A Redox Switch Based on Dihydro[5]helicene: Drastic Chiroptical Response Induced by Reversible C−C Bond Making/Breaking upon Electron Transfer

Abstract
Helicity and axial chirality are reversibly interconverted in the novel redox pair 1 and 22+; the compounds exhibit drastic UV/Vis and circular dichroism spectral changes as well as dynamic structural changes upon electron transfer, thus furnishing an unprecedented multi‐output response system with high bistability. X=S or O.