【摘要】 以4′-正-烷氧基联苯基-4-甲酸和2,5-二羟基苯醌为原料,通过酯化和还原反应合成了一系列新的液晶性2,5-双[4′-(正-烷氧基联苯基)-4-碳酰氧基]对苯二醌(化合物1)和2,5-双[4-′(正-烷氧基联苯基)-4-碳酰氧基]对苯二酚(化合物2).化合物2的结构通过元素分析、红外光谱和核磁共振波谱等方法确证,其液晶行为用示差扫描量热法(DSC)和偏光显微镜(POM)表征.发现化合物2加热至各自的熔点以上都能形成液晶态,在液晶态可以观察到近晶相和向列相的典型织构.随分子中末端烷氧基碳原子数增加,化合物2的熔点(Tm)和液晶态的清亮点(Ti)呈规律性变化,近晶相范围和近晶相-向列相转变温度渐增,而向列相范围递减.更多还原

【Abstract】 A series of novel liquid crystalline 2,5-bis[4′-(n-alkoxylbiphenyl)-4-carboxyl]quinone(Compound 1) and 2,5-bis[4′-(n-alkoxylbiphenyl)-4-carboxyl]hydroquinone(Compound 2) are synthesized via esterization and reactions by using 4′-(nalkoxy-biphenyl)-4-carboxylic acid and 2,5-dihydroxyquinone as raw materials. The structures of Compound 2 are identified by using elemental analysis,infrared spectra and nuclear magnetion reasonance.The liquid crystalline behavior of Compound 2 is characterized by differential scanning calorimetry(DSC) and polarizing optical microscopy(POM).It is found that Compound 2 goes into liquid crystal phase when heated to its respective melting point(T_m).The typical smectic phase and nematic phase texture can be observed.Both T_m and isotropization temperature(T_i) of Compound 2 change regularly with the carbon numbers of the end alkoxy groups.There is a gradual increase in smectic phase length and so is the smectic-nematic transition temperature.At the same time there is a gradual decrease in nematic phase length.更多还原