Prof. Dr. Thomas Braun

Profil

• Aktivierung von C-H- und C-F-Bindungen an Rhodium-Komplexen zur Funktionalisierung fluorierter Olefine und Ether

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 01/2022 - 01/2026 Projektleitung: Prof. Dr. Thomas Braun

• Aktivierung von SF6 an Rhodium-Komplexen

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 01/2016 - 12/2018 Projektleitung: Prof. Dr. Thomas Braun

• Aktivierung von SF6 an Rhodium- und Platin-Komplexen

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 03/2019 - 11/2022 Projektleitung: Prof. Dr. Thomas Braun

• AvH Forschungskostenzuschuss Hr. Oscar Torres Anton

  Quelle ↗

  Förderer: Alexander von Humboldt-Stiftung: Forschungskostenzuschuss Zeitraum: 09/2017 - 08/2019 Projektleitung: Prof. Dr. Thomas Braun

• CL Katalyse II: A1

  Quelle ↗

  Förderer: DFG Exzellenzinitiative Cluster Zeitraum: 11/2017 - 12/2018 Projektleitung: Prof. Dr. Thomas Braun

• Cluster: Integrale Konzepte der Katalyse II(D4)

  Quelle ↗

  Förderer: DFG Exzellenzinitiative Cluster Zeitraum: 11/2012 - 10/2017 Projektleitung: Prof. Dr. Thomas Braun

• Cluster: Integrale Konzepte der Katalyse (Teilbereich A 4)

  Quelle ↗

  Förderer: DFG Exzellenzinitiative Cluster Zeitraum: 11/2007 - 10/2012 Projektleitung: Prof. Dr. Thomas Braun

• Die Aufdeckung des photo-induzierten Assemblierungsmechanismus des lichtgetriebenen Wasseroxidationskomplexes in Photosystem II

  Quelle ↗

  Förderer: DFG Exzellenzinitiative Cluster Zeitraum: 11/2017 - 12/2018 Projektleitung: Prof. Dr. Athina Zouni

• EXC 2008 1_2 AG Braun - Carbonylation

  Quelle ↗

  Förderer: DFG Exzellenzstrategie Cluster Zeitraum: 01/2023 - 12/2025 Projektleitung: Prof. Dr. Thomas Braun

• EXC 2008: Unifying Systems in Catalysis (UniSysCat)

  Quelle ↗

  Förderer: DFG Exzellenzstrategie Cluster Zeitraum: 01/2019 - 12/2025 Projektleitung: Prof. Dr. Arne Thomas

• EXC 314/1: Carbonylation of Alkanes (AG Braun)

  Quelle ↗

  Förderer: DFG Exzellenzstrategie Cluster Zeitraum: 01/2019 - 12/2022 Projektleitung: Prof. Dr. Thomas Braun

• GRK 1582/2: Fluor als Schlüsselelement. Durch neue Synthesekonzepte zu Verbindungen mit einzigartigen Eigenschaften

  Quelle ↗

  Förderer: DFG Graduiertenkolleg Zeitraum: 09/2009 - 08/2018 Projektleitung: Prof. Dr. Thomas Braun

• Iridium catalysed hydroboration and borylation of fluorinated compounds

  Quelle ↗

  Förderer: Alexander von Humboldt-Stiftung Zeitraum: 05/2015 - 04/2017 Projektleitung: Prof. Dr. Thomas Braun

• Katalytische Carbonylierung von Alkanen

  Quelle ↗

  Förderer: Einstein Zentrum Zeitraum: 10/2021 - 09/2024 Projektleitung: Prof. Dr. Thomas Braun

• Metallvermittelte Funktionalisierung und Synthese fluorierter Aromaten und Aldehyde I

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 04/2007 - 03/2009 Projektleitung: Prof. Dr. Thomas Braun

• Metallvermittelte Funktionalisierung und Synthese fluorierter Aromaten und Aldehyde II

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 03/2007 - 04/2008 Projektleitung: Prof. Dr. Thomas Braun

• Palladium- und Platin-Silyl-Komplexe als reaktive Zwischenstufen zur katalytischen Hydrogenolyse von Disilanen

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 11/2009 - 10/2013 Projektleitung: Prof. Dr. Thomas Braun

• Platin-Silyl-Komplexe als reaktive Zwischenstufen zur katalytischen Hydrogenolyse von Disilanen

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 02/2014 - 01/2017 Projektleitung: Prof. Dr. Thomas Braun

• Rhodium- und Iridium-vermittelte Oxygenierungen mit Sauerstoff: Isolierung reaktiver Peroxido-Intermediate

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 09/2011 - 07/2015 Projektleitung: Prof. Dr. Thomas Braun

• Rhodium-vermittelte Oxygenierungen und Oxidationsreaktionen mit Sauerstoff: Isolierung reaktiver Intermediate mit Peroxo-Einheiten

  Quelle ↗

  Förderer: DFG Sachbeihilfe Zeitraum: 02/2007 - 09/2011 Projektleitung: Prof. Dr. Thomas Braun

• SFB 1109/1: Slioxane, Alumoxane und Alumosiloxane als Modelle für Oberflächendefekte in Hydrolyse- und Kondensationsreaktionen (TP A01)

