Fullerene electrosynthesis

This chapter presents an up-to-date account of the redox properties of the pristine fullerenes and a large number of their derivatives as revealed by electrochemical studies in solution. The description here is as exhaustive as possible, although not completely comprehensive due to the large number of reports on the subject that have appeared over the years. A section on electrosynthesis of fullerene derivatives is included, with special emphasis on the retro-cyclopropanation reaction, a reaction that has led to the formation of novel derivatives as well as... 

In conclusion, the above surface film formation processes are expected to occur with all types of the carbons mentioned (including doped diamonds and fullerenes) in nonaqueous solvents containing metal ion salts. Hence, when carbon electrodes are utilized for electroanalysis or electrosynthesis in such solutions at low potentials, they should be considered as modified electrodes covered with surface films that are, at least partially, electronic insulators (but may be ion conductors). 

The two-electron reduction of Ceo to produce Ceo can be achieved electrochemically in the presence of methyl iodide to yield the dimethyl adduct, Mc2Ceo [139]. In this context, catalytic currents are observed for the electrochemical reduction of Ceo or C70 to produce Ceo or C70 , respectively, in the presence of vicinal dibromides [140] or a,to-dihaloalkanes [141, 142]. Electrosynthesis of methano-fullerenes has been achieved by the reaction of Ceo with j o-brominated and... 

Recently, non-oxide HTSCs such as derivatives of fullerenes [549,550] were discovered, as well as certain high-melting compounds of transition metals [551, 552]. The electrochemistry of fullerenes has already been transformed into an actively developed independent field [550,553,554]. The electrosynthesis of a number of carbides, sulfides, borides, and their analogs represents a well-known method for their production [23,555]. Hence, electrochemistry also plays an active role in the new directions of the HTSC chemistry. 

In this chapter we concentrate exclusively on the most important aspects of the electrochemistry of 50 and the other pristine higher fullerenes, namely, C70, 75, 73, Cg2, and Cg4. A vast number of derivatives of 50 and a few of C70, 75, and C7g have been prepared, and their redox properties have been studied using electrochemical techniques. However, due to space limitations, it is impossible to cover this subject here and to give it the justice that it deserves. Since several comprehensive reviews on fullerenes and their derivatives have appeared recently, the reader is referred to these for details [6]. Nevertheless, it has been recently discovered that controlled potential electrolysis can be used as a synthetic tool for the preparation of new fullerene derivatives, as well as for the separation of otherwise inseparable fullerene isomers. Thus, a short section covering electrosynthesis of fullerene derivatives is included at the end of this chapter. 

Reduction of fullerenes is a method of choice for preparing fullerene adducts, since the fullerene anions exhibit nucleophilic behavior. Fullerene derivatives, such as alkyl fullerenes, were prepared by chemical reduction of the fullerene [169] or via organic electrosynthesis [38], mostly via [147c],... 

Interesting polyfullerenes such as 8 and 9 have been described by the group of RoncaU [44]. These polymers were obtained by electrosynthesis of electron donor 3,4-ethylenedioxythiophene and 3-alkylsulfanylthiophene, carrying fullerene moieties via alkyl spacers of different length. This type of precursor allows for a ready and efficient electropolymerization at low oxidation potentials. Note that 9a, b are... 

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