Theoretical investigation of Diels-Alder reaction mechanism and regioselectivity with functionalized fullerene derivatives

Density functional theory (DFT) was used to study the mechanism of Diels-Alder (DA) reaction between 2-Methyl- 1,3 Butadiene (MBD) with B12N12, B6N6C12 and B6C12N6 fullerens in the gas phase. In this mechanism, B-N bonds of four-membered and six-membered rings of nanocages were chosen to react with MBD. Due to the existence of two types of B-N bonds, two competitive pathways (a and b) were investigated. The effect of the substitution of carbon atoms instead of boron and nitrogen atoms on the stability of the structures and the regioselectivity of the DA reaction was examined. The potential energy of all structures and the activation barrier for all reaction pathways was evaluated. The chemical reactivity of fullerens using the molecular quantum descriptors was assessed. To evaluate the global electron density transfer in transition states (TS) structures, the natural bond orbital (NBO) analysis was performed.