【作者】 李明；

【导师】 黄飞鹤；

【作者基本信息】 浙江大学 ， 化学， 2024， 博士

【摘要】 超分子大环主体是超分子化学的核心研究主题之一,对构建各式各样性能优异且具有实际应用价值的超分子功能材料具有重要意义。柱芳烃作为一类新型的大环主体分子,自被发现以来,由于其丰富的衍生化能力、刚性柱状的富电子空腔、液相和固相下丰富的主客体化学以及优异的自组装特性,成为了超分子化学领域持续关注的对象。近年来,随着对柱芳烃固相主客体化学性质研究的不断深入,科学家们更期望探索和构筑基于柱芳烃的固相组装体并寻求其潜在的应用。因此,基于前人研究的基础,论文作者博士期间的工作主要针对柱芳烃多样化晶态组装体的构筑及其应用展开研究。具体来讲,本论文主体内容包括如下四个部分:在第一部分工作中,论文作者系统地研究了全乙基取代的柱[5]芳烃（Et P5）和柱[6]芳烃（Et P6）分别与缺电子化合物1,5-二氟-2,4-二硝基苯（DFN）和四氟-1,4-苯醌（TFB）之间的外壁相互作用,并成功构筑了一系列基于主体Et P5/Et P6和客体分子DFN/TFB的超分子电荷转移晶态组装体。当以六边形大环Et P6和DFN/TFB作为构建基元时,论文作者首次基于柱芳烃成功制备了具有精妙的六边形超分子镶嵌结构的晶态组装体,解决了开发新型多边形大环作为构建基元用于高度有序的超分子镶嵌难题,并实现了其大规模的可控自组装。此外,论文作者还发现最终得到的共晶组装体中的分子堆积排列可以在不同的结晶条件下进行调控。这项工作不仅系统探索了基于柱[n]芳烃少有研究的外络合相互作用,还首次报道了基于柱[n]芳烃超分子镶嵌结构的制备,为超分子化学提供了新的视角。在第二部分工作中,论文作者将可变化学计量比共晶的概念扩展到了柱[n]芳烃化学领域,并表明通过此晶体工程手段可以合理地构建多样化的固态超分子结构。具体而言,论文作者报道了一系列基于柱[n]芳烃（n=5,6）和1,2,4,5-四氰基苯（TCNB）的可变化学计量比共晶体,并证明了将柱[n]芳烃与客体TCNB的空腔内部络合和外络合协调的结合,能够成功构筑一系列具有不同超分子结构的有机电荷转移共晶组装体。本工作所制备的共晶组装材料还表现出颜色和发光特性均有所差异的固态物理化学特征。此外,论文作者还构筑了一类在固态超分子化学领域十分独特的晶态组装体,其中两组单独的主客体复合物共存于同一超分子结构中,这类具有混合主客体复合组分的晶态材料经活化后表现出对正溴代烷烃的气致变色行为。这项工作突出了一种在固态下构建多样化晶态自组装超分子结构并调节其发光和对底物响应等特性的新策略。在第三部分工作中,论文作者基于全溴乙基取代的柱[5]芳烃（Br P5）与1,3-二甲基咪唑碘盐离子液体（G1）之间的离子对识别行为,制备了一种新型的[2]准轮烷。¹H NMR实验证明,在氘代氯仿溶液中,Br P5和G1形成了摩尔比为1:1,且结合常数（K_a）为967±72 M^-1的主客体复合物。此外,论文作者还成功构筑了Br P5和G1在固体状态下的晶态组装体,为它们之间的主客体络合行为提供了更为直观的证据。有趣的是,由于温度依赖的主客体相互作用,这种[2]准轮烷显示出超分子相互作用诱导的低临界溶解温度相变行为。实验结果表明,可以通过改变浓度一定时的主客体摩尔比以及主体与客体以一定比例混合时的浓度对其温度响应行为进行调控。这项工作不仅丰富了柱芳烃液相和固相组装体的类型,还构建了一种具有有趣功能的超分子组装材料。在第四部分工作中,论文作者报道了一种利用正丙基取代的柱[5]芳烃（Pr P5）改变一种染料分子反-4-[4-（二甲基氨基）苯乙烯基]-1-甲基吡啶六氟磷酸盐（DMASP）固态下的堆积并调控其固态光物理性质的策略。基于主客体的离子对识别行为,柱芳烃大环骨架的存在会导致客体分子内运动受限,因此在溶液和晶体状态下均可以观察到明显的荧光发射增强现象。单晶X射线衍射分析进一步证实了主客体复合晶体中的离子对络合行为,并揭示了固态组装体中主客体的化学计量比为2:1。在主客体复合物共晶体中,位于一维通道内的DMASP分子显示出不定的取向,从而改变了共晶体固态下的堆积环境,进而影响了材料的光学性质。具体而言,主客体复合物共晶组装体的晶态光致发光量子产率约为DMASP的四倍,而且还表现出二次谐波活性。这项工作不仅报道了一种基于柱芳烃的独特离子对分子识别系统,还为通过共晶工程调节特定分子的晶态光物理性质提供了有趣的线索。更多还原