  Quelle ↗

  Förderer: DFG Sonderforschungsbereich Zeitraum: 04/2014 - 12/2017 Projektleitung: Prof. Dr. Thomas Braun

• SFB 1109/2: Slioxane, Alumoxane und Alumosiloxane als Modelle für Oberflächendefekte in Hydrolyse- und Kondensationsreaktionen (TP A 01)

  Quelle ↗

  Förderer: DFG Sonderforschungsbereich Zeitraum: 01/2018 - 12/2018 Projektleitung: Prof. Dr. Thomas Braun

• SFB 1349/1: Fluorierte Aluminium‐Verbindungen als Lewis‐Säuren zur Aktivierung kleiner Moleküle (TP B04)

  Quelle ↗

  Förderer: DFG Sonderforschungsbereich Zeitraum: 01/2019 - 12/2022 Projektleitung: Prof. Dr. Thomas Braun

• SFB 1349/1: Steuerung von Fluorierungsreaktionen durch Wasserstoffbrücken in der Koordinationssphäre von Au- und Pt-Fluorido-Komplexen (TP A01)

  Quelle ↗

  Förderer: DFG Sonderforschungsbereich Zeitraum: 01/2019 - 12/2022 Projektleitung: Prof. Dr. Thomas Braun

• SFB 1349/2: Fluorierte Aluminium‐Verbindungen als Lewis‐Säuren zur Aktivierung kleiner Moleküle (TP B04)

  Quelle ↗

  Förderer: DFG Sonderforschungsbereich Zeitraum: 01/2023 - 12/2026 Projektleitung: Prof. Dr. Thomas Braun, Prof. Dr. Sebastian Hasenstab-Riedel

• SFB 1349/2: Steuerung von C-F-Bindungsaktivierung und Fluorierungsreaktionen durch Fluor-Spezifische Wechselwirkungen in der Koordinationssphäre von Metall-Verbindungen (TP A01)

  Quelle ↗

  Förderer: DFG Sonderforschungsbereich Zeitraum: 01/2023 - 12/2026 Projektleitung: Prof. Dr. Thomas Braun

• Science & Startups Berlin

  T

  26 Treffer57.0%
  • Zuwendung im Rahmen des Programms „exist – Existenzgründungen aus der Wissenschaft“ aus dem Bundeshaushalt, Einzelplan 09, Kapitel 02, Titel 68607, Haushaltsjahr 2026, sowie aus Mitteln des Europäischen Strukturfonds (hier Euro-päischer Sozialfonds Plus – ESF Plus) Förderperiode 2021-2027 – Kofinanzierung für das Vorhaben: „exist Women“
    T

    57.0%

• nanofluor GmbH

  PT

  147 Treffer56.6%
  • Entwicklung von wenig löslichen, homodispers nanoskopischen Metallfluoriden in Zahnzementen, Kompositfüllmaterialien und in Prophylaxepräparaten zum Einsatz im Dentalbereich
    P

    56.6%

• Peugeot Citroen Automobiles S.A.

  PT

  118 Treffer54.5%
  • EU: Monomer Sequence Control in Polymers: Toward Next-Generation Precision Materials (EURO-SEQUENCES)
    P

    54.5%

• Ionera Technologies GmbH

  PT

  117 Treffer54.5%
  • EU: Monomer Sequence Control in Polymers: Toward Next-Generation Precision Materials (EURO-SEQUENCES)
    P

    54.5%

• TechOnYou Srl

  PT

  123 Treffer54.4%
  • EU: Hybrid Organic/Inorganic Memory Elements for Integration of Electronic and Photonic Circuitry (HYMEC)
    P

    54.4%

• Scriba Nanotecnologie SRL

  P

  81 Treffer52.9%
  • Integrated Self-Assembled SWITCHable Systems and Materials: Towards Responsive Organic Electronics – A Multi-Site Innovative Training Action (iSwitch)
    P

    52.9%

• A.P.E. Research srl

  PT

  193 Treffer52.9%
  • Integrated Self-Assembled SWITCHable Systems and Materials: Towards Responsive Organic Electronics – A Multi-Site Innovative Training Action (iSwitch)
    P

    52.9%
  • EU: Bottom-Up Generation of atomicalLy Precise syntheTIc 2D MATerials for High Performance in Energy and Electronic Applications – A Multi-Site Innovative Training Action (ULTIMATE)
    T

    51.9%

• BASF SE

  PT

  156 Treffer52.9%
  • Integrated Self-Assembled SWITCHable Systems and Materials: Towards Responsive Organic Electronics – A Multi-Site Innovative Training Action (iSwitch)
    P

    52.9%
  • SIB-DE_Forschung - Sodium-Ion-Battery Deutschland (SIB:DE Initiative) - Eignung der Natrium-Ionen-Technologie für die europäische Energie- und Mobilitätswende
    P

    50.9%

• TIAMAT Energy

  PT

  55 Treffer52.8%
  • Twinning for Rechargeable Sodium-Ion Battery Research (TwinBat)
    T

    52.8%

• Gebze Teknik Universitesi Teknoloji Transfer Ofisi Anonim

  PT

  57 Treffer52.8%
  • Twinning for Rechargeable Sodium-Ion Battery Research (TwinBat)
    T

    52.8%

• Functionalization of Fluorinated Molecules by Transition-Metal-Mediated C–F Bond Activation To Access Fluorinated Building Blocks

  2014

  Chemical Reviews · 829 Zitationen · DOI

  ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTFunctionalization of Fluorinated Molecules by Transition-Metal-Mediated C–F Bond Activation To Access Fluorinated Building BlocksTheresia Ahrens, Johannes Kohlmann, Mike Ahrens, and Thomas Braun*View Author Information Humboldt-Universität zu Berlin, Department of Chemistry, Brook-Taylor-Straße 2, 12489 Berlin, Germany*Phone: +49-03-2093-3913. Fax: +49-03-2093-7468. E-mail: [email protected]Cite this: Chem. Rev. 2015, 115, 2, 931–972Publication Date (Web):October 27, 2014Publication History Received14 May 2014Published online27 October 2014Published inissue 28 January 2015https://pubs.acs.org/doi/10.1021/cr500257chttps://doi.org/10.1021/cr500257creview-articleACS PublicationsCopyright © 2014 American Chemical SocietyRequest reuse permissionsArticle Views16260Altmetric-Citations679LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Bond activation,Chemical reactions,Cross coupling reaction,Ligands,Reaction products Get e-Alerts

• Synthesis of Fluorinated Building Blocks by Transition‐Metal‐Mediated Hydrodefluorination Reactions

  2013

  Angewandte Chemie International Edition · 417 Zitationen · DOI

  The activation and functionalization of carbon-fluorine bonds can be considered as a major challenge in organometallic chemistry. The growing demand for means to introduce fluorine into new materials or into biologically active molecules has inspired the development of diverse synthetic strategies. Hydrodefluorination is regarded as a promising approach to access partially fluorinated building blocks from readily available perfluorinated bulk chemicals. We provide an overview of transition-metal-based complexes and catalysts that were developed to mediate hydrodefluorination reactions. Special emphasis will be placed on discussing the underlying mechanistic patterns and their impact on scope and selectivity. In addition, future requirements for further developing this field will be highlighted.

• C−F Activation of Fluorinated Arenes using NHC-Stabilized Nickel(0) Complexes: Selectivity and Mechanistic Investigations

  2008

  Journal of the American Chemical Society · 244 Zitationen · DOI

  The reaction of [Ni2((i)Pr2Im)4(COD)] 1a or [Ni((i)Pr2Im)2(eta(2)-C2H4)] 1b with different fluorinated arenes is reported. These reactions occur with a high chemo- and regioselectivity. In the case of polyfluorinated aromatics of the type C6F5X such as hexafluorobenzene (X = F) octafluorotoluene (X = CF3), trimethyl(pentafluorophenyl)silane (X = SiMe3), or decafluorobiphenyl (X = C6F5) the C-F activation regioselectively takes place at the C-F bond in the para position to the X group to afford the complexes trans-[Ni((i)Pr2Im)2(F)(C6F5)]2, trans-[Ni((i)Pr2Im)2(F)(4-(CF3)C6F4)] 3, trans-[Ni((i)Pr2Im)2(F)(4-(C6F5)C6F4)] 4, and trans-[Ni((i)Pr2Im)2(F)(4-(SiMe3)C6F4)] 5. Complex 5 was structurally characterized by X-ray diffraction. The reaction of 1a with partially fluorinated aromatic substrates C6H(x)F(y) leads to the products of a C-F activation trans-[Ni((i)Pr2Im)2(F)(2-C6FH4)] 7, trans-[Ni((i)Pr2Im)2(F)(3,5-C6F2H3)] 8, trans-[Ni((i)Pr2Im)2(F)(2,3-C6F2H3)] 9a and trans-[Ni((i)Pr2Im)2(F)(2,6-C6F2H3)] 9b, trans-[Ni((i)Pr2Im)2(F)(2,5-C6F2H3)] 10, and trans-[Ni((i)Pr2Im)2(F)(2,3,5,6-C6F4H)] 11. The reaction of 1a with octafluoronaphthalene yields exclusively trans-[Ni((i)Pr2Im)2(F)(1,3,4,5,6,7,8-C10F7)] 6a, the product of an insertion into the C-F bond in the 2-position, whereas for the reaction of 1b with octafluoronaphthalene the two isomers trans-[Ni((i)Pr2Im)2(F)(1,3,4,5,6,7,8-C10F7)] 6a and trans-[Ni((i)Pr2Im)2(F)(2,3,4,5,6,7,8-C10F7)] 6b are formed in a ratio of 11:1. The reaction of 1a or of 1b with pentafluoropyridine at low temperatures affords trans-[Ni((i)Pr2Im)2(F)(4-C5NF4)] 12a as the sole product, whereas the reaction of 1b performed at room temperature leads to the generation of trans-[Ni((i)Pr2Im)2(F)(4-C5NF4)] 12a and trans-[Ni((i)Pr2Im)2(F)(2-C5NF4)] 12b in a ratio of approximately 1:2. The detection of intermediates as well as kinetic studies gives some insight into the mechanistic details for the activation of an aromatic carbon-fluorine bond at the {Ni((i)Pr2Im)2} complex fragment. The intermediates of the reaction of 1b with hexafluorobenzene and octafluoronaphthalene, [Ni((i)Pr2Im)2(eta(2)-C6F6)] 13 and [Ni((i)Pr2Im)2(eta(2)-C10F8)] 14, have been detected in solution. They convert into the C-F activation products. Complex 14 was structurally characterized by X-ray diffraction. The rates for the loss of 14 at different temperatures for the C-F activation of the coordinated naphthalene are first order and the estimated activation enthalpy Delta H(double dagger) for this process was determined to be Delta H(double dagger) = 116 +/- 8 kJ mol(-1) (Delta S(double dagger) = 37 +/- 25 J K(-1) mol(-1)). Furthermore, density functional theory calculations on the reaction of 1a with hexafluorobenzene, octafluoronaphthalene, octafluorotoluene, 1,2,4-trifluorobenzene, and 1,2,3-trifluorobenzene are presented.

