Conformation of the −NH2 group in a single crystal of p-chloroaniline as determined by combined Zeeman effects on the 35Cl and 14N nuclear quadrupole resonances

Publisher Website
Google Scholar
Abstract
The Zeeman effect on the nuclear quadrupole resonance of both 35Cl and 14N nuclei in a single crystal of p‐chloroaniline has been studied at room temperature. A spectrometer was employed which was capable of working at the resonance frequency of either nucleus without altering the position of the crystal. Novel features of the spectrometer were both a frequency stabilizing apparatus working at the 14N resonance frequency and the attachment of an electronic computer for direct and accurate ``on‐line'' determination of spectral parameters. The relative orientations of the electric field gradient tensors on both nuclei have been obtained. Furthermore, by studying the 14N linewidth dependence on the static magnetic field orientation, information has also been gained about the position of the −NH2 protons in the electric field gradient tensor principal axes mainframe. Some remarkable experimental results can be interpreted theoretically when the treatment of the magnetic dipole interaction between 14N and 1H in the −NH2 group is pushed beyond first order. Analogous information has been gained by also studying a single crystal of p‐bromoaniline.