Strained Porphyrin Tape-Cycloparaphenylene Hybrid Nanorings

V-shaped porphyrin dimers, with masked para-phenylene bridges, undergo efficient oxidative coupling to form meso-meso linked cyclic porphyrin oligomers. Reductive aromatization unmasks the para-phenylenes, increasing the strain. Oxidation then fuses the porphyrin dimers, providing a nanoring with curved walls. The strain in this macrocycle bends the para-phenylene and fused porphyrin dimer units (radii of curvature: 11.4 Å and 19.0 Å, respectively), but it does not significantly alter the electronic structure of the fused porphyrins.