Synthesis and Structure of meso-Substituted Dibenzihomoporphyrins

Abstract

Bench‐stable meso‐substituted di(p/m‐benzi)homoporphyrins were synthesized through acid‐catalyzed condensation of dipyrrole derivatives with aryl aldehydes. The insertion of a 1,1,2,2‐tetraphenylethene (TPE) or but‐2‐ene‐2,3‐diyldibenzene unit in the porphyrin framework results in the formation of dibenzihomoporphyrins, merging the features of hydrocarbons and porphyrins. Single crystal X‐ray analyses established the non‐planar structure of these molecules, with the phenylene rings out of the mean plane, as defined by the dipyrromethene moiety and the two meso‐carbon atoms. Spectroscopic and structural investigations show that the macrocycles exhibit characteristics of both TPE or but‐2‐ene‐2,3‐diyldibenzene and dipyrromethene units indicating the non‐aromatic characteristics of the compounds synthesized. Additionally, the dibenzihomoporphyrins were found to generate singlet oxygen, potentially allowing their use as photosensitizers.