
- Max-Planck-Institut für Chemische Energie Konversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Dimitrios A. Pantazis
- Max-Planck-Institut für Chemische Energie Konversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Frank Neese
- Max-Planck-Institut für Chemische Energie Konversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Mathieu Rouzières
- CNRS, CRPP, UPR 8641, F-33600 Pessac, France
- CRPP,
UPR 8641, Université Bordeaux, F-33600 Pessac, France
| | - Rodolphe Clérac
- CNRS, CRPP, UPR 8641, F-33600 Pessac, France
- CRPP,
UPR 8641, Université Bordeaux, F-33600 Pessac, France
| | - Carole Duboc
- CNRS
UMR 5250, DCM, Université Grenoble Alpes, F-38000 Grenoble, France
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40
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Rhine MA, Sanders BC, Patra AK, Harrop TC. Overview and New Insights into the Thiol Reactivity of Coordinated NO in {MNO}6/7/8 (M = Fe, Co) Complexes. Inorg Chem 2015; 54:9351-66. [DOI: 10.1021/acs.inorgchem.5b00883] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Melody A. Rhine
- Department of Chemistry
and Center for Metalloenzyme Studies, The University of Georgia, 140 Cedar Street, Athens, Georgia 30602, United States
| | - Brian C. Sanders
- Department of Chemistry
and Center for Metalloenzyme Studies, The University of Georgia, 140 Cedar Street, Athens, Georgia 30602, United States
| | - Ashis K. Patra
- Department of Chemistry
and Center for Metalloenzyme Studies, The University of Georgia, 140 Cedar Street, Athens, Georgia 30602, United States
| | - Todd C. Harrop
- Department of Chemistry
and Center for Metalloenzyme Studies, The University of Georgia, 140 Cedar Street, Athens, Georgia 30602, United States
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41
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Faponle AS, Quesne MG, Sastri CV, Banse F, de Visser SP. Differences and comparisons of the properties and reactivities of iron(III)-hydroperoxo complexes with saturated coordination sphere. Chemistry 2015; 21:1221-36. [PMID: 25399782 PMCID: PMC4316188 DOI: 10.1002/chem.201404918] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Indexed: 11/06/2022]
Abstract
Heme and nonheme monoxygenases and dioxygenases catalyze important oxygen atom transfer reactions to substrates in the body. It is now well established that the cytochrome P450 enzymes react through the formation of a high-valent iron(IV)-oxo heme cation radical. Its precursor in the catalytic cycle, the iron(III)-hydroperoxo complex, was tested for catalytic activity and found to be a sluggish oxidant of hydroxylation, epoxidation and sulfoxidation reactions. In a recent twist of events, evidence has emerged of several nonheme iron(III)-hydroperoxo complexes that appear to react with substrates via oxygen atom transfer processes. Although it was not clear from these studies whether the iron(III)-hydroperoxo reacted directly with substrates or that an initial O-O bond cleavage preceded the reaction. Clearly, the catalytic activity of heme and nonheme iron(III)-hydroperoxo complexes is substantially different, but the origins of this are still poorly understood and warrant a detailed analysis. In this work, an extensive computational analysis of aromatic hydroxylation by biomimetic nonheme and heme iron systems is presented, starting from an iron(III)-hydroperoxo complex with pentadentate ligand system (L5(2)). Direct C-O bond formation by an iron(III)-hydroperoxo complex is investigated, as well as the initial heterolytic and homolytic bond cleavage of the hydroperoxo group. The calculations show that [(L5(2))Fe(III)(OOH)](2+) should be able to initiate an aromatic hydroxylation process, although a low-energy homolytic cleavage pathway is only slightly higher in energy. A detailed valence bond and thermochemical analysis rationalizes the differences in chemical reactivity of heme and nonheme iron(III)-hydroperoxo and show that the main reason for this particular nonheme complex to be reactive comes from the fact that they homolytically split the O-O bond, whereas a heterolytic O-O bond breaking in heme iron(III)-hydroperoxo is found.
