Synthesis and properties of mesogenic esters containing the heterocyclic 1,3,4-oxadiazole.

The synthesis and mesomorphic properties of 5-(5'-n-octyl)thienyl-2-alkylthio-1 ,3,4-oxadiazoles (series 8) and 4-(5'-alkylthio-1,3,4-oxadiazol-2-yl)phenyl-5 ''-n-octylthiophene-2-carboxylates (series 11) are reported, for the number of carbon atoms in the alkyl chains (R') varying from 4 to 10. Series 8 did not show mesophases, series 11 shows enantiotropic nematic phase and monotropic smectic C (S-c) phase, this is closely associated with the linearity of the molecules.