Generation in Solution and Quenching Experiments

Fullerenes can be easily chemically reduced by the reaction with electropositive metals [1, 97-99], for example, alkali- and alkaline earth metals. The anions Cjq (n = 1-5) can be generated in solution by titrating a suspension of in liquid ammonia with a solution of Rb in liquid ammonia [100], whereupon the resulting anions dissolve. Monitoring of this titration is possible by detecting the characteristic NIR absorption of each anion by UV/Vis/NIR spectroscopy. The solubility of the alkali metal fullerides in the polar solvent NHj demonstrates their salt character. 

Ultrasound-aided reduction of Cjq and C7Q with Li metal to anionic species can be carried out in THF as the solvent [50]. In contrast to the parent fullerenes, the anions Cgo and are very soluble in THF. Solutions generated this way are deep red-brown. Alkylation of a C50 and C q polyanion mixture with excess Mel leads to polymethylated fullerenes with up to 24 methyl groups covalently bound (see also Chapter 1). 

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