Exploiting Intermolecular Interactions between Alkyl-Functionalized Redox-Active Molecule Pairs to Enhance...

Area of Science:

• Materials Science
• Electrochemistry
• Photochemistry

Background:

• Optimizing electron transfer rates is crucial for light-harvesting and redox-active systems.
• Molecular structure modifications are key to controlling electron transfer kinetics.
• The role of alkyl chains in mediating electron transfer remains incompletely understood.

Purpose of the Study:

• To quantify the impact of long alkyl chains on electron transfer kinetics.
• To investigate electron transfer between cobalt tris(bipyridine) and carbazole/thiophene molecules.
• To demonstrate alkyl chains as a tool for enhancing donor-acceptor electron transfer.

Main Methods:

• Transient absorption spectroscopy was employed to study electron transfer dynamics.
• Synthesis and characterization of donor-acceptor molecules with and without alkyl chains.
• Kinetic analysis of electron transfer under varying alkyl chain configurations.

Main Results:

• Electron transfer was slightly hindered when alkyl chains were present on only molecules or mediators.
• Electron transfer rates increased up to 13-fold when alkyl chains were on both donor and acceptor molecules and mediators.
• This enhancement was attributed to alkyl-alkyl chain interactions promoting mediator proximity.

Conclusions:

• Long alkyl chains can unexpectedly enhance electron transfer rates between redox-active molecules and mediators.
• Intermolecular alkyl-alkyl chain interactions can be leveraged to improve electron transfer efficiency.
• This finding offers a novel strategy for designing efficient molecular systems for energy conversion and storage.