Pure quadrupole resonance of¹⁴N in some five-membered heterocyclic compounds

The pure quadrupole resonance spectra for the 14N nucleus in five-membered heterocycles is reported and interpreted in terms of the electron distribution around the nitrogen atom in these compounds. Although reasonable agreement with the predictions of simple molecular orbital theory is obtained, the calculated electron distributions are very sensitive to the assumptions made concerning the hybridization of the sigma orbital framework.