Orientational order of liquid crystals by 11B NMR spectroscopy

The use of 11B NMR spectroscopy to obtain information on the orientational order of a borinated calamitic liquid crystal (4DBF2) was here shown for the first time. The combination of spectra recorded on a liquid crystalline sample uniformly aligned in the magnetic field, giving access to quadrupolar splittings, with solid state stationary and MAS spectra recorded on a powdered sample, providing the quadrupolar parameters useful for the interpretation of the quadrupolar splittings, can be seen as a self-consisting method of general applicability to liquid crystals containing boron atoms on the molecular core.

122Highlights► 11B NMR gives reliable orientational order parameters in liquid crystals. ► 11B NMR spectra on powder samples furnishes quadrupolar parameters. ► Orientation of EFG tensor in a molecular frame is necessary to determine order parameters.