1
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Kumar R, Maji A, Biswas B, Draksharapu A. Amphoteric reactivity of a putative Cu(II)- mCPBA intermediate. Dalton Trans 2024; 53:5401-5406. [PMID: 38426906 DOI: 10.1039/d3dt03747a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
In copper-based enzymes, Cu-hydroperoxo/alkylperoxo species are proposed as key intermediates for their biological activity. A vast amount of literature is available on the functional and structural mimics of enzymatic systems with heme and non-heme ligand frameworks to stabilize high valent metal intermediates, mostly at low temperatures. Herein, we report a reaction between [CuI(NCCH3)4]+ and meta-chloroperoxybenzoic acid (mCPBA) in CH3CN that produces a putative CuII(mCPBA) species (1). 1 was characterized by UV/Vis, resonance Raman, and EPR spectroscopies. 1 can catalyze both electrophilic and nucleophilic reactions, demonstrating its amphoteric behavior. Additionally, 1 can also conduct electron transfer reactions with a weak reducing agent such as diacetyl ferrocene, making it one of the reactive copper-based intermediates. One of the most important aspects of the current work is the easy synthesis of a CuII(mCPBA) adduct with no complicated ligands for stabilization. Over time, 1 decays to form a CuII paddle wheel complex (2) and is found to be unreactive towards substrate oxidation.
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Affiliation(s)
- Rakesh Kumar
- Southern Laboratories - 208A, Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Anweshika Maji
- Southern Laboratories - 208A, Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Bhargab Biswas
- Southern Laboratories - 208A, Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Apparao Draksharapu
- Southern Laboratories - 208A, Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
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2
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Cao Q, Diefenbach M, Maguire C, Krewald V, Muldoon MJ, Hintermair U. Water co-catalysis in aerobic olefin epoxidation mediated by ruthenium oxo complexes. Chem Sci 2024; 15:3104-3115. [PMID: 38425537 PMCID: PMC10901482 DOI: 10.1039/d3sc05516g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 01/05/2024] [Indexed: 03/02/2024] Open
Abstract
We report the development of a versatile Ru-porphyrin catalyst system which performs the aerobic epoxidation of aromatic and aliphatic (internal) alkenes under mild conditions, with product yields of up to 95% and turnover numbers (TON) up to 300. Water is shown to play a crucial role in the reaction, significantly increasing catalyst efficiency and substrate scope. Detailed mechanistic investigations employing both computational studies and a range of experimental techniques revealed that water activates the RuVI di-oxo complex for alkene epoxidation via hydrogen bonding, stabilises the RuIV mono-oxo intermediate, and is involved in the regeneration of the RuVI di-oxo complex leading to oxygen atom exchange. Distinct kinetics are obtained in the presence of water, and side reactions involved in catalyst deactivation have been identified.