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Affiliation(s)
- Abayomi S Faponle
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester131 Princess Street, Manchester M1 7DN (UK) E-mail:
| | - Matthew G Quesne
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester131 Princess Street, Manchester M1 7DN (UK) E-mail:
| | - Chivukula V Sastri
- Department of Chemistry, Indian Institute of Technology Guwahati781039, Assam (India)
| | - Frédéric Banse
- Institut de Chimie Moleculaire et des Materiaux d'Orsay, Laboratoire de Chimie Inorganique, Université Paris-Sud11 91405 Orsay Cedex (France) E-mail:
| | - Sam P de Visser
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester131 Princess Street, Manchester M1 7DN (UK) E-mail:
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42
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Deb T, Jensen MP. Electrophilic alkylation of pseudotetrahedral nickel(II) arylthiolate complexes. Inorg Chem 2015; 54:87-96. [PMID: 25494529 DOI: 10.1021/ic5018328] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A kinetic study is reported for reactions of pseudotetrahedral nickel(II) arylthiolate complexes [(Tp(R,Me))Ni-SAr] (Tp(R,Me) = hydrotris{3-R-5-methyl-1-pyrazolyl}borate, R = Me, Ph, and Ar = C6H5, C6H4-4-Cl, C6H4-4-Me, C6H4-4-OMe, 2,4,6-Me3C6H2, 2,4,6-(i)Pr3C6H2) with organic electrophiles R'X (i.e., MeI, EtI, BzBr) in low-polarity organic solvents (toluene, THF, chloroform, dichloromethane, or 1,2-dichloroethane), yielding a pseudotetrahedral halide complex [(Tp(R,Me))Ni-X] (X = Cl, Br, I) and the corresponding organosulfide R'SAr. Competitive reactions with halogenated solvents and adventitious air were also examined. Akin to reactions of analogous and biomimetic zinc complexes, a pertinent mechanistic question is the nature of the reactive nucleophile, either an intact thiolate complex or a free arylthiolate resulting from a dissociative pre-equilibrium. The observed kinetics conformed to a second-order rate law, first order with respect to the complex and electrophile, and no intermediate complexes were observed. In the absence of a mechanistically diagnostic rate law, a variety of mechanistic probes were examined, including kinetic effects of varying the metal, solvent, electrophile, and temperature, as well as the 3-pyrazolyl and arylthiolate substituents. Compared to zinc analogues, the effect of Ni-SAr covalency is also of interest herein. The results are broadly interpreted with respect to the disparate mechanistic pathways.
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Affiliation(s)
- Tapash Deb
- Department of Chemistry and Biochemistry, Ohio University , Athens, Ohio 45701, United States
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43
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Miyamoto K, Hirobe M, Uchiyama M, Ochiai M. Stereoselective synthesis and reaction of gold(i) (Z)-enethiolates. Chem Commun (Camb) 2015; 51:7962-5. [DOI: 10.1039/c5cc02000j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bench-top-storable (Z)-enethiol reagents: gold (Z)-1-decenylthiolates were synthesized stereoselectively in high yields.
