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Hoffmann KF, Wiesner A, Müller C, Steinhauer S, Beckers H, Kazim M, Pitts CR, Lectka T, Riedel S. Structural proof of a [C-F-C] + fluoronium cation. Nat Commun 2021; 12:5275. [PMID: 34489464 PMCID: PMC8421340 DOI: 10.1038/s41467-021-25592-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 08/11/2021] [Indexed: 11/16/2022] Open
Abstract
Organic fluoronium ions can be described as positively charged molecules in which the most electronegative and least polarizable element fluorine engages in two partially covalent bonding interactions to two carbon centers. While recent solvolysis experiments and NMR spectroscopic studies on a metastable [C–F–C]+ fluoronium ion strongly support the divalent fluoronium structure over the alternative rapidly equilibrating classical carbocation, the model system has, to date, eluded crystallographic analysis to confirm this phenomenon in the solid state. Herein, we report the single crystal structure of a symmetrical [C–F–C]+ fluoronium cation. Besides its synthesis and crystallographic characterization as the [Sb2F11]− salt, vibrational spectra are discussed and a detailed analysis concerning the nature of the bonding situation in this fluoronium ion and its heavier halonium homologues is performed, which provides detailed insights on this molecular structure. Unlike other halogen atoms, the ability for fluorine to exist in a [C–X–C]+ connectivity pattern has only been shown in spectroscopic studies. Here the authors present a single crystal structure of a fluoronium cation, characterized by X-ray diffraction.
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Affiliation(s)
- Kurt F Hoffmann
- Fachbereich Biologie, Chemie, Pharmazie, Institut für Chemie und Biochemie - Anorganische Chemie, Freie Universität Berlin, Berlin, Germany
| | - Anja Wiesner
- Fachbereich Biologie, Chemie, Pharmazie, Institut für Chemie und Biochemie - Anorganische Chemie, Freie Universität Berlin, Berlin, Germany
| | - Carsten Müller
- Fachbereich Biologie, Chemie, Pharmazie, Institut für Chemie und Biochemie - Anorganische Chemie, Freie Universität Berlin, Berlin, Germany
| | - Simon Steinhauer
- Fachbereich Biologie, Chemie, Pharmazie, Institut für Chemie und Biochemie - Anorganische Chemie, Freie Universität Berlin, Berlin, Germany
| | - Helmut Beckers
- Fachbereich Biologie, Chemie, Pharmazie, Institut für Chemie und Biochemie - Anorganische Chemie, Freie Universität Berlin, Berlin, Germany
| | - Muhammad Kazim
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, USA
| | - Cody Ross Pitts
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, USA.,Department of Chemistry, University of California, Davis, Davis, CA, USA
| | - Thomas Lectka
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, USA.
| | - Sebastian Riedel
- Fachbereich Biologie, Chemie, Pharmazie, Institut für Chemie und Biochemie - Anorganische Chemie, Freie Universität Berlin, Berlin, Germany.
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Hämmerling S, Voßnacker P, Steinhauer S, Beckers H, Riedel S. Friedel-Crafts Type Methylation with Dimethylhalonium Salts. Chemistry 2020; 26:14377-14384. [PMID: 32277527 PMCID: PMC7702172 DOI: 10.1002/chem.202001457] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Indexed: 11/15/2022]
Abstract
The dimethylchloronium salt [Me2 Cl][Al(OTeF5 )4 ] is used to methylate electron-deficient aromatic systems in Friedel-Crafts type reactions as shown by the synthesis of N-methylated cations, such as [MeNC5 F5 ]+ , [MeNC5 F4 I]+ , and [MeN3 C3 F3 ]+ . To gain a better understanding of such fundamental Friedel-Crafts reactions, the role of the dimethylchloronium cation has been evaluated by quantum-chemical calculations.
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Affiliation(s)
- Sebastian Hämmerling
- Institut für Chemie und BiochemieFreie Universität BerlinFabeckstr.34/3614195BerlinGermany
| | - Patrick Voßnacker
- Institut für Chemie und BiochemieFreie Universität BerlinFabeckstr.34/3614195BerlinGermany
| | - Simon Steinhauer
- Institut für Chemie und BiochemieFreie Universität BerlinFabeckstr.34/3614195BerlinGermany
| | - Helmut Beckers
- Institut für Chemie und BiochemieFreie Universität BerlinFabeckstr.34/3614195BerlinGermany
| | - Sebastian Riedel
- Institut für Chemie und BiochemieFreie Universität BerlinFabeckstr.34/3614195BerlinGermany
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