A Porphyrin with a CC Unit at Its Center

The molecule (CC)TTP (TTP = tetra-p-tolylporphyrin) and the triflate salt of its dication, [(CC)TTP][OTf]2, have been synthesized and characterized. NMR spectroscopy, nucleus-independent chemical shift calculations, and the crystal structure of (CC)TTP indicate that (CC)TTP is antiaromatic and (CC)TTP2+ is aromatic.