عنوان المقالة:Synthesis and characterization of new mesogenic esters derived from 1,2,4-oxadiazole and study the effect of alkoxy chain length in their liquid crystalline properties
ABSTRACT
In this study, a new series of non-symmetrically 3,5-disubstituted of 1,2,4-oxadiazole derivatives,
4-[5-(4-methylphenyl)-1,2,4-oxadiazol-3-yl]-phenyl-4-alkoxybenzoate (G1–G11), which containing
ether and ester linkages in the same molecule, is synthesized using different synthetic procedures
and their structures are confirmed by several spectroscopic techniques (FT-IR and 1
H nuclear
magnetic resonance). The mesomorphic properties of these compounds are studied by differential
scanning calorimetry (DSC) and polarized optical microscopy (POM); all these derivatives
exhibited as mesogens and displayed an enantiotropic liquid crystal with nematic texture, the
nematogenic phase of these materials was appeared in wide temperature ranges on heating and
cooling cycles that were observed by POM and DSC. The influence of 1,2,4-oxadiazole ring and
the elongation of alkyl chain in the mesomorphic properties of this series were investigated. The
mesogenic behaviour of this series was compared with the compounds possessing a somewhat
similar structure.
غسان قيس علي | Ghassan Qays Ali | 5051