In the first proven SN2′ fullerene reaction, both C3 and C1 C60F36 hydrolyse to C1 isomers of C60F35OH that eliminate HF to give epoxides C60F34O; C60F36O oxides are shown to be ethers, and a fourth isomer of C60F36 exists

Abstract

On standing in organic solvents containing traces of water, C₃ and C₁ isomers of C₆₀F₃₆ slowly convert to C₁ isomers of C₆₀F₃₅OH. Both fluorofullerenols eliminate HF during EI mass spectrometry to give C₆₀F₃₄O epoxides, one fullerenol being much less stable than the other to the extent that the mass spectrum shows only the epoxide. Both C₆₀F₃₅OH isomers have C₁ symmetry, one being identified by the remarkable linear relationship between chemical shifts in its ¹⁹F NMR spectrum and those in the spectrum of C₁ C₆₀F₃₆; the spectrum of the other shows the pattern of C₃ C₆₀F₃₆ rendered asymmetrical by the replacement of one F by OH. The reactions are facilitated by the presence of isolated double bonds, and provide the first proven examples of an S_N2′ reaction of a fullerene derivative. Our observation explains why only a limited number of fluorines are readily replaced in C₆₀F₃₆ and why C₆₀F₁₈ is by contrast much more resistant to hydrolysis. We have isolated also a pure isomer of C₆₀F₃₆O, which is shown to be an oxahomofullerene (ether) apparently derived from C₁ C₆₀F₃₆, and an impure fraction comprising a fourth isomer of C₆₀F₃₆, a trifluoromethyl derivative of C₆₀F₃₆, a second isomer of C₆₀F₃₆O, and an unknown species of 1392 u.