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Affiliation(s)
- Kazunori Miyamoto
- Graduate School of Pharmaceutical Sciences
- The University of Tokyo
- Hongo
- Japan
- Advanced Elements Chemistry Research Team
| | - Masaya Hirobe
- Graduate School of Pharmaceutical Sciences
- University of Tokushima
- Tokushima 770-8505
- Japan
| | - Masanobu Uchiyama
- Graduate School of Pharmaceutical Sciences
- The University of Tokyo
- Hongo
- Japan
- Advanced Elements Chemistry Research Team
| | - Masahito Ochiai
- Graduate School of Pharmaceutical Sciences
- University of Tokushima
- Tokushima 770-8505
- Japan
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44
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Ray K, Pfaff FF, Wang B, Nam W. Status of Reactive Non-Heme Metal–Oxygen Intermediates in Chemical and Enzymatic Reactions. J Am Chem Soc 2014; 136:13942-58. [DOI: 10.1021/ja507807v] [Citation(s) in RCA: 351] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Kallol Ray
- Department
of Chemistry, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
| | - Florian Felix Pfaff
- Department
of Chemistry, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
| | - Bin Wang
- Department
of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea
| | - Wonwoo Nam
- Department
of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea
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45
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Liu J, Meier KK, Tian S, Zhang JL, Guo H, Schulz CE, Robinson H, Nilges MJ, Münck E, Lu Y. Redesigning the blue copper azurin into a redox-active mononuclear nonheme iron protein: preparation and study of Fe(II)-M121E azurin. J Am Chem Soc 2014; 136:12337-44. [PMID: 25082811 DOI: 10.1021/ja505410u] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Much progress has been made in designing heme and dinuclear nonheme iron enzymes. In contrast, engineering mononuclear nonheme iron enzymes is lagging, even though these enzymes belong to a large class that catalyzes quite diverse reactions. Herein we report spectroscopic and X-ray crystallographic studies of Fe(II)-M121E azurin (Az), by replacing the axial Met121 and Cu(II) in wild-type azurin (wtAz) with Glu and Fe(II), respectively. In contrast to the redox inactive Fe(II)-wtAz, the Fe(II)-M121EAz mutant can be readily oxidized by Na2IrCl6, and interestingly, the protein exhibits superoxide scavenging activity. Mössbauer and EPR spectroscopies, along with X-ray structural comparisons, revealed similarities and differences between Fe(II)-M121EAz, Fe(II)-wtAz, and superoxide reductase (SOR) and allowed design of the second generation mutant, Fe(II)-M121EM44KAz, that exhibits increased superoxide scavenging activity by 2 orders of magnitude. This finding demonstrates the importance of noncovalent secondary coordination sphere interactions in fine-tuning enzymatic activity.
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Affiliation(s)
- Jing Liu
- Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
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46
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You Y, Nam W. Designing photoluminescent molecular probes for singlet oxygen, hydroxyl radical, and iron–oxygen species. Chem Sci 2014. [DOI: 10.1039/c4sc01637h] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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47
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Zou XW, Liu YC, Hsu NS, Huang CJ, Lyu SY, Chan HC, Chang CY, Yeh HW, Lin KH, Wu CJ, Tsai MD, Li TL. Structure and mechanism of a nonhaem-iron SAM-dependent C-methyltransferase and its engineering to a hydratase and an O-methyltransferase. ACTA ACUST UNITED AC 2014; 70:1549-60. [PMID: 24914966 DOI: 10.1107/s1399004714005239] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 03/06/2014] [Indexed: 12/16/2022]
Abstract
In biological systems, methylation is most commonly performed by methyltransferases (MTs) using the electrophilic methyl source S-adenosyl-L-methionine (SAM) via the S(N)2 mechanism. (2S,3S)-β-Methylphenylalanine, a nonproteinogenic amino acid, is a building unit of the glycopeptide antibiotic mannopeptimycin. The gene product of mppJ from the mannopeptimycin-biosynthetic gene cluster is the MT that methylates the benzylic C atom of phenylpyruvate (Ppy) to give βMePpy. Although the benzylic C atom of Ppy is acidic, how its nucleophilicity is further enhanced to become an acceptor for C-methylation has not conclusively been determined. Here, a structural approach is used to address the mechanism of MppJ and to engineer it for new functions. The purified MppJ displays a turquoise colour, implying the presence of a metal ion. The crystal structures reveal MppJ to be the first ferric ion SAM-dependent MT. An additional four structures of binary and ternary complexes illustrate the molecular mechanism for the metal ion-dependent methyltransfer reaction. Overall, MppJ has a nonhaem iron centre that bind, orients and activates the α-ketoacid substrate and has developed a sandwiched bi-water device to avoid the formation of the unwanted reactive oxo-iron(IV) species during the C-methylation reaction. This discovery further prompted the conversion of the MT into a structurally/functionally unrelated new enzyme. Through stepwise mutagenesis and manipulation of coordination chemistry, MppJ was engineered to perform both Lewis acid-assisted hydration and/or O-methyltransfer reactions to give stereospecific new compounds. This process was validated by six crystal structures. The results reported in this study will facilitate the development and design of new biocatalysts for difficult-to-synthesize biochemicals.