• Routes to fluorinated organic derivatives by nickel mediated C–F activation of heteroaromatics

  2002

  Chemical Communications · 221 Zitationen · DOI

  New fluorinated azaheterocycles can be synthesised regio- and chemo-selectively via C-F activation of fluorinated precursors at nickel, with subsequent functionalisation and release from the coordination sphere of the metal; the requirements for productive C-F activation are significantly different from those for C-H bond activation.

• A Highly Reactive Rhodium(I)–Boryl Complex as a Useful Tool for CH Bond Activation and Catalytic CF Bond Borylation

  2010

  Angewandte Chemie International Edition · 177 Zitationen · DOI

  CF bond borylation: A 16-electron rhodium(I)–boryl complex was synthesized by borylation of a rhodium(I)–fluorine complex. The former reacts with benzene or 2,3,5,6-tetrafluoropyridine by CH activation. A catalytic CF borylation reaction of pentafluoropyridine was also developed, which uses [Rh(Bpin)(PEt3)3] as a catalyst and Me3SiSiMe3 as a solvent. pin=pinacol. Detailed facts of importance to specialist readers are published as "Supporting Information". Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

• Catalytic CF Activation and Hydrodefluorination of Fluoroalkyl Groups

  2009

  Angewandte Chemie International Edition · 168 Zitationen · DOI

  A powerful fluoride trap: The extremely Lewis acidic silyl cation [Et(3)Si](+) is an active catalyst for the hydrodefluorination of fluoroalkyl groups at room temperature (see example). The carborane anion [CHB(11)H(5)Cl(6)](-) plays an essential role in the catalytic cycle as a weakly coordinating anion that stabilizes cationic intermediates.

• Contrasting Reactivity of Fluoropyridines at Palladium and Platinum:  C−F Oxidative Addition at Palladium, P−C and C−F Activation at Platinum

  2004

  Organometallics · 156 Zitationen · DOI

  The divergent behavior of palladium(0) and platinum(0) is revealed in the reactivity of [M(PR3)2] (M = Pd or Pt; R = Cy or iPr) toward pentafluoropyridine and 2,3,5,6-tetrafluoropyridine. The palladium complexes react with pentafluoropyridine at 100 °C to yield the fluoride complexes trans-[Pd(F)(4-C5NF4)(PR3)2]. They do not react with 2,3,5,6-tetrafluoropyridine. The reaction of platinum(0) complexes [Pt(PR3)2] with pentafluoropyridine in THF at ambient temperature yields trans-[Pt(R)(4-C5NF4)(PR3)(PFR2)] complexes, whereas the reaction of [Pt(PCy3)2] with 2,3,5,6-tetrafluoropyridine results in C−H activation to form cis-[Pt(H)(4-C5NF4)(PCy3)2]; this complex may be converted to the trans isomer by photolysis. The cis-hydride also forms during the reaction of [Pt(PCy3)2] with C5NF5 in hexane. These reactions also contrast with earlier studies of the reactivity of the same substrates toward {Ni(PEt3)2}, which yield [Ni(F)(2-C5NF5)(PEt3)2] with pentafluoropyridine and [Ni(F)(2-C5NF4H)(PEt3)2] with tetrafluoropyridine. Thus palladium has different regioselectivity from nickel and is the least reactive. Platinum is capable of both C−F and C−H activation and is alone in the triad in undergoing rearrangement to the alkyl complex with the fluorophosphine ligand. Mechanisms for the rearrangement are proposed. The platinum dihydride complex trans-[Pt(H)2(PR3)2] reacts with pentafluoropyridine at room temperature, yielding a 1:1:1 mixture of trans-[PtH(FHF)(PR3)2], trans-[Pt(H)(4-C5NF4)(PR3)2], and trans-[Pt(R)(4-C5NF4)(PR3)(PFR2)]. Crystal structures are reported for trans-[Pd(F)(4-C5NF4)(PCy3)2]·H2O·C6H6, trans-[Pd(F)(4-C5NF4)(PiPr3)2], trans-[Pt(C6H11)(4-C5NF4)(PCy3)(PFCy2)]· CH2Cl2, and cis-[Pt(H)(4-C5NF4)(PCy3)2].

• Catalytic C-F activation of polyfluorinated pyridines by nickel-mediated cross-coupling reactions.

