Influence of Dispersion Interactions in the Diels-Alder Reaction of Cyclopentadiene, Anthracene and Tetracene with C60: A DFT Examination

The activation and thermodynamic parameters of the Diels-Alder reaction of cyclopentadiene, anthracene and tetracene with C-60 fullerene are estimated at the DFT level using PBE0, B3LYP and CAM-B3LYP functionals and the effect of accounting for dispersion interactions in various semi-empirical Grimme models on these parameters. Structural characteristics of the reagents, products, pre-reaction van der Waals complex, and transition state are obtained. Taking into account dispersion corrections have practically no effect on the geometric characteristics of structures with the covalent type of the bond, as well as on the structure of the transition state. Still, it has a noticeable effect only on the structure of the pre-reaction complex, in which the interparticle interaction has a van der Waals character. At the same time, taking into account dispersion corrections plays a significant role in assessing the thermodynamic and activation parameters of the reaction. An analysis of the performed calculations showed that the combination of PBE0/def2-TZVP with the D4 model for dispersion interactions could be recommended for the Diels-Alder reaction considered above.