1
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Sarker RK, Zargarian D. Reactions of cyclonickelated complexes with hydroxylamines and TEMPO˙: isolation of new TEMPOH adducts of Ni(II) and their reactivities with nucleophiles and oxidants. Dalton Trans 2024; 53:10208-10219. [PMID: 38826045 DOI: 10.1039/d4dt00605d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
This contribution describes a study on the reactivities of the complexes [{κP,κC-(i-Pr)2PO-Ar}Ni(μ-Br)]2, 1a-d (Ar: C6H4, a; 3-Cl-C6H3, b; 3-OMe-C6H3, c; 4-OMe-napthalenyl, d), with hydroxylamines in the presence of TEMPO˙ (TEMPO˙ = (2,2,6,6-tetramethylpiperidinyl-1-yl)oxyl). The results of this study showed that treating 1a-d with a mixture of Et2NOH and TEMPO˙ did not afford the desired oxidation-induced functionalization of the Ni-aryl moiety in 1a-d, giving instead the corresponding κO-TEMPOH adducts [{κP,κC-(i-Pr)2PO-Ar}Ni(Br)(κO-TEMPOH)], 3a-d (TEMPOH = N-hydroxy-2,2,6,6-tetramethylpiperidine). The TEMPOH moiety in these zwitterionic compounds 3 can be displaced by a large excess of acetonitrile (MeCN), 10 equiv. of morpholine, or 1-2 equivalents of imidazole. Although these reactions have given the authenticated products [{κP,κC-(i-Pr)2PO-C6H4}Ni(Br)(NCMe)], 4a, [{κP,κC-(i-Pr)2PO-C6H4}Ni(Br)(morpholine)], 5a, and [{κP,κC-(i-Pr)2PO-C6H4}Ni(imidazole)2]Br, 6a, a few other products were also detected by NMR, indicating that the observed reactivities are far more complex than simple substitution of the TEMPOH moiety. Similarly, treating 3a with AgOC(O)CF3 results in the isolation of [{κP,κC-(i-Pr)2PO-C6H4}Ni{OC(O)CF3}(κO-TEMPOH)], 7a, arising from the substitution of the bromo ligand, whereas spectroscopic evidence suggests further reactivity, possibly including displacement of TEMPOH and oxidative decomposition.
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Affiliation(s)
- Rajib K Sarker
- Département de Chimie, Université de Montréal, Montréal, Québec, H3C 3J7, Canada.
| | - Davit Zargarian
- Département de Chimie, Université de Montréal, Montréal, Québec, H3C 3J7, Canada.
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2
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Bols ML, Ma J, Rammal F, Plessers D, Wu X, Navarro-Jaén S, Heyer AJ, Sels BF, Solomon EI, Schoonheydt RA. In Situ UV-Vis-NIR Absorption Spectroscopy and Catalysis. Chem Rev 2024; 124:2352-2418. [PMID: 38408190 DOI: 10.1021/acs.chemrev.3c00602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
This review highlights in situ UV-vis-NIR range absorption spectroscopy in catalysis. A variety of experimental techniques identifying reaction mechanisms, kinetics, and structural properties are discussed. Stopped flow techniques, use of laser pulses, and use of experimental perturbations are demonstrated for in situ studies of enzymatic, homogeneous, heterogeneous, and photocatalysis. They access different time scales and are applicable to different reaction systems and catalyst types. In photocatalysis, femto- and nanosecond resolved measurements through transient absorption are discussed for tracking excited states. UV-vis-NIR absorption spectroscopies for structural characterization are demonstrated especially for Cu and Fe exchanged zeolites and metalloenzymes. This requires combining different spectroscopies. Combining magnetic circular dichroism and resonance Raman spectroscopy is especially powerful. A multitude of phenomena can be tracked on transition metal catalysts on various supports, including changes in oxidation state, adsorptions, reactions, support interactions, surface plasmon resonances, and band gaps. Measurements of oxidation states, oxygen vacancies, and band gaps are shown on heterogeneous catalysts, especially for electrocatalysis. UV-vis-NIR absorption is burdened by broad absorption bands. Advanced analysis techniques enable the tracking of coking reactions on acid zeolites despite convoluted spectra. The value of UV-vis-NIR absorption spectroscopy to catalyst characterization and mechanistic investigation is clear but could be expanded.
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Affiliation(s)
- Max L Bols
- Laboratory for Chemical Technology (LCT), University of Ghent, Technologiepark Zwijnaarde 125, 9052 Ghent, Belgium
| | - Jing Ma
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Fatima Rammal
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Dieter Plessers
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Xuejiao Wu
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Sara Navarro-Jaén
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Alexander J Heyer
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Bert F Sels
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Edward I Solomon
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Robert A Schoonheydt
- Department of Microbial and Molecular Systems, Center for Sustainable Catalysis and Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
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3
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Lesnikov VK, Golovanov IS, Nelyubina YV, Aksenova SA, Sukhorukov AY. Crown-hydroxylamines are pH-dependent chelating N,O-ligands with a potential for aerobic oxidation catalysis. Nat Commun 2023; 14:7673. [PMID: 37996433 PMCID: PMC10667252 DOI: 10.1038/s41467-023-43530-6] [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: 07/06/2023] [Accepted: 11/13/2023] [Indexed: 11/25/2023] Open
Abstract
Despite the rich coordination chemistry, hydroxylamines are rarely used as ligands for transition metal coordination compounds. This is partially because of the instability of these complexes that undergo decomposition, disproportionation and oxidation processes involving the hydroxylamine motif. Here, we design macrocyclic poly-N-hydroxylamines (crown-hydroxylamines) that form complexes containing a d-metal ion (Cu(II), Ni(II), Mn(II), and Zn(II)) coordinated by multiple (up to six) hydroxylamine fragments. The stability of these complexes is likely to be due to a macrocycle effect and strong intramolecular H-bonding interactions between the N-OH groups. Crown-hydroxylamine complexes exhibit interesting pH-dependent behavior where the efficiency of metal binding increases upon deprotonation of the hydroxylamine groups. Copper complexes exhibit catalytic activity in aerobic oxidation reactions under ambient conditions, whereas the corresponding complexes with macrocyclic polyamines show poor or no activity. Our results show that crown-hydroxylamines display anomalous structural features and chemical behavior with respect to both organic hydroxylamines and polyaza-crowns.
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Affiliation(s)
- Vladislav K Lesnikov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991, Leninsky prospect, 47, Moscow, Russian Federation
| | - Ivan S Golovanov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991, Leninsky prospect, 47, Moscow, Russian Federation
| | - Yulia V Nelyubina
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 119991, Vavilova str. 28, Moscow, Russian Federation
- Moscow Institute of Physics and Technology (National Research University), 141700, Institutskiy per. 9, Dolgoprudny, Moscow Region, Russian Federation
| | - Svetlana A Aksenova
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 119991, Vavilova str. 28, Moscow, Russian Federation
- Moscow Institute of Physics and Technology (National Research University), 141700, Institutskiy per. 9, Dolgoprudny, Moscow Region, Russian Federation
| | - Alexey Yu Sukhorukov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991, Leninsky prospect, 47, Moscow, Russian Federation.
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4
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Zhao J, Zhuo Y, Diaz DE, Shanmugam M, Telfer AJ, Lindley PJ, Kracher D, Hayashi T, Seibt LS, Hardy FJ, Manners O, Hedison TM, Hollywood KA, Spiess R, Cain KM, Diaz-Moreno S, Scrutton NS, Tovborg M, Walton PH, Heyes DJ, Green AP. Mapping the Initial Stages of a Protective Pathway that Enhances Catalytic Turnover by a Lytic Polysaccharide Monooxygenase. J Am Chem Soc 2023; 145:20672-20682. [PMID: 37688545 PMCID: PMC10515631 DOI: 10.1021/jacs.3c06607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Indexed: 09/11/2023]
Abstract
Oxygenase and peroxygenase enzymes generate intermediates at their active sites which bring about the controlled functionalization of inert C-H bonds in substrates, such as in the enzymatic conversion of methane to methanol. To be viable catalysts, however, these enzymes must also prevent oxidative damage to essential active site residues, which can occur during both coupled and uncoupled turnover. Herein, we use a combination of stopped-flow spectroscopy, targeted mutagenesis, TD-DFT calculations, high-energy resolution fluorescence detection X-ray absorption spectroscopy, and electron paramagnetic resonance spectroscopy to study two transient intermediates that together form a protective pathway built into the active sites of copper-dependent lytic polysaccharide monooxygenases (LPMOs). First, a transient high-valent species is generated at the copper histidine brace active site following treatment of the LPMO with either hydrogen peroxide or peroxyacids in the absence of substrate. This intermediate, which we propose to be a CuII-(histidyl radical), then reacts with a nearby tyrosine residue in an intersystem-crossing reaction to give a ferromagnetically coupled (S = 1) CuII-tyrosyl radical pair, thereby restoring the histidine brace active site to its resting state and allowing it to re-enter the catalytic cycle through reduction. This process gives the enzyme the capacity to minimize damage to the active site histidine residues "on the fly" to increase the total turnover number prior to enzyme deactivation, highlighting how oxidative enzymes are evolved to protect themselves from deleterious side reactions during uncoupled turnover.
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Affiliation(s)
- Jingming Zhao
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Ying Zhuo
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Daniel E. Diaz
- Department
of Chemistry, University of York, Heslington, York YO10 5DD, U.K.
| | - Muralidharan Shanmugam
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Abbey J. Telfer
- Department
of Chemistry, University of York, Heslington, York YO10 5DD, U.K.
