1
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Kumar P, M B, Rasool A, Demeshko S, Bommakanti S, Mukhopadhyay N, Gupta R, Dar MA, Ghosh M. Bioinspired Diiron Complex with Proton Shuttling and Redox-Active Ligand for Electrocatalytic Hydrogen Evolution. Inorg Chem 2024. [PMID: 38985539 DOI: 10.1021/acs.inorgchem.4c01112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2024]
Abstract
A μ-oxo diiron complex, featuring the pyridine-2,6-dicarboxamide-based thiazoline-derived redox-active ligand, H2L (H2L = N2,N6-bis(4,5-dihydrothiazol-2-yl)pyridine-2,6-dicarboxamide), was synthesized and thoroughly characterized. [FeIII-(μ-O)-FeIII] showed electrocatalytic hydrogen evolution reaction activity in the presence of different organic acids of varying pKa values in dimethylformamide. Through electrochemical analysis, we found that [FeIII-(μ-O)-FeIII] is a precatalyst that undergoes concerted two-electron reduction to generate an active catalyst. Fourier transform infrared spectrum of reduced species and density functional theory (DFT) investigation indicate that the active catalyst contains a bridged hydroxo unit which serves as a local proton source for the Fe(III) hydride intermediate to release H2. We propose that in this active catalyst, the thiazolinium moiety acts as a proton-transferring group. Additionally, under sufficiently strong acidic conditions, bridged oxygen gets protonated before two-electron reduction. In the presence of exogenous acids of varying strengths, it displays electro-assisted catalytic response at a distinct applied potential. Stepwise electron-transfer and protonation reactions on the metal center and the ligand were studied through DFT to understand the thermodynamically favorable pathways. An ECEC or EECC mechanism is proposed depending on the acid strength and applied potential.
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Affiliation(s)
- Pankaj Kumar
- Department of Chemistry, Ashoka University, Sonipat, Delhi NCR, Haryana 131029, India
| | - Bharath M
- Department of Chemistry, Ashoka University, Sonipat, Delhi NCR, Haryana 131029, India
| | - Anjumun Rasool
- Department of Chemistry, Islamic University of Science and Technology, Awantipora, Jammu and Kashmir 192122, India
| | - Serhiy Demeshko
- University of Göttingen, Institute of Inorganic Chemistry, Tammannstrasse 4, Göttingen D 37077, Germany
| | - Suresh Bommakanti
- School of Chemical Sciences, National Institute of Science Education and Research Bhubaneswar, Jatni, Khurda, Odisha 752050, India
| | - Narottom Mukhopadhyay
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | - Rajeev Gupta
- Department of Chemistry, University of Delhi, Delhi 110007, India
| | - Manzoor Ahmad Dar
- Department of Chemistry, Islamic University of Science and Technology, Awantipora, Jammu and Kashmir 192122, India
| | - Munmun Ghosh
- Department of Chemistry, Ashoka University, Sonipat, Delhi NCR, Haryana 131029, India
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2
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Wen C, Li T, Huang Z, Kang QK. Oxidative Dehydrogenation of Alkanes through Homogeneous Base Metal Catalysis. CHEM REC 2023; 23:e202300146. [PMID: 37283443 DOI: 10.1002/tcr.202300146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 05/25/2023] [Indexed: 06/08/2023]
Abstract
Preparing valuable olefins from cheap and abundant alkane resources has long been a challenging task in organic synthesis, which mainly suffers from harsh reaction conditions and narrow scopes. Homogeneous transition metals catalyzed dehydrogenation of alkanes has attracted much attention for its excellent catalytic activities under relatively milder conditions. Among them, base metal catalyzed oxidative alkane dehydrogenation has emerged as a viable strategy for olefin synthesis for its usage of cheap catalysts, compatibility with various functional groups, and low reaction temperature. In this review, we discuss recent development of base metal catalyzed alkane dehydrogenation under oxidative conditions and their application in constructing complex molecules.
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Affiliation(s)
- Chenxi Wen
- School of Chemistry and Material Sciences, Hangzhou Institute of Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, Hangzhou, 310024, China
| | - Ting Li
- School of Chemistry and Material Sciences, Hangzhou Institute of Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, Hangzhou, 310024, China
| | - Zheng Huang
- School of Chemistry and Material Sciences, Hangzhou Institute of Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, Hangzhou, 310024, China
- The State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Qi-Kai Kang
- School of Chemistry and Material Sciences, Hangzhou Institute of Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, Hangzhou, 310024, China
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3
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Zhao L, Zhong Q, Tian J, Luo M, Yang C, Guo L, Xia W. Electrochemical Synthesis of β-Functionalized Ketones via Ring-Opening of Cycloalkanols. Org Lett 2022; 24:4421-4426. [PMID: 35686882 DOI: 10.1021/acs.orglett.2c01649] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The electrochemical deconstructive functionalization of cycloalkanols with nucleophiles has been studied, which allows functionalization to occur exclusively at the β-position of ketones. The substrate scope includes a wide range of cycloalkanols as well as diverse N, O, C, and P-centered nucleophiles, providing ready access to β-functionalized ketones as products. Mechanistic studies support the generation of α,β-unsaturated ketones as key intermediates followed by Michael addition with nucleophiles.
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Affiliation(s)
- Lulu Zhao
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Qiwen Zhong
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Jian Tian
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Mengqi Luo
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Chao Yang
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Lin Guo
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Wujiong Xia
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China.,School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
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4
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Lee JL, Biswas S, Sun C, Ziller JW, Hendrich MP, Borovik AS. Bioinspired Di-Fe Complexes: Correlating Structure and Proton Transfer over Four Oxidation States. J Am Chem Soc 2022; 144:4559-4571. [PMID: 35192354 DOI: 10.1021/jacs.1c12888] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Metalloproteins with active sites containing di-Fe cores exhibit diverse chemical reactivity that is linked to the precise transfer of protons and electrons which directly involve the di-Fe units. The redox conversions are commonly corroborated by spectroscopic methods, but the associated structural changes are often difficult to assess, particularly those related to proton movements. This report describes the development of di-Fe complexes in which the movements of protons and electrons are pinpointed during the stepwise oxidation of a di-FeII species to one with an FeIIIFeIV core. Complex formation was promoted using the phosphinic amido tripodal ligand [poat]3- (N,N',N″-[nitrilotris(ethane-2,1-diyl)]tris(P,P-diphenylphosphinic amido)) that provided dynamic coordination spheres that assisted in regulating both electron and proton transfer processes. Oxidation of an [FeII-(μ-OH)-FeIII] complex led to the corresponding di-FeIII species containing a hydroxido bridge that was not stable at room temperature and converted to a species containing an oxido bridging ligand and protonation of one phosphinic amido group to form [Hpoat]2-. Deprotonation led to a new species with an [FeIII-(μ-O)-FeIII] core that could be further oxidized to its FeIIIFeIV analogue. Reactions with phenols suggest homolytic cleavage of the O-H bond to give products that are consistent with the initial formation of a phenoxyl radical─spectroscopic studies indicated that the electron is transferred to the FeIV center, and the proton is initially transferred to the more sterically hindered oxido ligand but then relocates to [poat]3-. These findings offer new mechanistic insights related to the stability of and the reactions performed by di-Fe enzymes.