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Affiliation(s)
- Qun Cao
- School of Chemistry and Chemical Engineering, Queen's University Belfast Northern Ireland UK
- Dynamic Reaction Monitoring Facility, Institute for Sustainability, University of Bath UK
| | - Martin Diefenbach
- Theoretical Chemistry, Department of Chemistry, Technische Universität Darmstadt Germany
| | - Calum Maguire
- School of Chemistry and Chemical Engineering, Queen's University Belfast Northern Ireland UK
| | - Vera Krewald
- Theoretical Chemistry, Department of Chemistry, Technische Universität Darmstadt Germany
| | - Mark J Muldoon
- School of Chemistry and Chemical Engineering, Queen's University Belfast Northern Ireland UK
| | - Ulrich Hintermair
- Dynamic Reaction Monitoring Facility, Institute for Sustainability, University of Bath UK
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3
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Gao Y, Chen N, Jiang X, Yang X. Application of α-bromination reaction on acetophenone derivatives in experimental teaching: a chemical innovation experiment engaging junior undergraduates. BMC Chem 2024; 18:38. [PMID: 38383516 PMCID: PMC10882791 DOI: 10.1186/s13065-024-01145-y] [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: 12/04/2023] [Accepted: 02/13/2024] [Indexed: 02/23/2024] Open
Abstract
The α-bromination reaction of carbonyl compounds is a significant topic in the field of organic chemistry. However, due to the lack of suitable brominating reagents, the application of this reaction in undergraduate organic chemistry experiments is limited. In this study, three junior undergraduates successfully conducted an innovative experiment under the guidance of teachers. The bromination of various acetophenone derivatives was investigated by employing pyridine hydrobromide perbromide as the brominating agent, with a focus on exploring the effects of reaction time, reaction temperature, and dosage of the brominating agent. The results demonstrated that 4-chloro-α-bromo-acetophenone could be synthesized at 90 ℃ using 4-chloroacetophenone as a substrate and acetic acid as a solvent with a molar ratio of substrate to brominator being 1.0:1.1. Through the experimental teaching of 18 junior undergraduates, it was observed that all the students successfully completed the experiment within a time frame of 4-5 h, with a notable achievement yield exceeding 80% observed in 14 students. This innovative experiment exhibits significant advantages in terms of safety, high yield, cost-effectiveness, and repeatability. Furthermore, while reinforcing fundamental skills in chemistry experimentation among students, it enhances their scientific literacy levels and fosters innovation consciousness as well as practical aptitude. Consequently, this approach is highly suitable for widespread implementation and integration into undergraduate experimental pedagogy.
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Affiliation(s)
- Yongguang Gao
- Department of Chemistry, Tangshan Normal University, Tangshan, China.
| | - Na Chen
- Department of Chemistry, Tangshan Normal University, Tangshan, China
| | - Xiaoye Jiang
- Department of Chemistry, Tangshan Normal University, Tangshan, China
| | - Xiaochun Yang
- Department of Chemistry, Tangshan Normal University, Tangshan, China
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4
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Mukherjee G, Velmurugan G, Kerscher M, Kumar Satpathy J, Sastri CV, Comba P. Mechanistic Insights into Amphoteric Reactivity of an Iron-Bispidine Complex. Chemistry 2024; 30:e202303127. [PMID: 37942658 DOI: 10.1002/chem.202303127] [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: 09/26/2023] [Revised: 11/08/2023] [Accepted: 11/09/2023] [Indexed: 11/10/2023]
Abstract
The reactivity of FeIII -alkylperoxido complexes has remained a riddle to inorganic chemists owing to their thermal instability and impotency towards organic substrates. These iron-oxygen adducts have been known as sluggish oxidants towards oxidative electrophilic and nucleophilic reactions. Herein, we report the synthesis and spectroscopic characterization of a relatively stable mononuclear high-spin FeIII -alkylperoxido complex supported by an engineered bispidine framework. Against the notion, this FeIII -alkylperoxido complex serves as a rare example of versatile reactivity in both electrophilic and nucleophilic reactions. Detailed mechanistic studies and computational calculations reveal a novel reaction mechanism, where a putative superoxido intermediate orchestrates the amphoteric property of the oxidant. The design of the backbone is pivotal to convey stability and reactivity to alkylperoxido and superoxido intermediates. Contrary to the well-known O-O bond cleavage that generates an FeIV -oxido species, the FeIII -alkylperoxido complex reported here undergoes O-C bond scission to generate a superoxido moiety that is responsible for the amphiphilic reactivity.
