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Weak Links To Differentiate Weak Bonds: Size-Selective Response of π-Conjugated Macrocycle Gels to Ammonium Ions
- Kang, Suk-il, Lee, Milim, Lee, Dongwhan
- Journal of the American Chemical Society 2019 v.141 no.14 pp. 5980-5986
- ammonium, chemical structure, gels, phase transition, spectral analysis
- Molecular-level host–guest interactions can drive gel-to-sol phase transitions of the bulk material. Using supramolecular gels constructed from π-conjugated aza-crown macrocycles, we have investigated the effects of guest chemical structures on the kinetics of gel disassembly. While ammonium ions bind only weakly to the individual macrocycles in solution, gel-to-sol transitions of self-assembled macrocycles occur readily under ambient conditions. This net signal amplification process was monitored conveniently by time-dependent spectroscopic studies to reveal a straightforward correlation between the response rate and shape/size of the guest species. Well-designed weak links thus respond to subtle differences in weak bonds and translate them into visually discernible macroscopic signaling events.