  2001

  Chemical Communications · 148 Zitationen · DOI

  The cross-coupling reaction of pentafluoropyridine with tributyl(vinyl)tin affording 2-vinyltetrafluoropyridine by activation of a carbon-fluorine bond is catalysed by [NiF(2-C5NF4)(PEt3)2]; a similar reaction is observed with 2,3,5,6-tetrafluoropyridine.

• C–F Bond Activation of Highly Fluorinated Molecules at Rhodium: From Model Reactions to Catalysis

  2011

  European Journal of Inorganic Chemistry · 145 Zitationen · DOI

  Abstract Rhodium complexes are excellent tools for the activation of aromatic and olefinic carbon–fluorine bonds. C–F bond cleavage reactions are key steps for the derivatization of highly fluorinated compounds via stoichiometric or catalytic reaction pathways. The reaction routes involve hydrodefluorinations, but also the selective introduction of functional groups at distinctive positions, to provide access to new fluorinated building blocks. One can identify two general types of rhodium precursors that can induce the C–F activation step. Cyclopentadienyl compounds have been applied for thermal and photochemical C–F bond cleavage reactions of aromatics in solution, but oxidative addition steps have also been investigated in matrix isolation studies at low temperature. Square‐planar hydrido, silyl, and boryl complexes are often involved in unique stoichiometric and catalytic processes for the derivatization of aromatics and olefins.

• Catalytic C−C Coupling Reactions at Nickel by C−F Activation of a Pyrimidine in the Presence of a C−Cl Bond:  The Crucial Role of Highly Reactive Fluoro Complexes

  2005

  Organometallics · 140 Zitationen · DOI

  Treatment of [Ni(COD)2] (COD = 1,5-cyclooctadiene) with 5-chloro-2,4,6-trifluoropyrimidine (1) in the presence of PiPr3 or PPh3 effects the formation of the fluoro complexes trans-[NiF(4-C4N2ClF2)(PiPr3)2] (3) and trans-[NiF(4-C4N2ClF2)(PPh3)2] (4). The chloro complex trans-[NiCl(4-C4N2ClF2)(PPh3)2] (5) can be prepared by reaction of 4 with Me3SiCl. In contrast, a reaction of 1 with [Pd(PPh3)4] leads to the insertion of a {Pd(PPh3)2} unit into the C−Cl bond yielding trans-[PdCl(5-C4N2F3)(PPh3)2] (6). Treatment of 4 with an excess of TolB(OH)2 at 273 K results in the slow formation of trans-[NiF(4-C4N2TolClF)(PPh3)2] (7) and subsequently 5-chloro-2-fluoro-4,6-ditolylpyrimidine (8). Quenching of a solution of 7 with Me3SiCl leads to the chloro derivative trans-[NiCl(4-C4N2TolClF)(PPh3)2] (9). Treatment of 4 with PhB(OH)2 followed by addition of Me3SiCl gives the complex trans-[NiCl(4-C4N2PhClF)(PPh3)2] (10). In catalytic experiments, 1 is converted with the boronic acids TolB(OH)2, PhB(OH)2, and p-F3CC6H4B(OH)2 into the 5-chloro-2-fluoro-4,6-diarylpyrimidines 8, 11, and 12 in 73%, 88%, and 37% yield, respectively, when 10% of 4 is employed as catalyst. The molecular structures of the complexes 5, 6, and 10 have been determined by X-ray crystallography. The studies reported in this paper represent the first catalytic C−C coupling reactions involving the activation of a C−F bond in the presence of a thermodynamically weaker C−Cl bond. They provide a route to access 5-chloro-2-fluoro-4,6-diarylpyrimidines, which have not been described before. There is considerable evidence that the presence of the fluoro ligand in 4 is crucial for the transmetalation step to occur and for the catalytic cycle to proceed.

• CF Activation at Rhodium Boryl Complexes: Formation of 2‐Fluoroalkyl‐1,3,2‐Dioxaborolanes by Catalytic Functionalization of Hexafluoropropene

  2009

  Angewandte Chemie International Edition · 138 Zitationen · DOI

  Fluorinated building blocks by C-F bond cleavage: Catalytic C-F activation reactions that give novel dioxaborolanes have been developed (see scheme). The reactions proceed at room temperature, and catalytic intermediates are presumably rhodium hydride and boryl species.

• The Nature of the Active Phase in the Heteropolyacid Catalyst H4PvMo11O40·32H2O Used for the Selective Oxidation of Isobutyric Acid

  1995

  Journal of Catalysis · 138 Zitationen · DOI

• Conversion of Hexafluoropropene into 1,1,1-Trifluoropropane by Rhodium-Mediated CF Activation

  2002

  Angewandte Chemie International Edition · 126 Zitationen · DOI

  Rapid and regioselective CF bond activation of hexafluoropropene occurs on reaction with 1. Treatment of the resulting complex 2 with hydrogen yields the rhodium fluoro complex 3 and 1,1,1-trifluoropropane (4). Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2002/z19051_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

• Synthese fluorierter Bausteine durch Übergangsmetall‐vermittelte Hydrodefluorierungsreaktionen

