Discrimination of pseudo‐ meta and pseudo‐ para diamino‐octafluoro[2.2]paracyclophanes by 1 H, 19 F, and 13 C NMR

Pseudo‐ meta and pseudo‐ para diamino‐octafluoro[2.2]paracyclophanes are challenging to separate either by chromatography or recrystallization, but through the use of a mixture of the two isomers, the 1 H, 19 F, and 13 C NMR spectra of these compounds have been fully and unambiguously assigned using...

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Published in:Magnetic resonance in chemistry 2012-12, Vol.50 (12), p.809-812
Main Authors: Roche, Alex J., Marchione, Alexander A.
Format: Article
Language:English
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Summary:Pseudo‐ meta and pseudo‐ para diamino‐octafluoro[2.2]paracyclophanes are challenging to separate either by chromatography or recrystallization, but through the use of a mixture of the two isomers, the 1 H, 19 F, and 13 C NMR spectra of these compounds have been fully and unambiguously assigned using 1 H COSY, 1 H‐ 19 F HOESY, 1 H‐ 13 C HSQC, 1 H‐ 13 C HMBC, and 19 F‐ 13 C HSQC techniques. This permits the easy identification of either of the individual isomers. In addition, the 13 C 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 1 H resonances and shield 13 C. Copyright © 2012 John Wiley & Sons, Ltd.
ISSN:0749-1581
1097-458X
DOI:10.1002/mrc.3882