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Affiliation(s)
- Justin L Lee
- Department of Chemistry, University of California,1102 Natural Sciences II, Irvine, California 92697, United States
| | - Saborni Biswas
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Chen Sun
- Department of Chemistry, University of California,1102 Natural Sciences II, Irvine, California 92697, United States
| | - Joseph W Ziller
- Department of Chemistry, University of California,1102 Natural Sciences II, Irvine, California 92697, United States
| | - Michael P Hendrich
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - A S Borovik
- Department of Chemistry, University of California,1102 Natural Sciences II, Irvine, California 92697, United States
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5
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Murray PD, Cox JH, Chiappini ND, Roos CB, McLoughlin EA, Hejna BG, Nguyen ST, Ripberger HH, Ganley JM, Tsui E, Shin NY, Koronkiewicz B, Qiu G, Knowles RR. Photochemical and Electrochemical Applications of Proton-Coupled Electron Transfer in Organic Synthesis. Chem Rev 2022; 122:2017-2291. [PMID: 34813277 PMCID: PMC8796287 DOI: 10.1021/acs.chemrev.1c00374] [Citation(s) in RCA: 158] [Impact Index Per Article: 79.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Indexed: 12/16/2022]
Abstract
We present here a review of the photochemical and electrochemical applications of multi-site proton-coupled electron transfer (MS-PCET) in organic synthesis. MS-PCETs are redox mechanisms in which both an electron and a proton are exchanged together, often in a concerted elementary step. As such, MS-PCET can function as a non-classical mechanism for homolytic bond activation, providing opportunities to generate synthetically useful free radical intermediates directly from a wide variety of common organic functional groups. We present an introduction to MS-PCET and a practitioner's guide to reaction design, with an emphasis on the unique energetic and selectivity features that are characteristic of this reaction class. We then present chapters on oxidative N-H, O-H, S-H, and C-H bond homolysis methods, for the generation of the corresponding neutral radical species. Then, chapters for reductive PCET activations involving carbonyl, imine, other X═Y π-systems, and heteroarenes, where neutral ketyl, α-amino, and heteroarene-derived radicals can be generated. Finally, we present chapters on the applications of MS-PCET in asymmetric catalysis and in materials and device applications. Within each chapter, we subdivide by the functional group undergoing homolysis, and thereafter by the type of transformation being promoted. Methods published prior to the end of December 2020 are presented.
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Affiliation(s)
- Philip
R. D. Murray
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - James H. Cox
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Nicholas D. Chiappini
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Casey B. Roos
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | | | - Benjamin G. Hejna
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Suong T. Nguyen
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Hunter H. Ripberger
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Jacob M. Ganley
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Elaine Tsui
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Nick Y. Shin
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Brian Koronkiewicz
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Guanqi Qiu
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
| | - Robert R. Knowles
- Department of Chemistry, Princeton
University, Princeton, New Jersey 08544, United States
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6
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Salamone M, Galeotti M, Romero-Montalvo E, van Santen JA, Groff BD, Mayer JM, DiLabio GA, Bietti M. Bimodal Evans-Polanyi Relationships in Hydrogen Atom Transfer from C(sp 3)-H Bonds to the Cumyloxyl Radical. A Combined Time-Resolved Kinetic and Computational Study. J Am Chem Soc 2021; 143:11759-11776. [PMID: 34309387 PMCID: PMC8343544 DOI: 10.1021/jacs.1c05566] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Indexed: 12/11/2022]
Abstract
The applicability of the Evans-Polanyi (EP) relationship to HAT reactions from C(sp3)-H bonds to the cumyloxyl radical (CumO•) has been investigated. A consistent set of rate constants, kH, for HAT from the C-H bonds of 56 substrates to CumO•, spanning a range of more than 4 orders of magnitude, has been measured under identical experimental conditions. A corresponding set of consistent gas-phase C-H bond dissociation enthalpies (BDEs) spanning 27 kcal mol-1 has been calculated using the (RO)CBS-QB3 method. The log kH' vs C-H BDE plot shows two distinct EP relationships, one for substrates bearing benzylic and allylic C-H bonds (unsaturated group) and the other one, with a steeper slope, for saturated hydrocarbons, alcohols, ethers, diols, amines, and carbamates (saturated group), in line with the bimodal behavior observed previously in theoretical studies of reactions promoted by other HAT reagents. The parallel use of BDFEs instead of BDEs allows the transformation of this correlation into a linear free energy relationship, analyzed within the framework of the Marcus theory. The ΔG⧧HAT vs ΔG°HAT plot shows again distinct behaviors for the two groups. A good fit to the Marcus equation is observed only for the saturated group, with λ = 58 kcal mol-1, indicating that with the unsaturated group λ must increase with increasing driving force. Taken together these results provide a qualitative connection between Bernasconi's principle of nonperfect synchronization and Marcus theory and suggest that the observed bimodal behavior is a general feature in the reactions of oxygen-based HAT reagents with C(sp3)-H donors.
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Affiliation(s)
- Michela Salamone
- Dipartimento
di Scienze e Tecnologie Chimiche, Università
“Tor Vergata”, Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
| | - Marco Galeotti
- Dipartimento
di Scienze e Tecnologie Chimiche, Università
“Tor Vergata”, Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
| | - Eduardo Romero-Montalvo
- Department
of Chemistry, The University of British
Columbia, 3247 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - Jeffrey A. van Santen
- Department
of Chemistry, The University of British
Columbia, 3247 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - Benjamin D. Groff
- Department
of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520-8107, United States
| | - James M. Mayer
- Department
of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520-8107, United States
| | - Gino A. DiLabio
- Department
of Chemistry, The University of British
Columbia, 3247 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - Massimo Bietti
- Dipartimento
di Scienze e Tecnologie Chimiche, Università
“Tor Vergata”, Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
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7
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Shteinman AA, Mitra M. Nonheme mono- and dinuclear iron complexes in bio-inspired C H and C C bond hydroxylation reactions: Mechanistic insight. Inorganica Chim Acta 2021. [DOI: 10.1016/j.ica.2021.120388] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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8
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Zhang H, Su X, Xie F, Liao R, Zhang M. Iron‐Catalyzed Water Oxidation: O–O Bond Formation via Intramolecular Oxo–Oxo Interaction. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202100060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Hong‐Tao Zhang
- Center of Basic Molecular Science (CBMS) Department of Chemistry Tsinghua University Beijing 100084 China
| | - Xiao‐Jun Su
- Center of Basic Molecular Science (CBMS) Department of Chemistry Tsinghua University Beijing 100084 China
| | - Fei Xie
- Center of Basic Molecular Science (CBMS) Department of Chemistry Tsinghua University Beijing 100084 China
| | - Rong‐Zhen Liao
- Key Laboratory for Large-Format Battery Materials and System School of Chemistry and Chemical Engineering Huazhong University of Science and Technology Wuhan 430074 China
| | - Ming‐Tian Zhang
- Center of Basic Molecular Science (CBMS) Department of Chemistry Tsinghua University Beijing 100084 China
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9
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Zhang HT, Su XJ, Xie F, Liao RZ, Zhang MT. Iron-Catalyzed Water Oxidation: O-O Bond Formation via Intramolecular Oxo-Oxo Interaction. Angew Chem Int Ed Engl 2021; 60:12467-12474. [PMID: 33769654 DOI: 10.1002/anie.202100060] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Indexed: 12/30/2022]
Abstract
Herein, we report the importance of structure regulation on the O-O bond formation process in binuclear iron catalysts. Three complexes, [Fe2 (μ-O)(OH2 )2 (TPA)2 ]4+ (1), [Fe2 (μ-O)(OH2 )2 (6-HPA)]4+ (2) and [Fe2 (μ-O)(OH2 )2 (BPMAN)]4+ (3), have been designed as electrocatalysts for water oxidation in 0.1 M NaHCO3 solution (pH 8.4). We found that 1 and 2 are molecular catalysts and that O-O bond formation proceeds via oxo-oxo coupling rather than by the water nucleophilic attack (WNA) pathway. In contrast, complex 3 displays negligible catalytic activity. DFT calculations suggested that the anti to syn isomerization of the two high-valent Fe=O moieties in these catalysts takes place via the axial rotation of one Fe=O unit around the Fe-O-Fe center. This is followed by the O-O bond formation via an oxo-oxo coupling pathway at the FeIV FeIV state or via oxo-oxyl coupling pathway at the FeIV FeV state. Importantly, the rigid BPMAN ligand in complex 3 limits the anti to syn isomerization and axial rotation of the Fe=O moiety, which accounts for the negligible catalytic activity.
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Affiliation(s)
- Hong-Tao Zhang
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Xiao-Jun Su
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Fei Xie
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Rong-Zhen Liao
- Key Laboratory for Large-Format Battery Materials and System, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Ming-Tian Zhang
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing, 100084, China
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10
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Tsui E, Wang H, Knowles RR. Catalytic generation of alkoxy radicals from unfunctionalized alcohols. Chem Sci 2020; 11:11124-11141. [PMID: 33384861 PMCID: PMC7747465 DOI: 10.1039/d0sc04542j] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 09/21/2020] [Indexed: 12/12/2022] Open
Abstract
Alkoxy radicals have long been recognized as powerful synthetic intermediates with well-established reactivity patterns. Due to the high bond dissociation free energy of aliphatic alcohol O-H bonds, these radicals are difficult to access through direct homolysis, and conventional methods have instead relied on activation of O-functionalized precursors. Over the past decade, however, numerous catalytic methods for the direct generation of alkoxy radicals from simple alcohol starting materials have emerged and created opportunities for the development of new transformations. This minireview discusses recent advances in catalytic alkoxy radical generation, with particular emphasis on progress toward the direct activation of unfunctionalized alcohols enabled by transition metal and photoredox catalysis.