- Harwell
Science and Innovation Campus, Diamond Light
Source Ltd., Didcot, Oxfordshire OX11 0DE, U.K.
| | - Peter J. Lindley
- Department
of Chemistry, University of York, Heslington, York YO10 5DD, U.K.
| | - Daniel Kracher
- Institute
of Molecular Biotechnology, Graz University
of Technology, Petersgasse
14, Graz 8010, Austria
| | - Takahiro Hayashi
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Lisa S. Seibt
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Florence J. Hardy
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Oliver Manners
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Tobias M. Hedison
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Katherine A. Hollywood
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Reynard Spiess
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Kathleen M. Cain
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Sofia Diaz-Moreno
- Harwell
Science and Innovation Campus, Diamond Light
Source Ltd., Didcot, Oxfordshire OX11 0DE, U.K.
| | - Nigel S. Scrutton
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | | | - Paul H. Walton
- Department
of Chemistry, University of York, Heslington, York YO10 5DD, U.K.
| | - Derren J. Heyes
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Anthony P. Green
- Manchester
Institute of Biotechnology, The University
of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
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5
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Abstract
Nitroxides, also known as nitroxyl radicals, are long-lived or stable radicals with the general structure R1R2N-O•. The spin distribution over the nitroxide N and O atoms contributes to the thermodynamic stability of these radicals. The presence of bulky N-substituents R1 and R2 prevents nitroxide radical dimerization, ensuring their kinetic stability. Despite their reactivity toward various transient C radicals, some nitroxides can be easily stored under air at room temperature. Furthermore, nitroxides can be oxidized to oxoammonium salts (R1R2N═O+) or reduced to anions (R1R2N-O-), enabling them to act as valuable oxidants or reductants depending on their oxidation state. Therefore, they exhibit interesting reactivity across all three oxidation states. Due to these fascinating properties, nitroxides find extensive applications in diverse fields such as biochemistry, medicinal chemistry, materials science, and organic synthesis. This review focuses on the versatile applications of nitroxides in organic synthesis. For their use in other important fields, we will refer to several review articles. The introductory part provides a brief overview of the history of nitroxide chemistry. Subsequently, the key methods for preparing nitroxides are discussed, followed by an examination of their structural diversity and physical properties. The main portion of this review is dedicated to oxidation reactions, wherein parent nitroxides or their corresponding oxoammonium salts serve as active species. It will be demonstrated that various functional groups (such as alcohols, amines, enolates, and alkanes among others) can be efficiently oxidized. These oxidations can be carried out using nitroxides as catalysts in combination with various stoichiometric terminal oxidants. By reducing nitroxides to their corresponding anions, they become effective reducing reagents with intriguing applications in organic synthesis. Nitroxides possess the ability to selectively react with transient radicals, making them useful for terminating radical cascade reactions by forming alkoxyamines. Depending on their structure, alkoxyamines exhibit weak C-O bonds, allowing for the thermal generation of C radicals through reversible C-O bond cleavage. Such thermally generated C radicals can participate in various radical transformations, as discussed toward the end of this review. Furthermore, the application of this strategy in natural product synthesis will be presented.
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Affiliation(s)
- Dirk Leifert
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
| | - Armido Studer
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
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6
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Mehara J, Roithová J. Copper(II)‐TEMPO Interaction. Isr J Chem 2023. [DOI: 10.1002/ijch.202300011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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7
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Copper Pyrithione (CuPT)-Catalyzed Oxidation of Secondary and Primary Benzyl Alcohols with Molecular oxygen or Air Under Mild Conditions. Catal Letters 2022. [DOI: 10.1007/s10562-022-04172-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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8
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Kayser AK, Wolczanski PT, Cundari TR, Bollmeyer MM, Lancaster KM, MacMillan SN. TEMPO coordination and reactivity in group 6; pseudo-pentagonal planar (η 2-TEMPO) 2CrX (X = Cl, TEMPO). Chem Commun (Camb) 2022; 58:9818-9821. [PMID: 35975596 DOI: 10.1039/d2cc03838b] [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
The exposure of CrCl2(THF)2 to 1 equiv. of TEMPO and 1 equiv. [TEMPO]Na afforded (η2-O,N-TEMPO)2CrCl (1, 67%); addition of [TEMPO]Na to 1 yielded (η2-O,N-TEMPO)2Cr(TEMPO) (2). Both 1 and 2 exhibit pseudo-pentagonal planar (PPP) geometry, instead of myriad alternatives. Calculations and spectral studies suggest the solid-state geometry persists in solution.
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Affiliation(s)
- Ann K Kayser
- Dept. of Chemistry and Chemical Biology Baker Laboratory, Cornell University, Ithaca, NY, 14853, USA.
| | - Peter T Wolczanski
- Dept. of Chemistry and Chemical Biology Baker Laboratory, Cornell University, Ithaca, NY, 14853, USA.
| | - Thomas R Cundari
- Dept. of Chemistry, CasCam, University of North Texas, Denton, TX, 76201, USA
| | - Melissa M Bollmeyer
- Dept. of Chemistry and Chemical Biology Baker Laboratory, Cornell University, Ithaca, NY, 14853, USA.
| | - Kyle M Lancaster
- Dept. of Chemistry and Chemical Biology Baker Laboratory, Cornell University, Ithaca, NY, 14853, USA.
| | - Samantha N MacMillan
- Dept. of Chemistry and Chemical Biology Baker Laboratory, Cornell University, Ithaca, NY, 14853, USA.
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9
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Shaum JB, Nikolaev A, Steffens HC, Gonzalez L, Walker S, Samoshin AV, Hammersley G, La EH, Read de Alaniz J. Copper-Mediated Single-Electron Approach to Indoline Amination: Scope, Mechanism, and Total Synthesis of Asperazine A. J Org Chem 2022; 87:9907-9914. [PMID: 35876810 DOI: 10.1021/acs.joc.2c00923] [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
Pyrroloindolines bearing a C3-N linkage comprise the core of many biologically active natural products, but many methods toward their synthesis are limited by the sterics or electronics of the product. We report a single electron-based approach for the synthesis of this scaffold and demonstrate high-yielding aminations, regardless of electronic or steric demands. The transformation uses copper wire and isopropanol to promote the reaction. The broad synthetic utility of this heterogeneous copper-catalyzed approach to access pyrroloindolines, diketopiperazine, furoindoline, and (+)-asperazine is included, along with experiments to provide insight into the mechanism of this new process.
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Affiliation(s)
- James B Shaum
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Andrei Nikolaev
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Helena C Steffens
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Luis Gonzalez
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Shamon Walker
- Materials Department and Materials Research Laboratory, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Andrey V Samoshin
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Gabrielle Hammersley
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Ellia H La
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
| | - Javier Read de Alaniz
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106, United States
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10
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Jia X, He J. Three copper (II) complexes derived from 2‐methylquinoline and cyclic secondary amines: Synthesis and catalytic application in C‐N bond forming reactions. Appl Organomet Chem 2022. [DOI: 10.1002/aoc.6743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Xuefeng Jia
- Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, School of Chemical and Material Science Shanxi Normal University Taiyuan Shanxi China
| | - Jieting He
- Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, School of Chemical and Material Science Shanxi Normal University Taiyuan Shanxi China
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11
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Theoretical perspective on mononuclear copper-oxygen mediated C–H and O–H activations: A comparison between biological and synthetic systems. CHINESE JOURNAL OF CATALYSIS 2022. [DOI: 10.1016/s1872-2067(21)63974-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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12
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Sasaki Y, Yokoo K, Mori K. Catalytic Magnesium-Oppenauer Oxidation of Alcohols. CHEM LETT 2022. [DOI: 10.1246/cl.220022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Yuta Sasaki
- Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588
| | - Kazuma Yokoo
- Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588
| | - Keiji Mori
- Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588
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13
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Wolff N, Rivada‐Wheelaghan O, Tocqueville D. Molecular Electrocatalytic Hydrogenation of Carbonyls and Dehydrogenation of Alcohols. ChemElectroChem 2021. [DOI: 10.1002/celc.202100617] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Niklas Wolff
- Laboratoire d'Électrochimie Moléculaire Université de Paris, CNRS F-75006 Paris France
| | | | - Damien Tocqueville
- Laboratoire d'Électrochimie Moléculaire Université de Paris, CNRS F-75006 Paris France
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14
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Nutting JE, Mao K, Stahl SS. Iron(III) Nitrate/TEMPO-Catalyzed Aerobic Alcohol Oxidation: Distinguishing between Serial versus Integrated Redox Cooperativity. J Am Chem Soc 2021; 143:10565-10570. [PMID: 34232661 DOI: 10.1021/jacs.1c05224] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Aerobic alcohol oxidations catalyzed by transition metal salts and aminoxyls are prominent examples of cooperative catalysis. Cu/aminoxyl catalysts have been studied previously and feature "integrated cooperativity", in which CuII and the aminoxyl participate together to mediate alcohol oxidation. Here we investigate a complementary Fe/aminoxyl catalyst system and provide evidence for "serial cooperativity", involving a redox cascade wherein the alcohol is oxidized by an in situ-generated oxoammonium species, which is directly detected in the catalytic reaction mixture by cyclic step chronoamperometry. The mechanistic difference between the Cu- and Fe-based catalysts arises from the use iron(III) nitrate, which initiates a NOx-based redox cycle for oxidation of aminoxyl/hydroxylamine to oxoammonium. The different mechanisms for the Cu- and Fe-based catalyst systems are manifested in different alcohol oxidation chemoselectivity and functional group compatibility.
