【作者】 郭楠；

【导师】 胡建设；

【作者基本信息】 东北大学 ， 有机化学， 2020， 硕士

【摘要】 液晶是兼具晶体有序性和液体流动性的物质,由于其良好的光电性能、热性能等优点,近年来引起人们的广泛关注。胆甾醇和薯蓣皂素是源于生物体的天然生物液晶基元,本身具有良好的生物相容性,分子结构中含有多个手性碳原子(C*),也易与其他官能团键接进行化学改性,因此被广泛研究和应用。本文的设计思想是将亚甲基柔性间隔基引入胆甾醇和薯蓣皂素两种生物液晶基元,通过改变化合物结构中亚甲基柔性间隔基的长度调节液晶性能,期望得到兼具液晶性和生物相容性的新型手性液晶化合物,为今后合成液晶聚碳酸酯医用高分子材料奠定了一定的基础。论文的第2章,将以甘油和苯甲醛为原料合成的5-羟基-1,3-二噁烷分别与丁二酸酐、己二酸、辛二酸、癸二酸进行酯化反应合成四种羧酸化合物:4-(2-苯基-1,3-二噁烷-5-氧基)-4-羰基丁酸(A1)、6-(2-苯基-1,3-二噁烷-5-氧基)-6-羰基己酸(A2)、8-(2-苯基-1,3-二噁烷-5-氧基)-8-羰基辛酸(A3)、10-(2-苯基-1,3-二噁烷-5-氧基)-10-羰基癸酸(A4)。通过傅里叶变换红外光谱仪(FT-IR)和核磁共振仪(1H NMR)对其进行结构表征,通过差示扫描量热仪(DSC)和热重分析仪(TGA)对其进行热性能表征,并探讨亚甲基柔性间隔基对其热性能的影响。研究结果表明:随着亚甲基柔性间隔基长度的增加,化合物熔点呈下降趋势,但其热稳定性随着亚甲基柔性间隔基长度的增加呈上升趋势。论文的第3章,将胆甾醇作为天然生物液晶基元分别引入到化合物A2-A4中,合成三种含胆甾基元的新型手性液晶化合物:6-(2-苯基-1,3-二噁烷-5-氧基)-6-羰基己酸胆甾醇酯(C1)、8-(2-苯基-1,3-二噁烷-5-氧基)-8-羰基辛酸胆甾醇酯(C2)、10-(2-苯基-1,3-二噁烷-5-氧基)-10-羰基癸酸胆甾醇酯(C3)。通过FT-IR和1HNMR对其进行结构表征,通过偏光显微镜(POM)DSC对其进行液晶性能表征,通过TGA对其进行热稳定性表征,并探讨亚甲基柔性间隔基长度对其液晶性能和热性能的影响。结果表明:C1-C3均为胆甾相热致液晶化合物,可呈现焦锥织构;随着亚甲基柔性间隔基的增加,化合物C1-C3的玻璃化温度、清亮点和热分解温度均呈下降趋势。论文的第4章,将薯蓣皂素分别与丁二酸酐、己二酸、辛二酸反应,合成了三种具有不同亚甲基柔性间隔基长度的含薯蓣皂素基元的新型手性液晶中间体:4-薯蓣皂素氧基-4-羰基丁酸(D1)、6-薯蓣皂素氧基-6-羰基己酸(D2)和8-薯蓣皂素氧基-8-羰基辛酸(D3)。通过FT-IR和1H NMR对其进行结构表征,通过POM和DSC对其进行液晶性能表征,并探讨亚甲基柔性间隔基对其液晶性能的影响。结果表明:D1-D3均为胆甾相热致液晶化合物,可呈现焦锥织构;且随着亚甲基柔性间隔基的增加,化合物D1-D3的玻璃化温度和清亮点均呈下降趋势。更多还原

