Generation of an extremely bent pyrene system using kinetic stabilization

Abstract

A series of pyrenophanes was designed with the goal of providing kinetic stabilization to the bent pyrene system and, therefore, providing a means to generate more highly bent pyrene systems than ever before. Four members of this series were synthesized, isolated, and characterized. The lowest homologue was calculated to have a pyrene system that is just slightly less bent (θcalc = 106.8°) than the previous record holder for an isolated compound (θexpt = 109.2°). The next smaller member of the series was obtained as a minor component of a mixture with its direct synthetic precursor and a follow-on product after a 60 d reaction. Compelling MS and 1H NMR evidence was obtained for the formation of this compound; the pyrene system of which was calculated be extremely bent (θcalc = 130.4°).