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Affiliation(s)
- Jordan E Nutting
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Kaining Mao
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Shannon S Stahl
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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15
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Golovanov IS, Malykhin RS, Lesnikov VK, Nelyubina YV, Novikov VV, Frolov KV, Stadnichenko AI, Tretyakov EV, Ioffe SL, Sukhorukov AY. Revealing the Structure of Transition Metal Complexes of Formaldoxime. Inorg Chem 2021; 60:5523-5537. [PMID: 33826845 DOI: 10.1021/acs.inorgchem.0c03362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Aerobic reactions of iron(III), nickel(II), and manganese(II) chlorides with formaldoxime cyclotrimer (tfoH3) and 1,4,7-triazacyclononane (tacn) produce indefinitely stable complexes of general formula [M(tacn)(tfo)]Cl. Although the formation of formaldoxime complexes has been known since the end of 19th century and applied in spectrophotometric determination of d-metals (formaldoxime method), the structure of these coordination compounds remained elusive until now. According to the X-ray analysis, [M(tacn)(tfo)]+ cation has a distorted adamantane-like structure with the metal ion being coordinated by three oxygen atoms of deprotonated tfoH3 ligand. The metal has a formal +4 oxidation state, which is atypical for organic complexes of iron and nickel. Electronic structure of [M(tacn)(tfo)]+ cations was studied by XPS, NMR, cyclic (CV) and differential pulse (DPV) voltammetries, Mössbauer spectroscopy, and DFT calculations. Unusual stabilization of high-valent metal ion by tfo3- ligand was explained by the donation of electron density from the nitrogen atom to the antibonding orbital of the metal-oxygen bond via hyperconjugation as confirmed by the NBO analysis. All complexes [M(tacn)(tfo)]Cl exhibited high catalytic activity in the aerobic dehydrogenative dimerization of p-thiocresol under ambient conditions.
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Affiliation(s)
- Ivan S Golovanov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospect, 47, Moscow, Russia, 119991
| | - Roman S Malykhin
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospect, 47, Moscow, Russia, 119991
| | - Vladislav K Lesnikov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospect, 47, Moscow, Russia, 119991
| | - Yulia V Nelyubina
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov str. 28, Moscow, Russia, 119991
| | - Valentin V Novikov
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov str. 28, Moscow, Russia, 119991
| | - Kirill V Frolov
- Shubnikov Institute of Crystallography of FSRC "Crystallography and Photonics," Russian Academy of Sciences, Leninsky prospect, 59, Moscow, Russia, 119991
| | - Andrey I Stadnichenko
- Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, 5 Ac. Lavrentiev Avenue, Novosibirsk, Russia, 630090
| | - Evgeny V Tretyakov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospect, 47, Moscow, Russia, 119991
| | - Sema L Ioffe
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospect, 47, Moscow, Russia, 119991
| | - Alexey Yu Sukhorukov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospect, 47, Moscow, Russia, 119991.,Plekhanov Russian University of Economics, Stremyanny per. 36, Moscow, Russia, 117997
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16
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Zsombor-Pindera J, Effaty F, Escomel L, Patrick B, Kennepohl P, Ottenwaelder X. Five Nitrogen Oxidation States from Nitro to Amine: Stabilization and Reactivity of a Metastable Arylhydroxylamine Complex. J Am Chem Soc 2020; 142:19023-19028. [PMID: 33124796 DOI: 10.1021/jacs.0c09300] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Redox noninnocent ligands enhance the reactivity of the metal they complex, a strategy used by metalloenzymes and in catalysis. Herein, we report a series of copper complexes with the same ligand framework, but with a pendant nitrogen group that spans five different redox states between nitro and amine. Of particular interest is the synthesis of a unprecedented copper(I)-arylhydroxylamine complex. While hydroxylamines typically disproportionate or decompose in the presence of transition metal ions, the reactivity of this metastable species is arrested by the presence of an intramolecular hydrogen bond. Two-electron oxidation yields a copper(II)-(arylnitrosyl radical) complex that can dissociate to a copper(I) species with uncoordinated arylnitroso. This combination of ligand redox noninnocence and hemilability provides opportunities in catalysis for two-electron chemistry via a one-electron copper(I/II) shuttle, as exemplified with an aerobic alcohol oxidation.
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Affiliation(s)
- Joseph Zsombor-Pindera
- Department of Chemistry and Biochemistry, Concordia University, Montreal, QC H4B 1R6, Canada.,Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Farshid Effaty
- Department of Chemistry and Biochemistry, Concordia University, Montreal, QC H4B 1R6, Canada
| | - Léon Escomel
- Department of Chemistry and Biochemistry, Concordia University, Montreal, QC H4B 1R6, Canada
| | - Brian Patrick
- Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Pierre Kennepohl
- Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Xavier Ottenwaelder
- Department of Chemistry and Biochemistry, Concordia University, Montreal, QC H4B 1R6, Canada
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17
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Zhu L, Li J, Yang J, Au-Yeung HY. Cross dehydrogenative C-O coupling catalysed by a catenane-coordinated copper(i). Chem Sci 2020; 11:13008-13014. [PMID: 34094485 PMCID: PMC8163234 DOI: 10.1039/d0sc05133k] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Catalytic activity of copper(i) complexes supported by phenanthroline-containing catenane ligands towards a new C(sp3)–O dehydrogenative cross-coupling of phenols and bromodicarbonyls is reported. As the phenanthrolines are interlocked by the strong and flexible mechanical bond in the catenane, the active catalyst with an open copper coordination site can be revealed only transiently and the stable, coordinatively saturated Cu(i) pre-catalyst is quickly regenerated after substrate transformation. Compared with a control Cu(i) complex supported by non-interlocked phenanthrolines, the catenane-supported Cu(i) is highly efficient with a broad substrate scope, and can be applied in gram-scale transformations without a significant loss of the catalytic activity. This work demonstrates the advantages of the catenane ligands that provide a dynamic and responsive copper coordination sphere, highlighting the potential of the mechanical bond as a design element in transition metal catalyst development. The use of a catenane-supported copper(i) complex for the cross dehydrogenative C–O coupling of phenols and bromodicarbonyls is described.![]()
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Affiliation(s)
- Lihui Zhu
- Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong P. R. China
| | - Jiasheng Li
- Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong P. R. China
| | - Jun Yang
- Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong P. R. China
| | - Ho Yu Au-Yeung
- Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong P. R. China .,State Key Laboratory of Synthetic Chemistry, The University of Hong Kong Pokfulam Road Hong Kong P. R. China
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18
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DiMucci IM, MacMillan SN, Walroth RC, Lancaster KM. Scrutinizing "Ligand Bands" via Polarized Single-Crystal X-ray Absorption Spectra of Copper(I) and Copper(II) Bis-2,2'-bipyridine Species. Inorg Chem 2020; 59:13416-13426. [PMID: 32871080 DOI: 10.1021/acs.inorgchem.0c01800] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
High-energy resolution fluorescence-detected Cu K-edge X-ray absorption spectroscopy (XAS) and single-crystal polarized XAS data are presented toward refining the assignments of bands assigned as excitations from Cu 1s to ligand-localized molecular orbitals. These have been previously dubbed "XAS-metal-ligand charge transfer" (XAS-MLCT) bands. Data are presented for a series of [Cu(xbpy)2]n+ complexes (xbpy = 2,2'-bipyridine (1n+), 4,4'-bisamino-2,2'-bipyridine (2n+), and 4,4'-dimethoxy-2,2'-bipyridine (3n+); n = 1 and 2). Dipolar dependencies of these "XAS-MLCT" bands in both Cu1+ and Cu2+ species lead to reassignment of these features as owing their intensities primarily to Cu 1s → Cu 4p excitations. The transition densities are Cu-localized, highlighting that XAS-MLCT features in Cu XAS spectra are not "charge transfer" transitions but rather quasi-atomic transitions. Although scrutiny of the acceptor orbitals supports assignment as Cu 1s → ligand π* transitions, it ultimately appears that while the ligand orbital energetics govern the positions of these bands the intensity is conferred through a small degree of metal 4p mixing into otherwise ligand-dominated acceptor molecular orbitals.
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Affiliation(s)
- Ida M DiMucci
- Cornell Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Samantha N MacMillan
- Cornell Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Richard C Walroth
- Stanford Synchrotron Radiation Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Kyle M Lancaster
- Cornell Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
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19
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Wu T, MacMillan SN, Rajabimoghadam K, Siegler MA, Lancaster KM, Garcia-Bosch I. Structure, Spectroscopy, and Reactivity of a Mononuclear Copper Hydroxide Complex in Three Molecular Oxidation States. J Am Chem Soc 2020; 142:12265-12276. [PMID: 32531159 DOI: 10.1021/jacs.0c03867] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Structural, spectroscopic, and reactivity studies are presented for an electron transfer series of copper hydroxide complexes supported by a tridentate redox-active ligand. Single crystal X-ray crystallography shows that the mononuclear [CuOH]1+ core is stabilized via intramolecular H-bonds between the H-donors of the ligand and the hydroxide anion when the ligand is in its trianionic form. This complex undergoes two reversible oxidation processes that produce two metastable "high-valent" CuOH species, which can be generated by addition of stoichiometric amounts of 1e- oxidants. These CuOH species are characterized by an array of spectroscopic techniques including UV-vis absorption, electron paramagnetic resonance (EPR), and X-ray absorption spectroscopies (XAS), which together indicate that all redox couples are ligand-localized. The reactivity of the complexes in their higher oxidation states toward substrates with modest O-H bond dissociation energies (e.g., 4-substitued-2,6-di-tert-butylphenols) indicates that these complexes act as 2H+/2e- oxidants, differing from the 1H+/1e- reactivity of well-studied [CuOH]2+ systems.
