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

• DOI: 10.1021/jacs.1c03432
• Publication Date: 2021-06-03T01:49:44Z
• Authors: Shuai-Liang Yang; Gen Li; Meng-Yue Guo; Wan-Shan Liu; Ran Bu; En-Qing Gao
• Keywords: Cooperativity; Proton affinity

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 adsorption to benefit gas separation, but potential binding cooperativity is largely ignored study sensory MOFs. Here, we report first demonstration protonation MOF relevant pH response fluorescence proton conduction. The built Zr-O clusters bipyridyl-based tetracarboxylate linkers excellent hydrolytic stability. shows unique features two synchronous abrupt turn-off turn-on fluorescent transitions. transitions, which afford high sensitivity small fluctuations, are due pyridyl sites with Hill coefficient 1.6. dual-emission response, leads visual color change, ascribable proton-triggered switching between (n, π*) (π, emissions. latter emission be quenched by electron donating anion-dependent through photoinduced transfer ground-state charge transfer. Associated protonation, conductivity abruptly enhanced at low orders, overhigh acid concentration adverse because excessive anions interrupt conducting networks. Our work new perspectives MOFs should shed light on development conductive