Core chirality based tailoring of the liquid crystalline properties of supermolecular tetrapedes

A series of novel supermolecular star-shaped tetrapede chiral liquid crystals (LCs), incorporating carbohydrates, methyl alpha-D-glucopyranoside or methyl alpha-D-mannopyranoside, as chiral cores surrounded by four cyanobiphenyl mesogenic groups linked by either C6 or C11 alkyl chain spacers, have been synthesised. These non-conventional thermotropic carbohydrate-based chiral liquid crystals exhibit chiral nematic and smectic A mesophases over broad temperature ranges. The mesomorphic properties were characterized by polarized optical microscopy (POM) and differential scanning calorimetry (DSC). The effect of the flexible spacer length in addition to the stereogenic and conformational properties of the chiral cores is discussed.