Microwave spectra of [15n] and [13c] pyridines, quadrupole coupling constants, dipole moment and molecular structure of pyridine

Abstract The microwave spectra of two ring-substituted species of pyridine have been remeasured, and the spectra of the two remaining species investigated and assigned. 14 N quadrupole coupling splittings were analyzed and used to determine the quadrupole coupling constants, while the derived center frequencies were fitted to give improved values for the rotational constants. A complete substitution structure can now be presented. The dipole moment of pyridine was redetermined from Stark measurements in the spectrum of [ 15 N]pyridine.