Abstract: Twenty four lateral difluorine substituted biphenyl liquid crystals were synthesized from 4-alkyl-cyclohexanecarboxylic acid and 4-bromo-2,3-difluoro-phenol by Grignard reaction, Huang Ming-long reduction, iodination, acid reaction, Suzuki cross-coupling reaction, Williamson reaction and esterification. The total yield is 4.2%~8.7%. The molecular structures of the compounds were confirmed with nuclear magnetic(1H NMR, 13C NMR), infrared spectrometry, and mass spectrometry. Differential scanning calorimetry and polarising optical microscopy were used to measure the liquid crystal display properties of the target compounds. The results showed that the length of alkyl chain not only affects the melting and clearing point of compounds, but also the liquid crystal phase transition. Terminal olefins can reduce the melting point(about 3.7 ℃), improve the clearing point(about by 24.8 ℃), and broaden the nematic phase interval(from 54.1 ℃ to 82.6 ℃). Ester group can increase the clearing points and eliminate smectic phase. This series of compounds has potentials for use in the vertical alignment(VA) and in-plane switching(IPS) display modes.

Key words: liquid crystal, lateral two fluorine, biphenyl, terminal olefins, ester group, ethers