UV spectroscopy of monosubstituted derivatives of 1,2-dihydro-C60-fullerenes

UV spectroscopy is used to determine the molar absorption coefficients of C₆₀ fullerene and monosubstituted 1,2-dihydro-C₆₀-fullerenes in different solvents. It is found that the extinction coefficient of C₆₀ at 330 nm (the main absorption band most frequently used for qualitative and quantitative determination of the C₆₀ content) is independent of the nature of the solvent and is ～54400 M^?1·cm^?1. The molar absorption coefficients of a series of monosubstituted 1,2-dihydro-C₆₀-fullerenes are practically independent of the chemical structure and the length of the substituent and are 35700 M^?1·cm^?1 (λ ～ 328 nm) and 115250 M^?1·cm^?1 (λ ～ 257 nm). It is shown that the substitution in fullerene proceeds via the double 6,6 bond, as evidenced by the absorption band at 424 nm in the spectra of these compounds, which is characteristic of monosubstituted methanofullerenes.