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Controlled Core‐Modification of a Porphyrin into an Antiaromatic Isophlorin
Author(s) -
Panchal Santosh P.,
Gadekar Santosh C.,
Anand Venkataramanarao G.
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201511883
Subject(s) - antiaromaticity , porphyrin , dication , chemistry , ring (chemistry) , yield (engineering) , photochemistry , aromaticity , materials science , molecule , organic chemistry , metallurgy
Abstract Partial core‐modification of a porphyrin can be employed to synthesize the 20π antiaromatic isophlorin. Unlike the tetra‐, tri‐, and dipyrrole derivatives of a porphyrin, a monopyrrole porphyrin exhibits antiaromatic characteristics. It undergoes a two‐electron reversible ring oxidation to yield the 18π aromatic dication. 1 H NMR analysis provides distinct evidence of the altered electronic characteristics through typical paratropic and diatropic ring current effects for the 4n and the (4n+2) π‐electron systems, respectively.