【作者】 刘明；

【导师】 黄飞鹤；

【作者基本信息】 浙江大学 ， 化学， 2009， 博士

【摘要】 作为超分子化学领域中最基本的两种机械互锁结构之一,索烃分子由于其构造学上的巧妙与美感、独特的理化性质,以及在纳米功能材料和分子机器等方面的潜在应用价值,受到了越来越多的关注与研究。随着许多模板合成方法的发展,许多形态各异、功能多变的索烃结构已被合成和研究。利用本课题组发展起来的穴醚体系与百草枯衍生物间的良好的供体/受体模板作用,我们合成了一系列基于穴醚的新的索烃结构。这种结构有别于常见的“环套环”的索烃结构,而是一种“分子环”与“分子笼子”的互锁结构。在利用多种技术手段详细表征这类新颖结构的基础上,我们初步探索了这类索烃分子在溶液中的运动特性,并首次利用单晶结构探讨了索烃分子在固态中的自组装行为。我们发现这类新的索烃在结构特征、运动特性以及自组装方式上都与传统的供体/受体索烃有较大的差异：1)考虑到穴醚的三维空间结构对索烃关环的位阻影响,这类索烃的产率相当可观,这主要得益于穴醚主体对百草枯衍生物非常强的络合能力；2)通过对其结构特征的研究发现,与传统的基于冠醚和百草枯衍生物的索烃结构相比,这类结构空间上更加紧凑,主、客体组分间相互作用力更强：除了π供体/π受体堆积作用和C-H…π作用外,穴醚空间结构带来的众多的氢键作用在形成和稳定索烃结构的过程中起到了更加重要的作用；3)对索烃结构在溶液中运动特性的初步研究发现,正是由于这类索烃分子主、客体组分间强大的相互作用力,增加了组分间相对运动需要克服的能量壁垒,很大程度的限制了这类索烃分子的“运动能力”；4)通过晶体结构的研究发现,部分索烃结构在固体中能自组装形成非常有趣的超分子结构(如包络中性水分子的[2]索烃和[3]索烃、索烃二聚体以及超分子主链聚索烃结构)；5)对索烃分子在固态下的自组装行为的初步研究发现,索烃结构中微小的变化都能引起索烃分子自组装过程的较大差异,在穴醚主体第三条链上引入芳香环以及羰基后,大大增加了索烃分子自组装的方式与途径。另一方面,我们高效的制备了一种具有光响应性的新偶氮穴醚主体。通过不同波长的光照射,能很好的控制这种穴醚的顺反异构。这种偶氮穴醚主体展现了一种光调控的"ON-OFF"的络合N,N’-二甲基-2,7-氮杂芘盐(DAP)客体的能力：反式构型时不能络合DAP,而通过紫外光照射变为顺式后则能很好的络合DAP分子,这种络合与解络过程能通过变换不同波长的光照射反复进行。我们多种研究手段来证实了这种光响应体系的有效性,并初步分析探索了这种光响应体系的作用机制：光响应的偶氮苯基团的顺反异构引起穴醚主体空腔体积的变化,改变了主、客体间的尺寸匹配程度,进而影响两者的络合情况。此外,DAP客体具有的荧光特性,又赋予了这种光响应主客体体系宝贵的荧光输出信号。这种制备简单,调控方便而且有荧光信号输出的光响应体系,将会是目前应用最多的环糊精-偶氮苯体系的有力补充,会方便我们制备更加复杂的光控超分子体系。基于这种体系,我们还制备和研究了一种光控的双稳态准轮烷结构。更多还原

【Abstract】 As one kind of the basic interlocked structures, catenanes have acquired more and more attentions not only because of their topologic interesting but also due to their potential applications in molecular electronics and nanotechnology. Various kinds of catenanes have been successfully constructed by template-directed protocols.We synthesized a series of novel catenanes based on different kinds of cryptands, benefited from the good template effect between the cryptands and the paraquat derivatives. In these structures, bisparaquat cyclophane rings are mechanically interlocked with three-dimensional cryptand "molecular cage", which is different from ordinary catenanes composed of mechanically interlocked two-dimensional rings. Besides characterizing these catenanes by different method, we studied their movement characteristic in solution, and for the first time we explored the self-assembly behavior of catenanes in solid state using single crystal data. It’s found that the novel catenanes have many differences compared with the traditional donor/acceptor catenanes:1) The yields of these catenanes were impressive considering the steric effect from three-dimensional cryptands in the ring-close step, which should benifited from the high association constants between the cryptands and paraquat derivatives; 2) Compared with the traditional donor/acceptor catenanes based on crown ethers, the structure of these catenanes were more compact, and the interactions between the host and guest components were stronger. Besides theπ-donor/π-acceptor stacking and C-H…πinteractions, there were more hydrogen bonds interaction abundantly offered by the three-dimensional structure of the cryptands. And the hydrogen bonds interaction should play a more significant role in the formation and stabilization of the catenanes; 3) It’s found that the energy barrier, which the interlocked components’movements should overcome, increased a lot as a result of the stronger interactions between the host and guest components, which will restrict the flexible of these catenanes; 4) From the studies of their crystal structures, some interesting supramolecular structures were found, such as catnanes "captured" H2O molecules in their cavity, catenane dimer and supramolecular main-chain-ploycatenane structures; 5) The tiny change in catenane structures would make a huge difference in their self-assembly processes. And it’s found incorporated aromatic rings and carbonyl group would increase their self-assembly approaches to form high-level structures.The second part of my work involved constructing a new photo-responsive host-guest system. A new cryptand was efficient synthesized, which can be well controlled between cis and trans isomers by irradiating different wavelength light or being heated. It’s found tha this cryptand exhibit an ON-OFF binding ability with 2,7-dimethyldiazapyrenium salt derivative (DAP):this cryptand bound the diazapyrenium salt derivative at cis isomer only, which have been well demonstrated by various methods. The operation mechanism should be: the cis-trans transform of azobenzene unit in the cryptand changed the cavity of the host, which would result in the change of association ability between the host and the guest. The fluorescence properties of DAP molecule endued this system with detectable output fluorescence signals, which would make the monitoring of the photo-responsive system’s operation more convenient. The new effective photo-responsive host-guest system will benefit us to make much more interesting complicated photo-responsive supramolecular systems. We also reported a photocontrolled bistable pseudorotaxane based on this system.更多还原