Collect. Czech. Chem. Commun. 2011, 76, 481-501
Published online 2011-04-20 11:35:49

Cooperative effects in the annelation of benzene by multiple etheno groups

Xiaoguang Bao, David A. Hrovat and Weston Thatcher Borden*

Department of Chemistry and the Center for Advanced, Scientific Computing and Modeling, University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5070, USA


The results of B3LYP/6-31G(d) calculations show that there is a strong cooperative effect on the energies that result from annelating benzene with 1, 2, and 3 etheno groups, to form 3, 4, and 5 respectively. The etheno annelation energies have been decomposed into two major contributors – etheno annelation, with all the bonds in the six-membered ring constrained to have the same C–C bond length as in D6h benzene, and optimization of the C–C bond lengths in the annelated benzene ring. The energies computed for each of these two steps show that the etheno groups behave cooperatively in both of them. The origin of the cooperativity, calculated for each step, is described and discussed.

Keywords: Cooperative effects; Bond alternation; Orbital mixing; Mathematical model; Carbocycles; Density functional calculations.

References: 48 live references.