Stereochemical course of the high-energy chlorine-38-for-chlorine substitution in cis/trans-1,2-dichlorohexafluorocyclobutanes in solutions

The stereochemistry of the high-energy chlorine-38-for-chlorine substitution process was studied in the cis/trans isomers of 1,2-dichlorohexafluorocyclobutanes. The experimental results indicate that the substitution occurs mostly under retention (>81%) in the presence of hydrogen containing solvents, while in the neat systems and in n-perfluoroheptane solution the yields of inverted product drastically increase. The results are explained in terms of a modified solvent-solute interaction model, which also considers the possible interaction of the reactive molecules making up the solvent environment with the reacting intermediates forming the substituted products. Alternatively the observed results could be interpreted by assuming a solvent effect on the energy distribution of the reacting 38Cl, resulting in changes in the relative importance of the reaction channels leading to substitution via retention and inversion, respectively