Reactions of Three Bis(viologen) Tetraquaternary Salts and Their Reduced Radicals

Article abstract of DOI:10.1021/ja00272a037

Monoradical trications X^3+. and diradical dications X^2+.. were produced by reduction of three bis(viologen) X⁴⁺ (1,1''-alkanediylbis(1'-alkyl-4,4'-bipyridinium)) tetraquaternary salts.The spectral properties of X^3+. and its disproportionation kinetics were examined by e_aq^-/CO2^- reduction of X⁴⁺.Reduction potentials of the X^4+/3+ and X^3+/2+ couples were determined by cyclic voltametry and spectral examination of equilibrated mixtures of X⁴⁺ and X^2+.. radicals.These potentials were used to apply successfully the Marcus theory to reduction of X⁴⁺ by SO2^- and oxidation of X^3+. and of X^2+.. by O2 and cobalt(III) complexes.The reactivity toward O2 and the comproportionation of X^2+.. (with X⁴⁺) is believed to be influenced by the tendency of X^2+.. to form an intramolecularly associated conformation.