Porphyrin system containing [2.2]paracyclophane units

Meso-tetrakis([2.2]paracyclophanyl)porphyrin was obtained from [2.2]paracyclophanecarbaldehyde and pyrrole. Replacement of phenyl groups in meso-tetraphenylporphyrin by paracyclophanyl substituents remarkably influences the electronic structure of the molecule, causing bathochromic shifts of all uv-vis absorption bands, and changing the ring current of the porphyrin core. The shifts in the electron spectrum are substantially greater than those observed for other porphyrin derivatives characterized by their extended π-electron systems, such as meso-tetrakis(2-phenylethenyl)porphyrin and meso-tetrakisbiphenylporphyrin.