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Affiliation(s)
- Elaine Tsui
- Department of Chemistry , Princeton University , Princeton , NJ 08544 , USA .
| | - Huaiju Wang
- Department of Chemistry , Princeton University , Princeton , NJ 08544 , USA .
| | - Robert R Knowles
- Department of Chemistry , Princeton University , Princeton , NJ 08544 , USA .
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11
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Ansari M, Senthilnathan D, Rajaraman G. Deciphering the origin of million-fold reactivity observed for the open core diiron [HO-Fe III-O-Fe IV[double bond, length as m-dash]O] 2+ species towards C-H bond activation: role of spin-states, spin-coupling, and spin-cooperation. Chem Sci 2020; 11:10669-10687. [PMID: 33209248 PMCID: PMC7654192 DOI: 10.1039/d0sc02624g] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 06/16/2020] [Indexed: 01/26/2023] Open
Abstract
High-valent metal-oxo species have been characterised as key intermediates in both heme and non-heme enzymes that are found to perform efficient aliphatic hydroxylation, epoxidation, halogenation, and dehydrogenation reactions. Several biomimetic model complexes have been synthesised over the years to mimic both the structure and function of metalloenzymes. The diamond-core [Fe2(μ-O)2] is one of the celebrated models in this context as this has been proposed as the catalytically active species in soluble methane monooxygenase enzymes (sMMO), which perform the challenging chemical conversion of methane to methanol at ease. In this context, a report of open core [HO(L)FeIII-O-FeIV(O)(L)]2+ (1) gains attention as this activates C-H bonds a million-fold faster compared to the diamond-core structure and has the dual catalytic ability to perform hydroxylation as well as desaturation with organic substrates. In this study, we have employed density functional methods to probe the origin of the very high reactivity observed for this complex and also to shed light on how this complex performs efficient hydroxylation and desaturation of alkanes. By modelling fifteen possible spin-states for 1 that could potentially participate in the reaction mechanism, our calculations reveal a doublet ground state for 1 arising from antiferromagnetic coupling between the quartet FeIV centre and the sextet FeIII centre, which regulates the reactivity of this species. The unusual stabilisation of the high-spin ground state for FeIV[double bond, length as m-dash]O is due to the strong overlap of with the orbital, reducing the antibonding interactions via spin-cooperation. The electronic structure features computed for 1 are consistent with experiments offering confidence in the methodology chosen. Further, we have probed various mechanistic pathways for the C-H bond activation as well as -OH rebound/desaturation of alkanes. An extremely small barrier height computed for the first hydrogen atom abstraction by the terminal FeIV[double bond, length as m-dash]O unit was found to be responsible for the million-fold activation observed in the experiments. The barrier height computed for -OH rebound by the FeIII-OH unit is also smaller suggesting a facile hydroxylation of organic substrates by 1. A strong spin-cooperation between the two iron centres also reduces the barrier for second hydrogen atom abstraction, thus making the desaturation pathway competitive. Both the spin-state as well as spin-coupling between the two metal centres play a crucial role in dictating the reactivity for species 1. By exploring various mechanistic pathways, our study unveils the fact that the bridged μ-oxo group is a poor electrophile for both C-H activation as well for -OH rebound. As more and more evidence is gathered in recent years for the open core geometry of sMMO enzymes, the idea of enhancing the reactivity via an open-core motif has far-reaching consequences.
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Affiliation(s)
- Mursaleem Ansari
- Department of Chemistry , Indian Institute of Technology Bombay , Mumbai 400076 , India .
| | - Dhurairajan Senthilnathan
- Center for Computational Chemistry , CRD , PRIST University , Vallam , Thanjavur , Tamilnadu 613403 , India
| | - Gopalan Rajaraman
- Department of Chemistry , Indian Institute of Technology Bombay , Mumbai 400076 , India .
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12
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Bím D, Chalupský J, Culka M, Solomon EI, Rulíšek L, Srnec M. Proton-Electron Transfer to the Active Site Is Essential for the Reaction Mechanism of Soluble Δ 9-Desaturase. J Am Chem Soc 2020; 142:10412-10423. [PMID: 32406236 DOI: 10.1021/jacs.0c01786] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
A full understanding of the catalytic action of non-heme iron (NHFe) and non-heme diiron (NHFe2) enzymes is still beyond the grasp of contemporary computational and experimental techniques. Many of these enzymes exhibit fascinating chemo-, regio-, and stereoselectivity, in spite of employing highly reactive intermediates which are necessary for activations of most stable chemical bonds. Herein, we study in detail one intriguing representative of the NHFe2 family of enzymes: soluble Δ9 desaturase (Δ9D), which desaturates rather than performing the thermodynamically favorable hydroxylation of substrate. Its catalytic mechanism has been explored in great detail by using QM(DFT)/MM and multireference wave function methods. Starting from the spectroscopically observed 1,2-μ-peroxo diferric P intermediate, the proton-electron uptake by P is the favored mechanism for catalytic activation, since it allows a significant reduction of the barrier of the initial (and rate-determining) H-atom abstraction from the stearoyl substrate as compared to the "proton-only activated" pathway. Also, we ruled out that a Q-like intermediate (high-valent diamond-core bis-μ-oxo-[FeIV]2 unit) is involved in the reaction mechanism. Our mechanistic picture is consistent with the experimental data available for Δ9D and satisfies fairly stringent conditions required by Nature: the chemo-, stereo-, and regioselectivity of the desaturation of stearic acid. Finally, the mechanisms evaluated are placed into a broader context of NHFe2 chemistry, provided by an amino acid sequence analysis through the families of the NHFe2 enzymes. Our study thus represents an important contribution toward understanding the catalytic action of the NHFe2 enzymes and may inspire further work in NHFe(2) biomimetic chemistry.
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Affiliation(s)
- Daniel Bím
- J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, Prague 8 182 23, Czech Republic.,Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 166 10, Czech Republic
| | - Jakub Chalupský
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 166 10, Czech Republic
| | - Martin Culka
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 166 10, Czech Republic
| | - Edward I Solomon
- Department of Chemistry, Stanford University, 333 Campus Drive, Stanford, California 94305-5080, United States
| | - Lubomír Rulíšek
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 166 10, Czech Republic
| | - Martin Srnec
- J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, Prague 8 182 23, Czech Republic
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14
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Trehoux A, Guillot R, Clemancey M, Blondin G, Latour JM, Mahy JP, Avenier F. Bioinspired symmetrical and unsymmetrical diiron complexes for selective oxidation catalysis with hydrogen peroxide. Dalton Trans 2020; 49:16657-16661. [DOI: 10.1039/d0dt03308a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Two new symmetrical and unsymmetrical diiron(iii) complexes were synthesized and characterized by X-ray diffraction analysis, mass spectrometry, UV-visible and Mössbauer spectroscopies. They were then used for selective oxidation catalysis.
