OXYGEN-ATOM TRANSFER FROM ALKYLPEROXYL RADICALS TO AROMATIC TELLURIDES

The reactions of alkylperoxyl radicals with the diaryl tellurides bis( 4-aminophenyl) telluride and bis(4-hydroxyphenyl) telluride were studi ed by pulse- and gamma-radiolysis techniques in aqueous media. The dia ryl tellurides served predominantly (similar to 70%) as one-electron r eductants toward the CCl3OO radical (k = 1.5 x 10(9) and 2.5 x 10(9) dm(3) mol(-1) s(-1) respectively), whereas they acted essentially (gre ater than or equal to 92%) as oxygen atom recipients in their reaction s with the (CH3)(2)C(OH)CH2OO radical (k = 1.7 x 10(8) and 3.7 x 10(7 ) dm(3) mol(-1) s(-1) respectively), producing the corresponding diary l telluroxides. The latter reaction mode was corroborated by the quant itative interception of a reducing alpha-hydroxylalkyl radical, the pr oduct of beta-scission of its precursor, the alkoxyl radical (CH3)(2)C (OH)CH2O. On the basis of detailed energetic and mechanistic consider ations the oxygen transfer is proposed to be a concerted one-step reac tion without the intermediacy of an adduct.