Mesomorphic properties of 1-(4-n-alkoxyphenyl)-3-(5-n- alkyl-2-thienyl)propan-1,3-diones and their isoxazole and pyrazole derivatives.

The liquid crystalline behavior of 1 -(4-n-alkoxyphenyl)-3-(5-n-propyl-2-th ienyl) propan-1,3-diones (series RnO2R3) and 1-(4-n-alkoxyphenyl)-3-(5-n-he xyl-2-thienyl) propan-1,3-diones (series RnO2R6) and the isoxazole and pyra zole derivatives for the number of carbon atoms in the alkoxy chain from th ee to nine, has been studied by optical microscopy, DSC and X-ray technique s. Series RnO2R3 did not show mesophases, two members of the series RnO2R6, With SIX and eight carbon atoms in the alkoxy chain shows monotropic nemat ic mesophases. The majority of the isoxazole;and pyrazole compounds show me sogenic property, isoxazole nematic and smectic C phase and pyrazole smecti c A. The synthesized 1-methyl substituted pyrazole did not show mesophases.