Competitive Charge Separation Pathways in a Flexible Molecular Folda-Dimer.

Area of Science:

• Photochemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Molecular folda-dimers offer tunable photophysical properties.
• Controlling conformation is key to directing charge separation pathways.

Purpose of the Study:

• Investigate the photophysical properties of a PDI-AnEt2-PDI folda-dimer.
• Characterize charge separation dynamics in different conformations and solvent polarities.

Main Methods:

• Synthesis of the PDI-AnEt2-PDI molecular folda-dimer.
• Spectroscopic characterization of photophysical properties.
• Analysis of photoinduced charge separation dynamics in various solvents.

Main Results:

• The folda-dimer exists in open and folded conformations based on solvent polarity.
• The open form undergoes bridge electron transfer, independent of solvent polarity.
• The folded form exhibits symmetry-breaking charge separation (SBCS) between PDI units.
• Excimer formation observed in the open form, but not in the folded form.

Conclusions:

• Conformational flexibility significantly influences photophysical pathways in folda-dimers.
• The folded conformation preferentially leads to SBCS.
• Design principles for folda-dimers can be established to tune photophysical outcomes.