Mesogens with four-benzene molecular core and two lactate units in the chiral chain

We prepared and studied new series of mesogens with a molecular core based on two biphenyls connected via ester linkage, with the biphenyl in central part laterally substituted by a chlorine atom. The studied compounds have two lactate groups and methylbutyl in the chiral chain and they exhibit the SmA phase in a very broad temperature range. We pursued the mesomorphic property and confirmed the phase identification by X-ray measurements. Additionally, we compared the studied compounds with previously prepared analogous materials. In comparison with homologues with different positions of the lateral substitution, we attempted to explain modified mesomorphic properties and absence of tilted mesophases for the studied series. We performed ab-initio calculations and found that the dipole moment is oriented along the long molecular axis, so its small transversal component probably causes the stability of the SmA phase and lack of ferroelectricity or antiferroelectricity.