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Altenhof AR, Kaseman DC, Mason HE, Alvarez MA, Malone MW, Williams RF. On the effects of quadrupolar relaxation in Earth's field NMR spectra. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 355:107540. [PMID: 37722217 DOI: 10.1016/j.jmr.2023.107540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 08/11/2023] [Accepted: 08/15/2023] [Indexed: 09/20/2023]
Abstract
There is growing interest in using low-field magnetic resonance experiments for routine chemical characterization. Earth's field NMR is one such technique that can garner structural information and enable sample differentiation with low cost and highly portable designs. The resulting NMR spectra are primarily influenced by J-couplings, resulting in so-called J-coupled spectra (JCS). Many small molecules include atoms with NMR-active nuclei that are quadrupolar either at natural abundance or are often isotopically enriched (e.g.,2H, 6Li, 11B, 14N, 17O, etc.) where the effects of quadrupolar J-couplings and relaxation on JCS of strongly- and weakly-coupled spin systems have not been explored to date. Herein, using a set of seven fluoropyridine samples with unique substitution and J-couplings, we demonstrate that the 14N relaxation rates can induce drastic line-broadening in the JCS. This includes a previously unexplored unique line broadening mechanism enabled by strongly coupled spins at low-field. Numerical simulations are used to model and refine the magnitudes and signs of J-couplings, as well as indirectly determine the 14N relaxation rates in a single 1D experiment that has a higher fidelity than observed in high-field NMR experiments.
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Affiliation(s)
- Adam R Altenhof
- MPA-Q, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
| | | | - Harris E Mason
- C-IIAC, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Marc A Alvarez
- B-TEK, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Michael W Malone
- MPA-Q, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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Jaeger AD, Walter R, Ehm C, Lentz D. Gallium Hydrides and O/N-Donors as Tunable Systems in C-F Bond Activation. Chem Asian J 2018; 13:2908-2915. [PMID: 30028089 DOI: 10.1002/asia.201801030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Indexed: 12/15/2022]
Abstract
The gallium hydrides (iBu)2 GaH (1 a), LiGaH4 (1 b) and Me3 N⋅GaH3 (1 c) hydrodefluorinate vinylic and aromatic C-F bonds when O and N donor molecules are present. 1 b exhibits the highest reactivity. Quantitative conversion to the hydrodefluorination (HDF) products could be observed for hexafluoropropene and 1,1,3,3,3-pentafluoropropene, 94 % conversion of pentafluoropyridine and 49 % of octafluorotoluene. Whereas for the HDF with 1 b high conversions are observed when catalytic amounts of O donor molecules are added, for 1 a, the addition of N donor molecules lead to higher conversions. The E/Z selectivity of the HDF of 1,1,3,3,3-pentafluoropropene is donor-dependent. DFT studies show that HDF proceeds in this case via the gallium hydride dimer-donor species and a hydrometallation/elimination sequence. Selectivities are sensitive to the choice of donor, as the right donor can lead to an on/off switching during catalysis, that is, the hydrometallation step is accelerated by the presence of a donor, but the donor dissociates prior to elimination, allowing the inherently more selective donorless gallium systems to determine the selectivity.
