Mesomorphic properties of liquid crystalline compounds with chalconyl central linkage in two phenyl rings

In order to investigate the influence of the central linking group and the effect of flexibility on mesomorphism, we have synthesised a newly homologous series 3-(3-butoxyphenyl)-1-(4-n-alkoxy phenyl) prop-2-en-1-one (series-l) consisting of 13 homologues C₁–C₈, C₁₀, C₁₂, C₁₄, C₁₆ and C₁₈. In the present series, mesophase commences from the C₆ homologue. C₁–C₅ homologues did not exhibit liquid crystalline (LC) property, while C₆–C₁₂ homologues exhibited an enantiotropic nematic phase and the rest of the homologues C₁₄–C₁₈ displayed monotropic SmC and nematic mesophase. The transition temperatures of the synthesised compounds were determined by an optical polarising microscopy equipped with a heating stage. All newly synthesised compounds were confirmed by ¹H-NMR, ¹³C-NMR, IR and elemental analysis.