Spin-echo and autocorrelation experiments as an aid in the analysis of complex spectra from liquid-crystalline samples

Abstract

The proton spectrum of p-dimethoxybenzene containing deuterated methyl groups and dissolved in a liquid-crystal solvent has been analysed. The analysis was aided by recording a proton spin-echo spectrum, which gives the proton–proton dipolar couplings, and a two-dimensional autocorrelation spectrum, which identifies the sub-spectra in the proton spectrum. The quadrupolar splitting and deuteron–deuteron dipolar coupling within each CD₃ group were obtained from a deuteron spin-echo spectrum. These data are consistent with a planar arrangement for the carbons and oxygens in the lowest-energy conformation.