Charge Transfer from the Solvent Radical Cation to Solutes Studied in Pulse‐Irradiated Liquid n‐Butyl Chloride

Abstract

Abstract Charge transfer from n‐butyl chloride radical cations (BuCl + ) to 11 solutes (S) (alkanes, alkenes, aromatics, and amines) was studied by pulse radiolysis. Using a mechanism proposed for radiation‐induced ionic processes in liquid n‐butyl chloride the rate constants of the reaction magnified image were determined. At gas phase ionization potential differences Δ I = ( I BuCl ‐ I s ) smaller than 1.5 eV the rate constants increased rapidly with increasing Δ I and reached for larger Δ I nearly constant values of about 10 10 dm 3 mol −1 s −1 . The dependence of the rate constants on the ionization potential differences k vs. Δ I is explained in terms of a two‐step process consisting of migration of solvent cations and electron transfer from the solute molecule to the solvent cation. The probability of the last step was calculated using the Franck‐Condon principle. In the framework of a simplified model taking into account vibrational stretching and deformation modes of the reactants and solvent modes in thermally averaged form a reasonable fit of the k vs. Δ I behaviour was obtained.