title: Discrimination of pseudo-meta and pseudo-para diamino-octafluoro[2.2]paracyclophanes by (1)H, (19)F, and (13)C NMR.
abstract: 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.
authors.affiliation: Department of Chemistry, Rutgers, The State University of New Jersey, Camden, NJ 08102, USA. alroche@crab.rutgers.edu
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Roche
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Marchione