Photostimulated Covalent Linkage Transformation Isomerizing Covalent Organic Frameworks for Improved Photocatalytic Performances.
Zheng LinShujing LiuWeijun WengChangchun WangJia GuoPublished in: Small (Weinheim an der Bergstrasse, Germany) (2023)
Covalent organic frameworks (COFs) offer a desirable platform to explore multichoromophoric arrays for photocatalytic conversion. Symmetric arrangement of choromophoric modules over π-extended frameworks enhances exciton delocalization while impairing excitation density and accordingly photochemical reactivity. Herein, a photoisomerization-driven strategy is proposed to break the excited-state symmetry of ketoenamine-linked COFs with multichoromophoric arrays. Incorporating electron-withdrawing benzothiadiazole facilitates the ultrafast excited-state intramolecular proton transfer (ESIPT) from enamine to keto within 140 fs, resulting in partially enolized COF isomers. The hybrid linkages containing imine and enamine bonds at the node of framework alter the symmetry of electronic structure and enforce the photoinduced charge separation. Increasing the imine-to-enamine ratio further promotes the electron transferred number in a long range, thereby affording the optimum photocatalytic hydrogen evolution rate. This work put forward an ESIPT-induced photoisomerization to build a symmetry-breaking COF with weakened exciton effect and enhanced photochemical reactivity.
Keyphrases
- electron transfer
- energy transfer
- visible light
- reduced graphene oxide
- fluorescent probe
- highly efficient
- solar cells
- high density
- quantum dots
- lymph node
- high glucose
- water soluble
- diabetic rats
- high throughput
- gold nanoparticles
- drug induced
- endothelial cells
- hepatitis c virus
- liquid chromatography
- mass spectrometry
- stress induced