【作者】 王伟；

【导师】 龚淑玲；

【作者基本信息】 武汉大学 ， 高分子化学与物理， 2015， 博士

【摘要】 杯芳烃本身具有疏水性的空腔,能通过自身的反应位点引入不同的官能团,通过主客体分子间多种非共价键作用力形成的超分子聚集体,在气体吸附、模拟酶催化、药物载体、纳米材料和富勒烯化学等方面得到了广泛的应用。然而目前基于杯芳烃的自组装体及其形成的纳米管的报道仍然不多,对杯芳烃自组装机理也了解甚少。本论文在实验室以前工作的基础之上,进一步深入地研究拥有不同构象和不同作用位点的杯[4]芳烃和硫杂杯[4]芳烃通过非共价键作用力形成纳米管的自组装行为。第一章首先介绍了超分子化学和主客体化学,接着较为详细地介绍了杯[4]芳烃主体分子的结构、构象及其衍生化反应,最后总结了通过非共价键作用力作为驱动力,包括氢键、π…π堆积作用和金属配位键等,形成杯[4]芳烃纳米管的研究进展。第二章合成了上缘含醛基、氰基和羧基基团的不同构象的杯[4]芳烃衍生物,上缘含醛基、氰基和羟基的锥式构象的硫杂杯[4]芳烃衍生物和上缘含醛基的部分锥式构象的硫杂杯[4]芳烃衍生物。通过最终的反应产物推测出杯[4]芳烃下缘异丙基的脱去是在醛基引入到杯芳烃上缘之后进行的。通过研究柱[5]芳烃反应的中间产物并结合文献分析,验证了Holler提出柱[5]芳烃的合成是通过阳离子反应机理的合理性。第三章研究了没有强氢键授受体存在的情况下,用氯仿/环己烷作为结晶溶剂,不同构象的硫杂杯[4]芳烃衍生物的自组装行为。与杯[4]芳烃相比,桥联S原子取代C原子使硫杂杯[4]芳烃拥有更大的空腔,更容易形成“头对头,,的二聚体结构；S原子形成的S…π和S…S等作用力能有效协助晶体进行自组装。结果显示：锥式构象的醛基硫杂杯[4]芳烃衍生物都通过分级拼接的方式形成了“头对头”的二聚体和蜂窝状的纳米管结构；锥式构象的氰基硫杂杯[4]芳烃衍生物在无法形成二聚体的情况下,通过与氯仿分子间的Cl…π、N…Cl和Cl…Cl作用力也形成了蜂窝状的纳米管结构；部分锥式构象的醛基硫杂杯[4]芳烃衍生物由于苯环倒置减少了环腔间的排斥,形成了“头对头”二聚体和蜂窝状的纳米管结构；下缘乙酸乙酯和苯甲酰基四取代的1,3-交替构象的硫杂杯[4]芳烃衍生物能通过S…π或S…S作用力以“肩并肩”的方式进行连接,形成沿杯芳烃环腔堆积的纳米管结构。从这些我们可以看出,主体分子的构象不是分子能否构成纳米管的决定因素,在分子骨架上引入适当的基团,并在合适的结晶环境下通过分子间的相互作用力能以恰当的排列方式形成纳米管。第四章研究了杯芳烃上缘存在强氢键授受体的情况下,分别用吡啶/甲醇和四氢呋喃/甲醇作为结晶溶剂,不同构象的杯[4]芳烃羧酸衍生物(羧酸数目≥2)自组装行为。锥式构象的杯[4]芳烃羧酸衍生物的羧基位于杯芳烃的同一侧,可以与其它主体分子和溶剂分子形成不同类型的氢键作用力;当同侧连有羧基的苯环向环腔收缩(二面角小于30°,杯芳烃分子倾向于形成由自身的两对羧基构成的氢键二聚体结构,当连有羧基的苯环向环外扩张,相邻的主体分子会形成由一对羧基间氢键构成的一维波浪结构。部分锥式和1,3-交替构象的杯[4]芳烃羧基衍生物,由于羧基在两侧,可以直接或者在溶剂的帮助下形成一维波浪形或者链状的结构。溶剂分子对自组装行为产生影响,吡啶容易通过O-H…N氢键形成“头对头”的二聚体结构,主导分子的自组装;四氢呋喃体现的是一个协助作用,填充在晶体所形成的空隙中；在缺少强氢键作用点的情况下,甲醇可以作为一个补充的氢键作用位点与主体分子间以“头对头”或“肩并肩”的方式相连接。第五章研究了没有强氢键授受体和S硫原子存在的情况下,不同构象的杯[4]芳烃衍生物的自组装行为。由于超分子作用点比较少,杯芳烃在分子间的弱相互作用力,如C-H…O、C-H…π和O…π等,协助下通过分子间紧密堆积的方式形成超分子网络结构。下缘取代基的位阻效应会影响杯[4]芳烃衍生物产生不同的自组装行为。当下缘没有取代基时,锥式构象的醛基杯[4]芳烃容易以分级拼接方式形成纳米管；当下缘的取代基为柔性较大的正丙基时,1,3-交替构象杯[4]芳烃四醛分子为了有效降低相邻分子之间的排斥力,分子发生了90°的旋转,通过两组相互垂直的醛基形成三维的C-H…O氢键,沿着分子环腔方向堆积形成了一维纳米通道；当下缘的取代基为位阻较大的异丙基时,1,3-交替构象杯[4]芳烃醛基衍生物的醛基向环腔内收缩,分子间通过密堆积形成三维结构；在杯[4]芳烃的上缘引入氰基或者下缘引入苯甲酰基可以提供不同类型的超分子作用点,协助杯芳烃聚集体的生成。更多还原

