三硝基芴酮诱导苯并菲及其低聚体液晶性能的研究
发布时间：2018-11-10 12:49
【摘要】：盘状液晶分子因为柔性侧链和平面对称结构的刚性核共同作用而展现出液晶性能。但是柔性侧链过多或过长、刚性中心核不规则、乃至分子是多聚体或高分子等原因都影响了盘状液晶分子的自组装性能。通过掺杂其他分子进行诱导可以改善分子的自组装性能,例如通过掺杂富电子的2,4,7-三硝基芴酮(TNF)与盘状液晶形成电荷转移复合物就是一种常见的方法。以往在研究烷氧基苯并菲(HAT)与TNF复合的工作中,关于两者的作用模式存在争议。Boden等人认为TNF是以ABABAB…型掺杂在HAT分子之间的;而Mulder等人则认为TNF只是分布在由HAT分子堆叠的柱状组装体之间。本论文第一部分即深入探究了烷氧基苯并菲(HAT)与TNF复合后的作用模式;此外,为了扩展研究内容的宽度,论文还设计合成了两类新型苯并菲四聚体,并探讨了其与TNF复合后的主客体性质和液晶性能。主要内容包括:一、TNF与五烷氧基苯并菲(HAT5)复合物液晶性能的研究。HAT5是典型的盘状液晶分子,可自组装成六方柱状相。通过添加TNF分子形成电子给体-受体复合物后,HAT5液晶相温度区间由原来的70℃-115℃扩宽到0℃-250℃,极大改善了其液晶的稳定性。X-小角散射实验发现,随着TNF掺杂浓度的增加,HAT5组装结构中的六方晶胞参数在减小,而两个柱状组装体之间的距离仍然是一个定值(0.34 nm)。这表明TNF分子并不是分布在HAT5堆叠的柱状组装体之间的位置,而是通过电荷转移作用位于两个HAT5分子之间,形成了ABABAB…型结构。显微镜测试结果也佐证了这一点,并得出二者的最佳复合比是2:3(HAT5:TNF),当二者比例达到1:1时,TNF达到饱和状态。二、TNF和苯并菲四聚体络合的主客体性质和液晶性能研究。我们设计合成了两种新型苯并菲四聚体衍生物,分别是以柱[5]芳烃为中心体的苯并菲四聚体(4HAT-P5A)和以四苯乙烯为中心体的苯并菲四聚体(4HAT5-TPE)。通过核磁共振和可见-紫外光谱测试表明,两种苯并菲四聚体分别与TNF分子形成了电子给体-受体络合物。通过核磁滴定研究了主客体之间的络合比和络合常数,发现溶液中两种络合物主客体的络合比均为1:2,络合常数4HTA-P5A与TNF的Ka=0.215×104 M-1,4HTA-TPE与TNF的Ka=8.807×104 M-1。进一步我们研究了两种苯并菲四聚体的液晶性质以及TNF掺杂后的诱导作用。结果发现,单独的苯并菲四聚体4HTA-P5A或4HTA-TPE均不能形成液晶态;在加入TNF诱导后,4HTA-P5A仍然没有液晶性质,而4HTA-TPE则表现出液晶性质,从常温到107℃出现柱状相液晶态。通过4HTA-TPE和TNF的二组分相图,得出了固态下二个化合物最佳的复合比例为1:3,这与HAT5和TNF最佳复合比是2:3是吻合的。这些研究工作扩展了苯并菲低聚物的研究领域,并有助于更深入了解电荷转移复合物的液晶行为,便于更好的设计和制备性能优良的液晶材料。
[Abstract]:Disk liquid crystal molecules exhibit liquid crystal properties due to the interaction of flexible side chains and rigid nuclei of planar symmetric structures. However, excessive or long flexible side chains, irregular rigid center nuclei and even polymer molecules affect the self-assembly performance of disk-like liquid crystal molecules. The self-assembly properties of the molecules can be improved by doping other molecules. For example, it is a common method to form charge-transfer complexes between (TNF) and disk liquid crystals by doping the electron-rich 2O4-7-trinitrofluorenone (TNF). In the past studies on the combination of alkoxy benzophenanthrene (HAT) and TNF, there has been a controversy about the mode of their action. Boden et al believe that TNF is based on ABABAB. Mulder et al think that TNF is only distributed between columnar assemblies stacked by HAT molecules. In the first part of this thesis, the interaction mode of alkoxy phenanthrene (HAT) and TNF was studied. In addition, in order to expand the width of the study, two new types of benzophenanthrene tetramer were designed and synthesized, and the host and guest properties and liquid crystal properties were discussed. The main contents are as follows: first, the liquid crystal properties of TNF / HAT5 complexes. HAT5 is a typical disk-like liquid crystal molecule, which can self-assemble into hexagonal columnar phase. By adding TNF molecule to form electron donor-receptor complex, the temperature range of HAT5 liquid crystal phase was widened from 70 鈩，
本文编号：2322513
[Abstract]:Disk liquid crystal molecules exhibit liquid crystal properties due to the interaction of flexible side chains and rigid nuclei of planar symmetric structures. However, excessive or long flexible side chains, irregular rigid center nuclei and even polymer molecules affect the self-assembly performance of disk-like liquid crystal molecules. The self-assembly properties of the molecules can be improved by doping other molecules. For example, it is a common method to form charge-transfer complexes between (TNF) and disk liquid crystals by doping the electron-rich 2O4-7-trinitrofluorenone (TNF). In the past studies on the combination of alkoxy benzophenanthrene (HAT) and TNF, there has been a controversy about the mode of their action. Boden et al believe that TNF is based on ABABAB. Mulder et al think that TNF is only distributed between columnar assemblies stacked by HAT molecules. In the first part of this thesis, the interaction mode of alkoxy phenanthrene (HAT) and TNF was studied. In addition, in order to expand the width of the study, two new types of benzophenanthrene tetramer were designed and synthesized, and the host and guest properties and liquid crystal properties were discussed. The main contents are as follows: first, the liquid crystal properties of TNF / HAT5 complexes. HAT5 is a typical disk-like liquid crystal molecule, which can self-assemble into hexagonal columnar phase. By adding TNF molecule to form electron donor-receptor complex, the temperature range of HAT5 liquid crystal phase was widened from 70 鈩，
本文编号：2322513
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