Successive Diels-Alder Cycloadditions of Cyclopentadiene to [10]CPP⊃C60: A Computational Study

Fullerenes have potential applications in many fields. To reach their full potential, fullerenes have to be functionalized. One of the most common reactions used to functionalize fullerenes is the Diels-Alder cycloaddition. In this case, it is important to control the regioselectivity of the cycloaddition during the formation of higher adducts. In C-60, successive Diels-Alder cycloadditions lead to the T-h-symmetric hexakisadduct. In this work, we explore computationally using density functional theory (DFT) how the presence of a [10]cycloparaphenylene ring encapsulating C-60 ([10]CPP superset of C-60) affects the regioselectivity of multiple additions to C-60. Our results show that the presence of the [10]CPP ring changes the preferred sites of cycloaddition compared to free C-60 and leads to the formation of the tetrakisadduct. Somewhat surprisingly, our calculations predict formation of this particular tetrakisadduct to be more favored in [10]CPP superset of C-60 than in free C-60.