G2(MP2,SVP) study of the relationship between the benzyl and tropyl radicals, and their cation analogues

The calculated heat of formation and ionization energy of the benzyl radical at the G2(MP2,SVP) level differ from recent experimental estimates by just 1 kJ mol−1. The ionization energy of the tropyl radical calculated at this level differs from experiment by 5 kJ mol−1. The heat of formation of tropyl, 281 ± 8 kJ mol−1, is significantly higher than experimental estimates, suggesting the need for experimental re-evaluation. The lowest energy path for rearrangement of the benzyl cation to tropylium proceeds through a single intermediate minimum, the 1-cycloheptatrienyl cation, and requires 272 kJ mol−1.