Probing Through-Bond and Through-Space Interactions in Singlet Fission-Based Pentacene Dimers

Interchromophoric interactions such as Coulombic coupling and exchange interactions are crucial to the functional properties of numerous pi- conjugated systems. Here, we use magnetic circular dichroism (MCD) spectros-copy to investigate interchromophoric interactions in singlet fission relevant pentacene dimers. Using a simple analytical model, we outline a general relationship between the geometry of pentacene dimers and their calculated MCD response. We analyze experimental MCD spectra of different covalently bridged pentacene dimers to reveal how the molecular structure of the `bridge affects the magnitude of through-space Coulombic and through-bond exchange interactions in the system. Our results show that through-bond interactions are significant in dimers with conjugated molecules as bridging units and these interactions promote the overall electronic coupling in the system. Our generalized approach paves the way for the application of MCD in investigating interchromophoric interactions across a range of pi-conjugated systems.

Automated summary

This study investigates interchromophoric interactions in pentacene dimers using magnetic circular dichroism (MCD) spectroscopy. By analyzing experimental MCD spectra, the molecular structure of the bridging units was found to affect the through-space Coulombic and through-bond exchange interactions. The results demonstrate the significant through-bond interactions in dimers with conjugated molecules as bridging units, which promote the overall electronic coupling in the system.