The synthesis and electrochemical study of new 2,2′-dialkyl viologens

Recent chemical evidence has shown that the alkyl groups of dialkylbipyridinium dihalides (viologens) exchange in the presence of nucleophiles. In order to study the long-term electrochemical reversibility of these materials, three new viologens have been synthesized which contain alkyl groups symmetrically substituted on the 2-positions of the bipyridine nucleus, and in one of which the alkyl groups are also bonded to the nitrogens of the pyridines forming six-membered cyclic systems. This compound exhibits no observable alkyl group exchange in the presence of nucleophiles. An electrochemical study of the new substituted viologens is reported along with a comparison with the parent compound.