Self-Assembled Cofacial Zinc–Porphyrin Supramolecular Nanocapsules as Tuneable ¹O₂ Photosensitizers

We demonstrate the benefits of using cofacial Zn–porphyrins as structural synthons in coordination-driven self-assembled prisms to produce cage-like singlet oxygen (¹O₂) photosensitizers with tunable properties. In particular, we describe the photosensitizing and emission properties of palladium- and copper-based supramolecular capsules, and demonstrate that the nature of the bridging metal nodes in these discrete self-assembled prisms strongly influences ¹O₂ generation at the Zn–porphyrin centers. The Pd^II-based prism is a particularly robust photosensitizer, whereas the Cu^II self-assembled prism is a dormant photosensitizer that could be switched to a ON state upon disassembly of the suprastructure. Furthermore, the well-defined cavity within the prisms allowed encapsulation of pyridine-based ligands and fullerene derivatives, which led to a remarkable guest tuning of the ¹O₂ production.