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Affiliation(s)
- Tong Wu
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States
| | - Samantha N MacMillan
- Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14853, United States
| | | | - Maxime A Siegler
- Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Kyle M Lancaster
- Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14853, United States
| | - Isaac Garcia-Bosch
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States
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20
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Rabeah J, Briois V, Adomeit S, La Fontaine C, Bentrup U, Brückner A. Multivariate Analysis of Coupled Operando EPR/XANES/EXAFS/UV-Vis/ATR-IR Spectroscopy: A New Dimension for Mechanistic Studies of Catalytic Gas-Liquid Phase Reactions. Chemistry 2020; 26:7395-7404. [PMID: 32118340 PMCID: PMC7317854 DOI: 10.1002/chem.202000436] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Indexed: 01/12/2023]
Abstract
Operando EPR, XANES/EXAFS, UV‐Vis and ATR‐IR spectroscopic methods have been coupled for the first time in the same experimental setup for investigation of unclear mechanistic aspects of selective aerobic oxidation of benzyl alcohol by a Cu/TEMPO catalytic system (TEMPO=2,2,6,6‐tetramethylpiperidinyloxyl). By multivariate curve resolution with alternating least‐squares fitting (MCR‐ALS) of simultaneously recorded XAS and UV‐Vis data sets, it was found that an initially formed (bpy)(NMI)CuI‐ complex (bpy=2,2′‐bipyridine, NMI=N‐methylimidazole ) is converted to two different CuII species, a mononuclear (bpy)(NMI)(CH3CN)CuII‐OOH species detectable by EPR and ESI‐MS, and an EPR‐silent dinuclear (CH3CN)(bpy)(NMI)CuII(μ‐OH)2⋅CuII (bpy)(NMI) complex. The latter is cleaved in the further course of reaction into (bpy)(NMI)(HOO)CuII‐TEMPO monomers that are also EPR‐silent due to dipolar interaction with bound TEMPO. Both Cu monomers and the Cu dimer are catalytically active in the initial phase of the reaction, yet the dimer is definitely not a major active species nor a resting state since it is irreversibly cleaved in the course of the reaction while catalytic activity is maintained. Gradual formation of non‐reducible CuII leads to slight deactivation at extended reaction times.
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Affiliation(s)
- Jabor Rabeah
- Leibniz-Institut für Katalyse an der Universität Rostock, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
| | - Valérie Briois
- Synchrotron SOLEIL, L'Orme des Merisiers, BP48, Saint-Aubin, 91192 Gif-sur Yvette, France
| | - Sven Adomeit
- Leibniz-Institut für Katalyse an der Universität Rostock, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
| | - Camille La Fontaine
- Synchrotron SOLEIL, L'Orme des Merisiers, BP48, Saint-Aubin, 91192 Gif-sur Yvette, France
| | - Ursula Bentrup
- Leibniz-Institut für Katalyse an der Universität Rostock, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
| | - Angelika Brückner
- Leibniz-Institut für Katalyse an der Universität Rostock, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
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21
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Das A, Ren Y, Hessin C, Desage-El Murr M. Copper catalysis with redox-active ligands. Beilstein J Org Chem 2020; 16:858-870. [PMID: 32461767 PMCID: PMC7214867 DOI: 10.3762/bjoc.16.77] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 04/08/2020] [Indexed: 01/15/2023] Open
Abstract
Copper catalysis finds applications in various synthetic fields by utilizing the ability of copper to sustain mono- and bielectronic elementary steps. Further to the development of well-defined copper complexes with classical ligands such as phosphines and N-heterocyclic carbenes, a new and fast-expanding area of research is exploring the possibility of a complementing metal-centered reactivity with electronic participation by the coordination sphere. To achieve this electronic flexibility, redox-active ligands can be used to engage in a fruitful “electronic dialogue” with the metal center, and provide additional venues for electron transfer. This review aims to present the latest results in the area of copper-based cooperative catalysis with redox-active ligands.
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Affiliation(s)
- Agnideep Das
- Université de Strasbourg, Institut de Chimie, UMR CNRS 7177, 67000 Strasbourg, France
| | - Yufeng Ren
- Sorbonne Université, Institut Parisien de Chimie Moléculaire, UMR CNRS 8232, 75005 Paris, France
| | - Cheriehan Hessin
- Université de Strasbourg, Institut de Chimie, UMR CNRS 7177, 67000 Strasbourg, France
| | - Marine Desage-El Murr
- Université de Strasbourg, Institut de Chimie, UMR CNRS 7177, 67000 Strasbourg, France
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22
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Carsch KM, DiMucci IM, Iovan DA, Li A, Zheng SL, Titus CJ, Lee SJ, Irwin KD, Nordlund D, Lancaster KM, Betley TA. Synthesis of a copper-supported triplet nitrene complex pertinent to copper-catalyzed amination. Science 2020; 365:1138-1143. [PMID: 31515388 DOI: 10.1126/science.aax4423] [Citation(s) in RCA: 96] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 05/29/2019] [Accepted: 08/13/2019] [Indexed: 01/17/2023]
Abstract
Terminal copper-nitrenoid complexes have inspired interest in their fundamental bonding structures as well as their putative intermediacy in catalytic nitrene-transfer reactions. Here, we report that aryl azides react with a copper(I) dinitrogen complex bearing a sterically encumbered dipyrrin ligand to produce terminal copper nitrene complexes with near-linear, short copper-nitrenoid bonds [1.745(2) to 1.759(2) angstroms]. X-ray absorption spectroscopy and quantum chemistry calculations reveal a predominantly triplet nitrene adduct bound to copper(I), as opposed to copper(II) or copper(III) assignments, indicating the absence of a copper-nitrogen multiple-bond character. Employing electron-deficient aryl azides renders the copper nitrene species competent for alkane amination and alkene aziridination, lending further credence to the intermediacy of this species in proposed nitrene-transfer mechanisms.
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Affiliation(s)
- Kurtis M Carsch
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Ida M DiMucci
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Diana A Iovan
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Alex Li
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Shao-Liang Zheng
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Charles J Titus
- Department of Physics, Stanford University, Stanford, CA, USA
| | - Sang Jun Lee
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Kent D Irwin
- Department of Physics, Stanford University, Stanford, CA, USA.,SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Dennis Nordlund
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Kyle M Lancaster
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA.
| | - Theodore A Betley
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
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23
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Recent Advances in Copper Catalyzed Alcohol Oxidation in Homogeneous Medium. Molecules 2020; 25:molecules25030748. [PMID: 32050493 PMCID: PMC7037375 DOI: 10.3390/molecules25030748] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 01/26/2020] [Accepted: 02/06/2020] [Indexed: 11/17/2022] Open
Abstract
The development of sustainable processes and products through innovative catalytic materials and procedures that allow a better use of resources is undoubtedly one of the most significant issues facing researchers nowadays. Environmental and economically advanced catalytic processes for selective oxidation of alcohols are currently focused on designing new catalysts able to activate green oxidants (dioxygen or peroxides) and applying unconventional conditions of sustainable significance, like the use of microwave irradiation as an alternative energy source. This short review aims to provide an overview of the recently (2015–2020) discovered homogeneous aerobic and peroxidative oxidations of primary and secondary alcohols catalyzed by copper complexes, highlighting new catalysts with potential application in sustainable organic synthesis, with significance in academia and industry.
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24
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Carsch KM, Lukens JT, DiMucci IM, Iovan DA, Zheng SL, Lancaster KM, Betley TA. Electronic Structures and Reactivity Profiles of Aryl Nitrenoid-Bridged Dicopper Complexes. J Am Chem Soc 2020; 142:2264-2276. [PMID: 31917556 PMCID: PMC7262786 DOI: 10.1021/jacs.9b09616] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dicopper complexes templated by dinucleating, pacman dipyrrin ligand scaffolds (Mesdmx, tBudmx: dimethylxanthine-bridged, cofacial bis-dipyrrin) were synthesized by deprotonation/metalation with mesitylcopper (CuMes; Mes: mesityl) or by transmetalation with cuprous precursors from the corresponding deprotonated ligand. Neutral imide complexes (Rdmx)Cu2(μ2-NAr) (R: Mes, tBu; Ar: 4-MeOC6H4, 3,5-(F3C)2C6H3) were synthesized by treatment of the corresponding dicuprous complexes with aryl azides. While one-electron reduction of (Mesdmx)Cu2(μ2-N(C6H4OMe)) with potassium graphite initiates an intramolecular, benzylic C-H amination at room temperature, chemical reduction of (tBudmx)Cu2(μ2-NAr) leads to isolable [(tBudmx)Cu2(μ2-NAr)]- product salts. The electronic structures of the thermally robust [(tBudmx)Cu2(μ2-NAr)]0/- complexes were assessed by variable-temperature electron paramagnetic resonance spectroscopy, X-ray absorption spectroscopy (Cu L2,3/K-edge, N K-edge), optical spectroscopy, and DFT/CASSCF calculations. These data indicate that the formally Class IIIA mixed valence complexes of the type [(Rdmx)Cu2(μ2-NAr)]- feature significant NAr-localized spin following reduction from electronic population of the [Cu2(μ2-NAr)] π* manifold, contrasting previous methods for engendering iminyl character through chemical oxidation. The reactivity of the isolable imido and iminyl complexes are examined for prototypical radical-promoted reactivity (e.g., nitrene transfer and H-atom abstraction), where the divergent reactivity is rationalized by the relative degree of N-radical character afforded from different aryl substituents.
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Affiliation(s)
- Kurtis M. Carsch
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - James T. Lukens
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Ida M. DiMucci
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Diana A. Iovan
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Shao-Liang Zheng
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Kyle M. Lancaster
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Theodore A. Betley
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
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25
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Szczepaniak G, Piątkowski J, Nogaś W, Lorandi F, Yerneni SS, Fantin M, Ruszczyńska A, Enciso AE, Bulska E, Grela K, Matyjaszewski K. An isocyanide ligand for the rapid quenching and efficient removal of copper residues after Cu/TEMPO-catalyzed aerobic alcohol oxidation and atom transfer radical polymerization. Chem Sci 2020. [DOI: 10.1039/d0sc00623h] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Three for the price of one: 1,4-bis(3-isocyanopropyl)piperazine allows for the removal of Cu impurities, can quench Cu-catalyzed reactions, and can prevent undesirable Glaser coupling.
