A Supramolecular [10]CPP Junction Enables Efficient Electron Transfer in Modular Porphyrin-[10]CPP⊃Fullerene...

Area of Science:

• Supramolecular Chemistry
• Organic Electronics
• Photochemistry

Background:

• Development of efficient electron donor-acceptor dyads is crucial for organic electronic devices.
• Rigid molecular bridges are needed to control charge transfer pathways and lifetimes.

Purpose of the Study:

• To synthesize and investigate photoinduced electron transfer across a [10]cycloparaphenylene ([10]CPP) bridge connecting a zinc porphyrin and various fullerenes.
• To explore the potential of [10]CPP as a supramolecular mediator for charge transport.

Main Methods:

• Synthesis of iodo-[10]cycloparaphenylene for creating porphyrin-[10]CPP conjugates.
• Binding studies of fullerenes (C60, C70, (C60)2) to the porphyrin-[10]CPP system.
• Fluorescence and pump-probe spectroscopy to analyze energy and charge transfer dynamics.

Main Results:

• Efficient photoinduced electron transfer was achieved across the [10]CPP bridge.
• Strong binding affinities (KA > 10^5 M^-1) were observed between the conjugate and fullerenes.
• Intramolecular energy transfer and efficient charge separation were confirmed, yielding charge-separated states with lifetimes up to 0.5 μs.
• Complex charge-transfer behavior was observed with dumbbell-shaped (C60)2.

Conclusions:

• [10]cycloparaphenylene serves as an effective rigid bridge for facilitating electron transfer in donor-acceptor systems.
• The synthesized porphyrin-[10]CPP conjugates demonstrate potential for creating stable charge-separated states.
• [10]CPP and its derivatives show promise as supramolecular mediators in organic electronic devices.