Issue 7, 2019

Dimerization of substituted 4-aryl-1,3-diacetylenes – quantum chemical calculations and kinetic studies

Abstract

Dimerization of substituted acetylenes is a very interesting tool to generate 1,3-butadiene 1,4-diradicals. Recently, we were able to show that substituents directly attached to the reaction centers as well as aryl systems have a great influence on the reaction barrier of the dimerization of arylacetylenes. Here, we investigate the dimerization of 4-aryl-1,3-diacetylenes by means of quantum chemical calculations and experimental studies. The focus of the study lies on the second acetylenic unit and the electronic nature of the aryl substituent. Both quantum chemical calculations and kinetic studies reveal that introducing a second alkyne unit accelerates the dimerization reaction by a factor of about 900 while the stabilizing effect on the diradical intermediate is even larger. The activation energy decreases with increasing donor ability of the aryl system. Moreover, it is found that the influence of the aryl system on the activation energy is not significantly smaller for the 4-aryl-1,3-diacetylenes compared to the corresponding arylacetylenes, although the distances between the aryl groups and the radical centers are larger in the 4-aryl-1,3-diacetylenes.

Graphical abstract: Dimerization of substituted 4-aryl-1,3-diacetylenes – quantum chemical calculations and kinetic studies

Supplementary files

Article information

Article type
Research Article
Submitted
24 jan 2019
Accepted
22 feb 2019
First published
26 feb 2019

Org. Chem. Front., 2019,6, 1010-1021

Dimerization of substituted 4-aryl-1,3-diacetylenes – quantum chemical calculations and kinetic studies

A. Janiszewski, J. Fax and G. Haberhauer, Org. Chem. Front., 2019, 6, 1010 DOI: 10.1039/C9QO00119K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements