Electroreduction of buckminsterfullerene, C60, in aprotic solvents: electron spin resonance characterization of singly, doubly, and triply reduced C60 in frozen solutions

ESR Spectroscopic Evidence on the Formation of NaC6and HC60in Y Zeolitic Nanocavities

“…[16][17][18] Extensive research has focused on spectroscopic, especially ESR, studies of fullerene anions or adduct radicals generated by various techniques. [19][20][21][22][23] In the present study we show, based on the close reexamination of our recently reported ESR spectra, [13][14][15] the formation and characterization of NaC60 and HC60 in NaY nanocavities.…”

“…Although the g 0 -values from Figure 1 are typical values for organic radicals, they are significantly larger than those (2.0006, 19 2.001, 20 1.998 21 ) of C 60 − in solutions. The large g 0 -values are considered to arise from the polar environment.…”

Discrete Fulleride Anions and Fullerenium Cations

“…A variety of solvent systems have been introduced including toluene/dichloromethane, 178 dichloromethane, pyridine, benzonitrile, THF, 53,[179][180][181][182] and water/γ-cyclodextrin. 183 From a synthetic point of view, however, electrochemical methods tend to work only when practical current densities can be achieved and when the products separate easily from the electrolyte solution.…”

“…The variation with cation is substantial. Room-temperature line widths have been reported in the range 10-54 G. 133 These features have led Eaton et al to conclude that electron-spin relaxation rates are the main determinant of the line width variation, but the whole problem of line width variation is made complex by the presence of low-lying excited states, 179 motional effects, 106,220 and environmentally induced distortions. 346 A more quantitative understanding of the broad, temperature-dependent signal is coming from pulsed EPR measurements of the traverse and longitudinal relaxation times of C 60 -in a tetraphenylphosphonium salt.…”

“…178 This is inconsistent with the observation of the sharp signal in frozen solutions of stoichiometric C 60 -salts. 116,117,179 Jones, Kadish, and co-workers proposed that the sharp signal was due to a small amount of C 60 2-arising from redox disproportionation. 179 This is inconsistent with Nernst equation quantitation and the persistence of the sharp signal in the presence of a large excess of C 60 .…”