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Affiliation(s)
- Alma D Jaeger
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstr. 34-36, 14195, Berlin, Germany
| | - Ruben Walter
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstr. 34-36, 14195, Berlin, Germany
| | - Christian Ehm
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126, Napoli, Italy
| | - Dieter Lentz
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstr. 34-36, 14195, Berlin, Germany
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Jaeger AD, Ehm C, Lentz D. Organocatalytic C−F Bond Activation with Alanes. Chemistry 2018; 24:6769-6777. [DOI: 10.1002/chem.201706061] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 02/13/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Alma D. Jaeger
- Freie Universität Berlin; Institut für Chemie und Biochemie, Anorganische Chemie; Fabeckstr. 34-36 14195 Berlin Germany
| | - Christian Ehm
- Università di Napoli Federico II; Dipartimento di Scienze Chimiche; Via Cintia 80126 Napoli Italy
| | - Dieter Lentz
- Freie Universität Berlin; Institut für Chemie und Biochemie, Anorganische Chemie; Fabeckstr. 34-36 14195 Berlin Germany
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Kalläne SI, Teltewskoi M, Braun T, Braun B. C–H and C–F Bond Activations at a Rhodium(I) Boryl Complex: Reaction Steps for the Catalytic Borylation of Fluorinated Aromatics. Organometallics 2015. [DOI: 10.1021/om500952x] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Sabrina I. Kalläne
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Michael Teltewskoi
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Thomas Braun
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Beatrice Braun
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
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Harris R, Pyper N, Richards R, Schulz G. N.M.R. spectra of molecules containing quadrupolar nuclei. Mol Phys 2006. [DOI: 10.1080/00268977000101121] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Reactions of polyfluoropyridines with bidentate nucleophiles: attempts to prepare deazapurine analogues. J Fluor Chem 2001. [DOI: 10.1016/s0022-1139(00)00335-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Reactions of polyfluoroaromatic compounds with electrophilic agents in the presence of tris(dialkylamino)phosphines. Russ Chem Bull 1997. [DOI: 10.1007/bf02505680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Reactions of polyhalogenopyridines. 13. Reaction of isomeric tetrafluorocyanopyridines and pentafluoropyridine with sodium N,N-dimethyldithiocarbamate. Chem Heterocycl Compd (N Y) 1996. [DOI: 10.1007/bf01176970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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10
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Efremov IV, Sipyagin AM, Pomytkin IA. Reactions of polyhalogenopyridines. 12. Reactions of 4-pentafluoroethylthio-2,3, 5,6-tetrafluoropyridine with nucleophilic agents. Chem Heterocycl Compd (N Y) 1996. [DOI: 10.1007/bf01165723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Sipyagin AM, Kunchenko BV. Reactions of polyhalopyridines 6. Synthesis of the isomeric trifluoromethyl-tetrachloropyridines. Chem Heterocycl Compd (N Y) 1994. [DOI: 10.1007/bf01169838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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Weigert F. (Perfluoroalkyl)polyfluoroarenes by copper-promoted cross-coupling of perfluoroalkyl halides and polyfluoroarenes. J Fluor Chem 1993. [DOI: 10.1016/s0022-1139(00)80410-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Fluorocarbon derivatives of nitrogen. Part 14. Studies on some (CF3)2 no-substituted fluoroaromatics; thermal rearrangement of 4-[bis(trifluoromethyl)amino-oxy]tetrafluoropyridine. J Fluor Chem 1988. [DOI: 10.1016/s0022-1139(00)83031-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Plevey RG, Rendell RW, Tatlow JC. Fluorinations with complex metal fluorides. Part 7. Fluorinations of the methyl pyridines with caesium tetrafluorocobaltate. J Fluor Chem 1982. [DOI: 10.1016/s0022-1139(00)81512-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Al-Saleh B, Banks R, Barlow M, Hornby J. Thermolysis of N,4-dichloroperfluorocyclohexa-2,5-dienylideneamine. J Fluor Chem 1978. [DOI: 10.1016/s0022-1139(00)82854-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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17
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Perfluordicarbonsäuren, VI [1] Darstellung der perfluorpyridin-2,3-dicarbonsäure durch oxidation von perfluorchinolin. J Fluor Chem 1976. [DOI: 10.1016/s0022-1139(00)82096-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Thermolytic trifluoromethylation of pentafluoropyridine. Russ Chem Bull 1970. [DOI: 10.1007/bf00854945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Emsley J, Phillips L. The effect of solvents on the chemical shift of fluorine nuclei in aromatic compounds. Mol Phys 1966. [DOI: 10.1080/00268976600101261] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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