ION RADICALS .18. REACTIONS OF THIANTHRENIUM PERCHLORATE AND THIANTHRENIUM TRICHLORODIIODIDE

The crystalline perchlorate and trichlorodiiodide of the thianthrene cation radical, C12H8S2+ClO4-, and C12H8S2+I2Cl3-, have been prepared. With these salts it has been possible to study the reactions of the thianthrene cation radical with water, iodide ion, chloride ion, triphenylamine, and, to some extent, the vinyl monomers styrene, α-methylstyrene, ethyl vinyl ether, 1,1-diphenylethylene, acrylonitrile, and methyl methacrylate. Electron transfer to the thianthrene cation radical is facile, depending on the relative redox potentials of the cation radical and the other reactant. The reaction of the perchlorate salt with water has been studied in detail. The products are equal amounts of thianthrene and thianthrene 5-oxide. Kinetic work shows that the water reacts with the dication, formed by disproportionation of the cation radical, rather than with the cation radical itself. The longer known reactions of the thianthrene cation radical in sulfuric acid solution are now clearly understandable. © 1969, American Chemical Society. All rights reserved.