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Affiliation(s)
- Alexandre Trehoux
- Université Paris-Saclay
- CNRS
- Institut de Chimie Moléculaire et des Matériaux d'Orsay
- Equipe de Chimie Bioorganique et Bioinorganique
- 91405 Orsay
| | - Régis Guillot
- Université Paris-Saclay
- CNRS
- Institut de Chimie Moléculaire et des Matériaux d'Orsay
- Equipe de Chimie Bioorganique et Bioinorganique
- 91405 Orsay
| | | | | | | | - Jean-Pierre Mahy
- Université Paris-Saclay
- CNRS
- Institut de Chimie Moléculaire et des Matériaux d'Orsay
- Equipe de Chimie Bioorganique et Bioinorganique
- 91405 Orsay
| | - Frédéric Avenier
- Université Paris-Saclay
- CNRS
- Institut de Chimie Moléculaire et des Matériaux d'Orsay
- Equipe de Chimie Bioorganique et Bioinorganique
- 91405 Orsay
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15
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Li Y, Handunneththige S, Farquhar ER, Guo Y, Talipov MR, Li F, Wang D. Highly Reactive Co III,IV2(μ-O) 2 Diamond Core Complex That Cleaves C-H Bonds. J Am Chem Soc 2019; 141:20127-20136. [PMID: 31794198 DOI: 10.1021/jacs.9b09531] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The selective activation of strong sp3 C-H bonds at mild conditions is a key step in many biological and synthetic transformations and an unsolved challenge for synthetic chemists. In nature, soluble methane monooxygenase (sMMO) is one representative example of nonheme dinuclear iron-dependent enzymes that activate strong sp3 C-H bonds by a high-valent diiron(IV) intermediate Q. To date, synthetic model complexes of sMMO-Q have shown limited abilities to oxidize strong C-H bonds. In this work, we generated a high-valent CoIII,IV2(μ-O)2 complex 3 supported by a tetradentate tris(2-pyridylmethyl)amine (TPA) ligand via one-electron oxidation of its CoIII2(μ-O)2 precursor 2. Characterization of 2 and 3 using X-ray absorption spectroscopy and DFT calculations showed that both species possess a diamond core structure with a short Co···Co distance of 2.78 Å. Furthermore, 3 is an EPR active species showing an S = 1/2 signal with clearly observable hyperfine splittings originated from the coupling of the 59Co nuclear spin with the electronic spin. Importantly, 3 is a highly reactive oxidant for sp3 C-H bonds, and an oxygenation reagent. 3 has the highest rate constant (1.5 M-1 s-1 at -60 °C) for oxidizing 9,10-dihydroanthracene (DHA) compared to diamond core complexes of other first-row transition metals including Mn, Fe and Cu reported previously. Specifically, 3 is about 4-5 orders of magnitude more reactive than the diiron analogs FeIII,IV2(μ-O)2 and FeIV2(μ-O)2 supported by TPA and related ligands. These findings shed light on future development of more reactive approaches for C-H bond activation by bioinspired dicobalt complexes.
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Affiliation(s)
- Yan Li
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Dynamics , University of Montana , Missoula , Montana 59803 , United States
| | - Suhashini Handunneththige
- Department of Chemistry and Biochemistry , New Mexico State University , Las Cruces , New Mexico 88003 , United States
| | - Erik R Farquhar
- CWRU Center for Synchrotron Biosciences, NSLS-II , Brookhaven National Laboratory , Upton , New York 11973 , United States.,School of Medicine , Case Western Reserve University , Cleveland , Ohio 44106 , United States
| | - Yisong Guo
- Department of Chemistry , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Marat R Talipov
- Department of Chemistry and Biochemistry , New Mexico State University , Las Cruces , New Mexico 88003 , United States
| | - Feifei Li
- Department of Chemistry and Biochemistry , New Mexico State University , Las Cruces , New Mexico 88003 , United States
| | - Dong Wang
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Dynamics , University of Montana , Missoula , Montana 59803 , United States
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16
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Kumar A, Sengupta A, Demeshko S, Mukherjee R. Structure, magnetism and reactivity of a {MnIII(μ-O)2MnIV}3+ core towards oxidation of phenols. Polyhedron 2019. [DOI: 10.1016/j.poly.2019.06.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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17
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Mognon L, Richardson S, Agonigi G, Bond T, Marchetti F, Wilton-Ely JD. Heterotrimetallic complexes of iron and ruthenium based on vinyliminium dithiocarboxylate ligands. J Organomet Chem 2019. [DOI: 10.1016/j.jorganchem.2019.02.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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18
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Karimpour T, Safaei E, Karimi B. A supported manganese complex with amine-bis(phenol) ligand for catalytic benzylic C(sp3)–H bond oxidation. RSC Adv 2019; 9:14343-14351. [PMID: 35519312 PMCID: PMC9064044 DOI: 10.1039/c9ra02284h] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 04/25/2019] [Indexed: 12/14/2022] Open
Abstract
With regards to the importance of direct and selective activation of C–H bonds in oxidation processes, we develop a supported manganese amine bis(phenol) ligand complex as a novel catalyst with the aim of obtaining valuable products such as carboxylic acids and ketones that have an important role in life, industry and academic laboratories. We further analyzed and characterized the catalyst using the HRTEM, SEM, FTIR, TGA, VSM, XPS, XRD, AAS, and elemental analysis (CHN) techniques. Also, the catalytic evaluation of our system for direct oxidation of benzylic C–H bonds under solvent-free condition demonstrated that the heterogeneous form of our catalyst has high efficiency in comparison with homogeneous ones due to more stability of the supported complex. Furthermore, the structural and morphological stability of our efficient recyclable catalytic system has been investigated and all of the data proved that the complex was firmly anchored to the magnetite nanoparticles. An environmentally friendly and efficient catalyst containing three interesting parts, Mn, the amine bis(phenolate) ligand (H3LGDC) and the magnetic nanoparticles for benzylic C–H bond oxidation.![]()
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Affiliation(s)
- Touraj Karimpour
- Department of Chemistry
- Institute for Advanced Studies in Basic Sciences (IASBS)
- Zanjan
- Iran
| | - Elham Safaei
- Department of Chemistry
- College of Sciences
- Shiraz University Shiraz
- Iran
| | - Babak Karimi
- Department of Chemistry
- Institute for Advanced Studies in Basic Sciences (IASBS)
- Zanjan
- Iran
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19
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Wang J, Huang B, Shi C, Yang C, Xia W. Visible-Light-Mediated Ring-Opening Strategy for the Regiospecific Allylation/Formylation of Cycloalkanols. J Org Chem 2018; 83:9696-9706. [PMID: 30067027 DOI: 10.1021/acs.joc.8b01225] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Here we describe a straightforward and efficient approach for regiospecific introduction of an allyl group into cycloalkanol molecules employing a visible-light-mediated ring-opening strategy. A wide range of distally allylated or formylated ketones is furnished from 1-aryl cycloalkanol precursors of variable ring sizes, providing a concise and practical access for the modification of complex natural products. Preliminary mechanistic studies demonstrate that the key O-centered radicals mediate the sequential ring cleavage and allylation/formylation.
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Affiliation(s)
- Junlei Wang
- State Key Lab of Urban Water Resource and Environment , Harbin Institute of Technology (Shenzhen) , Shenzhen 518055 , China
| | - Binbin Huang
- State Key Lab of Urban Water Resource and Environment , Harbin Institute of Technology (Shenzhen) , Shenzhen 518055 , China
| | - Chengcheng Shi
- State Key Lab of Urban Water Resource and Environment , Harbin Institute of Technology (Shenzhen) , Shenzhen 518055 , China
| | - Chao Yang
- State Key Lab of Urban Water Resource and Environment , Harbin Institute of Technology (Shenzhen) , Shenzhen 518055 , China
| | - Wujiong Xia
- State Key Lab of Urban Water Resource and Environment , Harbin Institute of Technology (Shenzhen) , Shenzhen 518055 , China
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20
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21
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Jasniewski AJ, Que L. Dioxygen Activation by Nonheme Diiron Enzymes: Diverse Dioxygen Adducts, High-Valent Intermediates, and Related Model Complexes. Chem Rev 2018; 118:2554-2592. [PMID: 29400961 PMCID: PMC5920527 DOI: 10.1021/acs.chemrev.7b00457] [Citation(s) in RCA: 304] [Impact Index Per Article: 50.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A growing subset of metalloenzymes activates dioxygen with nonheme diiron active sites to effect substrate oxidations that range from the hydroxylation of methane and the desaturation of fatty acids to the deformylation of fatty aldehydes to produce alkanes and the six-electron oxidation of aminoarenes to nitroarenes in the biosynthesis of antibiotics. A common feature of their reaction mechanisms is the formation of O2 adducts that evolve into more reactive derivatives such as diiron(II,III)-superoxo, diiron(III)-peroxo, diiron(III,IV)-oxo, and diiron(IV)-oxo species, which carry out particular substrate oxidation tasks. In this review, we survey the various enzymes belonging to this unique subset and the mechanisms by which substrate oxidation is carried out. We examine the nature of the reactive intermediates, as revealed by X-ray crystallography and the application of various spectroscopic methods and their associated reactivity. We also discuss the structural and electronic properties of the model complexes that have been found to mimic salient aspects of these enzyme active sites. Much has been learned in the past 25 years, but key questions remain to be answered.
