Peculiarities of the crystal structure of modified banana-shaped mesogen

The structure and phase behavior of an achiral banana-shaped compound-bis-{3,4,5-tri[4-(4-n-nonyloxybenzoyloxy)] benzoylamino}-1,3-phenylene (I)-have been investigated. This compound exhibits an enantiotropic high-temperature chiral mesophase; upon cooling it successively passes to the crystalline (Cr) phases: Crα (281.0-176.0°C), Crβ (175.0-72.0°C), and Crγ (71.0-40.0°C) (their temperature ranges of existence are indicated). The surface topology and results of linear measurements along the cross sections of certain portions of thin films of compound I in the Cr γ phase clearly prove the effect of the preserved chirality of the previous liquid-crystal phase in the crystalline state.