Evidence of columnar structure in compounds composed of banana-shaped molecules

The synthesis and mesomorphic properties of several achiral compounds composed of banana-shaped molecules are described. These compounds belong to three different homologous series. They have been examined by polarized light microscopy, differential scanning calorimetry, x-ray diffraction studies and electro-optic investigations. In the homologous series containing a lateral methyl group, three different mesophases viz. B6, B1 and B2 have been observed. In the compounds containing a chloro group, the B1 phase predominates, while the fluoro substituted compounds show the B2 phase.