According to obtained data, difference in dipole moments of reactants and TS structure was used to explain the solvent effect on the energy of activation for this cycloaddition reaction. All TS structures have dipole moment lower than reactants therefore TS must be relatively stabilized when the solvent polarity decreased. Other calculation on the frontier molecular orbitals of the TSs in different solvents show that HOMO-LUMO energy differences of the TSs can be influenced by the solvent polarity. In other words the solute-solvent interactions will highlighted the FMO effects. Computed rate and activation parameters of the cycloaddotion reaction in the gas phase and different solvents are accordance to experimental data. Negative of activation entropies in 1,4-dioxane, benzene, cyclohexane, hexane, THF and gas phase are -127.7, -127.6, -128.1, - 128.6, -127.7 and -102.1 (J/mol.K) implies that degrees of freedom at the TS decreased and confirmed the ring closing in the rds of the reaction.

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