  2013

  Angewandte Chemie · 124 Zitationen · DOI

  Abstract Die Aktivierung und Funktionalisierung von Kohlenstoff‐Fluor‐Bindungen ist eine der großen Herausforderungen für die metallorganische Chemie. Der steigende Bedarf an Wegen zur Einführung von Fluor in neue Materialien und biologisch aktive Moleküle hat die Entwicklung verschiedener Synthesestrategien inspiriert. Die Hydrodefluorierung wird als vielversprechender Ansatz angesehen, um teilfluorierte Bausteine aus leicht verfügbaren perfluorierten Basischemikalien zu gewinnen. Dieser Aufsatz fasst Aspekte zur Hydrodefluorierung mithilfe Übergangsmetall‐basierter Komplexe und Katalysatoren zusammen und legt dabei besonderes Augenmerk auf die zugrundeliegenden mechanistischen Muster und deren Einfluss auf Anwendungsbreite und Selektivität des jeweiligen Systems. Darüber hinaus werden Anstöße für eine künftige Weiterentwicklung dieses Forschungsgebietes gegeben.

• Nickel-Assisted Carbon-Fluorine Bond Activation of 2,4,6-Trifluoropyrimidine: Synthesis of New Pyrimidine and Pyrimidinone Derivatives

  1999

  Angewandte Chemie International Edition · 122 Zitationen · DOI

  Rapid and regioselective activation of the C-F bond of 2,4,6-trifluoropyrimidine occurs on reaction with [Ni(cod)(2)] (cod=1,5-cyclooctadiene) in the presence of PEt(3) to give 1, which can be converted into complex 2, containing a further N(3)-metalated pyrimidin-4-one unit. The novel pyrimidin-4-one 3 is released on protonation of 2.

• Hydrogenation of a Rhodium Peroxido Complex by Formate Derivatives: Mechanistic Studies and the Catalytic Formation of H₂O₂ from O₂

  2012

  Angewandte Chemie International Edition · 114 Zitationen · DOI

  Hydrogenation of dioxygen: The rhodium peroxido complex 1, which can be prepared from 2 and dioxygen, can be reduced with dihydrogen sources to yield hydrogen peroxide. In a catalytic experiment, hydrogen peroxide is produced from dioxygen and ammonium formate under ambient conditions in the presence of 1 (see scheme).

• C–F or C–H bond activation and C–C coupling reactions of fluorinated pyridines at rhodium: synthesis, structure and reactivity of a variety of tetrafluoropyridyl complexes

  2004

  Dalton Transactions · 114 Zitationen · DOI

  Reactions of [RhH(PEt3)3] (1) or [RhH(PEt3)4] (2) with pentafluoropyridine or 2,3,5,6-tetrafluoropyridine afford the activation product [Rh(4-C5NF4)(PEt3)3] (3). Treatment of 3 with CO, 13CO or CNtBu effects the formation of trans-[Rh(4-C5NF4)(CO)(PEt3)2] (4a), trans-[Rh(4-C5NF4)(13CO)(PEt3)2] (4b) and trans-[Rh(4-C5NF4)(CNtBu)(PEt3)2] (5). The rhodium(III) compounds trans-[RhI(CH3)(4-C5NF4)(PEt3)2] (6a) and trans-[RhI(13CH3)(4-C5NF4)(PEt3)2] (6b) are accessible on reaction of 3 with CH3I or 13CH3I. In the presence of CO or 13CO these complexes convert into trans-[RhI(CH3)(4-C5NF4)(CO)(PEt3)2] (7a), trans-[RhI(13CH3)(4-C5NF4)(CO)(PEt3)2] (7b) and trans-[RhI(13CH3)(4-C5NF4)(13CO)(PEt3)2] (7c). The trans arrangement of the carbonyl and methyl ligand in 7a-7c has been confirmed by the 13C-13C coupling constant in the 13C NMR spectrum of 7c. A reaction of 4a or 4b with CH3I or 13CH3I yields the acyl compounds trans-[RhI(COCH3)(4-C5NF4)(PEt3)2] (8a) and trans-[RhI(13CO13CH3)(4-C5NF4)(PEt3)2] (8b), respectively. Complex 8a slowly reacts with more CH3I to give [PEt3Me][Rh(I)2(COCH3)(4-C5NF4)(PEt3)](9). On heating a solution of 7a, the complex trans-[RhI(CO)(PEt3)2] (10) and the C-C coupled product 4-methyltetrafluoropyridine (11) have been obtained. Complex 8a also forms 10 at elevated temperatures in the presence of CO together with the new ketone 4-acetyltetrafluoropyridine (12). The structures of the complexes 3, 4a, 5, 6a, 8a and 9 have been determined by X-ray crystallography. 19F-1H HMQC NMR solution spectra of 6a and 8a reveal a close contact of the methyl groups in the phosphine to the methyl or acyl ligand bound at rhodium.

