Dynamical study of 2-pyrrolidone, δ-valerolactam and ε-caprolactam from quadrupolar relaxation of nitrogen-14 and oxygen-17

Abstract

The quadrupolar coupling constants of nitrogen-14 and oxygen-17 in 2-pyrrolidone, δ-valerolactam and ε-caprolactam in H₂O and CCl₄ solutions have been determined by using the ¹⁴N and ¹⁷O n.m.r. linewidths and carbon-13 relaxation times. Within the limits of experimental error affecting these parameters, the quadrupolar couplings of ¹⁴N and ¹⁷O have been found to be independent of ring size; this is corroborated by Townes–Dailey calculations. Furthermore, quadrupolar relaxation of ¹⁴N and ¹⁷O has proved to be a valuable aid towards a total analysis of the anisotropic motion of 2-pyrrolidone.