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Affiliation(s)
- Grzegorz Szczepaniak
- Faculty of Chemistry
- Biological and Chemical Research Centre
- University of Warsaw
- 02-089 Warsaw
- Poland
| | - Jakub Piątkowski
- Faculty of Chemistry
- Biological and Chemical Research Centre
- University of Warsaw
- 02-089 Warsaw
- Poland
| | - Wojciech Nogaś
- Faculty of Chemistry
- Biological and Chemical Research Centre
- University of Warsaw
- 02-089 Warsaw
- Poland
| | | | | | - Marco Fantin
- Department of Chemistry
- Carnegie Mellon University
- Pittsburgh
- USA
| | - Anna Ruszczyńska
- Faculty of Chemistry
- Biological and Chemical Research Centre
- University of Warsaw
- 02-089 Warsaw
- Poland
| | - Alan E. Enciso
- Department of Chemistry
- Northwestern University
- Evanston
- USA
| | - Ewa Bulska
- Faculty of Chemistry
- Biological and Chemical Research Centre
- University of Warsaw
- 02-089 Warsaw
- Poland
| | - Karol Grela
- Faculty of Chemistry
- Biological and Chemical Research Centre
- University of Warsaw
- 02-089 Warsaw
- Poland
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26
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Paradisi A, Johnston EM, Tovborg M, Nicoll CR, Ciano L, Dowle A, McMaster J, Hancock Y, Davies GJ, Walton PH. Formation of a Copper(II)-Tyrosyl Complex at the Active Site of Lytic Polysaccharide Monooxygenases Following Oxidation by H 2O 2. J Am Chem Soc 2019; 141:18585-18599. [PMID: 31675221 PMCID: PMC7007232 DOI: 10.1021/jacs.9b09833] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Indexed: 01/14/2023]
Abstract
Hydrogen peroxide is a cosubstrate for the oxidative cleavage of saccharidic substrates by copper-containing lytic polysaccharide monooxygenases (LPMOs). The rate of reaction of LPMOs with hydrogen peroxide is high, but it is accompanied by rapid inactivation of the enzymes, presumably through protein oxidation. Herein, we use UV-vis, CD, XAS, EPR, VT/VH-MCD, and resonance Raman spectroscopies, augmented with mass spectrometry and DFT calculations, to show that the product of reaction of an AA9 LPMO with H2O2 at higher pHs is a singlet Cu(II)-tyrosyl radical species, which is inactive for the oxidation of saccharidic substrates. The Cu(II)-tyrosyl radical center entails the formation of significant Cu(II)-(●OTyr) overlap, which in turn requires that the plane of the d(x2-y2) SOMO of the Cu(II) is orientated toward the tyrosyl radical. We propose from the Marcus cross-relation that the active site tyrosine is part of a "hole-hopping" charge-transfer mechanism formed of a pathway of conserved tyrosine and tryptophan residues, which can protect the protein active site from inactivation during uncoupled turnover.
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Affiliation(s)
- Alessandro Paradisi
- Department
of Chemistry, Centre of Excellence of Mass Spectrometry, Technology
Facility, and Department of Physics, University of York, Heslington, York YO10
5DD, United Kingdom
| | - Esther M. Johnston
- Department
of Chemistry, Centre of Excellence of Mass Spectrometry, Technology
Facility, and Department of Physics, University of York, Heslington, York YO10
5DD, United Kingdom
| | | | - Callum R. Nicoll
- Department
of Chemistry, Centre of Excellence of Mass Spectrometry, Technology
Facility, and Department of Physics, University of York, Heslington, York YO10
5DD, United Kingdom
| | - Luisa Ciano
- Department
of Chemistry, Centre of Excellence of Mass Spectrometry, Technology
Facility, and Department of Physics, University of York, Heslington, York YO10
5DD, United Kingdom
| | - Adam Dowle
- Department
of Chemistry, Centre of Excellence of Mass Spectrometry, Technology
Facility, and Department of Physics, University of York, Heslington, York YO10
5DD, United Kingdom
| | - Jonathan McMaster
- School
of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Y. Hancock
- Department
of Chemistry, Centre of Excellence of Mass Spectrometry, Technology
Facility, and Department of Physics, University of York, Heslington, York YO10
5DD, United Kingdom
- York
Cross-Disciplinary Centre for Systems Analysis, University of York, Heslington,
York YO10 5GE, United Kingdom
| | - Gideon J. Davies
- Department
of Chemistry, Centre of Excellence of Mass Spectrometry, Technology
Facility, and Department of Physics, University of York, Heslington, York YO10
5DD, United Kingdom
| | - Paul H. Walton
- Department
of Chemistry, Centre of Excellence of Mass Spectrometry, Technology
Facility, and Department of Physics, University of York, Heslington, York YO10
5DD, United Kingdom
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27
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DiMucci IM, Lukens JT, Chatterjee S, Carsch KM, Titus CJ, Lee SJ, Nordlund D, Betley TA, MacMillan SN, Lancaster KM. The Myth of d 8 Copper(III). J Am Chem Soc 2019; 141:18508-18520. [PMID: 31710466 PMCID: PMC7256958 DOI: 10.1021/jacs.9b09016] [Citation(s) in RCA: 116] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Seventeen Cu complexes with formal oxidation states ranging from CuI to CuIII are investigated through the use of multiedge X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculations. Analysis reveals that the metal-ligand bonding in high-valent, formally CuIII species is extremely covalent, resulting in Cu K-edge and L2,3-edge spectra whose features have energies that complicate physical oxidation state assignment. Covalency analysis of the Cu L2,3-edge data reveals that all formally CuIII species have significantly diminished Cu d-character in their lowest unoccupied molecular orbitals (LUMOs). DFT calculations provide further validation of the orbital composition analysis, and excellent agreement is found between the calculated and experimental results. The finding that Cu has limited capacity to be oxidized necessitates localization of electron hole character on the supporting ligands; consequently, the physical d8 description for these formally CuIII species is inaccurate. This study provides an alternative explanation for the competence of formally CuIII species in transformations that are traditionally described as metal-centered, 2-electron CuI/CuIII redox processes.
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Affiliation(s)
- Ida M. DiMucci
- Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, 162 Sciences Drive, Ithaca, New York 14853, United States
| | - James T. Lukens
- Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, 162 Sciences Drive, Ithaca, New York 14853, United States
| | - Sudipta Chatterjee
- Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, 162 Sciences Drive, Ithaca, New York 14853, United States
| | - Kurtis M. Carsch
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Charles J. Titus
- Department of Physics, Stanford University, Stanford, California 94305, United States
| | - Sang Jun Lee
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Dennis Nordlund
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Theodore A. Betley
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Samantha N. MacMillan
- Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, 162 Sciences Drive, Ithaca, New York 14853, United States
| | - Kyle M. Lancaster
- Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, 162 Sciences Drive, Ithaca, New York 14853, United States
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28
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Nakai S, Yatabe T, Suzuki K, Sasano Y, Iwabuchi Y, Hasegawa J, Mizuno N, Yamaguchi K. Methyl‐Selective α‐Oxygenation of Tertiary Amines to Formamides by Employing Copper/Moderately Hindered Nitroxyl Radical (DMN‐AZADO or 1‐Me‐AZADO). Angew Chem Int Ed Engl 2019; 58:16651-16659. [DOI: 10.1002/anie.201909005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 09/11/2019] [Indexed: 01/10/2023]
Affiliation(s)
- Satoru Nakai
- Department of Applied ChemistrySchool of EngineeringThe University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8656 Japan
| | - Takafumi Yatabe
- Department of Applied ChemistrySchool of EngineeringThe University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8656 Japan
| | - Kosuke Suzuki
- Department of Applied ChemistrySchool of EngineeringThe University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8656 Japan
| | - Yusuke Sasano
- Department of Organic ChemistryGraduate School of Pharmaceutical SciencesTohoku University 6-3 Aza-Aoba, Aramaki Aoba-ku Sendai 980-8578 Japan
| | - Yoshiharu Iwabuchi
- Department of Organic ChemistryGraduate School of Pharmaceutical SciencesTohoku University 6-3 Aza-Aoba, Aramaki Aoba-ku Sendai 980-8578 Japan
| | - Jun‐ya Hasegawa
- Institute for CatalysisHokkaido University Kita 21 Nishi 10, Kita-ku Sapporo 001-0021 Japan
| | - Noritaka Mizuno
- Department of Applied ChemistrySchool of EngineeringThe University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8656 Japan
| | - Kazuya Yamaguchi
- Department of Applied ChemistrySchool of EngineeringThe University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8656 Japan
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29
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Nakai S, Yatabe T, Suzuki K, Sasano Y, Iwabuchi Y, Hasegawa J, Mizuno N, Yamaguchi K. Methyl‐Selective α‐Oxygenation of Tertiary Amines to Formamides by Employing Copper/Moderately Hindered Nitroxyl Radical (DMN‐AZADO or 1‐Me‐AZADO). Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201909005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Satoru Nakai
- Department of Applied Chemistry School of Engineering The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8656 Japan
| | - Takafumi Yatabe
- Department of Applied Chemistry School of Engineering The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8656 Japan
| | - Kosuke Suzuki
- Department of Applied Chemistry School of Engineering The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8656 Japan
| | - Yusuke Sasano
- Department of Organic Chemistry Graduate School of Pharmaceutical Sciences Tohoku University 6-3 Aza-Aoba, Aramaki Aoba-ku Sendai 980-8578 Japan
| | - Yoshiharu Iwabuchi
- Department of Organic Chemistry Graduate School of Pharmaceutical Sciences Tohoku University 6-3 Aza-Aoba, Aramaki Aoba-ku Sendai 980-8578 Japan
| | - Jun‐ya Hasegawa
- Institute for Catalysis Hokkaido University Kita 21 Nishi 10, Kita-ku Sapporo 001-0021 Japan
| | - Noritaka Mizuno
- Department of Applied Chemistry School of Engineering The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8656 Japan
| | - Kazuya Yamaguchi
- Department of Applied Chemistry School of Engineering The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8656 Japan
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30
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Ryan MC, Whitmire LD, McCann SD, Stahl SS. Copper/TEMPO Redox Redux: Analysis of PCET Oxidation of TEMPOH by Copper(II) and the Reaction of TEMPO with Copper(I). Inorg Chem 2019; 58:10194-10200. [PMID: 31283193 DOI: 10.1021/acs.inorgchem.9b01326] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Copper salts and organic aminoxyls, such as TEMPO (2,2,6,6-tetramethylpiperidine-N-oxyl), are versatile catalysts for aerobic alcohol oxidation. Previous reports in the literature contain conflicting proposals concerning the redox interactions that take place between copper(I) and copper(II) salts with the aminoxyl and hydroxylamine species, TEMPO and TEMPOH, respectively. Here, we reinvestigate these reactions in an effort to resolve the conflicting claims in the literature. Under anaerobic conditions, CuIIX2 salts [X = acetate (OAc), trifluoroacetate (TFA), and triflate (OTf)] are shown to promote the rapid proton-coupled oxidation of TEMPOH to TEMPO: CuIIX2 + TEMPOH → CuIX + TEMPO + HX. In the reaction with acetate, however, slow reoxidation of CuIOAc occurs. This process requires both TEMPO and HOAc and coincides with the reduction of TEMPO to 2,2,6,6-tetramethylpiperidine. Analogous reactivity is not observed with trifluoroacetate and triflate species. Overall, the facility of the proton-coupled oxidation of TEMPOH by CuII salts suggests that this process could contribute to catalyst regeneration under aerobic oxidation conditions.
