Theoretical Study of Salt Effects on the Diels鈥揂lder Reaction of Cyclopentadiene with Methyl Vinyl Ketone Using RISM-SCF Theory

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• 作者：Norio Yoshida ; Hidetsugu Tanaka ; Fumio Hirata
• 刊名：Journal of Physical Chemistry B
• 出版年：2013
• 出版时间：November 14, 2013
• 年：2013
• 卷：117
• 期：45
• 页码：14115-14121
• 全文大小：333K
• 年卷期：v.117,no.45(November 14, 2013)
• ISSN：1520-5207

文摘

Salt effects on the Diels鈥揂lder reaction of cyclopentadiene with methyl vinyl ketone are investigated using reference interaction site model self-consistent field (RISM-SCF) theory. The rate of the reaction is accelerated by adding LiCl to the water solvent. The structures of four transition states, endo-cis, endo-trans, exo-cis, exo-trans, were found by geometry optimization of the cyclopentadiene and methyl vinyl ketone complexes. The endo-trans structure shows the lowest energy in both water and LiCl solution. The activation barrier of the reaction in LiCl solution is lower than that in water, and the difference is in good agreement with that from experiments. The decrease in the activation barrier arises from destabilization of the reactant species. The salt effect of LiCl makes all species concerning the reaction unstable by the hydrophobic effect; however, the increased hydrophobic effect in the TS complexes is suppressed by making the hydrogen bond, which is stronger compared with the reactant methyl vinyl ketone.