Physics

Electron transfer

Organic chemistry

Chemistry

Polymer chemistry

Materials science

Condensed matter physics

Fluorophore

Anthracene

Acceptor

Maleimide

Photoinduced electron transfer

Quantum mechanics

Intramolecular force

Photochemistry

Fluorescence

Advanced Materials

The immobilization of fluorescent photoinduced electron transfer (PET) switches/sensors into solid state, which usually cannot maintain their identical properties in solution, has remained a big challenge. Herein, a water‐stable anthracene and maleimide appended zirconium‐based‐metal–organic framework (Zr‐MOF; UiO‐68‐An/Ma) is reported. Unlike the regular intramolecular “fluorophore–spacer–receptor” format, the separated immobilization of fluorescent (anthracene) and acceptor (maleimide) groups into the framework of a multivariate MOF can also favor a pseudo‐intramolecular fluorescent PET process, resulting in UiO‐68‐An/Ma with very weak fluorescence. Interestingly, after Diels–Alder reaction or thiol‐ene reaction of maleimide groups, the pseudo‐intramolecular fluorescent PET process in UiO‐68‐An/Ma fails and the solid‐state fluorescence of the crystals is recovered. In addition, UiO‐68‐An/Ma shows an interesting application as solid‐state fluorescent turn‐on sensor for biothiols, with the naked eye response at a low concentration of 50 µmol L −1 within 5 min. This study represents a general strategy to enable the efficient tuning of fluorescent PET switches/sensors in solid state, and considering the fluorescence of the PET‐based MOFs can be restored after addition of analyte/target species, this research will definitely inspire to construct stimuli‐responsive fluorescent MOFs for interesting applications (e.g., logic gate) in future.

Tuning the Photoinduced Electron Transfer in a Zr‐MOF: Toward Solid‐State Fluorescent Molecular Switch and Turn‐On Sensor