| Fullerene is a molecular compound, which is a convex closed polyhedron composed of three-coordinated carbon atoms. The fullerens owe their name to engineer and architect Richard Buckminster Fuller, whose geodesic structures are built according to this principle. Initially, this class of compounds was limited to structures that included only five and hexagonal faces. Note that for the existence of such a closed polyhedron constructed of n vertices forming only five and hexagonal faces, according to the Euler theorem for polyhedra, the validity of the equality | n | - | e | + | f | = 2 (where | n |, | e | and | f | respectively, the number of vertices, edges and faces), a necessary condition is the presence of exactly 12 pentagonal faces and n / 2-10 hexagonal faces. If a molecule of a fullerene, in addition to carbon atoms, includes atoms of other chemical elements, then if the atoms of other chemical elements are located inside the carbon skeleton, such fullerenes are called endohedral, if outside - exohedral. |
Fullerene С60 |
Discovery history
In 1985, a group of researchers - Robert Curl, Harold Kroto, Richard Smalley, Heath and O'Brien - examined the mass spectra of graphite vapors obtained by laser irradiation (ablation) of a solid sample, and found peaks with a maximum amplitude corresponding to clusters consisting of 60 and 70 carbon atoms. They suggested that these peaks correspond to C60 and C70 molecules and hypothesized that the C60 molecule has the shape of a truncated icosahedron of symmetry Ih. Polyhedral carbon clusters are called fullerenes, and the most common C60 molecule is buckminsterfullerene (also called buckybear or bukibolom, English buckyball), named after the American architect Buckminster Fuller, who used to build floaters of his buildings, who use five-piece man-made floppers, who use five post-floets. which are the basic structural elements of the molecular frameworks of all fullerenes.
It should be noted that the discovery of fullerenes has its own background: the possibility of their existence was predicted in 1971 in Japan and theoretically substantiated in 1973 in the USSR. For the discovery of fullerenes Kroto, Smalley and Curle in 1996 was awarded the Nobel Prize in Chemistry. The only way to obtain fullerenes at the moment (October 2007) is their artificial synthesis. For a number of years these compounds have been intensively studied in laboratories in different countries, trying to establish the conditions for their formation, structure, properties, and possible areas of application. It has been established, in particular, that fullerenes are contained in significant amounts in soot formed in an arc discharge on graphite electrodes - they were simply not noticed before (see below).
Fullerenes in nature
After receiving in the laboratory, fullerenes were found in some samples of North Karelia shungites in fulgurites of the USA and India, meteorites and bottom sediments, which are 65 million years old.
On Earth, fullerenes are formed by burning natural gas and discharging lightning. In the summer of 2011, the results of air sampling over the Mediterranean Sea were published: fullerenes were found in all 43 air samples taken from Barcelona to Istanbul.
Fullerenes in large quantities were also found in space: in 2010 in the form of gas, in 2012 - in solid form.
Hydrated fullerene (HyFn); (C60 (H2O)n
Aqueous solution of C60HyFn
Hydrated fullerene C60 - C60HyFn is a strong, hydrophilic supramolecular complex consisting of a fullerene C60 molecule, enclosed in a first hydrate shell, which contains 24 water molecules: C60 (H2O) 24. The hydrate shell is formed as a result of donor-acceptor explosion. Aqueous solution of C60HyFnem oxygen electron vapors and electron-acceptor central particles on the fullerene surface. In this case, a water molecule oriented near the surface of the fullerene is interconnected by a bulk network of hydrogen bonds. The size of C60HyFn corresponds to 1.6-1.8 nm. Currently, the maximum concentration of C60, in the form of C60 HyFn, which could be created in water, is equivalent to 4 mg / ml. Photo of an aqueous solution of C60HyFn with a concentration of C600.22 mg / ml on the right.
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