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Control over Charge Separation by Imine Structural Isomerization in Covalent Organic Frameworks with Implications on CO2Photoreduction
- Source :
- Journal of the American Chemical Society; February 2024, Vol. 146 Issue: 7 p4489-4499, 11p
- Publication Year :
- 2024
-
Abstract
- Two-dimensional covalent organic frameworks (COFs) are an emerging class of photocatalytic materials for solar energy conversion. In this work, we report a pair of structurally isomeric COFs with reversed imine bond directions, which leads to drastic differences in their physical properties, photophysical behaviors, and photocatalytic CO2reduction performance after incorporating a Re(bpy)(CO)3Cl molecular catalyst through bipyridyl units on the COF backbone (Re-COF). Using the combination of ultrafast spectroscopy and theory, we attributed these differences to the polarized nature of the imine bond that imparts a preferential direction to intramolecular charge transfer (ICT) upon photoexcitation, where the bipyridyl unit acts as an electron acceptor in the forward imine case (f-COF) and as an electron donor in the reverse imine case (r-COF). These interactions ultimately lead the Re-f-COF isomer to function as an efficient CO2reduction photocatalyst, while the Re-r-COF isomer shows minimal photocatalytic activity. These findings not only reveal the essential role linker chemistry plays in COF photophysical and photocatalytic properties but also offer a unique opportunity to design photosensitizers that can selectively direct charges.
Details
- Language :
- English
- ISSN :
- 00027863 and 15205126
- Volume :
- 146
- Issue :
- 7
- Database :
- Supplemental Index
- Journal :
- Journal of the American Chemical Society
- Publication Type :
- Periodical
- Accession number :
- ejs65423020
- Full Text :
- https://doi.org/10.1021/jacs.3c10627