Guest-Anion-induced rotation-restricted emission in UiO-66-NH2and advanced structure elucidation

Qi Xue, Ka Hin Chan, Cheuk Ki Yim, Bryan Kit Yue Ng, Tianxiang Chen, Sarah J. Day, Chiu Tang, Shogo Kawaguchi, Kwok Yin Wong, Tsz Woon Benedict Lo

Research output: Journal article publicationJournal articleAcademic researchpeer-review

4 Citations (Scopus)


We report the guest-anion-induced photoluminescence enhancement of metal-organic frameworks (UiO-66-NH2), first based upon diffraction and computational evidence. We found that only limited anions, namely, carbonate and fluoride, can lead to a significant enhancement in photoluminescence, whereas their related anions, such as acetate and chloride, cannot. The optimized crystal structures reveal that the guest carbonate and fluoride ions interact with four framework amino functional groups through hydrogen bonding (ca. 1.6-1.7 Å) that ultimately forms a quaternary (-N(H))4···X- molecular bridge around the nodal center. Hence, the hydrogen-bonded molecular bridge not only restricts the intermolecular C-C rotation of the linker molecules but also greatly perturbs the electronic densities between the guest anions and the framework amino groups.

Original languageEnglish
Pages (from-to)5422-5429
Number of pages8
JournalChemistry of Materials
Issue number13
Publication statusPublished - 13 Jul 2021

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry


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