Synthesis and characterization of six-arm star-shaped liquid crystalline cyclotriphosphazenes

The synthesis and mesomorphic properties of a new class of liquid crystalline cyclotriphosphazenes with rigid cyanostilbene groups and flexible alkoxy groups are reported. The thermal behaviors of cyclotriphosphazene derivatives 5a-5d are studied by the means of differential scanning calorimetry, polarizing optical microscopy. Nematic phases were observed in compounds 5a-5d both on heating and cooling. The clear temperatures of compounds 5a-5d slightly increased with increasing length of terminal alkyl chain. Compounds 5a-5d showed different mesogenic region from minimum 5℃ to maximum 142℃.