A Structural Isomer of Nonaromatic Porphyrin: Preparation of 20π-Conjugated Porphycene Based on Electronic Perturbation

A porphycene having four CF3 groups at the β-pyrrolic positions affords a stable 20π-conjugated form in the presence of a 2H+−2e- donor due to the high redox potential of the tetrapyrrole ring framework. No visible band in the UV−vis spectrum and the highly ruffled structure determined by X-ray crystallography support its nonaromatic character. The ethylene bridge moiety in the 20π-conjugated framework displayed the olefinic reactivities.