Probing Charge Management across the ?-Systems of Nanographenes in Regioisomeric Electron Donor-Acceptor Architectures

Inspired by light-induced processes in nature to mimic the primaryevents in the photosynthetic reaction centers, novel functional materials combineelectron donors and acceptors, i.e., (metallo)porphyrins (ZnP) and fullerenes (C60),respectively, with emerging materials, i.e., nanographenes. We utilized hexa-peri-hexabenzocoronene (HBC) due to its versatility regarding functionalization andphysicochemical properties, to construct three regioisomeric ZnP-HBC-C60conjugates,which foster geometrical diversity by arranging ZnP and C60inortho-,meta-, andpara-positions to each other. The corresponding hexaarylbenzene (HAB) motifs, with aninterrupted pi-system, were also prepared. Transient absorption measurements disclosedthe fast population of charge transfer as well as singlet and triplet charge-separated states. With the help of density functional theory(DFT) calculations, we further conceive the communication across the HBCs and HABs. This work reveals the impact of both thegeometrical arrangement with respect to through-space versus through-bond interactions and the structural rigidity/flexibility on the charge management across the different pi-systems.

Automated summary

Inspired by natural light-induced processes, this study investigates the charge transfer properties and geometric effects of functional materials mimicking photosynthetic reaction centers.