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Affiliation(s)
- Gourab Mukherjee
- Department of Catalysis & Fine Chemicals, CSIR-Indian Institute of Chemical Technology Tarnaka, Hyderabad, 500007, India
| | - Gunasekaran Velmurugan
- Anorganisch-Chemisches Institut and, Interdisciplinary Center for Scientific Computing (IWR), Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany)
| | - Marion Kerscher
- Anorganisch-Chemisches Institut and, Interdisciplinary Center for Scientific Computing (IWR), Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany)
| | - Jagnyesh Kumar Satpathy
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
| | - Chivukula V Sastri
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
| | - Peter Comba
- Anorganisch-Chemisches Institut and, Interdisciplinary Center for Scientific Computing (IWR), Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany)
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5
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Jeong D, Selverstone Valentine J, Cho J. Bio-inspired mononuclear nonheme metal peroxo complexes: Synthesis, structures and mechanistic studies toward understanding enzymatic reactions. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2023.215021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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6
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Battistella B, Lohmiller T, Cula B, Hildebrandt P, Kuhlmann U, Dau H, Mebs S, Ray K. A New Thiolate-Bound Dimanganese Cluster as a Structural and Functional Model for Class Ib Ribonucleotide Reductases. Angew Chem Int Ed Engl 2023; 62:e202217076. [PMID: 36583430 DOI: 10.1002/anie.202217076] [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: 11/20/2022] [Revised: 12/24/2022] [Accepted: 12/29/2022] [Indexed: 12/31/2022]
Abstract
In class Ib ribonucleotide reductases (RNRs) a dimanganese(II) cluster activates superoxide (O2 ⋅- ) rather than dioxygen (O2 ), to access a high valent MnIII -O2 -MnIV species, responsible for the oxidation of tyrosine to tyrosyl radical. In a biomimetic approach, we report the synthesis of a thiolate-bound dimanganese complex [MnII 2 (BPMT)(OAc)2 ](ClO)4 (BPMT=(2,6-bis{[bis(2-pyridylmethyl)amino]methyl}-4-methylthiophenolate) (1) and its reaction with O2 ⋅- to form a [(BPMT)MnO2 Mn]2+ complex 2. Resonance Raman investigation revealed the presence of an O-O bond in 2, while EPR analysis displayed a 16-line St =1/2 signal at g=2 typically associated with a MnIII MnIV core, as detected in class Ib RNRs. Unlike all other previously reported Mn-O2 -Mn complexes, generated by O2 ⋅- activation at Mn2 centers, 2 proved to be a capable electrophilic oxidant in aldehyde deformylation and phenol oxidation reactions, rendering it one of the best structural and functional models for class Ib RNRs.
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Affiliation(s)
- Beatrice Battistella
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, 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
| | - Beatrice Cula
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Peter Hildebrandt
- Institut für Chemie, Fakultät II, Technische Universität Berlin, Straße des 17. Juni 135, 10623, 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
| | - Stefan Mebs
- Institut für Physik, Freie Universität zu Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Kallol Ray
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
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7
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Jeong D, Kim H, Cho J. Oxidation of Aldehydes into Carboxylic Acids by a Mononuclear Manganese(III) Iodosylbenzene Complex through Electrophilic C-H Bond Activation. J Am Chem Soc 2023; 145:888-897. [PMID: 36598425 DOI: 10.1021/jacs.2c09274] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The oxidation of aldehyde is one of the fundamental reactions in the biological system. Various synthetic procedures and catalysts have been developed to convert aldehydes into corresponding carboxylic acids efficiently under ambient conditions. In this work, we report the oxidation of aldehydes by a mononuclear manganese(III) iodosylbenzene complex, [MnIII(TBDAP)(OIPh)(OH)]2+ (1), with kinetic and mechanistic studies in detail. The reaction of 1 with aldehydes resulted in the formation of corresponding carboxylic acids via a pre-equilibrium state. Hammett plot and reaction rates of 1 with 1°-, 2°-, and 3°-aldehydes revealed the electrophilicity of 1 in the aldehyde oxidation. A kinetic isotope effect experiment and reactivity of 1 toward cyclohexanecarboxaldehyde (CCA) analogues indicate that the reaction of 1 with aldehyde occurs through the rate-determining C-H bond activation at the formyl group. The reaction rate of 1 with CCA is correlated to the bond dissociation energy of the formyl group plotting a linear correlation with other aliphatic C-H bonds. Density functional theory calculations found that 1 electrostatically interacts with CCA at the pre-equilibrium state in which the C-H bond activation of the formyl group is performed as the most feasible pathway. Surprisingly, the rate-determining step is characterized as hydride transfer from CCA to 1, affording an (oxo)methylium intermediate. At the fundamental level, it is revealed that the hydride transfer is composed of H atom abstraction followed by a fast electron transfer. Catalytic reactions of aldehydes by 1 are also presented with a broad substrate scope. This novel mechanistic study gives better insights into the metal oxygen chemistry and would be prominently valuable for development of transition metal catalysts.
