Red-Light-Driven C(sp²)-H Sulfonylation of Anilines Using a Recyclable Benzothiadiazole-Based Covalent Organic...

Area of Science:

• Organic Chemistry
• Materials Science
• Photocatalysis

Background:

• Traditional photocatalysis using NUV or blue light faces limitations like poor penetration and safety concerns.
• Red-light photocatalysis offers advantages but often lacks recyclable heterogeneous catalysts.
• Covalent organic frameworks (COFs) are emerging as promising materials for heterogeneous catalysis.

Purpose of the Study:

• To develop an efficient and recyclable heterogeneous photocatalyst for red-light-driven C(sp2)-H sulfonylation.
• To investigate the use of a benzothiadiazole-based covalent organic framework (Tp-BT COF) for this transformation.
• To address the limitations of homogeneous red-light photocatalysts.

Main Methods:

• Synthesis of a benzothiadiazole-based covalent organic framework (Tp-BT COF).
• Application of Tp-BT COF as a photocatalyst for C(sp2)-H sulfonylation of anilines under red-light irradiation.
• Evaluation of catalyst recyclability and reaction yields under mild conditions.
• Comparative studies with related COFs to understand structure-activity relationships.

Main Results:

• The Tp-BT COF efficiently catalyzed the red-light-driven C(sp2)-H sulfonylation of anilines.
• The reaction proceeded under mild conditions with minimal catalyst loading, yielding products in good to excellent yields.
• The Tp-BT COF demonstrated excellent stability and recyclability, retaining activity over six cycles.
• Comparative studies revealed the importance of the benzothiadiazole (BT) core and the AA stacking mode for catalytic performance.

Conclusions:

• Rationally designed photoactive COFs, like Tp-BT COF, are effective for sustainable red-light photocatalysis.
• Tp-BT COF offers an efficient, recyclable, and stable heterogeneous system for C(sp2)-H sulfonylation.
• This work highlights the potential of COFs in advancing red-light-mediated organic transformations.