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Das A, Charpentier O, Hessin C, Schleinitz J, Pianca D, Le Breton N, Choua S, Grimaud L, Gourlaouen C, Desage-El Murr M. Site-Selective Radical Aromatic C-H Functionalization of Alloxazine and Flavin through Ground-State Single Electron Transfer. Angew Chem Int Ed Engl 2024; 63:e202403417. [PMID: 38627209 DOI: 10.1002/anie.202403417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Indexed: 06/11/2024]
Abstract
Flavins and their alloxazine isomers are key chemical scaffolds for bioinspired electron transfer strategies. Their properties can be fine-tuned by functional groups, which must be introduced at an early stage of the synthesis as their aromatic ring is inert towards post-functionalization. We show that the introduction of a remote metal-binding redox site on alloxazine and flavin activates their aromatic ring towards direct C-H functionalization. Mechanistic studies are consistent with a synthetic sequence involving ground-state single electron transfer (SET) with an electrophilic source followed by radical-radical coupling. This unprecedented reactivity opens new opportunities in molecular editing of flavins by direct aromatic post-functionalization and the utility of the method is demonstrated with the site-selective C6 functionalization of alloxazine and flavin with a CF3 group, Br or Cl, that can be further elaborated into OH and aryl for chemical diversification.
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Affiliation(s)
- Agnideep Das
- Université de Strasbourg, Institut de Chimie, CNRS UMR7177, 4, rue Blaise Pascal, 67000, Strasbourg, France
| | - Oscar Charpentier
- Université de Strasbourg, Institut de Chimie, CNRS UMR7177, 4, rue Blaise Pascal, 67000, Strasbourg, France
| | - Cheriehan Hessin
- Université de Strasbourg, Institut de Chimie, CNRS UMR7177, 4, rue Blaise Pascal, 67000, Strasbourg, France
| | - Jules Schleinitz
- Laboratoire des biomolécules, LBM, Chemistry department École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France
| | - David Pianca
- Université de Strasbourg, Institut de Chimie, CNRS UMR7177, 4, rue Blaise Pascal, 67000, Strasbourg, France
| | - Nolwenn Le Breton
- Université de Strasbourg, Institut de Chimie, CNRS UMR7177, 4, rue Blaise Pascal, 67000, Strasbourg, France
| | - Sylvie Choua
- Université de Strasbourg, Institut de Chimie, CNRS UMR7177, 4, rue Blaise Pascal, 67000, Strasbourg, France
| | - Laurence Grimaud
- Laboratoire des biomolécules, LBM, Chemistry department École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France
| | - Christophe Gourlaouen
- Université de Strasbourg, Institut de Chimie, CNRS UMR7177, 4, rue Blaise Pascal, 67000, Strasbourg, France
| | - Marine Desage-El Murr
- Université de Strasbourg, Institut de Chimie, CNRS UMR7177, 4, rue Blaise Pascal, 67000, Strasbourg, France
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2
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Wu T, Puri A, Qiu YL, Ye D, Sarma R, Wang Y, Kowalewski T, Siegler MA, Swart M, Garcia-Bosch I. Tuning the Thermochemistry and Reactivity of a Series of Cu-Based 4H +/4e - Electron-Coupled-Proton Buffers. Inorg Chem 2024; 63:9014-9025. [PMID: 38723621 PMCID: PMC11110016 DOI: 10.1021/acs.inorgchem.4c00835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/08/2024] [Accepted: 04/30/2024] [Indexed: 05/21/2024]
Abstract
Electron-coupled-proton buffers (ECPBs) store and deliver protons and electrons in a reversible fashion. We have recently reported an ECPB based on Cu and a redox-active ligand that promoted 4H+/4e- reversible transformations (J. Am. Chem. Soc. 2022, 144, 16905). Herein, we report a series of Cu-based ECPBs in which the ability of these to accept and/or donate H• equivalents can be tuned via ligand modification. The thermochemistry of the 4H+/4e- ECPB equilibrium was determined using open-circuit potential measurements. The reactivity of the ECPBs against proton-coupled electron transfer (PCET) reagents was also analyzed, and the results obtained were rationalized based on the thermochemical parameters. Experimental and computational analysis of the thermochemistry of the H+/e- transfers involved in the 4H+/4e- ECPB transformations found substantial differences between the stepwise (namely, BDFE1, BDFE2, BDFE3, and BDFE4) and average bond dissociation free energy values (BDFEavg.). Our analysis suggests that this "redox unleveling" is critical to promoting the disproportionation and ligand-exchange reactions involved in the 4H+/4e- ECPB equilibria. The difference in BDFEavg. within the series of Cu-based ECPBs was found to arise from a substantial change in the redox potential (E1/2) upon modification of the ligand scaffold, which is not fully compensated for by a change in the acidity/basicity (pKa), suggesting "thermochemical decompensation".