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Affiliation(s)
- Donghyun Jeong
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan44919, Republic of Korea
| | - Hyokyung Kim
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan44919, Republic of Korea
| | - Jaeheung Cho
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan44919, Republic of Korea.,Graduate School of Carbon Neutrality, Ulsan National Institute of Science and Technology (UNIST), Ulsan44919, Republic of Korea
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8
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Mondal P, Ishigami I, Yeh SR, Wijeratne GB. The Role of Heme Peroxo Oxidants in the Rational Mechanistic Modeling of Nitric Oxide Synthase: Characterization of Key Intermediates and Elucidation of the Mechanism. Angew Chem Int Ed Engl 2022; 61:e202211521. [PMID: 36169890 PMCID: PMC9675724 DOI: 10.1002/anie.202211521] [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: 08/04/2022] [Indexed: 11/08/2022]
Abstract
Mammalian nitric oxide synthase (NOS) mediates the two-step O2 -dependent oxidative degradation of arginine, and has been linked to a medley of disease situations in humans. Nonetheless, its exact mechanism of action still remains unclear. This work presents the first NOS model system where biologically proposed heme superoxo and peroxo intermediates are assessed as active oxidants against oxime substrates. Markedly, heme peroxo intermediates engaged in a bioinspired oxime oxidation reaction pathway, converting oximes to ketones and nitroxyl anions (NO- ). Detailed thermodynamic, kinetic, and mechanistic interrogations all evince a rate-limiting step primarily driven by the nucleophilicity of the heme peroxo moiety. Coherent with other findings, 18 O and 15 N isotope substitution experiments herein suffice compelling evidence toward a detailed mechanism, which draw close parallels to one of the enzymatic proposals. Intriguingly, recent enzymatic studies also lend credence to these findings, and several relevant reaction intermediates have been observed during NOS turnover.
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Affiliation(s)
- Pritam Mondal
- Department of Chemistry and O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL 35205, USA
| | - Izumi Ishigami
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, The Bronx, NY 10461, USA
| | - Syun-Ru Yeh
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, The Bronx, NY 10461, USA
| | - Gayan B Wijeratne
- Department of Chemistry and O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL 35205, USA
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9
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Lueckheide MJ, Ertem MZ, Michon MA, Chmielniak P, Robinson JR. Peroxide-Selective Reduction of O 2 at Redox-Inactive Rare-Earth(III) Triflates Generates an Ambiphilic Peroxide. J Am Chem Soc 2022; 144:17295-17306. [PMID: 36083877 DOI: 10.1021/jacs.2c08140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Metal peroxides are key species involved in a range of critical biological and synthetic processes. Rare-earth (group III and the lanthanides; Sc, Y, La-Lu) peroxides have been implicated as reactive intermediates in catalysis; however, reactivity studies of isolated, structurally characterized rare-earth peroxides have been limited. Herein, we report the peroxide-selective (93-99% O22-) reduction of dioxygen (O2) at redox-inactive rare-earth triflates in methanol using a mild metallocene reductant, decamethylferrocene (Fc*). The first molecular praseodymium peroxide ([PrIII2(O22-)(18C6)2(EG)2][OTf]4; 18C6 = 18-crown-6, EG = ethylene glycol, -OTf = -O3SCF3; 2-Pr) was isolated and characterized by single-crystal X-ray diffraction, Raman spectroscopy, and NMR spectroscopy. 2-Pr displays high thermal stability (120 °C, 50 mTorr), is protonated by mild organic acids [pKa1(MeOH) = 5.09 ± 0.23], and engages in electrophilic (e.g., oxygen atom transfer) and nucleophilic (e.g., phosphate-ester cleavage) reactivity. Our mechanistic studies reveal that the rate of oxygen reduction is dictated by metal-ion accessibility, rather than Lewis acidity, and suggest new opportunities for differentiated reactivity of redox-inactive metal ions by leveraging weak metal-ligand binding events preceding electron transfer.
