Thermotropic liquid crystals based on 1,8,9,16-tetrasubstituted tetraphenylenes and their structure–property relationship studies

Twelve 1,8,9,16-tetraalkoxytetraphenylenes were synthesized and characterized, five of which exhibiting thermotropic liquid crystal properties were examined by differential scanning calorimetry (DSC), polarizing-light optical microscopy (POM) and variable-temperature X-ray diffractometry (VTXRD). The structure-property relationship of each mesomorphic solid is discussed in the context of the racemic/non-racemic nature of the sample, different chain length of n-alkyl substituents, effect of chain lipophilicity and intermolecular interactions.