Novel liquid crystals with a bent molecular shape containing a 1,5-disubstituted 2,3,4-trifluorophenyl unit. Banana-shaped liquid crystals - synthesis and properties

The synthesis, transition temperatures and chiral properties of a range of novel achiral and racemic liquid crystals with a bent molecular shape containing a 1,5-disubstituted 2,3,4-trifluorophenyl moiety are detailed in the context of the recently popular research topic of banana-shaped liquid crystals. The work represents a speculative extension of research into ferroelectric host materials with high dielectric biaxiality, and some interesting results are discussed. Notably, some achiral materials generate a columnar mesophase where the molecules are tilted within the columns, allowing the generation of chirality, other achiral materials exhibit a 'conventional' mesomorphism in the form of a smectic C phase, but an equal number of oppositely handed regions are generated. A racemic material generates an unidentified smectic phase, which exhibits chiral properties of single handedness despite the racemic nature.