Dimerization of pentacyclopentacorannulene C30H10 as a strategy to produce C60H20 as a precursor for C60

The chemical synthesis of C-60 fullerene in the laboratory is still a challenge. In order to achieve this goal, we propose a synthetic route based on the dimerization between two pentacyclopentacorannulene (C30H10) fragments employing the Diels-Alder cycloaddition reaction. Density functional calculations indicate that a step wise non-concerted dimerization mechanism of C30H10 is favored over a one stage dimerization. The step wise dimerization implies the sequential formation of 2, 4, 6, and 10 new C-C bonds between the two fragments. This leads to the formation of the Diels-Alder cycloadduct C60H20. The results then suggest the synthesis of C60H20 as a precursor for C-60. The synthesis of the analogue C60F20 has already been reported.