Theoretical studies on [2 + 2 + 2] reaction mechanisms of three ethynes. More accurate estimation of activation energy. (5th May 2013)

• Record Type: Journal Article
• Authors: Sakai, Shogo; Udagawa, Taro; Kato, Shohei; Nakada, Keita
• Is Part Of: Journal of physical organic chemistry. Volume 26:Number 6(2013:Jun.)
• Page Start: 517
• Page End: 522
• Publication Date: 2013-05-05
• Subjects: Chemistry, Physical organic -- Periodicals; 547.1
• DOI: 10.1002/poc.3119
• Languages: English
• ISSNs: 0894-3230

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>The mechanisms of the [2 + 2 + 2] cycloaddition reaction of three ethyne molecules were studied by <italic>ab initio</italic> molecular orbital and density functional methods. The transition states range from that of the concerted mechanism with D_3h symmetry to that of the stepwise mechanism with C₂ symmetry. The transition state structure and the activation energy depend on the basis set and computational method employed in the analysis. The activation energy barrier was determined to be in the range of 36–44 kcal/mol. The activation energy determined by various methods corresponds to the interaction energy, which is related to the electron correlation energy. The best estimation of the activation energy barrier is 41.6 kcal/mol, achieved from the relation between the interaction energy and the activation energy. Copyright © 2013 John Wiley &amp; Sons, Ltd.</p> </abstract>