DIPOLE-COUPLED C-13 SPECTRA, A SOURCE OF STRUCTURAL INFORMATION ON LIQUID-CRYSTALS

It is shown that the introduction of well-selected dipolar interactions into carbon-13 spin systems of liquid crystals can lead to well-resolved spectra with a rich content of structural information. Two possibilities are investigated: (a) selective isotope substitution, in particular by deuterium and nitrogen-15, and simultaneous proton decoupling;(6) two-dimensional separated local field carbon-13 spectroscopy. The methods are demonstrated by investigations of benzylidene anilines in their nematic phases. © 1979 Taylor & Francis Ltd.