Symmetric Isomers of Hydrofullerene C60H36

Fullerene hydrides: synthesis, properties, and structure

“…5): the symmetries are T, T h , S 6 , and D 3d . 105 It was found that the isomer with the T symmetry is energetically the most stable, which agrees with the semi-empirical AM1 calculations, 104 according to which this isomer is more stable than the isomer with the T h symmetry by 0.7 eV. It may be that the stability of the isomer with the T symmetry, associated with the presence of aromatic rings, is the cause of the inhibition of the more extensive reduction of fullerene.…”

“…Furthermore, the energy calculated for the molecule with the T h symmetry is higher by more than 2 eV than the energy of the most stable-isomer. 105 Additional information about the symmetry of C 60 H 36 is provided by the group-theoretical study of the IR and Raman spectra of the specimens obtained and also by the solid-phase 13 C NMR spectrum, which contains signals due to several different sp 3 -hybridised carbon atoms instead of the single signal expected for the T h structure. 147 Analysis of the entire set of data enabled the authors 147 to reject the T h structure for C 60 H 36 and to identify the structure with the S 6 symmetry as the most probable.…”

Fulleranes

“…Different 1 H and 13 C NMR experiments are evidently the main tools for studying hydrogenated fullerenes with NMR spectroscopy but also the chemical shift of 3 He encapsulated within the fullerene cage can be used to determine structure and isomer distribution of hydrogenated fullerenes. Determination of the hydrogen pattern in these molecules can be a daunting task considering the, in many cases, immense number of possible isomers (Balasubramanian 1991;Dunlap et al 1994). So, what kind of structural information can be gained from NMR spectroscopy that could help us solve this problem?…”

Synthesis and Structural Characterization of C70H38

“…Theoretically, the number of isomers for a specific hydrogenated fullerene structure is enormous. For example, C 60 H 18 has been calculated to have 6 10 14 such isomers [4] and C 60 H 36 roughly 1 10 13 , [4,5] but in practice stability constraints reduce that number significantly. For fullerene structures such as C 60 and C 70 , the stability is mainly determined by the combination of p-electronic and steric contributions to the total energy, whereas most of the isomers of hydrogenated structures are thought to be stabilized by pair-wise addition of hydrogen atoms.…”