# THE ELECTRONIC SPECTRUM OF THE CYCLOOCTATETRAENYL RADICAL ANION

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 Title: THE ELECTRONIC SPECTRUM OF THE CYCLOOCTATETRAENYL RADICAL ANION Creators: Kimmel, P. I.; Strauss, Herbert L. Issue Date: 1966 Publisher: Ohio State University Abstract: The properties of the cyclooctatetraenyl radical anion ($COT^{-}$) are anomalous in many respects. There is considerable evidence which indicates that the anion as well as the dianion of cyclo-octatetraene are planar, in contrast to the neutral molecule which has a tub-shaped $structure.^{1}$ This change in the geometry of the molecule tends to favor the disproportionation of the radical anion, $2COT^{-}\rightarrow COT+COT^{=}$ since the compression energy of the cyclooctatetraene must be overcome to produce either of the charged ions. It is found that the actual stability of the radical depends strongly on the nature of the solvent and the cations present, and that the energy changes involved in the disproportionation are affected significantly by ion pairing between the dianion and the cation. In order to further elucidate the behavior of the anion, we have obtained its EPR and electronic spectra, with the radical anion generated by continuous electrolysis in liquid ammonia, in which it is exceptionally stable. The EPR spectrum consists of nine lines characteristic of eight equivalent protons, with a splitting of 3.278 Gauss. A Pariser-Parr calculation on the excited states of the radical, assuming several possible geometries, agrees best with the observed spectrum for the planar case. Description: $^{1}$ H. L. Strauss, T. J. Katz and G. K. Fraenkel, J. Am. Chem. Soc., 85, 2360 (1963). Author Institution: Chemistry Department, University of California URI: http://hdl.handle.net/1811/14989 Other Identifiers: 1966-D-11