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Affiliation(s)
- Matthew J Lueckheide
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Mehmed Z Ertem
- Chemistry Division, Energy & Photon Sciences, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Michael A Michon
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Pawel Chmielniak
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Jerome R Robinson
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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10
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Zhou TP, Deng WH, Wu Y, Liao RZ. QM/MM Calculations Suggested Concerted O‒O Bond Cleavage and Substrate Oxidation by Nonheme Diiron Toluene/o‐xylene Monooxygenase. Chem Asian J 2022; 17:e202200490. [DOI: 10.1002/asia.202200490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/01/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Tai-Ping Zhou
- Huazhong University of Science and Technology School of chemistry and chemical engineering CHINA
| | - Wen-Hao Deng
- Huazhong University of Science and Technology School of chemistry and chemical engineering CHINA
| | - Yuzhou Wu
- Huazhong University of Science and Technology School of chemistry and chemical engineering CHINA
| | - Rong-Zhen Liao
- Huazhong University of Science and technology College of Chemistry and Chemical Engeneering Luoyulu 1037 430074 Wuhan CHINA
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11
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Yeh CCG, Mokkawes T, Bradley J, Le Brun NE, de Visser S. Second coordination sphere effects on the mechanistic pathways for dioxygen activation by a ferritin: involvement of a Tyr radical and the identification of a cation binding site. Chembiochem 2022; 23:e202200257. [PMID: 35510795 PMCID: PMC9401865 DOI: 10.1002/cbic.202200257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 05/05/2022] [Indexed: 11/09/2022]
Abstract
Ferritins are ubiquitous diiron enzymes involved in iron(II) detoxification and oxidative stress responses and can act as metabolic iron stores. The overall reaction mechanisms of ferritin enzymes are still unclear, particularly concerning the role of the conserved, near catalytic center Tyr residue. Thus, we carried out a computational study of a ferritin using a large cluster model of well over 300 atoms including its first- and second-coordination sphere. The calculations reveal important insight into the structure and reactivity of ferritins. Specifically, the active site Tyr residue delivers a proton and electron in the catalytic cycle prior to iron(II) oxidation. In addition, the calculations highlight a likely cation binding site at Asp65, which through long-range electrostatic interactions, influences the electronic configuration and charge distributions of the metal center. The results are consistent with experimental observations but reveal novel detail of early mechanistic steps that lead to an unusual mixed-valent iron(III)-iron(II) center.