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Affiliation(s)
- Michael C Ryan
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , United States
| | - Lauren D Whitmire
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , United States
| | - Scott D McCann
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , United States
| | - Shannon S Stahl
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , United States
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31
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Lim H, Thomas KE, Hedman B, Hodgson KO, Ghosh A, Solomon EI. X-ray Absorption Spectroscopy as a Probe of Ligand Noninnocence in Metallocorroles: The Case of Copper Corroles. Inorg Chem 2019; 58:6722-6730. [PMID: 31046257 PMCID: PMC6644708 DOI: 10.1021/acs.inorgchem.9b00128] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The question of ligand noninnocence in Cu corroles has long been a topic of discussion. Presented herein is a Cu K-edge X-ray absorption spectroscopy (XAS) study, which provides a direct probe of the metal oxidation state, of three Cu corroles, Cu[TPC], Cu[Br8TPC], and Cu[(CF3)8TPC] (TPC = meso-triphenylcorrole), and the analogous Cu(II) porphyrins, Cu[TPP], Cu[Br8TPP], and Cu[(CF3)8TPP] (TPP = meso-tetraphenylporphyrin). The Cu K rising-edges of the Cu corroles were found to be about 0-1 eV upshifted relative to the analogous porphyrins, which is substantially lower than the 1-2 eV shifts typically exhibited by authentic Cu(II)/Cu(III) model complex pairs. In an unusual twist, the Cu K pre-edge regions of both the Cu corroles and the Cu porphyrins exhibit two peaks split by 0.8-1.3 eV. Based on time-dependent density functional theory calculations, the lower- and higher-energy peaks were assigned to a Cu 1s → 3d x2- y2 transition and a Cu 1s → corrole/porphyrin π* transition, respectively. From the Cu(II) porphyrins to the corresponding Cu corroles, the energy of the Cu 1s → 3d x2- y2 transition peak was found to upshift by 0.6-0.8 eV. This shift is approximately half that observed between Cu(II) to Cu(III) states for well-defined complexes. The Cu K-edge XAS spectra thus show that although the metal sites in the Cu corroles are more oxidized relative to those in their Cu(II) porphyrin analogues, they are not oxidized to the Cu(III) level, consistent with the notion of a noninnocent corrole. The relative importance of σ-donation versus corrole π-radical character is discussed.
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Affiliation(s)
- Hyeongtaek Lim
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Kolle E. Thomas
- Department of Chemistry, UiT — The Arctic University of Norway, N-9037 Tromsø, Norway
| | - Britt Hedman
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Keith O. Hodgson
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Abhik Ghosh
- Department of Chemistry, UiT — The Arctic University of Norway, N-9037 Tromsø, Norway
| | - Edward I. Solomon
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
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32
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Abstract
The oxidation of alcohols to the corresponding carbonyl products is an important organic transformation and the products are used in a variety of applications. The development of catalytic methods for selective alcohol oxidation have garnered significant attention in an attempt to find a more sustainable method without any limitations. Copper, in combination with 2,2,6,6-tetramethyl-1-piperidine N-oxyl (TEMPO) and supported by organic ligands, have emerged as the most effective catalysts for selective alcohol oxidation and these catalyst systems are frequently compared to galactose oxidase (GOase). The efficiency of GOase has led to extensive research to mimic the active sites of these enzymes, leading to a variety of Cu/TEMPO· catalyst systems being reported over the years. The mechanistic pathway by which Cu/TEMPO· catalyst systems operate has been investigated by several research groups, which led to partially contradicting mechanistic description. Due to the disadvantages and limitations of employing TEMPO· as co-catalyst, alternative nitroxyl radicals or in situ formed radicals, as co-catalysts, have been successfully evaluated in alcohol oxidation. Herein we discuss the development and mechanistic elucidation of Cu/TEMPO· catalyst systems as biomimetic alcohol oxidation catalysts.
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33
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Lukens JT, DiMucci IM, Kurogi T, Mindiola DJ, Lancaster KM. Scrutinizing metal-ligand covalency and redox non-innocence via nitrogen K-edge X-ray absorption spectroscopy. Chem Sci 2019; 10:5044-5055. [PMID: 31183055 PMCID: PMC6530532 DOI: 10.1039/c8sc03350a] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 04/09/2019] [Indexed: 11/21/2022] Open
Abstract
A series of nitrogen K-edge XAS data obtained for coordination complexes of diverse transition metals is used to calibrate computational pre-edge peak energies and to afford estimates of metal–ligand covalencies. The approach is extended to probe an inner-sphere aminyl radical ligand.
Nitrogen K-edge X-ray absorption spectra (XAS) were obtained for 19 transition metal complexes bearing bipyridine, ethylenediamine, ammine, and nitride ligands. Time-dependent density functional theory (TDDFT) and DFT/restricted open configuration interaction singles (DFT/ROCIS) calculations were found to predict relative N K-edge XAS peak energies with good fidelity to experiment. The average difference (|ΔE|) between experimental and linear corrected calculated energies were found to be 0.55 ± 0.05 eV and 0.46 ± 0.04 eV, respectively, using the B3LYP hybrid density functional and scalar relativistically recontracted ZORA-def2-TZVP(-f) basis set. Deconvolution of these global correlations into individual N-donor ligand classes gave improved agreement between experiment and theory with |ΔE| less than 0.4 eV for all ligand classes in the case of DFT/ROCIS. In addition, calibration method-dependent values for the N 1s → 2p radial dipole integral of 25.4 ± 1.7 and 26.8 ± 1.9 are obtained, affording means to estimate the nitrogen 2p character in unfilled frontier molecular orbitals. For the complexes studied, nitrogen covalency values correlate well to those calculated by hybrid DFT with an R2 = 0.92 ± 0.01. Additionally, as a test case, a well-characterized PNP ligand framework (PNP = N[2-P(CHMe2)2-4-methylphenyl]21–) coordinated to NiII is investigated for its ability to act as a redox non-innocent ligand. Upon oxidation of (PNP)NiCl with [FeCp2](OTf) to its radical cation, [(PNP)NiCl](OTf) (OTf = triflate), a new low-energy feature emerges in the N K-edge XAS spectra. This feature is assigned as N 1s to a PNP-localized acceptor orbital exhibiting 27 ± 2% N 2p aminyl radical character, obtained using the aforementioned nitrogen covalency calibration. Combined, these data showcase a direct spectroscopic means of identifying redox-active N-donor ligands and also estimating nitrogen 2p covalency of frontier molecular orbitals in transition metal complexes.
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Affiliation(s)
- James T Lukens
- Department of Chemistry and Chemical Biology Cornell University , Baker Laboratory , Ithaca , NY 14853 , USA .
| | - Ida M DiMucci
- Department of Chemistry and Chemical Biology Cornell University , Baker Laboratory , Ithaca , NY 14853 , USA .
| | - Takashi Kurogi
- Department of Chemistry , University of Pennsylvania , 231 South 34th Street , Philadelphia , PA 19104 , USA
| | - Daniel J Mindiola
- Department of Chemistry , University of Pennsylvania , 231 South 34th Street , Philadelphia , PA 19104 , USA
| | - Kyle M Lancaster
- Department of Chemistry and Chemical Biology Cornell University , Baker Laboratory , Ithaca , NY 14853 , USA .
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34
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Trammell R, Rajabimoghadam K, Garcia-Bosch I. Copper-Promoted Functionalization of Organic Molecules: from Biologically Relevant Cu/O 2 Model Systems to Organometallic Transformations. Chem Rev 2019; 119:2954-3031. [PMID: 30698952 DOI: 10.1021/acs.chemrev.8b00368] [Citation(s) in RCA: 157] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Copper is one of the most abundant and less toxic transition metals. Nature takes advantage of the bioavailability and rich redox chemistry of Cu to carry out oxygenase and oxidase organic transformations using O2 (or H2O2) as oxidant. Inspired by the reactivity of these Cu-dependent metalloenzymes, chemists have developed synthetic protocols to functionalize organic molecules under enviormentally benign conditions. Copper also promotes other transformations usually catalyzed by 4d and 5d transition metals (Pd, Pt, Rh, etc.) such as nitrene insertions or C-C and C-heteroatom coupling reactions. In this review, we summarized the most relevant research in which copper promotes or catalyzes the functionalization of organic molecules, including biological catalysis, bioinspired model systems, and organometallic reactivity. The reaction mechanisms by which these processes take place are discussed in detail.
