The NMR spectra of some fluorinated pyridine derivatives

The 1 H and 19 F spectra of a variety of mono‐ and di‐ fluorinated pyridines are examined, and compared with the corresponding spectra of the pyridinium ions. The magnitudes and signs of the 1 H 19 F coupling constants are in general in accord with those observed for the corresponding 1 H 1 H couplings, with an exaggerated range. Large changes in the NMR parameters are observed on protonation of the nitrogen, 3 J (HF) changing sign in some of the α‐fluoropyridine derivatives.