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Affiliation(s)
- Tong Wu
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Ankita Puri
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Yi Lin Qiu
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Daniel Ye
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Rajdeep Sarma
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Yiwen Wang
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Tomasz Kowalewski
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | | | - Marcel Swart
- University
of Girona, Campus Montilivi (Ciències), Plaça de Sant Domènec, 17004 Girona, Spain
- ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain
| | - Isaac Garcia-Bosch
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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3
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Porte V, Milunovic MNM, Knof U, Leischner T, Danzl T, Kaiser D, Gruene T, Zalibera M, Jelemenska I, Bucinsky L, Jannuzzi SAV, DeBeer S, Novitchi G, Maulide N, Arion VB. Chemical and Redox Noninnocence of Pentane-2,4-dione Bis( S-methylisothiosemicarbazone) in Cobalt Complexes and Their Application in Wacker-Type Oxidation. JACS AU 2024; 4:1166-1183. [PMID: 38559722 PMCID: PMC10976605 DOI: 10.1021/jacsau.4c00005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/09/2024] [Accepted: 02/15/2024] [Indexed: 04/04/2024]
Abstract
Cobalt complexes with multiproton- and multielectron-responsive ligands are of interest for challenging catalytic transformations. The chemical and redox noninnocence of pentane-2,4-dione bis(S-methylisothiosemicarbazone) (PBIT) in a series of cobalt complexes has been studied by a range of methods, including spectroscopy [UV-vis, NMR, electron paramagnetic resonance (EPR), X-ray absorption spectroscopy (XAS)], cyclic voltammetry, X-ray diffraction, and density functional theory (DFT) calculations. Two complexes [CoIII(H2LSMe)I]I and [CoIII(LSMe)I2] were found to act as precatalysts in a Wacker-type oxidation of olefins using phenylsilane, the role of which was elucidated through isotopic labeling. Insights into the mechanism of the catalytic transformation as well as the substrate scope of this selective reaction are described, and the essential role of phenylsilane and the noninnocence of PBIT are disclosed. Among the several relevant species characterized was an unprecedented Co(III) complex with a dianionic diradical PBIT ligand ([CoIII(LSMe••)I]).
