Absorption Spectra of Radical Ions of Polyenes of Biological Interest

Abstract

The radical cations and anions of a number of carbonyl containing polyenes of biological importance have been generated, and their absorptions characterised using pulse radiolysis techniques. The wavelength maxima of the absorption bands are linearly dependent on the number of conjugated double bonds. The radical cation and the radical anion derived from the same parent molecule absorb at very similar wavelengths. There is a large hypsochromic shift in the radical anion absorption on changing from hexane to methanol solutions. The radical anions decay rapidly, in methanol, to form a species which is probably the protonated anion.