Dimerization of pentacyclopentacorannulene C(30)H(10) as a strategy to produce C(60)H(20) as a precursor for C(60)

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 (C(30)H(10)) fragments employing the Diels–Alder cycloaddition reaction. Density functional calculations indicate that a step wise non-concerted dimerization mechanism of C(30)H(10) 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 C(60)H(20). The results then suggest the synthesis of C(60)H(20) as a precursor for C(60). The synthesis of the analogue C(60)F(20) has already been reported.