Theoretical study of the cycloaddition reaction of C20 fullerene with pyridine and pyrimidine

A theoretical study at the levels of CAM-B3LYP and MP2 with 6-311G** basis set is reported, with the aim of understanding the possibility of cycloaddition reaction of C20 fullerene with pyridine and pyrimidine. For this purpose, several [2+2] and [4+2] cycloaddition reactions between C20 and pyridine or pyrimidine are considered and their thermodynamic and kinetic parameters are calculated. The results indicate that the [4+2] reactions are favorable in which fullerene plays the role of the dienophile. Calculation of global electron density transfer (GEDT) and molecular electrostatic potential (MEP) reveals that the transition states have polar character, so that C20 acts as electron acceptor.