【Abstract】 As calixarenes contain a π-based cavity and several reactable positions, they are broadly used as building blocks to construct well preorganized host molecules which have widely been applied in areas as gas adsorption, enzyme mimics, drug carries, nanotubes and fullerene chemistry, etc. However, reports based on self-assembly and assembly form calixarenes nanotubes are still not so many. Our research focuses on the nanotubes formed by the self-assembly of calixarene and thiacalixarene which contains different conformations and supramolecular action groups.In chapter one, the survey of supramolecular chemistry and host-guest chemistry are briefly introduced. The structural characteristics and modifications of calixarenes are also introduced. In the end, the nanotubes assembly based on calixarenes by n hydrogen bonding and π-π stacking interactions are reviewed.In chapter two, different conformations of calix[4]arene derivatives bearing aldehyde, cyano and carboxyl acid groups at the upper rim are synthesized. Cone thiacalix[4]arene derivatives contaning aldehyde, cyano and hydroxy groups at the upper rim are synthesized. Inferred by the reaction product, isopropyl groups are dealkylated after aldehyde groups have been introduced to the upper rim. The carbocation mechanism of pillararene formation is presented, which support Holler’s theory.In chapter three, during the absence of strong hydrogen bond, we use chloroform/ cyclohexane as a solvent for crystallization, and the self-assembly of nine thiacalix[4]arene derivatives are studied. Compared with the "classical" calixarenes, thiacalixarene has larger cavities and more favours of interdigitation aromatic yielding the classical head-to-head dimeric motif. S…π interaction between sulfur and neighbouring thiacalixarene can work in a positive way, making the assembling even more stable. Cone conformation thiacalix[4]arene derivatives bearing formyl groups form "head-to-head" dimers and "honeycomb" shaped nanotube structure by hierarchical self-assembly. Cone conformation thiacalix[4]arene derivatives bearing cyano groups are linked together through the connection of solvent molecules. CHCl3 molecules are oriented so as to form Cl…Cl, Cl…π and cyano…Cl interaction with neighbouring nanotubes. Because the invert aromatic ring reduces the repulsion, partial cone thiacalix [4] arene derivatives bearing cyano group also form "head-to-head" dimers and "honeycomb" shaped nanotube structure by hierarchical self-assembly. The neighboring of 1,3-alternate thiacalix[4]arene derivatives can connect each other in a "side-by-side" manner by S…π and S…S interaction. Through the study of the self-assembly behavior of thiacalix[4]arene derivatives, we find that the variation in the conformation of the host molecules does not dominate the formation in this case, as long as host molecules can be circumvented in an appropriate manner to form nanotubes.In chapter four, the influence of the crystallization medium (solvent/guest type) of different conformations calix[4]arene derivatives bearing carboxylic acid groups at the upper rim and on the formation of hydrogen-bonded nanotubes are studied. When the carboxyl acid groups are located in the same side (cone conformations), they can form different types of hydrogen bonded with other molecules.In the extended structure, neighboring calixarenes connect each other to form hydrogen-bonded dimeric capsules through complementary COOH…COOH if the carboxyl acid orientates towards the cavity (dihedral angle of less than 30°).Adjacent calixarenes will form hydrogen-bonded one-dimensional wave structure if carboxyl acid orientates outwards. Solvent plays a crucial role in supramolecular arrays. We can find that calixarenes assemble in the presence of pyridine (Py acting as a template) to form hydrogen-bonded dimeric capsules through complementary Py…COOH. Tetrahydrofuran is more just a facilitating role in the crystal and it can fill the gap. During the absence of strong hydrogen bonding of the case, methanol can be used as a complementary hydrogen bonding to connect calixarenes in a "head-to-head" or "side-by-side" manner.In chapter five, during the absence of strong hydrogen bond, the self-assembly of calix[4]arene derivatives are studied. Due to lack of supramolecular point, calixarene derivatives could form network structure by C-H-O, C-H-…π and O…π interactions. The steric effects of substituents groups at the lower rim will lead to different self-assembly behavior of calix[4]arene derivative. No substituent groups at the lower rim, cone conformation calix[4]arene derivatives bearing formyl groups form "honeycomb" shaped nanotube structure by hierarchical self-assembly.In order to reduce the repulsion of adjacent molecules that are synthesized by introduing n-propyl to the lower rims,1,3-alternate calix[4]arene tetraformyl connects each other by mutually perpendicular and formation of three-dimensional through C-H…O hydrogen bonds. For the tetraisopropoxy,1,3-alternate calix[4]arene tetraformyl forms three-dimensional structures by close-packed because the formyl groups orientate towards the cavity. Introduction of cyano or benzoyl groups to calixarenes can provide different supramolecular points, which can assist molecular self-assembly.更多还原