Chinese Journal of Organic Chemistry ›› 2022, Vol. 42 ›› Issue (3): 863-870.DOI: 10.6023/cjoc202108025 Previous Articles     Next Articles


紫精寡聚体的水相折叠和堆积及葫芦[n]脲(n=7, 8)调控

彭文昶a, 王辉a, 张丹维a,*(), 黎占亭a,b,*()   

  1. a 复旦大学化学系 上海市分子催化和功能材料重点实验室 上海 200438
    b 中国科学院上海有机化学研究所 有机功能分子合成与组装化学重点实验室 上海 200032
  • 收稿日期:2021-08-17 修回日期:2021-10-27 发布日期:2021-11-03
  • 通讯作者: 张丹维, 黎占亭
  • 基金资助:
    国家自然科学基金(21890732); 国家自然科学基金(21890730); 国家自然科学基金(21921003)

Folding and Aggregation of Oligoviologens in Water and Cucurbit[n]uril (n=7, 8) Modulation

Wen-Chang Penga, Hui Wanga, Dan-Wei Zhanga(), Zhan-Ting Lia,b()   

  1. a Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, Shanghai 200438
    b Key Laboratory of Synthetic and Self-Assembly Chemistry for Organic Functional Molecules, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032
  • Received:2021-08-17 Revised:2021-10-27 Published:2021-11-03
  • Contact: Dan-Wei Zhang, Zhan-Ting Li
  • Supported by:
    National Natural Science Foundation of China(21890732); National Natural Science Foundation of China(21890730); National Natural Science Foundation of China(21921003)

To study the conformations and aggregation of linear viologen radical cation-incorporated molecules in water, a series of water-soluble oligoviologens with different length and linkers were prepared. 1H NMR experiments in deuteroxide showed that cucurbit[7]uril (CB[7]) and cucurbit[8]uril (CB[8]) encapsulate their p-xylylene linkers instead of the bipyridinium units. UV-vis absorption experiments indicated that in the aqueous solution of sodium dithionite the viologen units of the oligomers were reduced to the radical cation species which were driven to dimerize through pleated conformations, leading to the formation of trisradical cation species. Dynamic light scattering experiments revealed that the foldamer dimers further aggregated to afford nanoscale particles. Adding CB[7] decomposed all the aggregated foldamer nanoparticles through 1:1 encapsulation of the viologen radical cation units, whereas the addition of CB[8] broke the foldamers and their large aggregates through 1:2 encapsulation of the viologen radical cations. Introducing a rigid linker to the linear viologen molecule could further enhance their stacking in the radical cation state. Although the folding and dimerization of linear viologen radical cation molecules have been established in acetonitrile in the literature, this study demonstrates that in water such multiple viologen radical cation molecules not only undergo folding to form stable dimers, but also further aggregate to give rise to nanoscale particles.

Key words: folding, aggregation, radical cation, cucurbit[n]uril (n=7,8), 4,4'-bipyridinium, aqueous medium