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Affiliation(s)
- Andrew J. Jasniewski
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
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22
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Sekino M, Furutachi H, Tojo R, Hishi A, Kajikawa H, Suzuki T, Suzuki K, Fujinami S, Akine S, Sakata Y, Ohta T, Hayami S, Suzuki M. New mechanistic insights into intramolecular aromatic ligand hydroxylation and benzyl alcohol oxidation initiated by the well-defined (μ-peroxo)diiron(iii) complex. Chem Commun (Camb) 2018; 53:8838-8841. [PMID: 28726874 DOI: 10.1039/c7cc04382a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A (μ-peroxo)diiron(iii) complex [Fe2(LPh4)(O2)(Ph3CCO2)]2+ (1-O2) with a dinucleating ligand (LPh4), generated from the reaction of a carboxylate bridged diiron(ii) complex [Fe2(LPh4)(Ph3CCO2)]2+ (1) with dioxygen in CH2Cl2, provides a diiron(iv)-oxo species as an active oxidant which is involved in either aromatic ligand hydroxylation or benzyl alcohol oxidation.
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Affiliation(s)
- Mio Sekino
- Department of Chemistry, Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
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23
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Nishizaki D, Iwahashi H. Oxygen-Centered Radicals Formed in the Reaction Mixtures Containing Chloroiron Tetraphenylporphyrin, Iodosylbenzene, and Ethanol. Inorg Chem 2017; 56:13166-13173. [DOI: 10.1021/acs.inorgchem.7b01949] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Daisuke Nishizaki
- Department of Chemistry, Wakayama Medical University, 580 Mikazura, Wakayama 6410011, Japan
| | - Hideo Iwahashi
- Department of Chemistry, Wakayama Medical University, 580 Mikazura, Wakayama 6410011, Japan
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24
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Ansari A, Ansari M, Singha A, Rajaraman G. Interplay of Electronic Cooperativity and Exchange Coupling in Regulating the Reactivity of Diiron(IV)-oxo Complexes towards C−H and O−H Bond Activation. Chemistry 2017; 23:10110-10125. [DOI: 10.1002/chem.201701059] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Azaj Ansari
- Department of Chemistry; CUH Haryana; Haryana 123031 India
| | | | - Asmita Singha
- Department of Chemistry; IIT Bombay; Mumbai 400076 India
| | - Gopalan Rajaraman
- Department of Chemistry; Indian Institute of Technology Bombay, Powai; Mumbai, Maharashtra 400076 India
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25
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Pokutsa A, Kubaj Y, Zaborovskyi A, Maksym D, Paczesniak T, Mysliwiec B, Bidzinska E, Muzart J, Sobkowiak A. V(IV)-catalyzed cyclohexane oxygenation promoted by oxalic acid: Mechanistic study. MOLECULAR CATALYSIS 2017. [DOI: 10.1016/j.mcat.2017.02.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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26
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Bernasconi L, Kazaryan A, Belanzoni P, Baerends EJ. Catalytic Oxidation of Water with High-Spin Iron(IV)–Oxo Species: Role of the Water Solvent. ACS Catal 2017. [DOI: 10.1021/acscatal.7b00568] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Leonardo Bernasconi
- STFC
Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX, United Kingdom
| | - Andranik Kazaryan
- Theoretical
Chemistry Section, Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Paola Belanzoni
- Department
of Chemistry, Biology and Biotechnology, University of Perugia and Institute of Molecular Science and Technologies (ISTM-CNR), Via Elce
di Sotto 8, I-06123 Perugia, Italy
| | - Evert Jan Baerends
- Theoretical
Chemistry Section, Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
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27
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Shen LQ, Kundu S, Collins TJ, Bominaar EL. Analysis of Hydrogen Atom Abstraction from Ethylbenzene by an FeVO(TAML) Complex. Inorg Chem 2017; 56:4347-4356. [DOI: 10.1021/acs.inorgchem.6b02796] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Longzhu Q. Shen
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Soumen Kundu
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Terrence J. Collins
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Emile L. Bominaar
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
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28
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Xue XS, Ji P, Zhou B, Cheng JP. The Essential Role of Bond Energetics in C-H Activation/Functionalization. Chem Rev 2017; 117:8622-8648. [PMID: 28281752 DOI: 10.1021/acs.chemrev.6b00664] [Citation(s) in RCA: 304] [Impact Index Per Article: 43.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The most fundamental concepts in chemistry are structure, energetics, reactivity and their inter-relationships, which are indispensable for promoting chemistry into a rational science. In this regard, bond energy, the intrinsic determinant directly related to structure and reactivity, should be most essential in serving as a quantitative basis for the design and understanding of organic transformations. Although C-H activation/functionalization have drawn tremendous research attention and flourished during the past decades, understanding the governing rules of bond energetics in these processes is still fragmentary and seems applicable only to limited cases, such as metal-oxo-mediated hydrogen atom abstraction. Despite the complexity of C-H activation/functionalization and the difficulties in measuring bond energies both for the substrates and intermediates, this is definitely a very important issue that should be more generally contemplated. To this end, this review is rooted in the energetic aspects of C-H activation/functionalization, which were previously rarely discussed in detail. Starting with a concise but necessary introduction of various classical methods for measuring heterolytic and homolytic energies for C-H bonds, the present review provides examples that applied the concept and values of C-H bond energy in rationalizing the observations associated with reactivity and/or selectivity in C-H activation/functionalization.
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Affiliation(s)
- Xiao-Song Xue
- State Key Laboratory of Elemento-organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering, Nankai University , Tianjin, 300071, China
| | - Pengju Ji
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University , Beijing, 100084, China
| | - Biying Zhou
- State Key Laboratory of Elemento-organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering, Nankai University , Tianjin, 300071, China
| | - Jin-Pei Cheng
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University , Beijing, 100084, China.,State Key Laboratory of Elemento-organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering, Nankai University , Tianjin, 300071, China
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29
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Peck SC, Wang C, Dassama LMK, Zhang B, Guo Y, Rajakovich LJ, Bollinger JM, Krebs C, van der Donk WA. O-H Activation by an Unexpected Ferryl Intermediate during Catalysis by 2-Hydroxyethylphosphonate Dioxygenase. J Am Chem Soc 2017; 139:2045-2052. [PMID: 28092705 PMCID: PMC5302023 DOI: 10.1021/jacs.6b12147] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Activation
of O–H bonds by inorganic metal-oxo complexes
has been documented, but no cognate enzymatic process is known. Our
mechanistic analysis of 2-hydroxyethylphosphonate dioxygenase
(HEPD), which cleaves the C1–C2 bond of its substrate to afford
hydroxymethylphosphonate on the biosynthetic pathway to
the commercial herbicide phosphinothricin, uncovered an example
of such an O–H-bond-cleavage event. Stopped-flow UV–visible
absorption and freeze-quench Mössbauer experiments identified
a transient iron(IV)-oxo (ferryl) complex. Maximal accumulation of
the intermediate required both the presence of deuterium in the substrate
and, importantly, the use of 2H2O as solvent.
The ferryl complex forms and decays rapidly enough to be on the catalytic
pathway. To account for these unanticipated results, a new mechanism
that involves activation of an O–H bond by the ferryl complex
is proposed. This mechanism accommodates all available data on the
HEPD reaction.
