Methylene Bridged Fullerenes - an External Probe

Bridged C7o The isomers 59 and 60 were reduced as a mixture and were distinguished according to their peak area ratio [168]. The H NMR spectrum of 59 contains two doublets at 2.27 ppm (Ha) and —0.25 ppm (Hb). The H NMR spectrum of 60 contains two doublets, one at 2.34 ppm (Ha), and the other, which lies under the solvent peak, at 3.6 ppm (Hb). The full assignment of the H NMR chemical shifts of the two isomers 59 and 60 was possible because the proton Ha of both isomers is located above the same 6-MR of the C70 framework. The substantial upheld shift of both Hb peaks, relative to the neutral fullerene, indicates an 

In isomer 61 the two protons are located over equivalent 6-MRs therefore, the H NMR of 61 contains one singlet. The signal appeared at 2.77 ppm, shielded by 0.11 ppm compared to neutral 61 [167]. 

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