Bingel-Hirsch Addition of Diethyl Bromomalonate to Ion-Encapsulated Fullerenes M@C60 (M=Ø, Li+, Na+, K+, Mg2+, Ca2+, and Cl-).

In the last 30 years, fullerene-based materials have become popular building blocks for devices with a broad range of applications. Among fullerene derivatives, endohedral metallofullerenes (EMFs, M@Cx) have been widely studied owing to their unique properties and reactivity. For real applications, fullerenes and EMFs must be exohedrally functionalized. It has been shown that encapsulated metal cations facilitate the Diels-Alder reaction in fullerenes. Herein, the Bingel-Hirsch (BH) addition of ethyl bromomalonate over a series of ion-encapsulated M@C60 (M=Ø, Li+, Na+, K+, Mg2+, Ca2+, and Cl-; Ø@C60 stands for C60 without any endohedral metal) is quantum mechanically explored to analyze the effect of these ions on the BH addition. The results show that the incarcerated ion has a very important effect on the kinetics and thermodynamics of this reaction. Among the systems studied, K+@C60 is the one that leads to the fastest BH reaction, whereas the slowest reaction is given by Cl-@C60.