新型苯甲酸-吡啶超分子液晶的合成:全氟烃基和介晶体刚性对液晶性的影响  

Synthesis of New Benzoic Acid-pyridine Supramolecular Liquid Crystals and the Influence of Perfluoroalkyl Chain and Rigidity of Mesogen on Mesomorphism

作　　者：郑述方[1] 赵可清[1] 余文浩[1] 汪必琴[1] 胡平[1] 

机构地区：[1]四川师范大学化学与材料科学学院,成都610066

出　　处：《化学学报》2009年第8期825-832,共8页Acta Chimica Sinica

基　　金：国家自然科学基金(Nos.50473062;50673069)资助项目

摘　　要：报道了4-正烷氧基苯甲酸和4-正全氟己基苯甲酸分别与吡啶衍生物3a,3b通过分子间氢键形成的超分子液晶化合物的合成和热致液晶性.目标超分子液晶化合物的介晶性和氢键的缔合通过热台偏光显微镜,差示扫描量热法,核磁和红外光谱进行了研究.结果显示:吡啶衍生物3a,3b不具有液晶性.4-正烷氧基苯甲酸与吡啶衍生物3a,3b形成的复合物4a和4b具有向列相和近晶C相,而4-全氟己基苯甲酸与吡啶衍生物3a,3b形成的复合物6a,6b则呈现多个近晶相.4a-n系列化合物比4b-n系列具有更高的熔点和清亮点,而4b-n系列存在明显的奇偶效应.红外光谱证实了羧基与吡啶基之间存在氢键.A series of hydrogen bonding supramolecular liquid crystals consisting of 4-n-alkoxybenzoic acid or 4-n-perfluorohexylbenzoic acid and pyridine derivatives 3a and 3b were reported. Their structures were investigated with nuclear magnetic resonance and infrared spectroscopy and their thermotropic properties were studied with polarized optical microscopy and differential scanning calorimetry. The results showed that no liquid crystalline properties were found for 3a and 3b. Complexes of 4-n-alkoxybenzoic acid with 3a and 3b displayed nematic phase and smectic C phase, while complexes of 4-perfluorohexylbenzoic acid with 3a and 3b exhibited multiple smectic phases. 4a-n had both higher melting and clear points than 4b-n, while 4b-n exhibited odd-even effect. The infrared spectra demonstrated the hydrogen bonds existed between the benzoic acid and pyridine moieties in the supramolecular systems.

关 键 词：氢键 液晶 超分子化学 疏氟效应 全氟己基苯甲酸 吡啶衍生物 

分 类 号：O753.2[理学—晶体学]