Aromatic Macrocycle Containing Amine and Imine Groups: Intramolecular Charge-Transfer and Multiple Redox Behavior

A cyclic compound that has alternating diphenylamine and quinodiimine units was obtained by condensation of anthraquinone with bis­(4-aminophenyl)­amine (aniline dimer) in 20% yield. The resulting macrocycle has an absorption of 462 nm, which is assigned to charge transfer transitions between electron-rich diphenylamine units and electron-poor anthraquinone diimine units. Cyclic voltammetry in acidic MeCN shows redox of anthraquinone diimine units (E_1/2 = 0.03 V vs Ag/Ag⁺) and of oxidation of amino groups of higher potentials (0.60 and 0.77 V).