Nile Red-Based Covalent Organic Framework as a Photocatalyst for C-H Bond Functionalization

Area of Science:

• Materials Science
• Organic Chemistry
• Photocatalysis

Background:

• Covalent organic frameworks (COFs) are of interest as photocatalysts.
• Symmetry restrictions in linkers hinder the development of heterogeneous photocatalysts.
• Postmodification offers a route to overcome these limitations.

Purpose of the Study:

• To synthesize a novel imine-based 2D-COF, NR0.17-COF, via postmodification with a Nile Red (NR) unit.
• To evaluate the photocatalytic activity of NR0.17-COF in C-H functionalization reactions.
• To demonstrate the scalability and recyclability of the developed heterogeneous photocatalyst.

Main Methods:

• Synthesis of an imine-based 2D-COF using a NR-alkyne scaffold for postmodification.
• Application of NR0.17-COF in various photoredox-catalyzed C-H functionalization reactions.
• Assessment of radical generation, functional group tolerance, scalability, and recyclability.

Main Results:

• NR0.17-COF exhibits remarkable photocatalytic activity in C-H functionalization under mild conditions and low-energy light.
• The framework effectively generates aryl, sulfur, and nitrogen radicals with good functional group tolerance.
• The heterogeneous photocatalyst demonstrates a 10-fold increase in reaction scale and recyclability up to six times, outperforming homogeneous systems.

Conclusions:

• Post-synthetic modification of COFs is a viable strategy for developing efficient heterogeneous photocatalysts.
• NR0.17-COF offers a scalable, recyclable, and versatile solution for photoredox-catalyzed C-H functionalization.
• This advancement holds significant potential for practical applications in organic synthesis and photocatalytic technology.