有玻璃态和液晶态的胆甾烯基苯并菲的合成及介晶性

将盘状液晶基元苯并菲与手性向列型液晶基元胆甾烯基结合的化合物, 可望出现全新的性质. 合成了含有胆甾烯基的苯并菲化合物C₁₈H₆(OC₅H₁₁)₅(OC₅H₁₀COOCh) (2), 2,7-C₁₈H₆(OC₅H₁₁)₄(OC₅H₁₀COOCh)₂ (4), C₁₈H₆(OR)₃(OC_nH_{2nCOO- Ch)3 (R＝C5H11, C7H15, C9H19, C11H23, n＝1, 5, 10) (6a～6f), C18H6(OC5H10COOCh)6 (Ch: cholesteryl) (8). 偏光显微镜和差示扫描量热法对这些化合物的热致介晶性研究结果显示, 化合物 4, 6a～6e具有手性盘状向列相和玻璃态, 8呈现近晶B相(SB)和玻璃态. 随间隔基长度n和烷基链R碳原子数的增加, 化合物玻璃化温度和清亮点呈下降趋势. 随着胆甾烯基数目减少, 化合物的玻璃化温度和清亮点降低.}

Synthesis and Mesomorphism of Cholesteryl-containing Triphenylenes with Glass States and Liquid Crystal Phases

The combination of disc-shaped triphenylene with cholesteryl moiety in one molecule would result in interesting physical properties. In this paper, cholesterol-based triphenylene derivatives C₁₈H₆(OC₅H₁₁)₅(OC₅H₁₀COOCh) (2), 2,7-C₁₈H₆(OC₅H₁₁)₄(OC₅H₁₀COOCh)₂ (4), C₁₈H₆(OR)₃(OC_nH_2nCOO- Ch)₃ (6a～6f) and C₁₈H₆(OC₅H₁₀COOCh)₆ (8) (R＝C₅H₁₁, C₇H₁₅, C₉H₁₉, C₁₁H₂₃, n＝1, 5, 10, Ch＝cholesteryl) were synthesized, and their thermotropic liquid crystalline properties were investigated by polarizing optical microscopy and differential scanning calorimetry. The results show that, compounds 4 and 6a～6e have glass states and chiral discotic nematic phases (N_D*), while 8 has smectic B phase and glass state. Their glass transition temperatures (T_g) and clearing points (T_c) decreased with lengthening spacer n and alkyl chain, and decreasing cholesteryl moieties.