pH-sensitive transformation of the peptidic bolaamphiphile self-assembly: Exploitation for the pH-triggered chemical reaction

Kwak, Jinyoung; Lee, Sang Yup

doi:10.1016/j.colsurfb.2013.12.031

Cited by 4 publications

(2 citation statements)

References 28 publications

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“…21,22 However, binding cooperativity remains unexplored for MOF-based sensors. The hydrogen ion, or proton, is the smallest ion and plays key roles in chemical, biological, and ecological processes, 36,37 and proton-responsive or pH-sensing materials have important applications in many fields. 38,39 Luminescent MOFs have recently attracted increasing interest in this regard.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The hydrogen ion, or proton, is the smallest ion and plays key roles in chemical, biological, and ecological processes, , and proton-responsive or pH-sensing materials have important applications in many fields. , Luminescent MOFs have recently attracted increasing interest in this regard. Generally, MOFs can respond to pH change through the basic, acidic, or hydrogen-bonding sites at the ligands. − Protonation/deprotonation at these sites can directly affect the ligand-centered emission or affect energy transfer processes.…”

Section: Introductionmentioning

confidence: 99%

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Positive Cooperative Protonation of a Metal–Organic Framework: pH-Responsive Fluorescence and Proton Conduction

et al. 2021

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Positive cooperative binding, a phenomenon prevalent in biological processes, holds great appeal for the design of highly sensitive responsive molecules and materials. It has been demonstrated that metal–organic frameworks (MOFs) can show positive cooperative adsorption to the benefit of gas separation, but potential binding cooperativity is largely ignored in the study of sensory MOFs. Here, we report the first demonstration of positive cooperative protonation of a MOF and the relevant pH response in fluorescence and proton conduction. The MOF is built of Zr–O clusters and bipyridyl-based tetracarboxylate linkers and has excellent hydrolytic stability. It shows a unique pH response that features two synchronous abrupt turn-off and turn-on fluorescent transitions. The abrupt transitions, which afford high sensitivity to small pH fluctuations, are due to cooperative protonation of the pyridyl sites with a Hill coefficient of 1.6. The synchronous dual-emission response, which leads to visual color change, is ascribable to proton-triggered switching between (n, π*) and (π, π*) emissions. The latter emission can be quenched by electron donating anion-dependent through photoinduced electron transfer and ground-state charge transfer. Associated with cooperative protonation, the proton conductivity of the MOF is abruptly enhanced at low pH by two orders, but overhigh acid concentration is adverse because excessive anions can interrupt the conducting networks. Our work shows new perspectives of binding cooperativity in MOFs and should shed new light on the development of responsive fluorescent MOFs and proton conductive materials.

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