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A common method used to produce fullerenes is to send a large current between two nearby graphite electrodes in an inert atmosphere. The resulting carbon plasma arc between the electrodes cools into sooty residue from which many fullerenes can be isolated. |
A common method used to produce fullerenes is to send a large current between two nearby graphite electrodes in an inert atmosphere. The resulting carbon plasma arc between the electrodes cools into sooty residue from which many fullerenes can be isolated. |
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== Possible dangers == |
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Although buckyballs have been thought in theory to be relatively inert, a presentation given to the [[American Chemical Society]] in [[March]] [[2004]] and described in an article in [[New Scientist]] on [[April 3]] [[2004]], suggests the molecule is injurious to organisms. An experiment by Eva Oberdörster at [[Southern Methodist University]], which introduced fullerenes into water at concentrations of 0.5 parts per million, found that [[largemouth bass]] suffered a 17-fold increase in cellular damage in the brain tissue after 48 hours. The damage was of the type [[lipid peroxidation]], which is known to impair the functioning of [[cell membrane]]s. There were also inflammatory changes in the liver and activation of genes related to the making of repair enzymes. At the time of presentation, the SMU work had not been [[peer review]]ed. |
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==Fullerene extract mixture (C<sub>60</sub>/C<sub>70</sub>) solubility== |
==Fullerene extract mixture (C<sub>60</sub>/C<sub>70</sub>) solubility== |
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The Fullerenes are a recently discovered allotrope of carbon (the best known being diamond and graphite). They are molecules composed entirely of carbon, taking the form of a hollow sphere, ellipsoid, or tube. Spherical fullerenes are sometimes called buckyballs, while cylindrical fullerenes are called buckytubesornanotubes.
The molecule was named for Richard Buckminster Fuller, a noted architect who popularized the geodesic dome. Since buckminsterfullerenes have a similar shape to that sort of dome, the name was thought to be appropriate.
Fullerenes are similar in structure to graphite, which is composed of a sheet of linked hexagonal rings, but they contain pentagonal (or sometimes heptagonal) rings that prevent the sheet from being planar.
The smallest fullerene in which no two pentagons share an edge (which is destabilizing — see pentalene) is C60 (buckminsterfullerene), and this is also the most common.
The structure of C60 is that of a truncated icosahedron, which resembles a round soccer ball of the type made of hexagons and pentagons, with a carbon atom at the corners of each hexagon and a bond along each edge. A polymerized single-walled nanotubule (P-SWNT) is a substance composed of polymerized fullerenes in which carbon atoms from one buckytube bond with carbons in other buckytubes.
In molecular beam experiments, discrete peaks were observed corresponding to molecules with the exact mass of 60, 70, or greater numbers of carbon atoms. Harold Kroto, from the University of Sussex, James Heath, Sean O'Brien, Robert Curl and Richard Smalley, from Rice University, discovered C60 and the fullerenes in 1985. Kroto, Curl, and Smalley were awarded the 1996 Nobel Prize in Chemistry for their roles in the discovery of this class of compounds. C60 and other fullerenes were later noticed occurring outside of a laboratory environment (e.g. in normal candle soot). By 1991, it was relatively easy to produce grams of fullerene powder using the techniques of Donald Huffman and Wolfgang Krätschmer. Fullerene purification remains a challenge to chemists and determines fullerene prices to a large extent. So called endohedral fullerenes have incorporated inside the cage atoms, ions or small molecules. Fullerene is an unusual reactant in many organic reactions such as the Bingel reaction discovered in 1993.
As of the early twenty-first century, the chemical and physical properties of fullerenes are still under heavy study, in both pure and applied research labs. 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.
Fullerenes are not very reactive due to the stability of the graphite-like bonds, and are also sparingly soluble in many solvents. Common solvents for the fullerenes include toluene and carbon disulfide. Solutions of pure Buckminsterfullerene have a deep purple color. Fullerenes are the only known allotrope of carbon that can be dissolved. Researchers have been able to increase the reactivity by attaching active groups to the surfaces of fullerenes. Buckminsterfullerene does not exhibit "superaromaticity". That is, the electrons in the hexagonal rings do not delocalize over the whole molecule.
Other atoms can be trapped inside fullerenes, and indeed recent evidence for a meteor impact at the end of the Permian period was found by analysing noble gases so preserved.
In the field of nanotechnology, heat resistance and superconductivity are some of the more heavily studied properties.
A common method used to produce fullerenes is to send a large current between two nearby graphite electrodes in an inert atmosphere. The resulting carbon plasma arc between the electrodes cools into sooty residue from which many fullerenes can be isolated.
Solvents that dissolve fullerenes are listed below in order of high solubility. The value in parentheses is the approximate saturated concentration.
In1999, researchers from the UniversityofVienna 
Administrator note demonstrated that the wave-particle duality applied to macro-molecules such as fullerene.
Inmathematical terms, the structure of a fullerene is a trivalent convex polyhedron with pentagonal and hexagonal faces. Using Euler formula F - E + V = 2, (plus the fact that every vertex in a fullerene structure belongs to exactly 3 faces) one can easily prove that there are exactly 12 pentagons in a fullerene. The smallest fullerene is C20, the dodecahedron. There are no fullerenes with 22 vertices. The number of fullerenes C2n grows rapidly with increasing n = 12,13, ... For instance, there are 1812 non-isomorphic fullerenes C60 but only one of them, the buckminsterfullerene alias truncated icosahedron, has no pair of adjacent pentagons.
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