Pentacene-Bridge Interactions in an Axially Chiral Binaphthyl Pentacene Dimer

Area of Science:

• Organic Chemistry
• Photochemistry
• Spectroscopy

Background:

• Molecular chirality offers insights into interactions within π-conjugated systems.
• Intramolecular singlet fission (iSF) is a crucial process in organic electronics.
• Understanding chromophore-bridge-chromophore (SFC-β-SFC) interactions is key to controlling iSF.

Purpose of the Study:

• To design and synthesize an axially chiral binaphthyl-bridged pentacene dimer (BNBP).
• To use the chiroptical response of BNBP as a probe for SFC-β-SFC interactions.
• To investigate the impact of these interactions on iSF dynamics.

Main Methods:

• Synthesis of a novel intramolecular singlet fission pentacene dimer (BNBP) with an axially chiral binaphthyl bridge.
• Analysis of chiroptical response in ground and excited states.
• Computational modeling using exciton coupling and quadratic response density functional theory (DFT).

Main Results:

• The chiral bridge induces significant one-handed excitonic coupling between pentacene units.
• BNBP displays a pronounced chiroptical response.
• DFT calculations show electronic density delocalization onto the binaphthyl bridge during higher energy singlet transitions.

Conclusions:

• Chiroptical techniques are effective for studying SFC-β-SFC interactions.
• These interactions play a critical role in modulating singlet fission.
• BNBP serves as a valuable molecular tool for probing iSF mechanisms.