EPR Study of New Bis-methano[60]fullerenes in Liquid

Methano[60]fullerenes with two and four nitroxide radicals are studied by EPR spectroscopy. It is shown that nitroxide derivatives of fullerene C-60 undergo conformational changes in liquid solution. It is established that transitions between the two conformations take place in the case of the biradical adduct of C-60 fullerene. For the tetraradical adduct in the trans-3 position, it is shown that the biradicals do not interact and behave independently; therefore, the two-conformational model provides a good description of the experimental data. A more complicated situation is implemented for the tetraradical adduct in the equatorial position. The biradicals are not independent for this system, and their interaction leads to an increase in the number of possible conformations. Thermodynamic parameters for these systems are calculated.