基于笼状鸟嘌呤四聚体超分子聚合物的制备与自组装  

Preparation and self-assembly of supramolecular polymers based on the G-quartet cage

作　　者：孙卫东[1] 毕云龙[1] 郑鹏程[1] 于书平[1] 韩克飞[1] 于景华[1] 朱红[1] 汪中明[1] 

机构地区：[1]北京化工大学理学院,北京100029

出　　处：《科学通报》2013年第34期3553-3560,共8页Chinese Science Bulletin

基　　金：国家自然科学基金(21176023;21276021);国家高技术研究发展计划(2011AA11A273)资助

摘　　要：合成了3种分别由碳链、醚氧链和硫醚链桥连的新型双鸟嘌呤衍生物(3,4,7),产物的结构经1H NMR和高分辨质谱确认.利用量子化学理论计算及高分辨质谱表征的方法探讨了化合物在不同碱金属离子(Li+,Na+,K+,Rb+,Cs+)存在下的自组装行为.研究表明,只有双鸟嘌呤衍生物4在碱金属离子存在下可以自组装形成一种笼状结构,并且在钾离子存在下能够形成超分子水凝胶.根据高分辨质谱和透射电子显微镜的表征结果,提出了这种超分子水凝胶可能的形成机理.Here we report three new bis-guanine derivatives（3,4,7） which are connected by alkyl chain, ether chain and thioether chain respectively. The interactions between the compounds and alkali metal ions（Li＋, Na＋, K＋, Rb＋, Cs＋） were investigated by means of high resolution mass spectrometry （HRMS）. The characteristics of the HRMS results show that only the bis-guanine connected by ether chain could self-assemble into a novel cage structure consisting of two G-quartets in the presence of alkali metal ions. The corresponding structures were optimized using the B3LYP density functional. To further study the properties of compound 4, the corresponding supramolecular polymers were prepared. Among the five supramolecular polymers in water, only 4-K＋ polymer could form supramolecular hydrogel. The structure of the supramolecular hydrogel was analyzed by HRMS and transmission electron microscope （TEM）. A possible formation mechanism of the hydrogel is proposed. Compound 4 self-assemble to form cage complex in the presence of potassium ion, and the potassium ion could well link two cage structure stably by coordination to the eight carbonyl oxygen atoms of two G-quartets. Then the cage complexes through the vertical stacking to form columnar unit in the presence of potassium ion. Nanorods structure was further obtained when the columnar interact with water molecule in the solution. Therefore, we conclude that （1） the linker of bis-guanine derivatives plays an important role in the self-assembly process. Among the three types of linkers only the ether chain can help to form cage structure in the presence of alkali metal ions; （2） compound 4 self-assemble to form supramolecular hydrogels in the presence of potassium ion selectively.

关 键 词：笼状结构 鸟嘌呤四聚体 超分子聚合物 制备 自组装 

分 类 号：O631.3[理学—高分子化学]