dc.description.abstract | Abstratct
Series 1 : A novel system of symmetric banana-shaped mesogens. The compound 1a and 1b exhibiting B6 phases.These compounds were all characterized by 1H, 13C-NMR spectroscopy, and their mesomorphic properties were studied by differential scanning calorimeter (DSC) and polarized optical microscopy (POM). The power X-ray data and electro-optical measurement gives astounding structural information suggest that previous investigations could be associated.
Series 2 : A novel system of symmetric dimers containing naphthalene units connected by terminal Schiff base as a linkage have been synthesized and investigated for their thermal behavior. All compounds were characterized by 1H, 13C-NMR spectroscopy and elemental analysis, and the mesomorphic behavior of these compounds was characterized by polarized optical microscopy and differential scanning calorimetry.
All symmetric dimers linked by a methylene spacer -(CH2)m- containing m = 5, 7 and 9 were mesogenic. The formation of mesophase was in fact sensitive to the spacer length, but not to the terminal chains. The dimeric derivatives with methylene spacer (m = 5) exhibited smectic X phase (SmX), identified by mosaic texture under microscope. In contrast, the dimeric derivatives with spacer length m = 7 or m = 9 exhibited smectic C (SmC) and nematic (N) phases, respectively. The results indicated that in these dimers the spacer length shows a remarkable influence more than terminal side-chains on the thermal behavior.
Series 3 : We successfully synthesized A copper(II) and palladium(II) complexes derived from 4-dodecyloxy phenyl-2-carboxylic acid-4-[(3,4-didodecyloxyphenylimino)methyl]-3-hydroxyphenylester was prepared and characterized. Liquid crystalline properties of these copper(II) and palladium (II) complexes were studied and investigated by differential scanning calorimeter (DSC) and polarized optical microscopy (POM). The structures of the mesophases for copper(II) and palladium (II) complexes were also characterized and confirmed as nematic phase or smectic C phase. | en_US |