Bent molecules with a 60° central core angle that form B7 and B2 phases.

Small-angle bent-core liquid-crystalline (LC) molecules based on a 1,2-bis(phenylethynyl)benzene central core have been synthesized that form banana smectic phases with a ferroelectric B7-antiferroelectric B2 phase sequence upon cooling. The formation of polar, switchable ferro-/antiferroelectric banana phases indicates that, despite the low core bend angle of approximately 60 degrees, banana smectic phases are still formed with the bend direction parallel to the layer. This study offers significant evidence that shows bent-core molecules with a 60 degrees bend angle can form the well-known B2 and B7 banana phases. Consequently, it may lead to the preparation of a wide variety of novel bent molecules with low bend angles that spontaneously form an LC phase with both polarization and chirality.