• C–F Activation and hydrodefluorination of fluorinated alkenes at rhodium

  2003

  Dalton Transactions · 111 Zitationen · DOI

  Reaction of [RhH(PEt3)4] (9) with hexafluoropropene (1) affords the C–F activation product [Rh{(Z)-CFCF(CF3)}(PEt3)3] (4) as well as Et3P(F){(Z)-CFCF(CF3)} (11). In contrast, addition of (E)-1,2,3,3,3-pentafluoropropene (8) to 9 yields [Rh{(E)-C(CF3)CHF}(PEt3)3] (12) together with [RhF(PEt3)3] (6) and (Z)-1,3,3,3-tetrafluoropropene (10). Treatment of 12 with hydrogen effects the formation of 1,1,1-trifluoropropane (2) and the fluoro compounds [RhF(PEt3)3] (6) and cis-mer-[Rh(H)2F(PEt3)3] (7). On treatment of 6 or of a mixture of 6 and 7 with HSiPh3 the complexes [RhH(PEt3)3] (3) and cis-fac-[Rh(H)2(SiPh3)(PEt3)3] (13) are obtained. Both compounds are capable of the C–F activation of hexafluoropropene (1) to afford 4. The molecular structure of complex 13 has been determined by X-ray crystallography.

• Hydrodefluorination of pentafluoropyridine at rhodium using dihydrogen: detection of unusual rhodium hydrido complexes

  2007

  Dalton Transactions · 109 Zitationen · DOI

  The pentafluoropyridyl complex [Rh(4-C5NF4)(PEt3)3] (3) reacts with H2 to give initially the dihydrido complex cis-mer-[Rh(H)2(4-C5NF4)(PEt3)3] (6). Within a few hours 2,3,5,6-tetrafluoropyridine as well as two rhodium(III) complexes mer-[Rh(H)3(PEt3)3] (mer-) and fac-[Rh(H)3(PEt3)3] (fac-) are formed. A catalytic C-F activation process for the formation of 2,3,5,6-tetrafluoropyridine starting from pentafluoropyridine and dihydrogen using 3 as a catalyst has been developed. Reaction of [RhH(PEt3)3] (1) with hydrogen affords fac-[Rh(H)3(PEt3)3] (fac-7) and mer-[Rh(H)3(PEt3)3] (mer-7) in a ratio of 1 : 7.25 at 193 K. The latter complex represents the first mononuclear rhodium compound bearing trans-hydrides.

• Catalytic CF Bond Activation of Hexafluoropropene by Rhodium: Formation of (3,3,3‐Trifluoropropyl)silanes

  2007

  Angewandte Chemie International Edition · 104 Zitationen · DOI

  A clean break: The novel catalytic conversion of hexafluoropropene into (3,3,3-trifluoropropyl)silanes by CF activation has been developed (see scheme). The reactions are catalyzed by the rhodium complex [Rh{(Z)-CFCF(CF3)}(PEt3)3], proceed at room temperature, and are highly selective.

• Consecutive Transformations of Tetrafluoropropenes: Hydrogermylation and Catalytic C−F Activation Steps at a Lewis Acidic Aluminum Fluoride

  2017

  Angewandte Chemie International Edition · 96 Zitationen · DOI

  Functionalization reactions of the refrigerants HFO-1234yf (2,3,3,3-tetrafluoropropene) and HFO-1234ze (1,3,3,3-tetrafluoropropene) were developed. The selectivity and reactivity towards CF₃ groups of C-F activation reactions can be controlled by employing either a germane or a silane as the hydrogen source. Unique transformations were designed to accomplish consecutive hydrogermylation and C-F activation steps. This allowed for an unprecedented transformation of an olefinic C-F bond into a C-H bond by heterogeneous catalysis. These reactions are catalyzed by nanoscopic aluminum chlorofluoride (ACF) under very mild conditions.

• Reactivity of a palladium fluoro complex towards silanes and Bu₃SnCHCH₂: catalytic derivatisation of pentafluoropyridine based on carbon–fluorine bond activation reactions

  2006

  Dalton Transactions · 92 Zitationen · DOI

  The chloro and azido complexes trans-[PdCl(4-C5NF4)(PiPr3)2] (3) and trans-[Pd(N3)(4-C5NF4)(PiPr3)2] (4) can be prepared by reaction of [PdF(4-C5NF4)(PiPr3)2] (2) with Et3SiCl or MeSiN3, respectively. In contrast, reactions of 2 with Ph3SiH or Me2FSiSiFMe2 give the products of reductive elimination 2,3,5,6-tetrafluoropyridine (5) or 4-(fluorodimethylsilyl)tetrafluoropyridine (6) as well as [Pd(PiPr3)2] (1). In a catalytic experiment, pentafluoropyridine can be converted with Ph3SiH into 5 in 62% yield, when 10% of 2 is employed as catalyst. Treatment of trans-[PdF(4-C5NF4)(PiPr3)2] (2) with Bu3SnCH=CH2 in THF at 50 degrees C results in the formation of [Pd(PiPr3)2] (1) and 4-vinyltetrafluoropyridine (7). Complex 2 is also active as a catalyst towards a Stille cross-coupling reaction of pentafluoropyridine with Bu3SnCH=CH2 to give 4-vinyltetrafluoropyridine (7) with a TON of 6. The molecular structure of the complex 3 has been determined by X-ray crystallography.

