Electrophotocatalysis with a Trisaminocyclopropenium Radical Dication

Area of Science:

• Photocatalysis and Electrocatalysis
• Organic Chemistry
• Green Chemistry

Background:

• Visible-light photocatalysis and electrocatalysis are key strategies for advancing chemical reactions.
• Combining these methods offers synergistic advantages for oxidation processes.
• Trisaminocyclopropenium (TAC) ions are emerging catalysts with unique electronic properties.

Purpose of the Study:

• To develop a novel electrophotocatalytic oxidation platform.
• To investigate the use of a trisaminocyclopropenium (TAC) ion catalyst for challenging oxidations.
• To achieve C-H/N-H coupling with azoles using a photoexcited catalytic intermediate.

Main Methods:

• Electrochemical oxidation of the TAC ion catalyst.
• Photoexcitation of the intermediate radical dication with visible light.
• Oxidation of benzene and halogenated benzenes via single-electron transfer (SET).
• C-H/N-H coupling reactions with azoles.

Main Results:

• Generation of a potent oxidizing species (3.33 V vs. SCE) from the photoexcited TAC intermediate.
• Successful oxidation of benzene and halogenated benzenes.
• Efficient C-H/N-H coupling with azoles.
• Elucidation of the oxidizing behavior and catalyst stability.

Conclusions:

• The developed electrophotocatalytic platform enables efficient oxidation and coupling reactions.
• The TAC ion catalyst, when photoexcited, generates a highly oxidizing species capable of SET.
• The catalyst's stability is attributed to its specific molecular conformation, paving the way for broader applications.