A novel pillar[5]arene-based supramolecular organic framework gel to achieve an ultrasensitive response by introducing the competition of cation⋯π and π⋯π interactions

• Published in: Soft matter 2018, Vol.14 (18), p.3624-3631
• Main Authors: Zhang, You-Ming, Li, Yong-Fu, Zhong, Kai-Peng, Qu, Wen-Juan, Chen, Xiao-Peng, Yao, Hong, Wei, Tai-Bao, Lin, Qi
• Format: Article
• Language: English
• Subjects: Cations; Competition; Cyclohexanol; Fluorescence; Gels; Iron; Logic circuits; Nanoparticles; Thin films
• ISSN: 1744-683X; 1744-6848
• DOI: 10.1039/C8SM00426A

Ultrasensitive response properties are an intriguing concern for stimuli-responsive materials. Herein, we report a novel method to achieve an ultrasensitive response by introducing the competition of cation⋯π and π⋯π interactions into a pillar[5]arene-based supramolecular organic framework ( SOF-AMP ). SOF-AMP was constructed with a novel bis-naphthalimide functionalized pillar[5]arene, which was able to form a stable supramolecular gel ( SOF-AMP-G ) in cyclohexanol. Interestingly, SOF-AMP-G shows an ultrasensitive response to Fe 3+ through the competition of cation⋯π and π⋯π interactions. Meanwhile, the Fe 3+ coordinated SOF ( MSOF-Fe ) shows an ultrasensitive response to H 2 PO 4 − . SOF-AMP-G displayed yellow fluorescence whereas, after the addition of 0.5 equiv. of Fe 3+ to SOF-AMP-G , the yellow fluorescence was quenched. The detection limit of SOF-AMP-G for Fe 3+ is 7.54 × 10 −9 M. More interestingly, the Fe 3+ coordinated SOF gel ( MSOF-Fe-G ) could sense H 2 PO 4 − with a fluorescence “turn-on”. The detection limit of MSOF-Fe-G for H 2 PO 4 − is 4.21 × 10 −9 M. Simultaneously, the Fe 3+ and H 2 PO 4 − responsive thin films based on these SOF gels were prepared. Moreover, these SOF gels could be used as ultrasensitive ion sensors, fluorescent display materials and sensitive logic gates.