Determination of the reaction enthalpy and kinetic parameters for the isomerization of bridged Dewar benzenes to 8,9-disubstituted [6]paracyclophanes by differential scanning calorimetry

Abstract

In solution the reaction enthalpy for the thermal isomerization of the Dewar isomers 2a and 2b to their corresponding 8,9-disubstituted [6]paracyclophanes 1a and 1b was determined as −128±13 kJ·mol −1 and −146±15 kJ·mol −1, while the activation energies were found to be 101±10 kJ·mol −1 and 117±12 kJ·mol −1 respectively. An improved calorimetric technique was employed using samples in sealed NMR tubes.