Single-atom photocatalyst for click reaction.

Area of Science:

• Materials Science
• Organic Chemistry
• Photochemistry

Background:

• Copper(I)-catalyzed azide-alkyne cycloaddition is a key click chemistry reaction.
• Homogeneous copper catalysis presents challenges for large-scale synthesis and mechanistic studies.
• Inspiration from natural photosynthetic systems for catalyst design.

Purpose of the Study:

• To develop a light-triggered, heterogeneous catalyst for click chemistry.
• To utilize a single-atom Cu(II)-loaded covalent organic framework (COF) as a robust photoinitiator and scaffold.
• To enable efficient generation of transient Cu(I) active sites via photoinduced electron transfer.

Main Methods:

• Design and synthesis of a single-atom Cu(II)-loaded COF.
• Investigation of light-triggered electron transfer from the COF ligand to Cu(II).
• Application in a model click chemistry reaction (benzylazide and phenylacetylene cycloaddition).

Main Results:

• Successful generation of transient Cu(I) species with submicrosecond lifetime upon light irradiation.
• Achieved 95% substrate conversion and >90% triazole yield in the model reaction.
• Demonstrated a controllable and robust heterogeneous catalytic system.

Conclusions:

• The developed COF-based system offers a sustainable approach to light-triggered click chemistry.
• This strategy provides a simplified and efficient alternative to traditional homogeneous copper catalysis.
• Potential broad applications in photolithography and polymer chemistry.