Synthesis and Photophysical Properties of Hexabenzocoronene-Tetrabenzoporphyrin Architectures

Porphyrin-based architectures have emerged as excellent candidates for artificial light-harvesting antennae. Although tetrabenzoporphyrins (TBPs), the pi-extended "bigger brothers" of porphyrins, benefit from increased absorptivity in the near-infrared (NIR), their utilization in light-harvesting systems is still in its infancy. Within this work, we prepared two donor-acceptor hetero dyads consisting of hexa-peri-hexabenzocoronenes (HBCs) to harvest high energetic near-UV light, and a TBP core, which serves as visible to NIR light antenna and as subsequent energy sink of the conjugate. The HBCs are either attached to themeso-position or via a maleimide-bridge on the periphery of the macrocycle. Upon excitation of the HBC moieties, both dyads exhibit an efficient energy transfer to the TBP core. Furthermore, the TBP-HBC dyads show superior light-harvesting properties compared to the respective HBC-porphyrin reference and the naturally occurring chlorophylls a/b.