Synthesis and Thermotropic Studies of Two Novel Series of Kinked Liquid Crystals: 2-(4\u27-Alkoxybiphen-4-yl)-6-methylquinolines and 2-(6-Alkoxynaphthalen-2-yl)-6-methylquinolines

Two novel homologous series of kinked (Z-shaped) liquid crystalline compounds were synthesized using a short two-step reaction. Yields of 30%–40% and 51%–57% were obtained for 2-(4\u27-alkoxybiphen-4-yl)-6-methylquinolines (nO-PPQMe, n = 3–8) and 2-(6-alkoxynaphthalen-2-yl)-6-methylquinolines (iO-NpQMe, i = 3–7), respectively. Spectral analyses agreed with the expected structures. The thermotropic behaviors of these compounds were investigated using polarized optical microscopy and differential scanning calorimetry. An enantiotropic nematic phase appeared to be the main mesophase in these two series of kinked liquid crystalline compounds, and an additional enantiotropic smectic C phase appeared when n = 8