Fluorination Effect of the Peripheral Chains on the Mesomorphic Properties in Discotic Liquid Crystals of Hexasubstituted Triphenylene

Two homologues of novel triphenylene mesogens possessing –O(CH2)3CF3 (F1) and –O(CH2)3(CF2)5CF3 (F6) were synthesized and investigated on the mesomorphic behavior to reveal that these show a hexagonal columnar (Colh) mesophase. The mesomorphic behavior is obviously different from those of the corresponding hydrocarbon homologues, –O(CH2)3CH3 (C1) and –O(CH2)8CH3 (C6). Interestingly, it was found that F1 shows a disordered Colh phase, though C1 forms only a plastic hexagonal columnar (Colhp) mesophase.