Synthesis and Mesogenic Properties of 5,5'-Bitropolone Derivatives (1)

Abstract

New troponoid liquid crystals with a bitropolone skelton were prepared. The ester derivatives (1) had enantiotropic smectic A and/or C phases with higher thermal stabilities than the corresponding benzenoid. However the ether derivatives (2) were not mesomorphic. From the X-ray diffraction studies of 2, the layer spacings were estimated to be 35.6 Å for smectic A and 36.5 Å for smectic C, respectively. The layer spacings are shoter than the calculated molecular length (43.6 Å) for a bitropolone derivative. This indicated that the molecular long axes ate tilted to the layer plane.