Electrochemical transformations of cycloheptatriene derivatives

Redox reactions of a series of substituted cycloheptatrienes are studied on a platinum electrode in acetonitrile using the cyclic voltammetry method. It was found that heptaphenyl-substituted cycloheptatrienes are irreversibly oxidized in two stages in the range of high anodic potentials to form unstable radical cations and dications. As opposed to the unsubstituted and monosubstituted cycloheptatrienes, they are not reduced at the potentials higher than −2 V (SCE). A new stable radical anion was found in the reduction of N-cycloheptatrienylphthalimide. Its spin density distribution is studied by ESR spectroscopy.