Trapping intermediates and comparing relative reactivities: a DFT M06-2X study on Diels-Alder cycloadditions of butadiene to C60 and C70

All possible types of DielsAlder cycloadditions of 1,3-cis-butadiene to C60 (2 in total) and to C70 (8 in total) were theoretically investigated by the M06-2X density functional method in gas phase and solutions. An intermediate between the reactant and the transition state was located for each reaction. These intermediates except one have not been experimentally or theoretically reported before. The reactivities of the 10 reactions in both the gas phase and solutions were systematically compared based on the calculated results. The present conclusion agrees with the experimental observations and partly disagrees with the previously theoretical conclusion. Copyright (c) 2012 John Wiley & Sons, Ltd.