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Affiliation(s)
- Rachel Trammell
- Department of Chemistry , Southern Methodist University , Dallas , Texas 75275 , United States
| | | | - Isaac Garcia-Bosch
- Department of Chemistry , Southern Methodist University , Dallas , Texas 75275 , United States
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35
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Chandra P, Jonas A, Fernandes AE. Synthesis of discrete catalytic oligomers and their potential in silica-supported cooperative catalysis. RSC Adv 2019; 9:14194-14197. [PMID: 35519338 PMCID: PMC9064013 DOI: 10.1039/c9ra00847k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 05/01/2019] [Indexed: 11/21/2022] Open
Abstract
The synthesis of discrete catalytic oligomers and their potential in supported cooperative catalysis are presented.
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Affiliation(s)
- Prakash Chandra
- Institute of Condensed Matter and Nanosciences
- Université catholique de Louvain
- 1348 Louvain-la-Neuve
- Belgium
| | - Alain M. Jonas
- Institute of Condensed Matter and Nanosciences
- Université catholique de Louvain
- 1348 Louvain-la-Neuve
- Belgium
| | - Antony E. Fernandes
- Institute of Condensed Matter and Nanosciences
- Université catholique de Louvain
- 1348 Louvain-la-Neuve
- Belgium
- Certech
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36
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He W, Kennepohl P. Direct experimental evaluation of ligand-induced backbonding in nickel metallacyclic complexes. Faraday Discuss 2019; 220:133-143. [PMID: 31544197 DOI: 10.1039/c9fd00041k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The details of ligand-induced backbonding in nickel diphosphine π complexes are explored using nickel L-edge (3d←2p) X-ray absorption spectroscopy as a means of quantifying the degree of backbonding derived from direct Ni 3d donation into the π ligand. It is observed that backbonding into weakly π acidic ligands such as alkenes and arenes is dominated by contributions from the diphosphine ligand via σ-donation, leading to activated metallacycles with a Ni(0) d10 metal centre. With more strongly π acidic ligands, however, metal contributions to backbonding increase substantially leading to a more electron-deficient metal centre that is best described as having a Ni(i) spectroscopic oxidation state.
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Affiliation(s)
- Weiying He
- The University of British Columbia, Department of Chemistry, 2036 Main Mall, Vancouver, British Columbia, Canada.
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37
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Niu P, Liu X, Shen Z, Li M. Electrochemical Performance of ABNO for Oxidation of Secondary Alcohols in Acetonitrile Solution. Molecules 2018; 24:E100. [PMID: 30597882 PMCID: PMC6337132 DOI: 10.3390/molecules24010100] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 12/23/2018] [Accepted: 12/27/2018] [Indexed: 11/16/2022] Open
Abstract
The ketones was successfully prepared from secondary alcohols using 9-azabicyclo[3.3.1]nonane-N-oxyl (ABNO) as the catalyst and 2,6-lutidine as the base in acetonitrile solution. The electrochemical activity of ABNO for oxidation of 1-phenylethanol was investigated by cyclic voltammetry, in situ Fourier transform infrared spectroscopy (FTIR) and constant current electrolysis experiments. The resulting cyclic voltammetry indicated that ABNO exhibited much higher electrochemical activity when compared with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) under the similar conditions. A reasonable reaction mechanism of the electrocatalytic oxidation of 1-phenylethanol to acetophenone was proposed. In addition, a series of secondary alcohols could be converted to the corresponding ketones at room temperature in 80⁻95% isolated yields.
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Affiliation(s)
- Pengfei Niu
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310032, China.
- Research Center of Analysis and Measurement, Zhejiang University of Technology, Hangzhou 310032, China.
| | - Xin Liu
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310032, China.
- Research Center of Analysis and Measurement, Zhejiang University of Technology, Hangzhou 310032, China.
| | - Zhenlu Shen
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310032, China.
| | - Meichao Li
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310032, China.
- Research Center of Analysis and Measurement, Zhejiang University of Technology, Hangzhou 310032, China.
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38
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Rajabimoghadam K, Darwish Y, Bashir U, Pitman D, Eichelberger S, Siegler MA, Swart M, Garcia-Bosch I. Catalytic Aerobic Oxidation of Alcohols by Copper Complexes Bearing Redox-Active Ligands with Tunable H-Bonding Groups. J Am Chem Soc 2018; 140:16625-16634. [PMID: 30400740 DOI: 10.1021/jacs.8b08748] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In this research article, we describe the structure, spectroscopy, and reactivity of a family of copper complexes bearing bidentate redox-active ligands that contain H-bonding donor groups. Single-crystal X-ray crystallography shows that these tetracoordinate complexes are stabilized by intramolecular H-bonding interactions between the two ligand scaffolds. Interestingly, the Cu complexes undergo multiple reversible oxidation-reduction processes associated with the metal ion (CuI, CuII, CuIII) and/or the o-phenyldiamido ligand (L2-, L•-, L). Moreover, some of the CuII complexes catalyze the aerobic oxidation of alcohols to aldehydes (or ketones) at room temperature. Our extensive mechanistic analysis suggests that the dehydrogenation of alcohols occurs via an unusual reaction pathway for galactose oxidase model systems, in which O2 reduction occurs concurrently with substrate oxidation.
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Affiliation(s)
| | - Yousef Darwish
- Department of Chemistry , Southern Methodist University , Dallas , Texas 75275 , United States
| | - Umyeena Bashir
- Department of Chemistry , Southern Methodist University , Dallas , Texas 75275 , United States
| | - Dylan Pitman
- Department of Chemistry , Southern Methodist University , Dallas , Texas 75275 , United States
| | - Sidney Eichelberger
- Department of Chemistry , Southern Methodist University , Dallas , Texas 75275 , United States
| | - Maxime A Siegler
- Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Marcel Swart
- ICREA , Pg. Lluís Companys 23 , 08010 Barcelona , Spain.,IQCC , University of Girona , Campus Montilivi (Ciències) , Girona , Spain
| | - Isaac Garcia-Bosch
- Department of Chemistry , Southern Methodist University , Dallas , Texas 75275 , United States
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39
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Siu JC, Sauer GS, Saha A, Macey RL, Fu N, Chauviré T, Lancaster KM, Lin S. Electrochemical Azidooxygenation of Alkenes Mediated by a TEMPO-N 3 Charge-Transfer Complex. J Am Chem Soc 2018; 140:12511-12520. [PMID: 30160949 PMCID: PMC6212300 DOI: 10.1021/jacs.8b06744] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We report a mild and efficient electrochemical protocol to access a variety of vicinally C-O and C-N difunctionalized compounds from simple alkenes. Detailed mechanistic studies revealed a distinct reaction pathway from those previously reported for TEMPO-mediated reactions. In this mechanism, electrochemically generated oxoammonium ion facilitates the formation of azidyl radical via a charge-transfer complex with azide, TEMPO-N3. DFT calculations together with spectroscopic characterization provided a tentative structural assignment of this charge-transfer complex. Kinetic and kinetic isotopic effect studies revealed that reversible dissociation of TEMPO-N3 into TEMPO• and azidyl precedes the addition of these radicals across the alkene in the rate-determining step. The resulting azidooxygenated product could then be easily manipulated for further synthetic elaborations. The discovery of this new reaction pathway mediated by the TEMPO+/TEMPO• redox couple may expand the scope of aminoxyl radical chemistry in synthetic contexts.
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Affiliation(s)
- Juno C. Siu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Gregory S. Sauer
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Ambarneil Saha
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Reed L. Macey
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Niankai Fu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Timothée Chauviré
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Kyle M. Lancaster
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Song Lin
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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40
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Huang Y, Chong X, Liu C, Liang Y, Zhang B. Boosting Hydrogen Production by Anodic Oxidation of Primary Amines over a NiSe Nanorod Electrode. Angew Chem Int Ed Engl 2018; 57:13163-13166. [DOI: 10.1002/anie.201807717] [Citation(s) in RCA: 202] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Indexed: 11/12/2022]
Affiliation(s)
- Yi Huang
- Tianjin Key Laboratory of Molecular Optoelectronic SciencesDepartment of ChemistrySchool of ScienceTianjin University, and Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072 China
| | - Xiaodan Chong
- Tianjin Key Laboratory of Molecular Optoelectronic SciencesDepartment of ChemistrySchool of ScienceTianjin University, and Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072 China
| | - Cuibo Liu
- Tianjin Key Laboratory of Molecular Optoelectronic SciencesDepartment of ChemistrySchool of ScienceTianjin University, and Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072 China
| | - Yu Liang
- Tianjin Key Laboratory of Molecular Optoelectronic SciencesDepartment of ChemistrySchool of ScienceTianjin University, and Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072 China
| | - Bin Zhang
- Tianjin Key Laboratory of Molecular Optoelectronic SciencesDepartment of ChemistrySchool of ScienceTianjin University, and Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072 China
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41
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Huang Y, Chong X, Liu C, Liang Y, Zhang B. Boosting Hydrogen Production by Anodic Oxidation of Primary Amines over a NiSe Nanorod Electrode. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201807717] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yi Huang
- Tianjin Key Laboratory of Molecular Optoelectronic SciencesDepartment of ChemistrySchool of ScienceTianjin University, and Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072 China
| | - Xiaodan Chong
- Tianjin Key Laboratory of Molecular Optoelectronic SciencesDepartment of ChemistrySchool of ScienceTianjin University, and Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072 China
| | - Cuibo Liu
- Tianjin Key Laboratory of Molecular Optoelectronic SciencesDepartment of ChemistrySchool of ScienceTianjin University, and Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072 China
| | - Yu Liang
- Tianjin Key Laboratory of Molecular Optoelectronic SciencesDepartment of ChemistrySchool of ScienceTianjin University, and Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072 China
| | - Bin Zhang
- Tianjin Key Laboratory of Molecular Optoelectronic SciencesDepartment of ChemistrySchool of ScienceTianjin University, and Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072 China
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42
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Goodwin CAP, Réant BLL, Kragskow JGC, DiMucci IM, Lancaster KM, Mills DP, Sproules S. Heteroleptic samarium(iii) halide complexes probed by fluorescence-detected L 3-edge X-ray absorption spectroscopy. Dalton Trans 2018; 47:10613-10625. [PMID: 29790545 PMCID: PMC6083822 DOI: 10.1039/c8dt01452c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The novel series of heteroleptic Sm(iii) halide complexes provides the backdrop for a fluorescence-detected Lα1 X-ray absorption spectroscopic study.