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Affiliation(s)
- Vincent Porte
- University
of Vienna, Institute of Organic Chemistry, Währinger Strasse 38, A-1090 Vienna, Austria
| | - Miljan N. M. Milunovic
- University
of Vienna, Institute of Inorganic Chemistry, Währinger Strasse 42, A-1090 Vienna, Austria
| | - Ulrich Knof
- Novartis
Pharma AG, CH-4056 Basel, Switzerland
| | - Thomas Leischner
- University
of Vienna, Institute of Organic Chemistry, Währinger Strasse 38, A-1090 Vienna, Austria
| | - Tobias Danzl
- University
of Vienna, Institute of Organic Chemistry, Währinger Strasse 38, A-1090 Vienna, Austria
| | - Daniel Kaiser
- University
of Vienna, Institute of Organic Chemistry, Währinger Strasse 38, A-1090 Vienna, Austria
| | - Tim Gruene
- University
of Vienna, Institute of Inorganic Chemistry, Währinger Strasse 42, A-1090 Vienna, Austria
| | - Michal Zalibera
- Institute
of Physical Chemistry and Chemical Physics, Faculty of Chemical and
Food Technology, Slovak University of Technology
in Bratislava, Radlinského 9, SK-81237 Bratislava, Slovak Republic
| | - Ingrid Jelemenska
- Institute
of Physical Chemistry and Chemical Physics, Faculty of Chemical and
Food Technology, Slovak University of Technology
in Bratislava, Radlinského 9, SK-81237 Bratislava, Slovak Republic
| | - Lukas Bucinsky
- Institute
of Physical Chemistry and Chemical Physics, Faculty of Chemical and
Food Technology, Slovak University of Technology
in Bratislava, Radlinského 9, SK-81237 Bratislava, Slovak Republic
| | - Sergio A. V. Jannuzzi
- Max
Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Serena DeBeer
- Max
Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | | | - Nuno Maulide
- University
of Vienna, Institute of Organic Chemistry, Währinger Strasse 38, A-1090 Vienna, Austria
| | - Vladimir B. Arion
- University
of Vienna, Institute of Inorganic Chemistry, Währinger Strasse 42, A-1090 Vienna, Austria
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4
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Gerhards L, Werr M, Hübner O, Solov'yov IA, Himmel HJ. Peculiar Differences between Two Copper Complexes Containing Similar Redox-Active Ligands: Density Functional and Multiconfigurational Calculations. Inorg Chem 2024; 63:961-975. [PMID: 38157840 DOI: 10.1021/acs.inorgchem.3c02949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Transition metal complexes featuring redox-active ligands often exhibit multiple redox states, influenced by the interplay between the metal center and the ligand. This study delves into the electronic structures of two mononuclear complexes of copper with two similar redox-active urea azine ligands. The ligands differ by the replacement of an NCH3 moiety by an S atom in the ligand backbone. Experimental analysis yields pronounced electronic structural disparities between these complexes, observable in both the solution and solid phases. Conventional quantum chemical methods, such as density functional theory using different functionals (B3LYP, TPSSh, and CAM-B3LYP), remain inadequate to rationalize the observed spectroscopic anomalies. However, a multiconfigurational approach elucidates the disparate behaviors of these complexes. Multireference perturbation theory, based on complete active space self-consistent field computations, identifies Cu(I) in the case of the complex with the NCH3 containing ligands and a state with substantial Cu(II) contributions in the case of the complex with the S atom containing ligands. In contrast, DFT indicates Cu(I) in both scenarios.
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Affiliation(s)
- Luca Gerhards
- Institute of Physics, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Street 9-11, Oldenburg 26129, Germany
| | - Marco Werr
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, Heidelberg 69120, Germany
| | - Olaf Hübner
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, Heidelberg 69120, Germany
| | - Ilia A Solov'yov
- Institute of Physics, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Street 9-11, Oldenburg 26129, Germany
- Research Center for Neurosensory Science, Carl von Ossietzky Universität Oldenburg, Oldenburg 26111, Germany
- Center for Nanoscale Dynamics (CENAD), Carl von OssietzkyUniversität Oldenburg, Institut Für Physik, Ammerländer Heerstreet 114-118, Oldenburg 26129, Germany
| | - Hans-Jörg Himmel
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, Heidelberg 69120, Germany
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5
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Adam MSS, Elsawy H, Sedky A, Makhlouf MM, Taha A. Catalytic potential of sustainable dinuclear (Cu2+ and ZrO2+) metal organic incorporated frameworks with comprehensive biological studies. J Taiwan Inst Chem Eng 2023. [DOI: 10.1016/j.jtice.2023.104747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
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6
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Lohmeyer L, Werr M, Kaifer E, Himmel H. Interplay and Competition Between Two Different Types of Redox-Active Ligands in Cobalt Complexes: How to Allocate the Electrons? Chemistry 2022; 28:e202201789. [PMID: 35894809 PMCID: PMC9804828 DOI: 10.1002/chem.202201789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Indexed: 01/09/2023]
Abstract
The field of molecular transition metal complexes with redox-active ligands is dominated by compounds with one or two units of the same redox-active ligand; complexes in which different redox-active ligands are bound to the same metal are uncommon. This work reports the first molecular coordination compounds in which redox-active bisguanidine or urea azine (biguanidine) ligands as well as oxolene ligands are bound to the same cobalt atom. The combination of two different redox-active ligands leads to mono- as well as unprecedented dinuclear cobalt complexes, being multiple (four or six) center redox systems with intriguing electronic structures, all exhibiting radical ligands. By changing the redox potential of the ligands through derivatisation, the electronic structure of the complexes could be altered in a rational way.
