Regulating Conformational Locking in Covalent Organic Framework for Selective and Recyclable Photocatalytic
Qiujian Xie1, Anqi Chen1, Zhu Gao1
1College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan, 410083, P. R. China.
Small (Weinheim an Der Bergstrasse, Germany)
|September 6, 2024
Summary
Researchers discovered a "conformational lock" (CL) effect in 2D covalent organic frameworks (COFs) using noncovalent interactions. This strategy enhances stability and efficiency for singlet oxygen (¹O₂) photocatalysis, advancing heterogeneous catalysis.
Area of Science:
- Materials Science
- Catalysis
- Supramolecular Chemistry
Background:
- Covalent organic frameworks (COFs) typically rely on covalent modifications for property tuning.
- Noncovalent interactions in two-dimensional (2D) COFs are underexplored for enhancing layer adhesion and bulk properties.
- Developing stable and efficient photocatalysts is crucial for advanced chemical transformations.
Purpose of the Study:
- To investigate the role of noncovalent forces, specifically the "conformational lock" (CL) effect, in 2D hydrazine-linked COFs.
- To utilize intralayer F-H interactions to stabilize interlayer adhesion and improve COF properties.
- To enhance the stability, selectivity, and efficiency of COFs as photocatalysts for singlet oxygen (¹O₂) triggered reactions.
Main Methods:
- Design and synthesis of fluorinated 2D hydrazine-linked COFs.
- Characterization of intralayer noncovalent interactions (F-H) and interlayer π-π stacking.
- Evaluation of photocatalytic performance in ¹O₂-dependent transformations.
- Assessment of catalyst stability over multiple reaction cycles.
Main Results:
- Discovery and regulation of the "conformational lock" (CL) effect driven by intralayer F-H interactions.
- Fluorinated COFs exhibited enhanced intersystem crossing for ¹O₂ generation and strong interlayer π-π stacking.
- The 4F-COF demonstrated superior photocatalytic conversion and selectivity (>98%) in ¹O₂-triggered reactions.
- High photocatalytic stability was observed over 7 continuous cycles.
Conclusions:
- Promoting intralayer noncovalent interactions in 2D COFs significantly enhances photocatalytic activity and stability.
- The CL strategy offers a facile approach to engineer robust and efficient COF photocatalysts.
- This work opens new avenues for developing advanced 2D COFs in heterogeneous catalysis.
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