Hexaaminobenzene derivatives: synthesis and unusual oxidation behavior

The syntheses and the electrochemical behavior of the monomeric peralkylated hexaamino(1,3)metacyclophane 4, the dimeric dodecaamino(1,3)cyclophane 5a, and the dodecaamino(1,3,5)cyclophane 6 are described. Electrochemical measurements show that the hexaaminobenzene units in 4 and 5a undergo an unusually slow two-electron transfer attributed to the deformation of the rings into bis-cyanine cations when oxidized to the respective dication. Further oxidations to tri-, tetra-, and hexacationic units occur at more positive potentials. In the dimeric structures, no interaction between the rings can be seen in the (1,3)cyclophane, but strong interaction for the (1,3,5)cyclophane is observed.