Reservoir effect in bichromophoric Fe^III complexes with a methylene bridge.

Area of Science:

• Sustainable chemistry
• Photocatalysis
• Coordination chemistry

Background:

• Noble metals in photocatalysis pose sustainability challenges.
• Iron complexes offer abundant alternatives but suffer from short photoactive state lifetimes.
• Multichromophoric systems with long-lived organic chromophores show promise for excited state energy storage.

Purpose of the Study:

• To investigate the effect of methylene bridges on electronic state decoupling in iron-based multichromophoric complexes.
• To enhance the excited state lifetimes of iron complexes for photocatalytic applications.
• To explore the potential of iron complexes as sustainable alternatives to noble metals in energy storage.

Main Methods:

• Synthesis of four multichromophoric iron complexes with phenyl and anthracenyl moieties.
• Ground and excited state characterization.
• Density Functional Theory (DFT) calculations.

Main Results:

• Methylene bridges effectively decouple electronic states in the iron complexes.
• The anthracenyl-substituted complexes exhibited reservoir effects.
• Excited state lifetimes exceeding 5 nanoseconds were achieved.

Conclusions:

• Short aliphatic bridges, specifically methylene, are crucial for realizing efficient electronic decoupling in iron-based multichromophoric systems.
• This strategy enables the development of iron complexes with extended excited state lifetimes, paving the way for sustainable photocatalysis.
• The findings support the use of iron as a viable, earth-abundant metal in advanced photocatalytic applications.