Trienyl free radical

Air Oxidation of Free Radicals. Curve 4 of Figure 2 represents the absorption spectrum after admitting air to the ultraviolet absorption cell. The bands at 258, 285, and 323 mp which we believe to be caused by the allyl, dienyl, and trienyl free radicals, respectively, were completely eliminated by the oxidation. 

Sauer and Ward (17), Table I, observed that the cyclodienyl free radical gave absorption maxima at 302 and 311 m/, depending on the medium. These values are somewhat higher than the 285 m/ peak which we attribute to the linear dienyl free radical in irradiated polyethylene. On the other hand the benzyl free radicals observed by Porter and Strachan (16) all have absorption maxima in the range of the bands at 323 mfi in irradiated polyethylene which we attribute to the linear trienyl free radical. (The band at 323 mp is clearly seen after the broad 310 peak has disappeared on warming to room temperature (2).)... 

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