Low-temperature NMR of ɛ-caprolactam
Autor: | Gerd Borgen, Frode Rise |
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Rok vydání: | 1993 |
Předmět: | |
Zdroj: | Magnetic Resonance in Chemistry. 31:51-53 |
ISSN: | 1097-458X 0749-1581 |
DOI: | 10.1002/mrc.1260310110 |
Popis: | The conformation of e-caprolactam (1-azacycloheptan-2-one) was studied by low-temperature 2 D 1 H and 13 C NMR. Only one conformer was found in solution from the 13 C NMR spectra recorded down to -155 o C. This conformer was shown, by infrared spectroscopy, to be the same as that found in the crystals of e-caprolactam. A conformational process with a free energy of activation of 43 kJ mol -1 , coalescence temperature -65 o C, was interpreted as geminal 1 H exchange. The assignments of the 13 C and 1 H shifts were made by 2 D NMR. Splitting of all averaged signals for germinal protons into axial and equatorial signals was demonstrated at -100 o C |
Databáze: | OpenAIRE |
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