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Affiliation(s)
- Spencer C Peck
- Department of Chemistry and Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.,Institute for Genomic Biology, University of Illinois at Urbana-Champaign , 1206 West Gregory Drive, Urbana, Illinois 61801, United States
| | - Chen Wang
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Laura M K Dassama
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Bo Zhang
- Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Yisong Guo
- Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Lauren J Rajakovich
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - J Martin Bollinger
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.,Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Carsten Krebs
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.,Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Wilfred A van der Donk
- Department of Chemistry and Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.,Institute for Genomic Biology, University of Illinois at Urbana-Champaign , 1206 West Gregory Drive, Urbana, Illinois 61801, United States
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30
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Martinie RJ, Blaesi EJ, Krebs C, Bollinger JM, Silakov A, Pollock CJ. Evidence for a Di-μ-oxo Diamond Core in the Mn(IV)/Fe(IV) Activation Intermediate of Ribonucleotide Reductase from Chlamydia trachomatis. J Am Chem Soc 2017; 139:1950-1957. [PMID: 28075562 DOI: 10.1021/jacs.6b11563] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
High-valent iron and manganese complexes effect some of the most challenging biochemical reactions known, including hydrocarbon and water oxidations associated with the global carbon cycle and oxygenic photosynthesis, respectively. Their extreme reactivity presents an impediment to structural characterization, but their biological importance and potential chemical utility have, nevertheless, motivated extensive efforts toward that end. Several such intermediates accumulate during activation of class I ribonucleotide reductase (RNR) β subunits, which self-assemble dimetal cofactors with stable one-electron oxidants that serve to initiate the enzyme's free-radical mechanism. In the class I-c β subunit from Chlamydia trachomatis, a heterodinuclear Mn(II)/Fe(II) complex reacts with dioxygen to form a Mn(IV)/Fe(IV) intermediate, which undergoes reduction of the iron site to produce the active Mn(IV)/Fe(III) cofactor. Herein, we assess the structure of the Mn(IV)/Fe(IV) activation intermediate using Fe- and Mn-edge extended X-ray absorption fine structure (EXAFS) analysis and multifrequency pulse electron paramagnetic resonance (EPR) spectroscopy. The EXAFS results reveal a metal-metal vector of 2.74-2.75 Å and an intense light-atom (C/N/O) scattering interaction 1.8 Å from the Fe. Pulse EPR data reveal an exchangeable deuterium hyperfine coupling of strength |T| = 0.7 MHz, but no stronger couplings. The results suggest that the intermediate possesses a di-μ-oxo diamond core structure with a terminal hydroxide ligand to the Mn(IV).
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Affiliation(s)
- Ryan J Martinie
- Department of Chemistry and ‡Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Elizabeth J Blaesi
- Department of Chemistry and ‡Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Carsten Krebs
- Department of Chemistry and ‡Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - J Martin Bollinger
- Department of Chemistry and ‡Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Alexey Silakov
- Department of Chemistry and ‡Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Christopher J Pollock
- Department of Chemistry and ‡Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
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31
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Drover MW, Love JA, Schafer LL. 1,3-N,O-Complexes of late transition metals. Ligands with flexible bonding modes and reaction profiles. Chem Soc Rev 2017; 46:2913-2940. [DOI: 10.1039/c6cs00715e] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
1,3-N,O-Chelating ligands are ubiquitous in nature owing to their occurrence as α-chiral amino acids in metalloproteins.
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Affiliation(s)
- Marcus W. Drover
- Department of Chemistry
- The University of British Columbia Vancouver
- Canada
| | - Jennifer A. Love
- Department of Chemistry
- The University of British Columbia Vancouver
- Canada
| | - Laurel L. Schafer
- Department of Chemistry
- The University of British Columbia Vancouver
- Canada
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32
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Yayla HG, Wang H, Tarantino KT, Orbe HS, Knowles RR. Catalytic Ring-Opening of Cyclic Alcohols Enabled by PCET Activation of Strong O-H Bonds. J Am Chem Soc 2016; 138:10794-7. [PMID: 27515494 DOI: 10.1021/jacs.6b06517] [Citation(s) in RCA: 238] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We report a new photocatalytic protocol for the redox-neutral isomerization of cyclic alcohols to linear ketones via C-C bond scission. Mechanistic studies demonstrate that key alkoxy radical intermediates in this reaction are generated via the direct homolytic activation of alcohol O-H bonds in an unusual intramolecular PCET process, wherein the electron travels to a proximal radical cation in concert with proton transfer to a weak Brønsted base. Effective bond strength considerations are shown to accurately forecast the feasibility of alkoxy radical generation with a given oxidant/base pair.
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Affiliation(s)
- Hatice G Yayla
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| | - Huaiju Wang
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| | - Kyle T Tarantino
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| | - Hudson S Orbe
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| | - Robert R Knowles
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
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33
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Miller DC, Tarantino KT, Knowles RR. Proton-Coupled Electron Transfer in Organic Synthesis: Fundamentals, Applications, and Opportunities. Top Curr Chem (Cham) 2016; 374:30. [PMID: 27573270 PMCID: PMC5107260 DOI: 10.1007/s41061-016-0030-6] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 04/21/2016] [Indexed: 10/21/2022]
Abstract
Proton-coupled electron transfers (PCETs) are unconventional redox processes in which both protons and electrons are exchanged, often in a concerted elementary step. While PCET is now recognized to play a central a role in biological redox catalysis and inorganic energy conversion technologies, its applications in organic synthesis are only beginning to be explored. In this chapter, we aim to highlight the origins, development, and evolution of the PCET processes most relevant to applications in organic synthesis. Particular emphasis is given to the ability of PCET to serve as a non-classical mechanism for homolytic bond activation that is complimentary to more traditional hydrogen atom transfer processes, enabling the direct generation of valuable organic radical intermediates directly from their native functional group precursors under comparatively mild catalytic conditions. The synthetically advantageous features of PCET reactivity are described in detail, along with examples from the literature describing the PCET activation of common organic functional groups.
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Affiliation(s)
- David C Miller
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Kyle T Tarantino
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Robert R Knowles
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA.
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34
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Nguyen LQ, Knowles RR. Catalytic C–N Bond-Forming Reactions Enabled by Proton-Coupled Electron Transfer Activation of Amide N–H Bonds. ACS Catal 2016. [DOI: 10.1021/acscatal.6b00486] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Lucas Q. Nguyen
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Robert R. Knowles
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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35
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Sankaralingam M, Jeon SH, Lee YM, Seo MS, Ohkubo K, Fukuzumi S, Nam W. An amphoteric reactivity of a mixed-valent bis(μ-oxo)dimanganese(III,IV) complex acting as an electrophile and a nucleophile. Dalton Trans 2016; 45:376-83. [PMID: 26620273 DOI: 10.1039/c5dt04292e] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A mixed-valent bis(μ-oxo)dimanganese(III,IV) complex, [(dpaq)Mn(III)(O)2Mn(IV)(dpaq)](+) (1), was prepared by reacting a hydroxomanganese(III) complex, [(dpaq)Mn(III)(OH)](+), with hydrogen peroxide in the presence of triethylamine. The mixed-valent bis(μ-oxo)dimanganese(III,IV) complex (1) was well characterised by UV-vis, EPR and CSI-MS techniques. The electrophilic reactivity of 1 was investigated in the oxidation of 2,6-di-tert-butylphenol derivatives by 1, in which the relative rate afforded a good Hammett correlation with a ρ value of -1.0. The nucleophilic character of 1 was then investigated in aldehyde deformylation reactions, using 2-phenylpropionaldehyde (2-PPA) and benzaldehyde derivatives as substrates. In contrast to the case of the reaction of 1 with 2,6-di-tert-butylphenol derivatives, a positive ρ value of 0.89 was obtained in the Hammett plot, demonstrating that the bis(μ-oxo)-dimanganese(III,IV) complex is an active nucleophilic oxidant. Thus, 1 exhibited an amphoteric reactivity in both electrophilic and nucleophilic oxidative reactions.
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Affiliation(s)
| | - So Hyun Jeon
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea.
| | - Yong-Min Lee
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea.
| | - Mi Sook Seo
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea.
| | - Kei Ohkubo
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea. and Department of Material and Life Science, Graduate School of Engineering, Osaka University, ALCA and SENTAN, Japan Science and Technology Agency (JST), 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
| | - Shunichi Fukuzumi
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea. and Department of Material and Life Science, Graduate School of Engineering, Osaka University, ALCA and SENTAN, Japan Science and Technology Agency (JST), 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
| | - Wonwoo Nam
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea.
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36
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Nesterova OV, Kopylovich MN, Nesterov DS. Stereoselective oxidation of alkanes with m-CPBA as an oxidant and cobalt complex with isoindole-based ligands as catalysts. RSC Adv 2016. [DOI: 10.1039/c6ra14382b] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Coordination compound of cobalt catalyses hydroxylation of inert C–H bonds with 98% retention of stereoconfiguration of alkane skeleton.
