The addition reactions between N-heterocyclic carbenes and fullerenes (C60 and C70): a density functional study

The potential energy surfaces for the addition reactions of N-heterocyclic carbene with C60 and C70 are characterized in detail, using density functional theory (M06-2X). These theoretical investigations strongly suggest that the one-point attack in formation of the single-bonded adduct is the most favorable reaction pathway at room temperature, rather than the production of the cycloadduct with a three-membered ring, from both kinetic and thermodynamic viewpoints. Also, this theoretical work indicates that the dispersion interactions cannot make the contributions to determine the regioselective formations for these NHC–fullerene Lewis acid–base adducts. These theoretical conclusions are consistent with the available experimental observations.