Enhanced Circularly Polarized Luminescence from Reorganized Chiral Emitters on the Skeleton of Zeolitic Imidazolate Framework

Chiral zeolitic imidazolate framework (ZIF) showing circularly polarized luminescence (CPL) has been successfully achieved through a ligand‐exchange approach by blending a binapthyl‐derived chiral emitter with ZIF‐8 rhombododecahedron nanoparticles. This approach solves a major trade‐off in CPL‐active materials: large luminescence dissymmetry factor (glum) always suffer from supression of luminescence efficiency, due to the magnetic and electronic dipole transition nature. Compared with the optical properties of chiral emitter in dilute solution, the obtained chiral ZIF nanomaterials showed enhanced fluorescence efficiency (from 0.3 to 0.4) while the |glum| value also exhibited significant amplification by one‐order of magnitude. In addition, the enantioselective fluorescence sensing in response to α‐hydroxycarboxylic acids has also been enhanced in chiral ZIF than the individual chiral emitter. The fact that reorganization and conjucation of chiral emitters to the skeleton of ZIF nanopaticles can greatly improve both luminescence quantum yield and circularly polarization which would facilitate the design of more efficient chiroptical materials.

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