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Affiliation(s)
- Oksana V. Nesterova
- Centro de Química Estrutural
- Instituto Superior Técnico
- Universidade de Lisboa
- 1049-001 Lisboa
- Portugal
| | - Maximilian N. Kopylovich
- Centro de Química Estrutural
- Instituto Superior Técnico
- Universidade de Lisboa
- 1049-001 Lisboa
- Portugal
| | - Dmytro S. Nesterov
- Centro de Química Estrutural
- Instituto Superior Técnico
- Universidade de Lisboa
- 1049-001 Lisboa
- Portugal
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37
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Balamurugan M, Suresh E, Palaniandavar M. Non-heme μ-Oxo- and bis(μ-carboxylato)-bridged diiron(iii) complexes of a 3N ligand as catalysts for alkane hydroxylation: stereoelectronic factors of carboxylate bridges determine the catalytic efficiency. Dalton Trans 2016; 45:11422-36. [DOI: 10.1039/c6dt01059h] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The stereoelectronic factors of carboxylate bridges in diiron(iii) complexes determine the efficiency of catalytic alkane hydroxylation with m-CPBA.
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Affiliation(s)
- Mani Balamurugan
- School of Chemistry
- Bharathidasan University
- Tiruchirappalli - 620024
- India
| | - Eringathodi Suresh
- Analytical Science Discipline
- Central Salt and Marine Chemicals Research Institute
- Bhavnagar - 364 002
- India
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38
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Sánchez RH, Zheng SL, Betley TA. Ligand Field Strength Mediates Electron Delocalization in Octahedral [((H)L)2Fe6(L')m](n+) Clusters. J Am Chem Soc 2015; 137:11126-43. [PMID: 26231520 PMCID: PMC5572642 DOI: 10.1021/jacs.5b06453] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
To assess the impact of terminal ligand binding on a variety of cluster properties (redox delocalization, ground-state stabilization, and breadth of redox state accessibility), we prepared three electron-transfer series based on the hexanuclear iron cluster [((H)L)2Fe6(L')m](n+) in which the terminal ligand field strength was modulated from weak to strong (L' = DMF, MeCN, CN). The extent of intracore M-M interactions is gauged by M-M distances, spin ground state persistence, and preference for mixed-valence states as determined by electrochemical comproportionation constants. Coordination of DMF to the [((H)L)2Fe6] core leads to weaker Fe-Fe interactions, as manifested by the observation of ground states populated only at lower temperatures (<100 K) and by the greater evidence of valence trapping within the mixed-valence states. Comproportionation constants determined electrochemically (Kc = 10(4)-10(8)) indicate that the redox series exhibits electronic delocalization (class II-III), yet no intervalence charge transfer (IVCT) bands are observable in the near-IR spectra. Ligation of the stronger σ donor acetonitrile results in stabilization of spin ground states to higher temperatures (∼300 K) and a high degree of valence delocalization (Kc = 10(2)-10(8)) with observable IVCT bands. Finally, the anionic cyanide-bound series reveals the highest degree of valence delocalization with the most intense IVCT bands (Kc = 10(12)-10(20)) and spin ground state population beyond room temperature. Across the series, at a given formal oxidation level, the capping ligand on the hexairon cluster dictates the overall properties of the aggregate, modulating the redox delocalization and the persistence of the intracore coupling of the metal sites.
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Affiliation(s)
- Raúl Hernández Sánchez
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Shao-Liang Zheng
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Theodore A. Betley
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
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39
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Xu K, Wang Y, Hirao H. Estrogen Formation via H-Abstraction from the O–H Bond of gem-Diol by Compound I in the Reaction of CYP19A1: Mechanistic Scenario Derived from Multiscale QM/MM Calculations. ACS Catal 2015. [DOI: 10.1021/acscatal.5b00510] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kai Xu
- Division
of Chemistry and Biological Chemistry, School of Physical and Mathematical
Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Yong Wang
- State
Key Laboratory for Oxo Synthesis and Selective Oxidation, Suzhou Research
Institute of LICP, Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences, Lanzhou 730000, China
| | - Hajime Hirao
- Division
of Chemistry and Biological Chemistry, School of Physical and Mathematical
Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
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40
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Ye S, Xue G, Krivokapic I, Petrenko T, Bill E, Que Jr L, Neese F. Magnetic circular dichroism and computational study of mononuclear and dinuclear iron(IV) complexes. Chem Sci 2015; 6:2909-2921. [PMID: 26417426 PMCID: PMC4583211 DOI: 10.1039/c4sc03268c] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 02/26/2015] [Indexed: 12/13/2022] Open
Abstract
High-valent iron(IV)-oxo species are key intermediates in the catalytic cycles of a range of O2-activating iron enzymes. This work presents a detailed study of the electronic structures of mononuclear ([FeIV(O)(L)(NCMe)]2+, 1, L = tris(3,5-dimethyl-4-methoxylpyridyl-2-methyl)amine) and dinuclear ([(L)FeIV(O)(μ-O)FeIV(OH)(L)]3+, 2) iron(IV) complexes using absorption (ABS), magnetic circular dichroism (MCD) spectroscopy and wave-function-based quantum chemical calculations. For complex 1, the experimental MCD spectra at 2-10 K are dominated by a broad positive C-term band between 12000 and 18000 cm-1. As the temperature increases up to ~20 K, this feature is gradually replaced by a derivative-shaped signal. The computed MCD spectra are in excellent agreement with experiment, which reproduce not only the excitation energies and the MCD signs of key transitions but also their temperature-dependent intensity variations. To further corroborate the assignments suggested by the calculations, the individual MCD sign for each transition is independently determined from the corresponding electron donating and accepting orbitals. Thus, unambiguous assignments can be made for the observed transitions in 1. The ABS/MCD data of complex 2 exhibit ten features that are assigned as ligand-field transitions or oxo- or hydroxo-to-metal charge transfer bands, based on MCD/ABS intensity ratios, calculated excitation energies, polarizations, and MCD signs. In comparison with complex 1, the electronic structure of the FeIV=O site is not significantly perturbed by the binding to another iron(IV) center. This may explain the experimental finding that complexes 1 and 2 have similar reactivities toward C-H bond activation and O-atom transfer.
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Affiliation(s)
- Shengfa Ye
- Max-Planck Institut für Chemische Energiekonversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr , Germany . ; ;
| | - Genqiang Xue
- Department of Chemistry , Center for Metals in Biocatalysis , University of Minnesota , 207 Pleasant St. SE , Minneapolis , Minnesota 55455 , USA .
| | - Itana Krivokapic
- Max-Planck Institut für Chemische Energiekonversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr , Germany . ; ;
| | - Taras Petrenko
- Max-Planck Institut für Chemische Energiekonversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr , Germany . ; ;
| | - Eckhard Bill
- Max-Planck Institut für Chemische Energiekonversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr , Germany . ; ;
| | - Lawrence Que Jr
- Department of Chemistry , Center for Metals in Biocatalysis , University of Minnesota , 207 Pleasant St. SE , Minneapolis , Minnesota 55455 , USA .