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Affiliation(s)
- Chieh-Chih George Yeh
- The University of Manchester, Department of Chemical Engineering, Oxford Road, Manchester, UNITED KINGDOM
| | - Thirakorn Mokkawes
- The University of Manchester, Department of Chemical Engineering, Manchester, UNITED KINGDOM
| | - Justin Bradley
- University of East Anglia, School of Chemistry, UNITED KINGDOM
| | - Nick E Le Brun
- University of East Anglia, School of Chemistry, UNITED KINGDOM
| | - Samuel de Visser
- The University of Manchester, Manchester Institute of Biotechnology, 131 Princess Street, M1 7DN, Manchester, UNITED KINGDOM
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12
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Zhao R, Zhang BB, Liu Z, Cheng GJ, Wang ZX. DFT Mechanistic Insights into Aldehyde Deformylations with Biomimetic Metal-Dioxygen Complexes: Distinct Mechanisms and Reaction Rules. JACS AU 2022; 2:745-761. [PMID: 35373207 PMCID: PMC8970012 DOI: 10.1021/jacsau.2c00014] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Indexed: 05/12/2023]
Abstract
Aldehyde deformylations occurring in organisms are catalyzed by metalloenzymes through metal-dioxygen active cores, attracting great interest to study small-molecule metal-dioxygen complexes for understanding relevant biological processes and developing biomimetic catalysts for aerobic transformations. As the known deformylation mechanisms, including nucleophilic attack, aldehyde α-H-atom abstraction, and aldehyde hydrogen atom abstraction, undergo outer-sphere pathways, we herein report a distinct inner-sphere mechanism based on density functional theory (DFT) mechanistic studies of aldehyde deformylations with a copper (II)-superoxo complex. The inner-sphere mechanism proceeds via a sequence mainly including aldehyde end-on coordination, homolytic aldehyde C-C bond cleavage, and dioxygen O-O bond cleavage, among which the C-C bond cleavage is the rate-determining step with a barrier substantially lower than those of outer-sphere pathways. The aldehyde C-C bond cleavage, enabled through the activation of the dioxygen ligand radical in a second-order nucleophilic substitution (SN2)-like fashion, leads to an alkyl radical and facilitates the subsequent dioxygen O-O bond cleavage. Furthermore, we deduced the rules for the reactions of metal-dioxygen complexes with aldehydes and nitriles via the inner-sphere mechanism. Expectedly, our proposed inner-sphere mechanisms and the reaction rules offer another perspective to understand relevant biological processes involving metal-dioxygen cores and to discover metal-dioxygen catalysts for aerobic transformations.
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Affiliation(s)
- Ruihua Zhao
- School
of Chemical Sciences, University of Chinese
Academy of Sciences, Beijing 100039, China
- Warshel
Institute for Computational Biology, School of Life and Health Sciences, The Chinese University of Hong Kong (Shenzhen), Shenzhen 518172, China
| | - Bei-Bei Zhang
- School
of Chemical Sciences, University of Chinese
Academy of Sciences, Beijing 100039, China
| | - Zheyuan Liu
- College
of Materials Science and Engineering, Fuzhou
University, Fuzhou 350108, China
| | - Gui-Juan Cheng
- Warshel
Institute for Computational Biology, School of Life and Health Sciences, The Chinese University of Hong Kong (Shenzhen), Shenzhen 518172, China
| | - Zhi-Xiang Wang
- School
of Chemical Sciences, University of Chinese
Academy of Sciences, Beijing 100039, China
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13
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Bagha UK, Satpathy JK, Mukherjee G, Barman P, Kumar D, de Visser SP, Sastri CV. Oxidative dehalogenation of halophenols by high-valent nonheme iron(IV)-oxo intermediates. Faraday Discuss 2022; 234:58-69. [PMID: 35170590 DOI: 10.1039/d1fd00064k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mononuclear high-valent iron(IV)-oxo intermediates are excellent oxidants towards oxygenation reactions by heme and nonheme metalloenzymes and their model systems. One of the most important functions of these intermediates in nature is to detoxify various environmental pollutants. Organic substrates, such as halogenated phenols, are known to be water pollutants which can be degraded to their less hazardous forms through an oxidation reaction by iron(IV)-oxo complexes. Metalloproteins in nature utilize various types of second-coordination sphere interactions to anchor the substrate in the vicinity of the active site. This concept of substrate-binding is well-known for natural enzymes, but is elusive for the relevant biomimetic model systems. Herein, we report the oxidative reactivity patterns of an iron(IV)-oxo intermediate, [FeIV(O)(2PyN2Q)]2+, (2PyN2Q = 1,1-di(pyridin-2yl)-N,N-bis(quinolin-2-ylmethyl)methanamine) with a series of mono-, di- and tri-halophenols. A detailed experimental study shows that the dehalogenation reactions of the halophenols by such iron(IV)-oxo intermediates proceed via an initial hydrogen atom abstraction from the phenolic O-H group. Furthermore, based on the size and nucleophilicity of the halophenol, an intermediate substrate-bound species forms that is a phenolate adduct to the ferric species, which thereafter leads to the formation of the corresponding products.
