Efficient Electron Transfer Driven by Excited-State Structural Relaxation in Corrole-Perylenedimiide Dyad

Area of Science:

• Supramolecular Chemistry
• Photochemistry
• Organic Synthesis

Background:

• Corroles and perylenediimides (PDIs) are important chromophores with distinct photophysical properties.
• Designing molecular dyads to control electronic communication and charge transfer is crucial for optoelectronic applications.

Purpose of the Study:

• To synthesize and characterize a novel sterically encumbered corrole-PDI dyad.
• To investigate the electronic communication and photophysical behavior of the dyad in its ground and excited states.
• To elucidate the role of structural relaxation in excited-state charge transfer dynamics.

Main Methods:

• Straightforward synthetic route for the corrole-PDI dyad.
• Steady-state absorption and cyclic voltammetry for ground-state electronic communication.
• Time-Dependent Density Functional Theory (TDDFT) for excited-state geometry optimization.
• Emission spectroscopy to probe excited-state interactions.
• Ultrafast spectroscopy to study electron and hole transfer dynamics.

Main Results:

• A sterically encumbered trans-A2B-corrole-PDI dyad was successfully synthesized.
• Weak electronic communication was observed in the ground state.
• Excited-state geometry optimization revealed a reduced interchromophoric distance, enhancing through-space electronic coupling.
• Emission spectra showed significant deviation, indicating interaction between corrole and PDI.
• Efficient sub-picosecond electron and hole transfer occurred upon selective excitation.
• Faster charge separation and recombination were observed compared to related dyads due to excited-state structural relaxation.

Conclusions:

• The synthesized corrole-PDI dyad exhibits unique photophysical properties driven by excited-state structural changes.
• Structural relaxation in the excited state plays a critical role in modulating electronic coupling and charge transfer rates.
• This study provides insights into the design of molecular systems for advanced photochemical applications.