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Affiliation(s)
- Xiao-Wei Zou
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Yu-Chen Liu
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Ning-Shian Hsu
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | | | - Syue-Yi Lyu
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Hsiu-Chien Chan
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Chin-Yuan Chang
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Hsien-Wei Yeh
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Kuan-Hung Lin
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Chang-Jer Wu
- Department of Food Science, National Taiwan Ocean University, Keelung 202, Taiwan
| | - Ming-Daw Tsai
- Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Tsung-Lin Li
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
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48
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Sheng Y, Abreu IA, Cabelli DE, Maroney MJ, Miller AF, Teixeira M, Valentine JS. Superoxide dismutases and superoxide reductases. Chem Rev 2014; 114:3854-918. [PMID: 24684599 PMCID: PMC4317059 DOI: 10.1021/cr4005296] [Citation(s) in RCA: 595] [Impact Index Per Article: 59.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Yuewei Sheng
- Department
of Chemistry and Biochemistry, University
of California Los Angeles, Los
Angeles, California 90095, United States
| | - Isabel A. Abreu
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
- Instituto
de Biologia Experimental e Tecnológica, Av. da República,
Qta. do Marquês, Estação Agronómica Nacional,
Edificio IBET/ITQB, 2780-157, Oeiras, Portugal
| | - Diane E. Cabelli
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Michael J. Maroney
- Department
of Chemistry, University of Massachusetts
Amherst, Amherst, Massachusetts 01003, United States
| | - Anne-Frances Miller
- Department
of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, United States
| | - Miguel Teixeira
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Joan Selverstone Valentine
- Department
of Chemistry and Biochemistry, University
of California Los Angeles, Los
Angeles, California 90095, United States
- Department
of Bioinspired Sciences, Ewha Womans University, Seoul 120-750, Republic of Korea
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49
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Hong S, Lee YM, Cho KB, Seo MS, Song D, Yoon J, Garcia-Serres R, Clémancey M, Ogura T, Shin W, Latour JM, Nam W. Conversion of high-spin iron(iii)–alkylperoxo to iron(iv)–oxo species via O–O bond homolysis in nonheme iron models. Chem Sci 2014. [DOI: 10.1039/c3sc52236a] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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50
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Horch M, Pinto AF, Utesch T, Mroginski MA, Romão CV, Teixeira M, Hildebrandt P, Zebger I. Reductive activation and structural rearrangement in superoxide reductase: a combined infrared spectroscopic and computational study. Phys Chem Chem Phys 2014; 16:14220-30. [DOI: 10.1039/c4cp00884g] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Local and global structural changes that enable reductive activation of superoxide reductase are revealed by a combined approach of infrared difference spectroscopy and computational methods.
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Affiliation(s)
- M. Horch
- Technische Universität Berlin
- Institut für Chemie
- 10623 Berlin, Germany
| | - A. F. Pinto
- Instituto de Tecnologia Química e Biológica António Xavier
- Universidade Nova de Lisboa
- Av. da República (EAN)
- P-2780-157 Oeiras, Portugal
| | - T. Utesch
- Technische Universität Berlin
- Institut für Chemie
- 10623 Berlin, Germany
| | - M. A. Mroginski
- Technische Universität Berlin
- Institut für Chemie
- 10623 Berlin, Germany
| | - C. V. Romão
- Instituto de Tecnologia Química e Biológica António Xavier
- Universidade Nova de Lisboa
- Av. da República (EAN)
- P-2780-157 Oeiras, Portugal
| | - M. Teixeira
- Instituto de Tecnologia Química e Biológica António Xavier
- Universidade Nova de Lisboa
- Av. da República (EAN)
- P-2780-157 Oeiras, Portugal
| | - P. Hildebrandt
- Technische Universität Berlin
- Institut für Chemie
- 10623 Berlin, Germany
| | - I. Zebger
- Technische Universität Berlin
- Institut für Chemie
- 10623 Berlin, Germany
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