21-Carbaporphyrin: a cyclopentadiene moiety entrapped into a porphyrin scaffold

Abstract

This minireview underscores the chemistry of 21-carbaporphyrins containing a plain cyclopentadiene moiety. Thus the cyclopentadiene incorporation afforded two 21-carbaporphyrin series represented by meso-tetraaryl-21-carbaporphyrin and [Formula: see text]-alkylated 21-carbaporphyrin with their properties evidently controlled by the nature of perimeter substitution. The synthetic strategy, physicochemical characterization and some insight in coordination properties of 21-carbaporphyrins have been illustrated. The formation of palladium(II), rhodium(III) and gold(III) meso-tetraaryl-21-carbaporphyrins via unprecedented intramolecular contractions of meta-benzi- or para-benziporphyrins has been also addressed.