Clusters, Fullerenes, and Nanotubes

All of the carbon atoms in buckminsterfullerene are equivalent and are sp -hybridized each one simultaneously belongs to one five-membered ring and two benzene-like six-membered rings. The strain caused by distortion of the rings from coplanarity is equally distributed among all of the carbons. 

Confirmation of the structure proposed for Cgo required isolation of enough material to allow the arsenal of modern techniques of structure determination to be applied. A quantum leap in fullerene research came in 1990 when a team led by Wolfgang Kratschmer of the Max Planck Institute for Nuclear Physics in Heidelberg and Donald Huffman of the University of Arizona successfully prepared buckminsterfullerene in amounts sufficient for its isolation, purification and detailed study. Not only was the buckminsterfullerene structure shown to be correct, but academic and industrial scientists around the world seized the opportunity afforded by the availability of Ceo in quantity to study its properties. 

Speculation about the stability of Cgo centered on the extent to which the aromaticity associated with its 20 benzene rings is degraded by their non- 

FIGURE 11.5 Graphite is a form of eiementai carbon composed of paraiiei sheets of fused benzene-iike rings. 

FIGURE 11.6 Buckminsterfuiierene (Ceo). Note that aii carbons are equivaient and that no five-membered rings are adjacent to one another. 

In general, the term nanoscale applies to dimensions on the order of 1-100 nanometers (1 nm = 10 m), and one goal of nanotechnology is to develop useful nanoscale devices nano-devlces). Because typical covalent bonds range from 0.1-0.2 nm, chemical structures hold promise as candidates on which to base nanodevices. Among them, much recent attention has been given to carbon-containing materials and even elemental carbon itself. 

CNTs themselves are of interest because of their electrical and mechanical properties, and functionally modified ones are being examined in applications ranging from medical diagnosis and therapy to photovoltaic systems. The methods used to add functionality to a CNT include among others (1) covalent attachment of a reactive group to the CNT via a chemical reaction, and (2) noncovalent coating of the outer surface of the CNT with a substance that itself bears a functional substituent. 

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Buckminsterfullerene (Chapter 11 essay Carbon Clusters Fullerenes and Nanotubes ) Name given to the Cgo cluster with structure resembling the geodesic domes of R Buck minster Fuller see front cover... 

Benzene Dreams and Creative Thinking Carbon Clusters Fullerenes and Nanotubes... 

Work on clusters also had its origin in this decade. Initial work led in following years to the production of the well-known Stuttgart pseudopoten-tials, which enables the realistic calculation of systems containing heavier elements. It also prepared the route to many studies on magic numbers in cluster chemistry and eventually to fullerenes and nanotubes. 

The present voliune combines reports and the current status of the principles of fullerene reactivity, of cluster modified fullerenes, of higher fullerenes and nanotubes and reviews potential applications of fullerene materials. This volume is also meant to inspire interested fullerene researchers to find elegant... 

Metal-carbide clusters are relevant to the fonnation of both endohedral fullerenes and carbon nanotubes [1351. There also exists a class of apparently stable metal-carbide cluster ions, = Ti, V, Cr, Zr and Hf), called... 

A cluster of carbon nanotubes that has formed a "rope." The surrounding material below the rope in the photograph consists of fullerenes and other carbon structures. 

A group of nanomaterials, as the only criterion of membership becomes particle size, is very diversified. Particular members of the group differ from each other by molecular geometry (i.e., nanotubes, fullerenes, crystal structures, clusters, etc.) and physicochemical characteristics (i.e., organic, inorganic, semiconductors, isolators, metals, nonmetals, etc.). Thus, it may and should be assumed that they also differ by the mechanism of action and - in consequence - defining one common applicability domain and QSAR model for all of them is impossible. 

Astakhova T.Yu., Menon M., Vinogradov G.A. (2003) Three-dimensional solitons in carbon nanotubes. Abstracts of 6th Biennial International Workshop Fullerenes and Atomic clusters (St.-Peterburg), 256. 

Figure 7.18 Direct observation of motions of the Er3N cluster and Er3N 4-C8o in CNTs (a) HRTEM images (upper, taken at 37 s lower, taken at 2 s) (b) suggested orientations (c) simulated images [185]. (Reprinted with permission from Y. Sato, et al., Structures of Dsd-Cso and 7h-Er3N C8o fullerenes and their rotation inside carbon nanotubes demonstrated by aberration-corrected electron microscopy, Nano Letters, 7, 3704-3708, 2007. 2007 American Chemical Society).

The single-wall carbon nanocone-nanohom packing efficiencies, and interaction-energy parameters, are intermediate between those of fullerene and single-wall carbon nanotube clusters. Therefore an in-between behaviour is expected. 

Clusters, Intermolecular and Solvent Eeffects, Fullerenes, Nanotubes. - n-... 

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