Reduction of fullerenes to fullerides

Reduction of fullerene s to fullerides — Reversible electrochemical reduction of Ceo in anhydrous dimethylformamide/toluene mixtures at low temperatures leads to the air-sensitive coloured anions Ceo , in = 1-6). The successive mid-point reduction potentials, 1/2, at -60°C are -0.82, -1.26, -1.82, -2.33, —2.89 and —3.34 V, respectively. Liquid NH3 solutions can also be used. Ceo is thus a very strong oxidizing agent, its first reduction potential being at least 1 V more positive than those of polycyclic aromatic hydrocarbons. C70 can also be reversibly reduced and various ions up to 70 have been detected. 

Chemical reduction by alkali metals leads to solid fullerides which are sometimes solvated. 

Takeuchi, M. Ozawa, X. Li, K. Saigo and K. Kitazawa, J. Chem. Soc., Chem. Commun., 1784-5 (1993) and references cited therein. 

fullerides M Ceo are known for n = 1 when M = Rb, Cs and for n = 2, 3,4 and 6 when M = Na, K, Rb and Cs. An important alternative route treats Ceo in toluene with a solution of Na[Mn(j) -C5Me5)2] in thf to give an 80% yield of the dark-purple, air- and moisture-sensitive crystalline solvate NaCeo-Sthf.  

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