Easy Entry into Reduced Ar-BIANH2 Compounds: A New Class of Quinone/Hydroquinone-Type Redox-Active Couples with an Easily Tunable Potential

Ar-BIANH(2) bearing different substituents on the aryl rings have been synthesized in high yield by reduction of the corresponding bis(aryl)acenaphthenequinonediimine (Ar-BIAN) compounds. The structure of p-CH3C6H4-BIANH(2) in the solid state was determined by X-ray diffraction. An exhaustive voltammetric investigation of the two parallel BIAN and BIANH(2) series afforded a first rationalization of the redox properties of these molecules, highlighting their analogies with quinone/hydroquinone systems. Such analogies, in combination with the much more negative reduction potential range of Ar-BIAN compounds with respect to quinones, can afford to extend the range of reduction potentials so far obtainable by the use of quinones.