Strained Porphyrin Tape-Cycloparaphenylene Hybrid Nanorings.

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