title: Controlled Core-Modification of a Porphyrin into an Antiaromatic Isophlorin.
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.
authors.affiliation: Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, 411008, Maharashtra, India.
authors.forename: Santosh P
authors.initials: SP
authors.lastname: Panchal
authors.affiliation: Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, 411008, Maharashtra, India.
authors.forename: Santosh C
authors.initials: SC
authors.lastname: Gadekar
authors.affiliation: Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, 411008, Maharashtra, India. vg.anand@iiserpune.ac.in.
authors.forename: Venkataramanarao G
authors.initials: VG
authors.lastname: Anand
keywords: aromaticity; conjugation; electron transfer; macrocycles; porphyrinoids