Pathways for the thermally induced dehydrogenation of C60H2

The thermolysis of C60H2 to yield C60 and H2 was studied by hybrid density functional theory (B3LYP/6-311G**//B3LYP/3-21G). The concerted loss of dihydrogen requires an activation energy of 92 kcal mol−1 at T=452 K. An alternative radical mechanism, which is first order in the C60H2 concentration, has an activation energy at 452 K of only 61 kcal mol−1. Monitoring of the C60H2 decomposition in 1,2-dichloro-[D4]-benzene solution by NMR spectroscopy indicates a pseudo first-order reaction with an activation energy of 61.38±2.35 kcal mol−1.