中文摘要：

以3-氨基-2-甲基苯甲酸为原料,合成了含希夫碱基团的5个不对称弯曲型液晶分子,通过1HNMR、HRMS测试手段对其结构进行了表征,采用示差扫描量热法（DSC）和偏光显微镜等方法研究了它们的液晶性和相变温度,发现不仅相变温度随着分子苯环数的下降而下降,其液晶相的稳定性也随着苯环数的下降而下降,含有5个苯环的化合物呈现多个近晶相和向列相,含4个苯环的化合物则只有一个近晶相和向列相,而3个环的化合物仅在降温的过程中呈现近晶相。

英文摘要：

With 3-amino-2-methylbenzoic acid as starting material,five asymmetric bent-core liquid crystals containing Schiff-base unit were synthesized.Their chemical structures were confirmed by 1H NMR and HRMS spectra,their liquid crystalline properties and phase transition temperatures were studied by DSC and polarizing microscopy with heating stage.It was found that the clearing points of the synthesized molecules were decreased with the decreasing of the number of benzene rings of the compounds,companying with the decreasing of the liquid crystal stability.The molecules with 5 benzene rings exhibit several semetic phases and nematic phase,whereas the molecules with 4 benzene rings exhibit one semetic phase and nematic phase,and the molecule with 3 benzene rings exhibit only monotropic semectic phase.