The addition of various oxidants to the near-linear Sm(ii) complex [Sm(N††)2] (1), where N†† is the bulky bis(triisopropylsilyl)amide ligand {N(SiiPr3)2}, afforded a family of heteroleptic three-coordinate Sm(iii) halide complexes, [Sm(N††)2(X)] (X = F, 2-F; Cl, 2-Cl; Br, 2-Br; I, 2-I). In addition, the trinuclear cluster [{Sm(N††)}3(μ2-I)3(μ3-I)2] (3), which formally contains one Sm(ii) and two Sm(iii) centres, was isolated during the synthesis of 2-I. Complexes 2-X are remarkably stable towards ligand redistribution, which is often a facile process for heteroleptic complexes of smaller monodentate ligands in lanthanide chemistry, including the related bis(trimethylsilyl)amide {N(SiMe3)2} (N′′). Complexes 2-X and 3 have been characterised by single crystal X-ray diffraction, elemental analysis, multinuclear NMR, FTIR and electronic spectroscopy. The Lα1 fluorescence-detected X-ray absorption spectra recorded at the Sm L3-edge for 2-X exhibited a resolved pre-edge peak defined as an envelope of quadrupole-allowed 2p → 4f transitions. The X-ray absorption spectral features were successfully reproduced using time-dependent density functional theoretical (TD-DFT) calculations that synergistically support the experimental observations as well as the theoretical model upon which the electronic structure and bonding in these lanthanide complexes is derived.
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Affiliation(s)
- Conrad A P Goodwin
- School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Benjamin L L Réant
- School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Jon G C Kragskow
- School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Ida M DiMucci
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York, 14853, USA.
| | - Kyle M Lancaster
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York, 14853, USA.
| | - David P Mills
- School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Stephen Sproules
- WestCHEM, School of Chemistry, The University of Glasgow, Glasgow G12 8QQ, UK.
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Chandra P, Jonas AM, Fernandes AE. Spatial Coordination of Cooperativity in Silica-Supported Cu/TEMPO/Imidazole Catalytic Triad. ACS Catal 2018. [DOI: 10.1021/acscatal.8b01399] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Prakash Chandra
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Alain M. Jonas
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Antony E. Fernandes
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
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Maurya YK, Noda K, Yamasumi K, Mori S, Uchiyama T, Kamitani K, Hirai T, Ninomiya K, Nishibori M, Hori Y, Shiota Y, Yoshizawa K, Ishida M, Furuta H. Ground-State Copper(III) Stabilized by N-Confused/N-Linked Corroles: Synthesis, Characterization, and Redox Reactivity. J Am Chem Soc 2018; 140:6883-6892. [DOI: 10.1021/jacs.8b01876] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Yogesh Kumar Maurya
- Department of Chemistry and Biochemistry, Graduate School of Engineering and Center for Molecular Systems, Kyushu University, Fukuoka 819-0395, Japan
| | - Katsuya Noda
- Department of Chemistry and Biochemistry, Graduate School of Engineering and Center for Molecular Systems, Kyushu University, Fukuoka 819-0395, Japan
| | - Kazuhisa Yamasumi
- Department of Chemistry and Biochemistry, Graduate School of Engineering and Center for Molecular Systems, Kyushu University, Fukuoka 819-0395, Japan
| | - Shigeki Mori
- Advanced Research Support Center, Ehime University, Matsuyama 790-8577, Japan
| | - Tomoki Uchiyama
- Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo 679-5198, Japan
| | - Kazutaka Kamitani
- Institute for Materials Chemistry and Engineering, Kyushu University, Fukuoka 819-0395, Japan
| | - Tomoyasu Hirai
- Institute for Materials Chemistry and Engineering, Kyushu University, Fukuoka 819-0395, Japan
| | - Kakeru Ninomiya
- Faculty of Engineering Sciences, Kyushu University, Fukuoka 816-8580, Japan
| | - Maiko Nishibori
- Faculty of Engineering Sciences, Kyushu University, Fukuoka 816-8580, Japan
| | - Yuta Hori
- Institute for Materials Chemistry and Engineering, Kyushu University, Fukuoka 819-0395, Japan
| | - Yoshihito Shiota
- Institute for Materials Chemistry and Engineering, Kyushu University, Fukuoka 819-0395, Japan
| | - Kazunari Yoshizawa
- Institute for Materials Chemistry and Engineering, Kyushu University, Fukuoka 819-0395, Japan
| | - Masatoshi Ishida
- Department of Chemistry and Biochemistry, Graduate School of Engineering and Center for Molecular Systems, Kyushu University, Fukuoka 819-0395, Japan
| | - Hiroyuki Furuta
- Department of Chemistry and Biochemistry, Graduate School of Engineering and Center for Molecular Systems, Kyushu University, Fukuoka 819-0395, Japan
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45
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Sizing up a supercharged ferryl. Proc Natl Acad Sci U S A 2018; 115:4532-4534. [PMID: 29666275 DOI: 10.1073/pnas.1804490115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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46
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Nutting JE, Rafiee M, Stahl SS. Tetramethylpiperidine N-Oxyl (TEMPO), Phthalimide N-Oxyl (PINO), and Related N-Oxyl Species: Electrochemical Properties and Their Use in Electrocatalytic Reactions. Chem Rev 2018; 118:4834-4885. [PMID: 29707945 DOI: 10.1021/acs.chemrev.7b00763] [Citation(s) in RCA: 525] [Impact Index Per Article: 87.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
N-Oxyl compounds represent a diverse group of reagents that find widespread use as catalysts for the selective oxidation of organic molecules in both laboratory and industrial applications. While turnover of N-oxyl catalysts in oxidation reactions may be accomplished with a variety of stoichiometric oxidants, N-oxyl reagents have also been extensively used as catalysts under electrochemical conditions in the absence of chemical oxidants. Several classes of N-oxyl compounds undergo facile redox reactions at electrode surfaces, enabling them to mediate a wide range of electrosynthetic reactions. Electrochemical studies also provide insights into the structural properties and mechanisms of chemical and electrochemical catalysis by N-oxyl compounds. This review provides a comprehensive survey of the electrochemical properties and electrocatalytic applications of aminoxyls, imidoxyls, and related reagents, of which the two prototypical and widely used examples are 2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO) and phthalimide N-oxyl (PINO).
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Affiliation(s)
- Jordan E Nutting
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , United States
| | - Mohammad Rafiee
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , United States
| | - Shannon S Stahl
- Department of Chemistry , University of Wisconsin-Madison , 1101 University Avenue , Madison , Wisconsin 53706 , United States
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47
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Dao R, Zhao C, Yao J, Li H. Distinguishing ionic and radical mechanisms of hydroxylamine mediated electrocatalytic alcohol oxidation using NO–H bond dissociation energies. Phys Chem Chem Phys 2018; 20:28249-28256. [DOI: 10.1039/c8cp06134c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
An idea is proposed to sort N-oxyl radicals with respect to their mechanisms of electrocatalytic alcohol oxidation by knowing the NO–H bond dissociation energies of their precursors.
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Affiliation(s)
- Rina Dao
- Department of Chemistry
- ZJU-NHU United R&D Center
- Zhejiang University
- Hangzhou 310027
- P. R. China
| | - Chenxuan Zhao
- Department of Chemistry
- ZJU-NHU United R&D Center
- Zhejiang University
- Hangzhou 310027
- P. R. China
| | - Jia Yao
- Department of Chemistry
- ZJU-NHU United R&D Center
- Zhejiang University
- Hangzhou 310027
- P. R. China
| | - Haoran Li
- Department of Chemistry
- ZJU-NHU United R&D Center
- Zhejiang University
- Hangzhou 310027
- P. R. China
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48
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Zhao L, Wei J, Zhang F, He C, Zheng S, Duan C. Redox-active copper triangles as an enzymatic molecular flask for light-driven hydrogen production. RSC Adv 2017. [DOI: 10.1039/c7ra09285g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A redox-active Cu-based triangle was developed to encapsulate fluorescein for photocatalytic hydrogen production. Control experiments and inactive ATP as an inhibitor were performed to confirm this enzymatic photocatalytic behaviour.
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Affiliation(s)
- Liang Zhao
- State Key Laboratory of Fine Chemicals
- Dalian University of Technology
- Dalian 116024
- P. R. China
| | - Jianwei Wei
- State Key Laboratory of Fine Chemicals
- Dalian University of Technology
- Dalian 116024
- P. R. China
| | - Feili Zhang
- State Key Laboratory of Fine Chemicals
- Dalian University of Technology
- Dalian 116024
- P. R. China
| | - Cheng He
- State Key Laboratory of Fine Chemicals
- Dalian University of Technology
- Dalian 116024
- P. R. China
| | - Sijia Zheng
- State Key Laboratory of Fine Chemicals
- Dalian University of Technology
- Dalian 116024
- P. R. China
| | - Chunying Duan
- State Key Laboratory of Fine Chemicals
- Dalian University of Technology
- Dalian 116024
- P. R. China
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