Mesomorphic properties and monolayer behaviour of novel liquid crystalline exo-calix[4] arene derivatives

Novel calix[4]arene derivatives are synthesized, These are pyrogallol-derived exo-calix[4]arenes with twelve 3-oxaalkanoyloxy chains and exo-calix[4]arenes in which eight or twelve rod-like units (phenylthiadiazole and phenylpyrimidine units) are fixed via spacers with the calix[4]arene central core. The liquid crystalline properties of these compounds are investigated by thermal optical microscopy between crossed polarizers, by differential scanning calorimetry and some of them also by X-ray diffraction. One of the 3-oxaalkanoates forms a hexagonal columnar mesophase, whereas most of the compounds incorporating calamitic units in We lateral chains give liquid crystalline materials with a smectic A-phase. Furthermore the behaviour of selected compounds us thin films at the air-water interface is studied using the Langmuir technique, They form condensed films whereby the molecular areas at the collapse points are determined by the densely packed lateral chains.