Folding of a dynamic macrocyclic system to stabilize its cation radical state†

Precise design of unsaturated systems remains an important factor that determines the quality of formed products based on a specific spatial orientation, but also defines the available π-electron density open for post-synthetic modulation via redox change. Three strictly defined reagents showing different degrees of flexibility, but also introducing two mutual orientations of the reacting ends (parallel and obtuse), determine the quality of the formed products obtained via an intramolecular or an intermolecular reaction. The redox-activated transformation of mono- and double-looped systems results in dissimilar oxidation states of a strongly π-conjugated dication (two-electron process) or a cation radical (one-electron process), derived from the differences in the dynamic skeleton documented for the monomer and dimer, respectively.