Esr Study of C₆₀^N- Anion Radicals in DMSO Solution

Abstract

With the aim to stabilize reduced C₆₀ molecules of solid fulleride as free anion radicals in solution, Na_xC₆₀ (x=l, 10) was dissolved in DMSO. The Na_xC₆₀ was chosen among the other alkali-metal fullerides due to the possibility to increase a number of intercalated Na atoms in a fee. lattice of C₆₀ A sufficiently high concentration of C₆₀ anion radicals of an order of magnitude larger than that usually achieved in solution by an electrochemical reduction was obtained. The sharp resonances with the linewidths of order of 0.1 G and with g=2.0004(6) −2.0012(8) of the room temperature ESR spectra of fluid solution were assigned from mono- to pentaanions of C₆₀. An appearance of additional sharp peaks at g=2.0016–2.0019 in the spectra of solution of nominal Na₁₀C₆₀, but Na₁C₆₀, tentatively related to C₆₀ ^n- with n>6. The results of this study showed a simple approach in an accomplishment of highly concentrated solutions of free anion radicals C₆₀ ^n-, as well as in stabilization of the anion radicals with increased n. In this way a homogeneity of alkali metal intercalation and characteristics of the solvent will be important.