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Sorgenfrei, N. ; Hioe, J. ; Greindl, J. ; Rothermel, K. ; Morana, F. ; Lokesh, N. ; Gschwind, Ruth Maria

NMR Spectroscopic Characterization of Charge Assisted Strong Hydrogen Bonds in Brønsted Acid Catalysis

Sorgenfrei, N., Hioe, J., Greindl, J., Rothermel, K., Morana, F., Lokesh, N. und Gschwind, Ruth Maria (2016) NMR Spectroscopic Characterization of Charge Assisted Strong Hydrogen Bonds in Brønsted Acid Catalysis. Journal of the American Chemical Society 138 (50), S. 16345-16354.

Veröffentlichungsdatum dieses Volltextes: 16 Mrz 2017 08:46
Artikel
DOI zum Zitieren dieses Dokuments: 10.5283/epub.35400


Zusammenfassung

Hydrogen bonding plays a crucial role in Bronsted acid catalysis. However, the hydrogen bond properties responsible for the activation of the substrate are still under debate. Here, we report an in depth study of the properties and geometries of the hydrogen bonds in (R)-TRIP imine complexes (TRIP: 3,3'-Bis(2,4,6-triisopropylphenyl)-1,1'-binaphthyl-2,2'-diylhydrogen phosphate). From NMR ...

Hydrogen bonding plays a crucial role in Bronsted acid catalysis. However, the hydrogen bond properties responsible for the activation of the substrate are still under debate. Here, we report an in depth study of the properties and geometries of the hydrogen bonds in (R)-TRIP imine complexes (TRIP: 3,3'-Bis(2,4,6-triisopropylphenyl)-1,1'-binaphthyl-2,2'-diylhydrogen phosphate). From NMR spectroscopic investigations H-1 and N-15 chemical shifts, a Steiner-Limbach correlation, a deuterium isotope effect as well as quantitative values of (1)J(NH), (2h)J(PH) and (3h)J(PN) were used to determine atomic distances (r(OH), r(NH), r(NO)) and geometry information. Calculations at SCS-MP2/CBS//TPSS-D3/def2-SVP-level of theory provided potential surfaces, atomic distances and angles. In addition, scalar coupling constants were computed at TPSS-D3/IGLO-III. The combined experimental and theoretical data reveal mainly ion pair complexes providing strong hydrogen bonds with an asymmetric single well potential. The geometries of the hydrogen bonds are not affected by varying the steric or electronic properties of the aromatic imines. Hence, the strong hydrogen bond reduces the degree of freedom of the substrate and acts as a structural anchor in the (R)-TRIP imine complex.



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Details

DokumentenartArtikel
Titel eines Journals oder einer ZeitschriftJournal of the American Chemical Society
Verlag:AMER CHEMICAL SOC
Ort der Veröffentlichung:WASHINGTON
Band:138
Nummer des Zeitschriftenheftes oder des Kapitels:50
Seitenbereich:S. 16345-16354
Datum2016
InstitutionenChemie und Pharmazie > Institut für Organische Chemie > Arbeitskreis Prof. Dr. Ruth Gschwind
Identifikationsnummer
WertTyp
10.1021/jacs.6b09243DOI
27936674PubMed-ID
Stichwörter / KeywordsORGANOCATALYTIC REDUCTIVE AMINATION; SCALAR COUPLINGS; LOW-BARRIER; ASYMMETRIC CATALYSIS; PHOSPHORIC-ACIDS; COMPLEXES; IMINES; ENANTIOSELECTIVITY; GEOMETRIES; MECHANISM;
Dewey-Dezimal-Klassifikation500 Naturwissenschaften und Mathematik > 540 Chemie
StatusVeröffentlicht
BegutachtetJa, diese Version wurde begutachtet
An der Universität Regensburg entstandenJa
URN der UB Regensburgurn:nbn:de:bvb:355-epub-354000
Dokumenten-ID35400

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