【Abstract】 Macrocyclic hosts represent a focal point in the realm of supramolecular chemistry,serving as key building blocks for the design and synthesis of a diverse array of high-performance supramolecular functional materials with practical applications.Among these hosts,pillar[n]arenes have emerged as a particularly intriguing class of macrocyclic molecules,drawing considerable attention in the field on account of their versatile derivatization capabilities,rigid pillar electron-rich cavities,rich host-guest chemistry in both solution and the solid state,and exceptional self-assembly properties.Recent advances in the exploration of the solid-state host-guest chemistry properties of pillar[n]arenes have fueled a growing interest in leveraging these molecules to construct solid-state assemblies for potential applications.This doctoral work focuses on the construction and application of diverse crystalline assemblies based on pillar[n]arenes.Specifically,the main sections of this dissertation are structured as the following four parts:In the first part,we systematically investigated the“exo-wall”interactions of perethylated pillar[5]arenes（Et P5）and pillar[6]arenes（Et P6）with electron-deficient compounds 1,5-difluoro-2,4-dinitrobenzene（DFN）and tetrafluoro-1,4-benzoquinone（TFB）.A series of charge-transfer crystalline supramolecular assemblies based on Et P5/Et P6 and guest molecules DFN/TFB were successfully constructed.Interestingly,fantastic hexagonal supramolecular tessellations based on Et P6 with DFN and TFB could be well prepared,thus addressing the challenges of developing novel suitable polygonal macrocycles as building blocks for the construction of highly ordered supramolecular tessellations and achieving their large-scale controllable self-assembly.Moreover,the self-assembled packing arrangements in the ultimate cocrystal superstructures were solvent-dependent and could be adjusted under different crystallization conditions.This work not only explored the rare exo-wall interactions based on pillar[n]arenes but also reported the fabrication of supramolecular tessellations based on pillararenes for the first time,showing a new perspective in supramolecular chemistry.In the second part,we extended the concept of variable stoichiometry cocrystals into the realm of pillararene chemistry and showed that this permitted the rational construction of a diverse set of supramolecular structures in the solid state.Specifically,we reported a series of variable stoichiometry cocrystals based on pillar[n]arenes（n=5,6）and tetracyanobenzene（TCNB）and showed that the combination of in-cavity complexation by pillar[n]arenes and outside binding with TCNB allowed several types of organic charge-transfer cocrystals with different self-assembled superstructures to be isolated.The variable stoichiometry cocrystals of this study displayed different solid-state physicochemical properties,including distinct colors and luminescence features.Among the ensembles produced in the present study,we discovered unique pillararene-based cocrystals containing a pair of distinct host-guest complexes within the same overall solid-state superstructure.These mixed cocrystalline materials were found to display vapochromic behavior toward n-bromoalkanes,including propyl bromide（C3）,bromobutane（C4）,and bromopentane（C5）.This work highlighted a new strategy for the construction of self-assembled superstructures in the solid state and for tuning their intrinsic characteristics,including their luminescent and substrate-responsive features.In the third part,we prepared a novel[2]pseudorotaxane based on the ion-pair recognition behavior between perbromoethylated pillar[5]arene（Br P5）and 1,3-dimethylimidazolium iodide ionic liquid（G1）.¹H NMR experiments revealed a 1:1host-to-guest stoichiometry with the association constant（K_a）of 967±72 M^-1 in chloroform-d.Additionally,crystalline assemblies between Br P5 and G1 were also successfully constructed in the solid state,providing intuitive evidence for their host–guest complexation behavior.Interestingly,on account of the temperature-dependent host–guest interactions,this[2]pseudorotaxane exhibited a supramolecular interaction induced lower critical solution temperature（LCST）phase transition behavior.According to the experimental results,the thermo-responsive behavior could be controlled by adjusting the molar ratio of the host to guest at a certain concentration and the concentrations of these two components at a certain molar ratio.This work not only enriched pillararene-based assemblies in both solution and the solid state,but also constructed a supramolecular material with intriguing functionalities.In the fourth part,we reported an ion-pair recognition strategy involving the utilization of a pillar[5]arene（Pr P5）to alter the solid-state packing and modulate the solid-state photophysical properties of a stilbazolium-type dye molecule trans-4’-（dimethylamino）-N-methyl-4-stilbazolium hexafluorophosphate（DMASP）.On account of the macrocyclic skeleton-induced restriction of the intramolecular motions of the guest,fluorescence emission enhancement was observed in both solution and the crystalline state.Support for the ion-pair encapsulation in the crystalline state came from a single crystal X-ray diffraction structure with a host-to-guest stoichiometry ratio of 2:1.In addition,DMASP molecules in the one-dimensional channels were found to display two opposite orientations in the resulting host-guest complex cocrystals,which was believed to change the overall solid-state packing environment and thus the material properties essentially.Specifically,the host-guest complex cocrystals exhibited roughly four-fold higher crystalline-state photoluminescence quantum yields than individual DMASP and possessed second harmonic generation（SHG）activity.This work not only reported a unique ion-pair molecular recognition system based on pillararenes but also provided interesting clues for the modulation of the crystalline-state photophysical properties of organic dyes via cocrystal engineering.更多还原