Fullerene Topics

• uses of fullerenes
• candle soot
• novel molecules
• nitrogen atom
• organic solar cells
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• carbon nanotubes
• chemistry and biology
• metal atoms
• angle strain
• carbon atoms
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• graphene
• energy minimum
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• popular science
• antimicrobial agents
• hybridized
• sp 2

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Fullerene, Fullerene

Spherical fullerenes are also called buckyballs , and cylindrical ones are called carbon nanotubes or buckytubes . Graphene is an example of a planar fullerene sheet. Fullerenes are similar in structure to graphite, which is composed of stacked sheets of linked hexagonal rings, but may also contain pentagonal (or sometimes heptagonal) rings that would prevent a sheet from being planar.

C 60 and other fullerenes were later noticed occurring outside the laboratory (e.g., in normal candle soot ). By 1991, it was relatively easy to produce gram-sized samples of fullerene powder using the techniques of Donald Huffman and Wolfgang Krtschmer.

Since buckminsterfullerenes have a similar shape to that sort of dome, the name was thought to be appropriate. As the discovery of the fullerene family came after buckminsterfullerene, the shortened name 'fullerene' was used to refer to the family of fullerenes.

This class of novel molecules comprises 80 carbon atoms (C80) forming a sphere which encloses a complex of three metal atoms and one nitrogen atom. These fullerenes encapsulate metals which puts them in the subset referred to as metallofullerenes. Trimetaspheres have the potential for use in diagnostics (as safe imaging agents), therapeutics and in organic solar cells.

Popular Science has published articles about the possible uses of fullerenes in armor. In April 2003, fullerenes were under study for potential medicinal use: binding specific antibiotics to the structure to target resistant bacteria and even target certain cancer cells such as melanoma. The October 2005 issue of Chemistry and Biology contains an article describing the use of fullerenes as light-activated antimicrobial agents.

The resulting carbon plasma arc between the electrodes cools into sooty residue from which many fullerenes can be isolated.

The sp 2 -hybridized carbon atoms, which are at their energy minimum in planar graphite, must be bent to form the closed sphere or tube, which produces angle strain. The characteristic reaction of fullerenes is electrophilic addition at 6,6-double bonds, which reduces angle strain by changing sp 2 -hybridized carbons into sp 3 -hybridized ones.

Common solvents for the fullerenes include aromatics, such as toluene, and others like carbon disulfide. Solutions of pure Buckminsterfullerene have a deep purple color. Solutions of C 70 are a reddish brown. The higher fullerenes C 76 to C 84 have a variety of colors. C 76 has two optical forms, while other higher fullerenes have several structural isomers. Fullerenes are the only known allotrope of carbon that can be dissolved in common solvents at room temperature.

These include the small fullerenes C 28 , Ab initio theoretical predictions of C28, C28H4, C28F4, (Ti at C28)H4, and M at C28 (M = Mg, Al, Si, S, Ca, Sc, Ti, Ge, Zr, and Sn) , Guo, Ting; Smalley, Richard E.; Scuseria, Gustavo E., 1993.

Researchers had originally been puzzled by C 72 being absent in fullerene plasma-generated soot extract, but found in endohedral samples. Small band gap fullerenes are highly reactive and bind to other fullerenes or to soot particles.

Conversely, and perhaps illustrative of how the various classes of compounds which fall under the general term fullerene cover a wide range of properties, Sayes, et al., found that in vivo inhalation of C 60 (OH) 24 and nano-C 60 in rats gave no effect, whereas in comparison quartz particles produced an inflammatory response under the same conditions (Nano Letters, 2007, Vol. 7, No. 8, 2399-2406). As stated above, nanotubes are quite different in chemical and physical properties to C 60 , i.e., molecular weight, shape, size, physical properties (such as solubility) all are very different, so from a toxicological standpoint, different results for C 60 and nanotubes are not suggestive of any discrepancy in the findings.

Since then, superconductivity has been reported in fullerene doped with various metals as well as potassium.

Fullerenes appeared in fiction well before scientists took serious interest in them. In New Scientist there used to be a weekly column called "Daedalus" written by David Jones, which contained humorous descriptions of unlikely technologies. In 1966 the columnist included a description of C 60 and other forms of graphite. This was meant as pure entertainment.

Bucky Balls were also mentioned in A&E's 2008 remake of The Andromeda Strain , which is based on the Michael Crichton novel of the same name; John Ringo uses fullerene as a carrier for antimatter in his Legacy of the Aldenata series. Other novels to make mention of them include Kim Stanley Robinson's Mars Trilogy; Iron by Poul Anderson and Neal Stephenson's The Diamond Age.

Source: Wikipedia > Fullerene