Dibenzo-p-dioxins in TFMS acid

The visible absorption maxima for a series of chlorinated dibenzo-p-dioxins in TFMS acid are tabulated in Table I. The visible absorption spectra of these compounds vary with the position and number of chlorine atoms. In general, a bathochromic shift was observed as more chlorine atoms were attached to the dibenzo-p-dioxin nucleus. 

Figure 1. ESR spectrum of dibenzo-p-dioxin in TFMS acid...

Studies were made on a series of chlorinated dibenzo-p-dioxin cation radicals in trifluoromethanesulfonic acid (TFMS acid). TFMS acid was... 

The 1-chloro- and 2-chlorodibenzo-p-dioxins, which readily dissolved in TFMS acid, formed cation radicals without UV irradiation or the addition of oxidizing agents. With the exception of broader resonance lines. Figure 3 shows that the five-line pattern observed with 1-chloro-dibenzo-p-dioxin is similar to that of the unsubstituted dibenzo-p-dioxin. Apparently, protons at the 2, 3, 7, and 8 positions became less equivalent... 

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