Redox Assisted Reversible Aromaticity Transition Between 30π Hückel and 28π Möbius Dication of a Core-Modified Isophlorinoid

Abstract

The electronic properties of a hexaphyrin was fine-tuned via core-modification leading to the formation of a Hückel aromatic 30π hexaphyrin which incorporates two pyrrole and four furan rings in the π-conjugated pathway. This Hückel aromatic hexaphyrin modified its conformation upon two-electron ring oxidation either with triflic acid or Meerwein salt [Et3O]+[SbCl6]− to yield 28π Möbius aromatic dication species. Reversible aromatic transition was established by spectroscopic techniques and further supported by quantum chemical calculations.