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 °C to maximum 142 °C.