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Affiliation(s)
- Lukas Lohmeyer
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Marco Werr
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Elisabeth Kaifer
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Hans‐Jörg Himmel
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
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7
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Telser J. Linewidth, field, and frequency in electron paramagnetic resonance (EPR) spectroscopy. J Biol Inorg Chem 2022; 27:605-609. [DOI: 10.1007/s00775-022-01961-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 08/31/2022] [Indexed: 10/14/2022]
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8
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Werr M, Kaifer E, Enders M, Asyuda A, Zharnikov M, Himmel H. A Copper(I) Complex with Two Unpaired Electrons, Synthesised by Oxidation of a Copper(II) Complex with Two Redox-Active Ligands. Angew Chem Int Ed Engl 2021; 60:23451-23462. [PMID: 34423532 PMCID: PMC8596453 DOI: 10.1002/anie.202109367] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 07/30/2021] [Indexed: 01/10/2023]
Abstract
Two homoleptic copper(II) complexes [Cu(L1)2 ] and [Cu(L2)2 ] with anionic redox-active ligands were synthesised, one with urea azine (L1) and the other with thio-urea azine (L2) ligands. One-electron oxidation of the complexes initiates an unprecedented redox-induced electron transfer process, leading to monocationic copper(I) complexes [Cu(L1)2 ]+ and [Cu(L2)2 ]+ with two oxidised ligands. While [Cu(L1)2 ]+ is best described as a CuI complex with two neutral radical ligands that couple antiferromagnetically, [Cu(L2)2 ]+ is a CuI complex with two clearly different ligand units in the solid state and with a magnetic susceptibility close to a diamagnetic compound. Further one-electron oxidation of the complex with L1 ligands results in a dication [Cu(L1)2 ]2+ , best described as a CuI complex with a twofold oxidised, monocationic ligand and a neutral radical ligand. The stability in at least three redox states, the accumulation of spin density at the ligands and the facile ligand-metal electron transfer make these complexes highly attractive for a variety of applications; here the catalytic aerobic oxidation of alcohols to aldehydes is tested.
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Affiliation(s)
- Marco Werr
- Anorganisch-Chemisches InstitutRuprecht-Karls Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Elisabeth Kaifer
- Anorganisch-Chemisches InstitutRuprecht-Karls Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Markus Enders
- Anorganisch-Chemisches InstitutRuprecht-Karls Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Andika Asyuda
- Angewandte Physikalische ChemieRuprecht-Karls Universität HeidelbergIm Neuenheimer Feld 25369120HeidelbergGermany
| | - Michael Zharnikov
- Angewandte Physikalische ChemieRuprecht-Karls Universität HeidelbergIm Neuenheimer Feld 25369120HeidelbergGermany
| | - Hans‐Jörg Himmel
- Anorganisch-Chemisches InstitutRuprecht-Karls Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
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