<title>Influence of length of alkyl terminal chain on mesomorphic properties of new chiral liquid crystalline homologous series of thiobenzoates</title>

Abstract

The convenient synthesis method and mesomorphic properties of novel liquid crystalline homologous series of the chiral thiobenzoate in which the chiral branched chain (S)-(l-methylheptyloxy) was attached to the biphenyl have been presented. They are liquid crystals compounds of the general formula MHOBSn ((S)-(+)-4-(l-methylheptyloxy)-biphenyl-(4'-alkylphenyl)-thiobenzoate, where n denotes number of carbon atoms in the alkyl chain). DSC and polarization microscopy and X-ray diffraction measurements shoved that (S)-MHOBSn possess a rich phase polymorphism: two high ordered tilted smectic phases SmG* and SmI* as well as ferroelectric smectic C, SmC* and chiral nematic phase (N*). All compounds containing stabile enantiotropic SmC* and N* phases. The influence of chemical purity of final compound on phase behaviour has been studied. The existence of weak intermolecular hydrogen bonds of(S)-MHOBSn was confirmed by FTIR method.