【Abstract】 Liquid crystal has both crystal ordering and liquid mobility.Due to its good photoelectric properties andthermal properties,liquid crystal has attracted widespread attention in recent years.Cholesterol and diosgenin are natural biological liquid crystal groups which are derived from organisms.Cholesterol and diosgenin have good biocompatibility,liquid crystal properties and chiral carbon atoms(C*)in the molecular structure.At the same time,cholesterol and diosgenin are easy to interact with other functional groups to chemical modify,hence they are widely studied and applied in many fields.The main idea of this study is to synthesize novel chiral liquid crystal compounds with cholesteryl and diosgenin groups,whose liquid crystal performance can be tailored by changing the length of the methylene flexible spacer in the compound structure.The novel chiral liquid crystal compounds with biocompatibility will extend the application of liquid crystals as polymer materials in biomedical fields,which will supply a foundation for the synthesis of liquid crystal polycarbonate medical polymer materials.In the second chapter,four carboxylic acid compounds containing carboxyl groups were synthesized by the reaction of 5-hydroxy-1,3-dioxane with succinic anhydride,adipic acid,suberic acid,sebacic acid,respectively,and the obtained carboxylic acid compounds were named as 4-(2-phenyl-1,3-dioxane-5-oxy)-4-carbonyl butyric acid(A1),6-(2-phenyl-1,3dioxane-5-oxy)-6-carbonyl hexanoic acid(A2),8-(2-phenyl-1,3-dioxane-5-oxy)-8-carbonyl octanoic acid(A3),10-(2-phenyl-1,3-dioxane-5-oxy)-10-carbonyl decanoic acid(A4).The structures of the obtained compouds were characterized by fourier transform infrared spectrometer(FT-IR)and nuclear magnetic resonance(1H NMR).The thermal properties were characterized by differential scanning calorimeter(DSC)and Thermogravimetric Analyzer(TGA),and the influence of the methylene flexible spacer on theirthermal properties was discussed.The results showed that the melting point of the compounds decreased with the increase of the methylene flexible spacer length,but their thermal stability increased.In the third chapter,three new chiral liquid crystal monomers were synthesized by reaction of cholesterol with there carboxylic acid compounds(A2-A4).These cholesterol ester compounds were named as cholesteryl 6-(2-phenyl-1,3-dioxane-5-oxy)-6-carbonyl hexanoate(C1),cholesteryl 8-(2-phenyl-1,3-dioxane-5-oxy)-8-carbonyl octanoate(C2),cholesteryl 10-(2phenyl-1,3-dioxane-5-oxy)-10-carbonyl decanoate(C3)The structures of C1-C3 were characterized by FT-IR and 1H NMR,and the liquid crystal properties were characterized by polarizing optical microscopy(POM)and DSC.At the same time,the thermal stability properties were characterized by TGA,and the influence of the methylene flexible spacer number on their thermal properties were discussed.The results showed that C1-C3 were cholesteric thermotropic liquid crystal compounds,and exhibited focal-conic textures.With the increase of the methylene flexible spacer numbers,the glass transition temperature,clearing point,and thermal stability of compounds C1-C3 all decreased.In the forth chapter,three liquid crystal intermediates were synthesized by reacting diosgenin with succinic anhydride,adipic acid,suberic acid,sebacic acid..They were named as 4-diosgeninoxy-4-carbonyl butyric acid(D1),6-diosgeninoxy-6-carbonyl hexanoic acid(D2)and 8-diosgeninoxy-8-carbonyl octanoic acid(D3).Then their structures were characterized by FT-IR and 1H NMR.And their liquid crystal properties were characterized by POM and DSC.D1-D3 were cholesteric thermotropic liquid crystal compounds.Their liquid crystal properties appearred when the temperature were raised to the melting point and the focal-conic textures could be observed.At the same time,the influence of the methylene flexible spacer numbers on their thermal properties was discussed.The glass transition temperature and the melting point of the compounds decreased with the increase of the methylene flexible chain length.更多还原