A Dynamic Helical Molecule with a High pi-Electron Density: Chiral Symmetry Breaking Memorized by One-electron Oxidation

Abstract

Herein, we designed oligo(o-phenylene) derivatives (OOPs) as a new helical motif. In the crystallization of a certain OOP derivative, a spontaneous symmetry breaking takes place, leading to the selective formation of either right-handed or left-handed crystal. While the OOP adopts ultimately tight helical conformation, its optically activity disappeared immediately in solution due to an unexpectedly fast racemization activated by a repulsive force operative between the condensed π-clouds. We demonstrated that removal of one electron from OOP gives rise to significant lowering of its dynamic nature, as a consequence of extensive delocalization of the resulting electronic hole over the helical structure.