Red edge effect and chromoselective photocatalysis with amorphous covalent triazine-based frameworks

Area of Science:

• Materials Science
• Photocatalysis
• Organic Chemistry

Background:

• Chromoselective photocatalysis utilizes light energy to drive specific reactions by selecting appropriate sensitizers.
• Existing sensitizers offer discrete redox potentials based on photon wavelength, limiting reaction control.
• Controlling reaction pathways and suppressing side reactions remains a challenge in photocatalysis.

Purpose of the Study:

• To design and synthesize two-dimensional amorphous covalent triazine-based frameworks (CTFs) with tunable electronic properties.
• To investigate the influence of the red edge effect (REE) in CTFs on photocatalytic activity and selectivity.
• To demonstrate the application of these CTFs in selective C-N cross-coupling reactions via dual Ni-photocatalysis.

Main Methods:

• Synthesis of two-dimensional amorphous covalent triazine-based frameworks (CTFs).
• Characterization of CTF electronic structure, focusing on intraband states and red edge effect (REE).
• Photocatalytic experiments involving bromination of electron-rich aromatic compounds using dual Ni-photocatalysis.

Main Results:

• CTFs with intraband states near the valence band and strong REE were successfully designed.
• Wavelength-dependent generation of excited sites with tunable redox potentials was achieved.
• Selective C-N cross-coupling products were formed using 625 nm photons, while dehalogenation was suppressed.

Conclusions:

• The designed CTFs exhibit excellent chromoselectivity in photocatalysis due to REE-induced tunable redox potentials.
• Wavelength control of charge carrier separation is crucial for efficient and selective photocatalytic transformations.
• These CTFs offer a promising platform for developing advanced photocatalytic systems with precise reaction control.