Abstract
Covalent organic frameworks (COFs) offer ordered - structures that are useful for developing light-emitting materials. However, most COFs are weak in luminescence. Here we report the conversion of less emissive COFs into light-emitting materials via a pinpoint surgery on the pore walls. Deprotonation of the N-H bond to form an anionic nitrogen species in the hydrazone linkage can eliminate the nitrogen-related fluorescence quenching pathway. The resulting COF enhances the fluorescence in a linear proportion to the progress of deprotonation, achieving a 3.8-fold improved emission. This pinpoint N-H cleavage on the pore walls can be driven only by the fluoride anion while other halogen anions, including chloride, bromide, and iodide, remain inactive, enabling the selective fluorescence switch-on sensing of the fluoride anion at a ppb level.
| Original language | English |
|---|---|
| Pages (from-to) | 12374-12377 |
| Number of pages | 4 |
| Journal | Journal of the American Chemical Society |
| Volume | 140 |
| Issue number | 39 |
| DOIs | |
| State | Published - Oct 3 2018 |
Funding
D.J. appreciates the start-up grant of NUS (R-143-000-A28- 133). K.H.L. was in part supported by an Energy Science and Engineering Fellowship at the University of Tennessee, Knoxville. K.H.L. acknowledges fruitful discussions with Q.V. Vuong. S.I. acknowledges support by the Laboratory Directed Research and Development (LDRD) Program of Oak Ridge National Laboratory. ORNL is managed by UT-Battelle, LLC, for DOE under contract DE-AC05-00OR22725. Z.L. appreciates the support by JSPS KAKENHI grant number JP18J13699.
| Funders | Funder number |
|---|---|
| Oak Ridge National Laboratory | |
| University of Tennessee | |
| Laboratory Directed Research and Development | |
| Japan Society for the Promotion of Science | 18K05257, 18J13699 |
| U.S. Department of Energy | DE-AC05-00OR22725 |
| National University of Singapore | R-143-000-A28- 133 |