Natural abundance proton‐coupled 15N NMR spectra of pyridines observed from proton polarization transfer experiments

Abstract

AbstractNatural abundance proton‐coupled 15N NMR spectra have been observed for pyridine and a series of mono‐ and disubstituted pyridines using polarization transfer achieved by the selective population transfer method. The magnitudes and signs of the 15N1H spin‐spin coupling constants between the ring‐nitrogen and ring‐protons are determined from complete iterative spectral analysis and/or selective population transfer experiments. Substituent effects on the 15N1H coupling constants are discussed and compared with those for 13C1H couplings in substituted benzenes.