Astatine redox potential

Halo-de-diazoniations are a series of reactions in which the replacement of the dia-zonio group changes from a heterolytic de-diazoniation in the case of the fluorination (Balz-Schiemann reaction) to transition metal-catalyzed chlorination and bromination (Sandmeyer reaction) and finally to iodination and astatination where no catalyst is necessary due to the favorable redox potentials of I and At- (I- E° = 1.3 V). 

Scheme 8 Redox states, reversible standard potentials (in acidic aqueous environment), and applications of astatine [14].

Astatine has properties very similar to those of iodine, but has a more metallic character. The oxidation of astatide to astatine occurs at a potential ca. 0.4 V less positive compared to that for the oxidation of iodine. Fundamental information about the redox chemistry of astatine is available in an earlier review [158] and standard data collections [14]. A summary of the approximate standard potentials and known redox states is given in Scheme 8. 

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