Fullerene related, 2-3, 12-19

One aspect that reflects the electronic configuration of fullerenes relates to the electrochemically induced reduction and oxidation processes in solution. In good agreement with the tlireefold degenerate LUMO, the redox chemistry of [60]fullerene, investigated primarily with cyclic voltammetry and Osteryoung square wave voltammetry, unravels six reversible, one-electron reduction steps with potentials that are equally separated from each other. The separation between any two successive reduction steps is -450 50 mV. The low reduction potential (only -0.44 V versus SCE) of the process, that corresponds to the generation of the rt-radical anion 131,109,110,111 and 1121, deserves special attention. 

High-resolution transmission electron microscopy (HREM) is the technique best suited for the structural characterization of nanometer-sized graphitic particles. In-situ processing of fullerene-related structures may be performed, and it has been shown that carbonaceous materials transform themselves into quasi-spherical onion-like graphitic particles under the effect of intense electron irradiation[l 1],... 

In addition to chemical or physical properties, a fascinating aspect of fullerene related materials is their central empty space, where atoms, molecules or particles can be enclosed. The enclosed particles are then protected by the robust graphitic layers from chemical or mechanical effects. The very long cavities of CNTs have a special potential due to their high aspect ratio and they can be used as templates to fabricate elongated nanostructures. 

CNTs, or changes of structure or melting point of liquid in nanometric cavities, etc. Many interesting experimental and theoretical studies are in progress on the CNT filling, and the obtained new knowledge will not only be useful for fullerene-related materials field, but also it will illuminate the development of the whole field of nanotechnologies. 

Another important group of fullerene-related compounds are the carbon nanotubes, the reference compounds of the carbon nano-science. They may be obtained by convenient variations of the preparation procedure mentioned. These are long tubular fullerenes with a concentric shell structure a few nanometres wide and often capped with C60-like hemisphere or faceted tips. They are mechanically very strong and either metallic conducting or semiconducting types have been obtained. 

Sloan J, Cook J, Green MLH, Hutchison JL, Tenne R (1997) Crystallization inside fullerene related structures. J. Mater. Chem. 7 1089-1095. 

Prassides K (2000) Polymer and dimer phases in doped fullerenes. In Andreoni W (ed) The physics of fullerene-based and fullerene-related materials. Kluwer Academic, Boston... 

Lanthanide metallofullerenes are novel forms of fullerene-related materials which were first obtained in their purified form in January 1993 (Shinohara et al., 1993a). Since then, as detailed in this paper, numerous investigations into various aspects of metallofullerenes have been intensively carried out by various research groups. These studies have revealed unique structural and novel electronic properties of the metallofullerenes. 

Sublimation is an efficient method to separate fullerene-related materials from other byproducts, such as carbon nanotubes and amorphous carbon [5]. This method can be scaled up easily and is solvent free, which is particularly suitable for industrial production. As discussed below, when sublimation is combined with other methods, some exciting results are obtained. 

E.Nierengarten Fullerenes principles and applications Royal Society of Chemistry 2007, ISBN 9780854045518 Fullerenes, Nanotubes and Carbon Nanostructures Marcel Dekker Inc New York, on line series on World Wide Web.online, N.Chaniotakis Fullerenes-bifunotionalisation (nanostructured for biosensing) in Nanomaterials for Biosensors , C. Kumar ed., Wiley-VCH, 2007, ISBN 978-3-527-31388-4 C.N.Kramer Fullerene research advances Nova Science Publishers Inc 2007, ISBN 9781600218248 MJ.,ang Progress in fullerene research Nova Science Publishers Inc 2007, ISBN 9781600218415 S.Margadonna Fullerene-related materials recent advances in their chemistry and physics Springer 2007, ISBN 9781402044588.]... 

The recent discovery that fullerene-related nanomaterials are formed under electrolytic conditions [14, 15] adds further technical and fundamental perspectives to the nanotube field. Using graphite electrodes immersed in molten LiCl under argon, nanotube production can be improved significantly. Depending upon the conditions, some 20-30% of the carbonaceous material formed may consist of graphitic nanotubes. Under other conditions quite different material is produced. 

Fullerene-related materials science has evolved rapidly over the past decade, and a fascinating field of nanotechnology has now opened up. Many applications of carbon nanotubes are envisaged, among which nano-scale engineering and electronics are prominent. 

Figure 14.25 Reprinted from Sloan, S., Hutchison, J.L., Tenne, R., Yishay, T.T., and Homyonferi, M. (1999) Defect and ordered tungsten oxides encapsulated (X 5S and Se) fullerene-related structures, J. Sol. St. Chem. 144, 100, Copyright 1999, with permission from Elsevier.

Andreoni, W., ed. 2000. The Physics of Fullerene-Based and Fullerene-Related Materials. Boston Kluwer Academic Publishers. 

Elemental carbon exhibits two main crystalline modifications. Diamond is cubic and graphite is hexagonai. Fullerene, a new form of carbon, will not be discussed fullerene related carbon nanotubes are discussed in Chapter 3. 

Another type of EDOT Cgo-derivatives has been prepared (see Figure 13.28) with the surprising ability to form self-assembled, chemically adsorbed monolayers on gold surfaces. Electro-oxidation lead to desorption of the SAM, traced by the disappearance of the fullerene related peaks. 

Finally, one should note that the fullerene cage concept is not just confined to carbon. Studies of boron nitride indicate that it too can form nanotubes [11,12]. Furthermore, most interestingly, Tenne and coworkers have shown that molybdenum and tungsten sulphides - long known to form layered materials also produce fullerene-related giant quasi-crystals [13,14]. 

Accordingly, the exterior surface is much more reactive than planar analogues, and is comparable to those of electron deficient polyolefins. This, in turn, rationalizes the high reactivity of the fullerene core towards photolytically and radiolytically generated carbon- and heteroatomic-centred radicals and also other neutral or ionic species [8]. The interior, in contrast, is shown to be practically inert [9]. Despite these surface related effects, the... 

Another interesting physical feature relates to the cliromophoric character of fullerenes. Based on the symmetry prohibitions, solutions of [60]fullerene absorb predominantly in the UV region, with distinct maxima at 220, 260 and 330 nm. In contrast to extinction coefficients on the order of 10 cm at these wavelengths, the visible region shows only relatively weak transitions (X at 536 nm s =710 cm ) [142]. 

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