• C–H and C–F Bond Activations at a Rhodium(I) Boryl Complex: Reaction Steps for the Catalytic Borylation of Fluorinated Aromatics

  2015

  Organometallics · 91 Zitationen · DOI

  Treatment of the rhodium(I) boryl complex [Rh(Bpin)(PEt3)3] (1, pin = pinacolato = O2C2Me4) with pentafluorobenzene, 1,3,5-trifluorobenzene, 1,3-difluorobenzene, or 3,5-difluoropyridine led to C–H activation reactions to give the aryl complexes [Rh(C6F5)(PEt3)3] (4), [Rh(2,4,6-C6F3H2)(PEt3)3] (5), [Rh(2,6-C6F2H3)(PEt3)3] (6), and [Rh{4-(3,5-C5NF2H2)}(PEt3)3] (8). For 5, 6, and 8 consecutive reactions with in situ generated HBpin occurred to yield [Rh(H)(PEt3)3] (7) and boronic esters. The boryl complex 1 gave with hexafluorobenzene or perfluorotoluene the C–F activation products [Rh(C6F5)(PEt3)3] (4) and [Rh(4-C6F4CF3)(PEt3)3] (9), respectively. The complexes 5, 6, and 9 react with B2pin2 to yield 1 and boronic ester derivatives. On the basis of these stoichiometric reactions catalytic C–H and C–F borylation reactions using 1 or 7 were developed to generate 2-Bpin-1,3,5-C6F3H2, 2-Bpin-1,3-C6F2H3, and 4-Bpin-C6F4CF3 from 1,3,5-trifluorobenzene, 1,3-difluorobenzene, or perfluorotoluene and B2pin2. On treatment of pentafluoropyridine with B2pin2 in the presence of 1 or 7 as catalyst 2-Bpin-C5NF4 was synthesized by C–F borylation at the 2-position. Using 2,3,5,6-tetrafluoropyridine, B2pin2, and catalytic amounts of 7 led to a C–H borylation reaction at the 4-position. 4-Bpin-C5NF4 can also be prepared by the reaction of 2,3,5,6-tetrafluoropyridine with stoichiometric amounts of HBpin or by the reaction of pentafluoropyridine with an excess of HBpin in the presence of 7, whereas the reaction of pentafluoropyridine with stoichiometric amounts of HBpin and 5 mol % 7 resulted in the formation of 2,3,5,6-tetrafluoropyridine via hydrodefluorination reaction at the 4-position. This regioselectivity contrasts the borylation of pentafluoropyridine at the 2-position with 1 as catalyst. Overall, the obtained fluorinated aryl boronic ester derivatives might serve as versatile building blocks.

• Coordination and oxidative addition of octafluoronaphthalene at a nickel centre: isolation of an intermediate in C–F bond activation

  2001

  New Journal of Chemistry · 87 Zitationen · DOI

  Reaction of [Ni(COD)2] with PEt3 and octafluoronaphthalene yielded the complex [Ni(η2-1,2-C10F8)(PEt3)2] 1, which was converted thermally into the C–F activation product trans-[NiF(2-C10F7)(PEt3)2] 2. The crystal structure of 1 shows asymmetric η2 coordination with significant distortions of the naphthalene unit compared to the “ free” ligand; DFT calculations reproduce the principal features of the geometry.

• Aromatic C–F activation at Ni in the presence of a carbon–chlorine bond: the nickel mediated synthesis of new pyrimidines

  2002

  Journal of the Chemical Society Dalton Transactions · 83 Zitationen · DOI

  Treatment of [Ni(COD)2]/PCy3 with 5-chloro-2,4,6-trifluoropyrimidine affords the C–F activation product trans-[NiF(4-C4N2ClF2)(PCy3)2] 2, which reacts with iodine to form 5-chloro-2,6-difluoro-4-iodo-pyrimidine 5.

• Bundesanstalt für Materialforschung und -prüfung

  SFB 1349/1: Fluorierte Aluminium‐Verbindungen als Lewis‐Säuren zur Aktivierung kleiner Moleküle (TP B04)

  other

• Charité – Universitätsmedizin Berlin

  EXC 2008: Unifying Systems in Catalysis (UniSysCat)

  university

• Freie Universität Berlin

  SFB 1349/2: Fluorierte Aluminium‐Verbindungen als Lewis‐Säuren zur Aktivierung kleiner Moleküle (TP B04)

  university

• Fritz-Haber-Institut der Max-Planck-Gesellschaft

  SFB 1349/1: Fluorierte Aluminium‐Verbindungen als Lewis‐Säuren zur Aktivierung kleiner Moleküle (TP B04)

  other

• Helmholtz-Zentrum Berlin für Materialien und Energie

  EXC 2008: Unifying Systems in Catalysis (UniSysCat)

  other

• Leibniz-Forschungsinstitut für Molekulare Pharmakologie

  EXC 2008: Unifying Systems in Catalysis (UniSysCat)

  other

• Max-Planck-Institut für Kolloid- und Grenzflächenforschung

  EXC 2008: Unifying Systems in Catalysis (UniSysCat)

  other

• Technische Universität Berlin

  SFB 1349/1: Fluorierte Aluminium‐Verbindungen als Lewis‐Säuren zur Aktivierung kleiner Moleküle (TP B04)

  university

• Universität Potsdam

  EXC 2008: Unifying Systems in Catalysis (UniSysCat)

  university

Name

Prof. Dr. Thomas Braun

Titel

Prof. Dr.

Fakultät

Mathematisch-Naturwissenschaftliche Fakultät

Institut

Institut für Chemie

Arbeitsgruppe

Anorganische Chemie

Telefon

+49 30 2093-3913

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