Thianthrene, 2,3,7,8-tetramethoxy

Thianthrene, 2,3,7,8-tetramethoxy-dication, 3, 968 Thianthrenedicarboxylic acids applications, 3, 993 Thianthrene-2,6-dicarboxylic acids... 

For mesitylene and durene, the kinetics have been followed by specular reflectance spectroscopy [17]. The results indicated that mesitylene produces a fairly stable radical cation that dimerizes. That of durene, however, is less stable and loses a proton to form a benzyl radical, which subsequently leads to a diphenylmethane. The stability of the radical cation increases with increasing charge delocalization, blocking of reactive sites, and stabilization by specific functional groups (phenyl, alkoxy, and amino) [18]. The complex reaction mechanisms of radical cations and methods of their investigation have been reviewed in detail [19a]. Fast-scan cyclovoltammetry gave kinetic evidence for the reversible dimerization of the radical cations of thianthrene and the tetramethoxy derivative of it. Rate constants and enthalpy values are reported for this dimerization [19b]. 

These results support the suggestion that the energy difference between folded and planar thianthrene conformations is small. However, 2,3,7,8-tetramethoxy-thianthrene radical cation [22], as both the hexachloroantimonate and triiodide salts, and thianthrene radical cation [20], as its tetrachloroaluminate salt, have been shown to be planar in the solid state. The dihedral angles 0 are 180° and 174°, respectively. These results provide strong evidence for delocalization in... 

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