Efficient Photoredox Cycles to Control Perylenediimide Self-Assembly

Area of Science:

• Organic Chemistry
• Photochemistry
• Materials Science

Background:

• Perylenediimide (PDI) derivatives are crucial in photocatalysis, hydrogen evolution, photo-responsive gels, and organic semiconductors.
• While PDI radical anions (PDI⋅^-) are easily formed, achieving the PDI dianion (PDI^2-) via photoreduction is challenging.

Purpose of the Study:

• To develop efficient methods for the 2-electron photoreduction of PDI derivatives.
• To explore novel strategies for generating PDI dianions under accessible conditions.

Main Methods:

• Investigated direct photoreduction of PDI aggregates under anaerobic conditions using UVC light.
• Explored indirect photoreduction in aerobic conditions utilizing acetone ketyl radicals generated by UVC light.
• Assessed the efficiency of the indirect photoreduction method for other dyes like naphthalenediimide (NDI) and methylviologen (MV²⁺).

Main Results:

• Achieved full 2-electron photoreduction of PDI derivatives to PDI dianions using UVC light.
• Demonstrated successful direct photoreduction under anaerobic conditions.
• Showcased efficient indirect photoreduction in aerobic conditions via acetone ketyl radicals.
• Confirmed the applicability of indirect photoreduction to NDI and MV²⁺.

Conclusions:

• Developed a novel and efficient method for the 2-electron photoreduction of PDI derivatives.
• The indirect photoreduction strategy using acetone ketyl radicals is versatile and effective for various dyes.
• This efficient photoreduction, achievable with simple LED light in aerobic conditions, is promising for dissipative light-driven systems and materials.