SYNTHESIS OF CHEMICALLY BONDED LIQUID-CRYSTALS FOR HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY - NEW PHASES VIA THE ORGANOCHLOROSILANE PATHWAY

Two bonded nematic liquid crystal stationary phases for use in high-performance liquid chromatography were prepared by reacting the silanized forms of [4-(allyloxy)benzoyl]biphenyl and 4-{[4-(allyloxy)-benzoyl]oxy}-4'-methoxybiphenyl with the surface of silica. The diffuse reflectance infrared Fourier transform and carbon-13 cross-polarization magic angle spinning NMR spectra of the two bonded phases confirmed that the reaction was successful. Carbon elemental analysis indicated a high loading of the liquid crystal on the surface. Van't Hoff plots using polyaromatic hydrocarbons as the solutes in an acetonitrile-water mobile phase indicated that phase transitions are occurring. The relative retention of anthracene and phenanthrene as a function of temperature is also sensitive to changes in the stationary phase morphology and reveals that more than a single transition is occurring over the temperature range studied.