新的偶氮型液晶冠醚配体及配合物的合成与表征

【作者】 唐斯甫；

【导师】 张淑媛；

【作者基本信息】 郑州大学 ， 无机化学， 2004， 硕士

【摘要】 本论文由以下四部分组成： 一．前言 对液晶的基本概念、液晶态的分类、表征方法、冠醚化合物及其应用、液晶冠醚和液晶冠醚配合物以及它们的研究现状作了简要的介绍。 二．偶氮型液晶冠醚配体的合成与表征 从分子设计出发，以顺(反)式-二氨基二苯并-18-冠-6、苯酚和联苯酚等为原料，通过重氮化和偶联反应合成了一类新的偶氮型液晶冠醚化合物。根据化合物分子中末端烷氧基和化合物构型的不同，将其分为2个系列，8个偶氮型液晶冠醚配体。结构式如下： 系列Ⅰ和系列Ⅱ： 顺式-4，4′-双[4′-(正烷氧基联苯基)-4-碳酰氧基苯基偶氮]二苯并-18-冠-6(8Ⅰ) 反式-4，4′-双[4′-(正烷氧基联苯基)-4-碳酰氧基苯基偶氮]二苯并-18-冠-6(8Ⅱ) 三．偶氮型液晶冠醚配合物的合成与表征 利用已合成的顺反2个系列8个配体分别与钾、钯、镧、铕等离子配位，合成了32个新的液晶冠醚配合物，对它们的结构进行了表征，研究了它们的液晶性能，以及配位作用对液晶性能的影响。 四．结论 中间体、配体和配合物的化学结构经元素分析、IR、UV-vis、~1H NMR、荧光和原子吸收等方法确证。具有液晶性的化合物通过DSC、POM和WAXD方法测试和表征。 优化和改进了合成路线，解决了反应溶剂的选择和产物的纯化与分离等一些关键性的技术和难题。对新的偶氮型液晶冠醚配体及配合物的液晶性能进行了较系统的研究，得到了一些具有创新性的研究成果，首次发现了反向壁织构。 研究结果表明： 一北合物3、81、sn和81、811的配合物均具有热致液晶性 二.以上化合物加热至各自的熔点以上都能形成液晶态，在液晶态可观察到向列相的纹影织构、反向壁织构等或近晶相的破碎焦锥织构、镶嵌织构和光栅织构等. 三.所有的化合物的液晶态均可经降温后在室温下长期保存下来;在液晶态均易在外力作用下，沿外力方向取向. 四.所有的配合物均为非电解质，摩尔电导率值较低.其中顺式配合物的摩尔电导率要高于反式构型配合物的摩尔电导率，而在同种构型中随着末端烷氧基碳原子数的增加，电导率减小. 五.配体与配合物均具有荧光性质，配体与金属配位后，最大激发波长红移，最大发射波长蓝移. 六.对于相同构型同系列的配体和配合物，熔点和清亮点均随化合物分子中末端烷氧基增大而逐渐降低，其中配合物的近晶相温度范围递增，向列相温度范围递减;反式构型配体和配合物的熔点和清亮点均高于相应的顺式构型配体和配合物的熔点和清亮点. 七.配合物的熔点低于相应配体的熔点(反式构型的钾、斓和馆的配合物除外)，而清亮点高于相应配体的清亮点，配合物的液晶态温度范围比配体的液晶态温度范围宽. 八，配体与金属离子配位后，改变了原有配体的液晶相态变化.更多还原

【Abstract】 The dissertation consists of four parts.1. PrefaceThe basic concept, classification and characterization of liquid crystal, crown ether compounds and their application, liquid crystalline crown ether and current research were introduced briefly.2. Synthesis and characterization of azo type liquid crystalline crown ether ligandsUsing cis(trara)-diaminodibenzo-18-crown-6 as raw materials, a novel kind of azo type liquid crystalline crown ether ligand was synthesized through diazotization and coupling reactions on the base of molecular design, which can be divided into two series, eight compounds according to the end alkoxy group and configuration of the compound. The chemical structures of them are shown as follows:Series I and IICz’s-4,4 - bis[4 -(n-alkoxylbiphenyl)-4-carboxylphenylazo]dibenzo-l 8-crown-6(8 I)Trans-4,4 -bis[4 -(n-alkoxylbiphenyl)-4-carboxylphenylazo]dibenzo-18-crown-6(8 II)3. Synthesis and characterization of azo type liquid crystalline crown ether complexes8 I A~8 I D and 8II A~8IID used as ligands, complex with K+, Pd2+, La3+and Eu3+ ion respectively, a new kind of azo type liquid crystalline crown ether complexes was therefore synthesized, which can be divided into eight series, 32 complexes according to the end alkoxy group, configuration and metal ion of the compound.4. ConclusionThe structures of the ligands and their complexes were characterized ed by means of IR, UV-Vis, 1H NMR, Elemental Analysis, fluorescence and atomic absorption method. The polarizing optical microscopy, DSC and WAXD were applied to identify the mesophase of the compounds.The synthesis procedure is optimized and improved. Some key techniques and thorny problems about the chose of solvents , the purification and separation of products are solved.The influence of end alkoxy group, configuration and eomplexation of the compound on the liquid crystalline behavior have been invested and some rules were generalized. It has been found for the first time that azo type crown ether liquid crystal can form inversion walls schlieren texture. Experimental results have shown that:1) Compounds 3,81, 8II and complexes of 8 I and 8II have thermotropic liquid crystal properties.2) Once heated to their own melting temperature, all the compounds obtained above will gointo liquid crystal phase. The typical Schlieren texture, inversion walls schlieren texture of nematic phase and broken focal-conies texture, mosaic texture and grating texture of smectic phase can be observed.3) The liquid crystal texture of all the compounds can be kept for a long time at room temperature upon quenching. In their liquid crystal state, all the compounds can be easily oriented in the direction of external force.4) All the complexes are nonelectrolytes, the molar conductivity is very small. The molarconductivities of cis- configuration complexes are higher than those of trans- complexes, and decrease with the increasing of carbon numbers in the end alkoxy group in the same configuration series of complexes.5) All the ligands and complexes have fluorescent properties. After eomplexation, the position of the most intense peak in the fluorescence excitation spectrum shift to longer wavelengths, the emission maximum, however, shifts towards shorter wavelengths.6) For ligands and their complexes of same configuration and same series, both Tm and T, decrease with the increase of carbon numbers in the end alkoxy group and the temperature range of smectic phase increase, whereas the temperature range of nematic phase decrease. Tm and T( of compounds having trans-configuration are higher than those of their corresponding cw-configuration compounds.7) Tm of complexes is smaller than their ligands (except trans- configuration complexes ofpotassium, lanthanum and europium), in the same time, Ti of complexes are higher than those of their ligands. So the liquid crystal phase length becomes broader after eomplexation.8) The liquid crystalline phase of ligands can be changed through complexation with metalion.更多还原