The equilibrium exhibits a very weak solvent dependence; ΔGaa—ee varies from 1.22 kcal mol1 in CDCl3 to 0.87 kcal mol1 in DMSO-d6. The free energy difference, Δaa—ee II 0.90 kcal mol1, in CD2Cl2 is determined by peak-area NMR measurements at 100°C. The reaction field theory ...