𝔖 Bobbio Scriptorium
✦   LIBER   ✦

19F NMR of five polyfluoronaphthalenes. Inter-ring FF coupling constants

✍ Scribed by R. S. Matthews

Publisher
John Wiley and Sons
Year
1982
Tongue
English
Weight
403 KB
Volume
18
Category
Article
ISSN
0749-1581

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

Analyses of the ^19^F and ^1^H spectra of 1,2,3,4,5‐pentafluoro‐, 1‐bromo‐4,5,6,7,8‐pentafluoro‐, 1,2,3,4,5,6‐hexafluoro‐, and 1‐bromo‐3,4,5,6,7,8‐hexafluoro‐naphthalene are presented, and it is observed that the Fermi contact mechanism does not, simply, account for the long range couplings. Calculations of the carbon‐carbon polarizability part of the Fermi contact term do, however, imply that inter‐ring F,F couplings should be almost constant from difluoro‐ to heptafluoro‐naphthalene. Within the limits of this study, the inter‐ring F,F couplings, excluding peri F,F couplings, do not vary substantially. The steric effect of substituting an α‐hydrogen with bromine, at a peri position and adjacent to fluorine, is to increase the F,F coupling at the opposed peri position by 20 Hz, an unusually high increase in J(FF)peri.

📜 SIMILAR VOLUMES

19F n.m.r. spectrum of hexafluoroquinazo
19F n.m.r. spectrum of hexafluoroquinazoline long-range inter-ring FF coupling constants
✍ R. S. Matthews 📂 Article 📅 1977 🏛 John Wiley and Sons 🌐 English ⚖ 400 KB

## Abstract The ^19^F n.m.r. spectrum of hexafluoroquinazoline has been analyzed giving the signs and magnitudes of all but two of the coupling constants, and supporting the analyses of the ^19^F n.m.r. spectra of heptafluoroquinoline and heptafluoroisoquinoline. Long range FF inter‐ring coupling

19F n.m.r spectra of polyfluoroquinoline
19F n.m.r spectra of polyfluoroquinolines. Long range inter-ring 19F19F coupling constants and 19F chemical shifts
✍ R. S. Matthews 📂 Article 📅 1976 🏛 John Wiley and Sons 🌐 English ⚖ 509 KB

## Abstract The signs and magnitudes of every fluorine–fluorine coupling constant in perfluoroquinoline (**1**), 2,4‐dichloropentafluoroquinoline (**2**) and 2‐bromohexafluoroquinoline (**3**) have been determined by ^19^F n.m.r. These provide an unambiguous assignment of the spectrum of the first

19F n.m.r spectra of heptafluoroisoquino
19F n.m.r spectra of heptafluoroisoquinoline and hexafluoro-1-methoxyisoquinoline. Long-range inter-ring coupling constants
✍ R. S. Matthews 📂 Article 📅 1976 🏛 John Wiley and Sons 🌐 English ⚖ 382 KB

## Abstract An analysis of the ^19^F n.m.r. spectra of heptafluoroisoquinoline and hexafluoro‐1‐methoxyisoquinoline is presented. As in heptafluoroquinoline, the inter‐ring FF coupling constants alternate in sign and magnitude and are positive over an odd number of bonds. They correlate with SCFMO