Kinetic Isotope and Pressure Effects in the Reaction of Leucocrystal Violet with Tetracyanoethylene and Chloranil

Abstract

The rates of reaction of Leucocrystal Violet (LCV) with chloranil (CA) and tetracyanoethylene (TCNE) were measured, and the kinetic isotope and pressure effects were examined. In the LCV–CA system, a very large isotope effect (kH⁄kD≈11) was observed, while in the LCV–TCNE system, it was not so large (kH⁄kD=5–6) suggesting the tunnel effect is not substantial. For both systems, the formation of a CT complex in equilibrium with the reactants was observed at low temperatures (<−50 °C). From the rate law, the isotope effect, the electronic and ESR spectra observed during the reaction, and their time dependence, possible reaction processes are proposed.