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Affiliation(s)
- Umesh Kumar Bagha
- Department of Chemistry, Indian Institute of Technology Guwahati, Assam, 781039, India.
| | | | - Gourab Mukherjee
- Department of Chemistry, Indian Institute of Technology Guwahati, Assam, 781039, India. .,Department of Chemical Science, Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai, 400005, India
| | - Prasenjit Barman
- Department of Chemistry, Indian Institute of Technology Guwahati, Assam, 781039, India. .,Department of Chemistry, Kaliyaganj College, West Bengal, 733129, India
| | - Devesh Kumar
- Department of Applied Physics, School for Physical Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow, 226025, India.
| | - Sam P de Visser
- Department of Chemistry, Indian Institute of Technology Guwahati, Assam, 781039, India. .,The Manchester Institute of Biotechnology, Department of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.
| | - Chivukula V Sastri
- Department of Chemistry, Indian Institute of Technology Guwahati, Assam, 781039, India.
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14
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Selaković Ž, Nikolić AM, Ajdačić V, Opsenica IM. Application of Transition Metal‐Catalyzed Decarbonylation of Aldehydes in the Total Synthesis of Natural Products. European J Org Chem 2022. [DOI: 10.1002/ejoc.202101265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Života Selaković
- Department of Organic Chemistry University of Belgrade – Faculty of Chemistry PO Box 51, Studentski trg 16 11158 Belgrade Serbia
| | - Andrea M. Nikolić
- Department of Organic Chemistry University of Belgrade – Faculty of Chemistry PO Box 51, Studentski trg 16 11158 Belgrade Serbia
| | - Vladimir Ajdačić
- Innovative Centre Faculty of Chemistry, Ltd. Studentski trg 12–16 11158 Belgrade Serbia
| | - Igor M. Opsenica
- Department of Organic Chemistry University of Belgrade – Faculty of Chemistry PO Box 51, Studentski trg 16 11158 Belgrade Serbia
- Department of Organic Chemistry University of Belgrade – Faculty of Chemistry PO Box 51, Studentski trg 16 11158 Belgrade Serbia
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15
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Palladium on carbon in PEG-400/Cyclohexane: Recoverable and recyclable catalytic system for efficient decarbonylation of aldehydes. JOURNAL OF THE SERBIAN CHEMICAL SOCIETY 2022. [DOI: 10.2298/jsc220128024t] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A simple methodology for the decarbonylation of aldehydes catalyzed by
commercially available palladium on carbon in a green two-solvent system is
reported. Various aromatic, aliphatic and heteroaromatic aldehydes were
transformed to the corresponding decarbonylated products in good yields.
Product isolation from the reaction mixture is operationally simple, and the
catalyst can be reused three times.
