NMR studies of pyridine- N-oxide. Determination of spectroscopic constants from [ 15N]-, [4- 2H], and the parent species

Abstract

Pyridine- N-oxide, [ 15N]pyridine- N-oxide, and [4- 2]pyridine- N-oxide have been investigated by NMR spectroscopy. 1H, 2H, and 13C spectra have been obtained and analyzed, in terms of chemical shifts and spin-spin coupling constants. Relaxation times have been measured for 2H and 13C and have been used to determine the correlation time τ c under the assumption of isotropic molecular diffusion. On the basis of experimental data and observed linewidth variations the nitrogen quadrupole coupling constant has been evaluated. The experimental data are correlated with semiempirical calculations within the azine series.