Electron-coupled through-space or fragment spin-spin coupling between 19F nuclei

Abstract

The indirect spin-spin coupling constants over four formal bonds between fluorine nuclei in 2-fluoro-5-nitrobenzotrifluoride, 2,5-difluorobenzotrifluoride, pentafluorobenzoyl fluoride, and 2-fluoro-6-chlorobenzoyl fluoride, are +12.94 ± 0.02, +13.0 ± 0.1, +38.8 ± 0.1, and +30.6 ± 0.1 Hz, respectively. These “through-space” or “fragment” interactions are compared with previous sign and magnitude measurements and are in agreement with two semiempirical theories.