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16
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Oxidative Transformations of 3,4-Dihydroxyphenylacetaldehyde Generate Potential Reactive Intermediates as Causative Agents for Its Neurotoxicity. Int J Mol Sci 2021; 22:ijms222111751. [PMID: 34769179 PMCID: PMC8583873 DOI: 10.3390/ijms222111751] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/25/2021] [Accepted: 10/27/2021] [Indexed: 11/16/2022] Open
Abstract
Neurogenerative diseases, such as Parkinson’s disease, are associated, not only with the selective loss of dopamine (DA), but also with the accumulation of reactive catechol-aldehyde, 3,4-dihydroxyphenylacetaldehyde (DOPAL), which is formed as the immediate oxidation product of cytoplasmic DA by monoamine oxidase. DOPAL is well known to exhibit toxic effects on neuronal cells. Both catecholic and aldehyde groups seem to be associated with the neurotoxicity of DOPAL. However, the exact cause of toxicity caused by this compound remains unknown. Since the reactivity of DOPAL could be attributed to its immediate oxidation product, DOPAL-quinone, we examined the potential reactions of this toxic metabolite. The oxidation of DOPAL by mushroom tyrosinase at pH 5.3 produced conventional DOPAL-quinone, but oxidation at pH 7.4 produced the tautomeric quinone-methide, which gave rise to 3,4-dihydroxyphenylglycolaldehyde and 3,4-dihydroxybenzaldehyde as products through a series of reactions. When the oxidation reaction was performed in the presence of ascorbic acid, two additional products were detected, which were tentatively identified as the cyclized products, 5,6-dihydroxybenzofuran and 3,5,6-trihydroxybenzofuran. Physiological concentrations of Cu(II) ions could also cause the oxidation of DOPAL to DOPAL-quinone. DOPAL-quinone exhibited reactivity towards the cysteine residues of serum albumin. DOPAL-oligomer, the oxidation product of DOPAL, exhibited pro-oxidant activity oxidizing GSH to GSSG and producing hydrogen peroxide. These results indicate that DOPAL-quinone generates several toxic compounds that could augment the neurotoxicity of DOPAL.
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17
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Lerch M, Achazi AJ, Mollenhauer D, Becker J, Schindler S. A Mechanistic Study on the Reaction of Non‐Heme Diiron(III)‐Peroxido Complexes with Benzoyl Chloride. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Markus Lerch
- Institute of Inorganic and Analytical Chemistry Justus-Liebig-Universität Gießen Heinrich-Buff-Ring 17 35392 Gießen Germany
| | - Andreas J. Achazi
- Institute of Physical Chemistry Justus-Liebig-Universität Gießen Heinrich-Buff-Ring 17 35392 Gießen Germany
| | - Doreen Mollenhauer
- Institute of Physical Chemistry Justus-Liebig-Universität Gießen Heinrich-Buff-Ring 17 35392 Gießen Germany
| | - Jonathan Becker
- Institute of Inorganic and Analytical Chemistry Justus-Liebig-Universität Gießen Heinrich-Buff-Ring 17 35392 Gießen Germany
| | - Siegfried Schindler
- Institute of Inorganic and Analytical Chemistry Justus-Liebig-Universität Gießen Heinrich-Buff-Ring 17 35392 Gießen Germany
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18
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Dobah F, Mazodze CM, Petersen WF. Cross-Dehydrogenative Cyclization-Dimerization Cascade Sequence for the Synthesis of Symmetrical 3,3'-Bisoxindoles. Org Lett 2021; 23:5466-5470. [PMID: 34232674 DOI: 10.1021/acs.orglett.1c01799] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The synthesis of symmetrical 3,3'-bisoxindoles from simple acyclic β-oxoanilides is reported. The described method forges three new C-C bonds in a single step via a sequential Mn(OAc)3·2H2O mediated oxidative radical cyclization-fragmentation-dimerization process. The scope of this reaction is demonstrated in the preparation of a variety of 3,3'-bisoxindoles, as well as its application toward the formal synthesis of the Calycanthaceae alkaloid, (±)-folicanthine.
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Affiliation(s)
- Farhaan Dobah
- Department of Chemistry, University of Cape Town, Rondebosch, Cape Town, 7700, South Africa
| | - C Munashe Mazodze
- Department of Chemistry, University of Cape Town, Rondebosch, Cape Town, 7700, South Africa
| | - Wade F Petersen
- Department of Chemistry, University of Cape Town, Rondebosch, Cape Town, 7700, South Africa
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Roach S, Faponle AS, Satpathy JK, Sastri CV, de Visser SP. Substrate sulfoxidation by a biomimetic cytochrome P450 Compound I mimic: How do porphyrin and phthalocyanine equatorial ligands compare? J CHEM SCI 2021. [DOI: 10.1007/s12039-021-01917-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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