含氟吡咯、吡咯烷液晶分子的合成与性能研究

SYNTHESIS AND MESOMORPHIC STUDIES ON LIQUID CRYSTALS WITH FLUORINATED PYRROLE,AND PYRROLIDINE

  • 摘要: 采用含氟砌块3-氟-4-吡咯烷苯酚,3-氟-4-(3,3,4,4-四氟)吡咯烷苯酚和3-氟-4-(3,4-二氟)吡咯苯酚合成了3个系列含氟氮杂环液晶新分子. 用差示扫描量热法(DSC)和偏光显微镜(POM)对其介晶性研究发现:相对末端为吡咯烷(n/m-4H)或3,3,4,4-四氟吡咯烷(n/m-4F)的分子,末端为3,4-二氟吡咯的分子(n/m-2F)更有利于液晶相的形成和稳定,它们具有宽的液晶相范围,而且都呈现为向列相. 当分子同时含双环己基液晶砌块和3,4-二氟吡咯端基时,就能获得宽的介晶相范围和高清亮点的向列相液晶. 通过选择不同的含氮杂环、引入含氟取代基团和调节液晶结构单元,有效地改善了这些液晶分子的物理和化学性质.

     

    Abstract: Three series of new fluorinated N-heterocycles liquid crystals were synthesized from the fluorinated block 3-fluoro-4-(pyrrolidin-1-yl)phenol (3-4H), 3-fluoro-4-(3,3,4,4- tetrafluoropyrrolidin-1-yl)phenol (3-4F) and 4-(3,4-difluoro-1H-pyrrol-1-yl)-3-fluorophenol (3-2F). Their mesogenic behavior was investigated with differential scanning calorimetry (DSC) and polarized optical microscopy (POM).The results showed that the 3,4-difluoropyrrole derivatives are more conductive to the formation and stability of a liquid crystal phase than the pyrrolidine or 3,3,4,4-tetrafluoropyrrolidine derivatives. The results of DSC, POM also show that 3,4-difluoropyrrole derivatives exihibit high clearing point and a broad temperature range of nematic phases. Compounds have a wide nematic phase and a high clearing point when we combine 3,4-difluoropyrrole as the terminal group and dicyclohexyl liquid crystal building block. The physical and chemical properties of the liquid crystal molecules can be adjusted by varying the type of N-heterocycles, introducing fluorine atoms and changing the length of terminal alkyl chain.

     

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