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In this thesis, the design and synthesis of two new types of fluorine - containing liquid crystalline compounds , and one type of liquid crystal phase transition has been studied by polarized light microscopy and DSC , get the following results : 1, with tetrafluorophenyl and 1,2 - the tetracyclic systems LCD substituted ethane structure : clear nematic phase texture , relative to the single -state , there is a wide temperature range of a nematic phase , a higher clearing point was observed by a polarizing microscope . With the increase of the number of carbon atoms in the terminal alkyl chain , the melting point and the clearing point of the downward trend. But in the DSC curve no appreciable clearing point , may not be detected because the phase transition enthalpy change value is too small instrument . 2, the tricyclic compounds containing a 4 - fluorophenyl ethylidene difluoro methyleneoxy : Exploration route of synthesis of such compounds , found in tetrafluoro- substituted benzene rings of the larger steric environment , alkynyl The keys can be directly through the Pd / C catalytic transfer hydrogenation , conversion is ethylene structure , this tricyclic compound and a liquid crystal phase .
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