pH‐Controlled Reversible Formation of a Supramolecular Hyperbranched Polymer Showing Fluorescence Switching |
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| Authors: | Bingran Yu Dr Baoyan Wang Shuwen Guo Qian Zhang Xiaorui Zheng Haitao Lei Prof?Dr Weisheng Liu Prof?Dr Weifeng Bu Yun Zhang Dr Xin Chen |
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| Institution: | 1. Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization of Gansu Province, State Key Laboratory of Applied Organic Chemistry and College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu, 730000 (P.R. China), Fax: (+86)?9318912582;2. National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083 (P.R. China) |
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| Abstract: | A π‐conjugated AB2 monomer 1 with a dibenzo24]crown‐8 (DB24C8) ring and two secondary amine centres has been synthesised. Treatment of a solution of 1 in dichloromethane with trifluoroacetic acid (TFA) leads to protonation of the amine groups, and then the DB24C8 rings are threaded by the dialkylammonium ion centres of other monomer molecules, leading to the formation of a supramolecular hyperbranched polymer, TFA‐ 1 . Rather strong π–π stacking interactions between the conjugated cores are evident in this polymer. The supramolecular hyperbranched polymer (SHP) can be completely depolymerised by adding a slight excess of N‐tert‐butyl‐N′,N′,N′′,N′′,N′′′,N′′′‐hexamethylphosphorimidic triamide, tetrabutylammonium fluoride, or tetrabutylammonium acetate. The acid–base‐controlled process induces a reversible change in the fluorescence intensities of the solutions due to the controllable presence of the π–π stacking interactions between the conjugated cores. This dynamic behaviour is significant with respect to “smart” supramolecular polymer materials. |
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| Keywords: | acid– base reaction fluorescence switch molecular recognition supramolecular chemistry π – π stacking |
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