Cation radicals of phenothiazines. Part 2. Electron transfer between aquacobalt(III) and N-alkylphenothiazines

Abstract

The kinetics of electron transfer between aquacobalt(III) and some N-alkylphenothiazines has been investigated by means of the stopped-flow technique. The reaction consists of a one-electron transfer with formation of the corresponding cation radicals. The reaction rates have been found to be independent of acidity in the range 0.40 ⩽[HClO₄]⩽ 2.00 mol dm^–3, suggesting that Co³⁺(aq) is the main reacting species. The results are discussed in terms of the Marcus cross-reaction equation for outer-sphere electron-transfer reactions.