| | - Frank Neese
- Max-Planck Institut für Chemische Energiekonversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr , Germany . ; ;
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41
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Hirao H, Ng WKH, Moeljadi AMP, Bureekaew S. Multiscale Model for a Metal–Organic Framework: High-Spin Rebound Mechanism in the Reaction of the Oxoiron(IV) Species of Fe-MOF-74. ACS Catal 2015. [DOI: 10.1021/acscatal.5b00475] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hajime Hirao
- Division of Chemistry and
Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Wilson Kwok Hung Ng
- Division of Chemistry and
Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Adhitya Mangala Putra Moeljadi
- Division of Chemistry and
Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Sareeya Bureekaew
- Division of Chemistry and
Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
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42
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Kazaryan A, Baerends EJ. Ligand Field Effects and the High Spin–High Reactivity Correlation in the H Abstraction by Non-Heme Iron(IV)–Oxo Complexes: A DFT Frontier Orbital Perspective. ACS Catal 2015. [DOI: 10.1021/cs501721y] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Andranik Kazaryan
- VU University Amsterdam, Theoretical Chemistry,
FEW, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Evert Jan Baerends
- VU University Amsterdam, Theoretical Chemistry,
FEW, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
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43
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Trehoux A, Roux Y, Guillot R, Mahy JP, Avenier F. Catalytic oxidation of dibenzothiophene and thioanisole by a diiron(III) complex and hydrogen peroxide. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.molcata.2014.09.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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44
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Computational investigation on the catalytic activity of Rh6 and Rh4Ru2 clusters towards methanol activation. Theor Chem Acc 2014. [DOI: 10.1007/s00214-014-1597-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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45
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Cook SA, Ziller JW, Borovik AS. Iron(II) complexes supported by sulfonamido tripodal ligands: endogenous versus exogenous substrate oxidation. Inorg Chem 2014; 53:11029-35. [PMID: 25264932 PMCID: PMC4203402 DOI: 10.1021/ic501531g] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
![]()
High-valent
iron species are known to act as powerful oxidants in both natural
and synthetic systems. While biological enzymes have evolved to prevent
self-oxidation by these highly reactive species, development of organic
ligand frameworks that are capable of supporting a high-valent iron
center remains a challenge in synthetic chemistry. We describe here
the reactivity of an Fe(II) complex that is supported by a tripodal
sulfonamide ligand with both dioxygen and an oxygen-atom transfer
reagent, 4-methylmorpholine-N-oxide (NMO). An Fe(III)–hydroxide
complex is obtained from reaction with dioxygen, while NMO gives
an Fe(III)–alkoxide product resulting from activation of a
C–H bond of the ligand. Inclusion of Ca2+ ions in
the reaction with NMO prevented this ligand activation and resulted
in isolation of an Fe(III)–hydroxide complex in which the Ca2+ ion is coordinated to the tripodal sulfonamide ligand and
the hydroxo ligand. Modification of the ligand allowed the Fe(III)–hydroxide
complex to be isolated from NMO in the absence of Ca2+ ions,
and a C–H bond of an external substrate could be activated
during the reaction. This study highlights the importance of robust
ligand design in the development of synthetic catalysts that utilize
a high-valent iron center. Oxidation of an
Fe(II) complex supported by a sulfonamido tripodal ligand was explored
with dioxygen and an O-atom transfer reagent. While dioxygen gave
an Fe(III)−hydroxido complex, the O-atom transfer reagent resulted
in C−H activation of the ligand to form an Fe(III)−alkoxide
species. Modification of the ligand prevented this ligand oxidation
and allowed for activation of C−H bonds on an external substrate.
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Affiliation(s)
- Sarah A Cook
- Department of Chemistry, University of California-Irvine , 1102 Natural Sciences II, Irvine, California 92697, United States
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46
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Pollock CJ, Lancaster KM, Finkelstein KD, DeBeer S. Study of iron dimers reveals angular dependence of valence-to-core X-ray emission spectra. Inorg Chem 2014; 53:10378-85. [PMID: 25211540 PMCID: PMC4186667 DOI: 10.1021/ic501462y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Transition-metal Kβ X-ray emission spectroscopy (XES) is a developing technique that probes the occupied molecular orbitals of a metal complex. As an element-specific probe of metal centers, Kβ XES is finding increasing applications in catalytic and, in particular, bioinorganic systems. For the continued development of XES as a probe of these complex systems, however, the full range of factors which contribute to XES spectral modulations must be explored. In this report, an investigation of a series of oxo-bridged iron dimers reveals that the intensity of valence-to-core features is sensitive to the Fe-O-Fe bond angle. The intensity of these features has a well-known dependence on metal-ligand bond distance, but a dependence upon bond angle has not previously been documented. Herein, we explore the angular dependence of valence-to-core XES features both experimentally and computationally. Taken together, these results show that, as the Fe-O-Fe angle decreases, the intensity of the Kβ″ feature increases and that this effect is modulated by increasing amounts of Fe np mixing into the O 2s orbital at smaller bond angles. The relevance of these findings to the identification of oxygenated intermediates in bioinorganic systems is highlighted, with special emphasis given to the case of soluble methane monooxygenase.
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Affiliation(s)
- Christopher J Pollock
- Max-Planck-Institut für Chemische Energiekonversion , Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
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47
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Wang D, Que L. Oxidation of water by a nonhaem diiron(IV) complex via proton-coupled electron transfer. Chem Commun (Camb) 2014; 49:10682-4. [PMID: 24108275 DOI: 10.1039/c3cc46391e] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A high-potential nonhaem (μ-oxo)diiron(IV) complex was found to oxidize water to a hydroxyl radical via PCET, instead of forming an O-O bond. The rate-determining step requires a second water molecule, proposed to act as a base to promote proton transfer. This work shows that additional factors besides a high redox potential are required to effect O-O bond formation.
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Affiliation(s)
- Dong Wang
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455, USA.
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48
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Chiang L, Savard D, Shimazaki Y, Thomas F, Storr T. FeIII Bipyrrolidine Phenoxide Complexes and Their Oxidized Analogues. Inorg Chem 2014; 53:5810-9. [DOI: 10.1021/ic500663x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Linus Chiang
- Department of Chemistry, Simon Fraser University , Burnaby, British Columbia V5A 1S6, Canada
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49
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Usharani D, Lacy DC, Borovik AS, Shaik S. Dichotomous hydrogen atom transfer vs proton-coupled electron transfer during activation of X-H bonds (X = C, N, O) by nonheme iron-oxo complexes of variable basicity. J Am Chem Soc 2013; 135:17090-104. [PMID: 24124906 PMCID: PMC3876471 DOI: 10.1021/ja408073m] [Citation(s) in RCA: 191] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We describe herein the hydrogen-atom transfer (HAT)/proton-coupled electron-transfer (PCET) reactivity for Fe(IV)-oxo and Fe(III)-oxo complexes (1-4) that activate C-H, N-H, and O-H bonds in 9,10-dihydroanthracene (S1), dimethylformamide (S2), 1,2-diphenylhydrazine (S3), p-methoxyphenol (S4), and 1,4-cyclohexadiene (S5). In 1-3, the iron is pentacoordinated by tris[N'-tert-butylureaylato)-N-ethylene]aminato ([H3buea](3-)) or its derivatives. These complexes are basic, in the order 3 ≫ 1 > 2. Oxidant 4, [Fe(IV)N4Py(O)](2+) (N4Py: N,N-bis(2-pyridylmethyl)bis(2-pyridyl)methylamine), is the least basic oxidant. The DFT results match experimental trends and exhibit a mechanistic spectrum ranging from concerted HAT and PCET reactions to concerted-asynchronous proton transfer (PT)/electron transfer (ET) mechanisms, all the way to PT. The singly occupied orbital along the O···H···X (X = C, N, O) moiety in the TS shows clearly that in the PCET cases, the electron is transferred separately from the proton. The Bell-Evans-Polanyi principle does not account for the observed reactivity pattern, as evidenced by the scatter in the plot of calculated barrier vs reactions driving forces. However, a plot of the deformation energy in the TS vs the respective barrier provides a clear signature of the HAT/PCET dichotomy. Thus, in all C-H bond activations, the barrier derives from the deformation energy required to create the TS, whereas in N-H/O-H bond activations, the deformation energy is much larger than the corresponding barrier, indicating the presence of a stabilizing interaction between the TS fragments. A valence bond model is used to link the observed results with the basicity/acidity of the reactants.
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Affiliation(s)
- Dandamudi Usharani
- Institute of Chemistry and the Lise-Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - David C. Lacy
- Department of Chemistry, University of California-Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
| | - A. S. Borovik
- Department of Chemistry, University of California-Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
| | - Sason Shaik
- Institute of Chemistry and the Lise-Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
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50
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Lu LQ, Li Y, Junge K, Beller M. Iron-catalyzed hydrogenation for the in situ regeneration of an NAD(P)H model: biomimetic reduction of α-keto-/α-iminoesters. Angew Chem Int Ed Engl 2013; 52:8382-6. [PMID: 23804227 DOI: 10.1002/anie.201301972] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 05/31/2013] [Indexed: 12/31/2022]
Affiliation(s)
- Liang-Qiu Lu
- Leibniz-Institut für Katalyse an der Universität Rostock, Albert-Einstein-Strasse 29a, 18059 Rostock, Germany
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