Discrimination of pseudo‐meta and pseudo‐para diamino‐octafluoro[2.2]paracyclophanes by 1H, 19F,and 13C NMR |
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Authors: | Alex J Roche Alexander A Marchione |
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Institution: | 1. Department of Chemistry, Rutgers, The State University of New Jersey, , Camden, NJ, USA;2. DuPont Central Research and Development, Experimental Station, , Wilmington, DE, USA |
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Abstract: | Pseudo‐meta and pseudo‐para diamino‐octafluoro2.2]paracyclophanes are challenging to separate either by chromatography or recrystallization, but through the use of a mixture of the two isomers, the 1H, 19F, and 13C NMR spectra of these compounds have been fully and unambiguously assigned using 1H COSY, 1H‐19F HOESY, 1H‐13C HSQC, 1H‐13C HMBC, and 19F‐13C HSQC techniques. This permits the easy identification of either of the individual isomers. In addition, the 13C spectrum of the pseudo‐ortho analogue is reported and assigned for the first time. The gem shift effect in this series of bridge‐fluorinated paracyclophanes serves to deshield 1H resonances and shield 13C. Copyright © 2012 John Wiley & Sons, Ltd. |
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Keywords: | NMR 19F 13C 1H HOESY 19F‐13C HSQC cyclophane paracyclophane |
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