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A geodesic polyarene in
organic chemistry Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clay ...
is a
polycyclic aromatic hydrocarbon A polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings. The simplest representative is naphthalene, having two aromatic rings and the three-ring compounds anthracene and phenanthrene. ...
with curved
convex Convex or convexity may refer to: Science and technology * Convex lens, in optics Mathematics * Convex set, containing the whole line segment that joins points ** Convex polygon, a polygon which encloses a convex set of points ** Convex polytop ...
or
concave Concave or concavity may refer to: Science and technology * Concave lens * Concave mirror Mathematics * Concave function, the negative of a convex function * Concave polygon, a polygon which is not convex * Concave set In geometry, a subset ...
surfaces. Examples include
fullerene A fullerene is an allotrope of carbon whose molecule consists of carbon atoms connected by single and double bonds so as to form a closed or partially closed mesh, with fused rings of five to seven atoms. The molecule may be a hollow sphere, ...
s,
nanotube A nanotube is a nanometer-scale hollow tube-like structure. Kinds of nanotubes * BCN nanotube, composed of comparable amounts of boron, carbon, and nitrogen atoms * Boron nitride nanotube, a polymorph of boron nitride * Carbon nanotube, includes ...
s,
corannulene Corannulene is a polycyclic aromatic hydrocarbon with chemical formula C20 H10. The molecule consists of a cyclopentane ring fused with 5 benzene rings, so another name for it is irculene. It is of scientific interest because it is a geode ...
s,
helicene In organic chemistry, helicenes are ortho-condensed polycyclic aromatic compounds in which benzene rings or other aromatics are angularly annulated to give helically-shaped chiral molecules. The chemistry of helicenes has attracted continuin ...
s and sumanene. The molecular orbitals of the carbon atoms in these systems are to some extent pyramidalized resulting a different
pi electron In chemistry, pi bonds (π bonds) are covalent chemical bonds, in each of which two lobes of an orbital on one atom overlap with two lobes of an orbital on another atom, and in which this overlap occurs laterally. Each of these atomic orbital ...
density on either side of the molecule with consequences for reactivity. One member of this group of organic compounds, ''pentaindenocorannulene'' (depicted below), can be considered a large fullerene fragment. The experimentally obtained curvature and degree of pyramidalizion (12.6° for the carbons of the pentagon at the center ) are both actually larger than that of
fullerene A fullerene is an allotrope of carbon whose molecule consists of carbon atoms connected by single and double bonds so as to form a closed or partially closed mesh, with fused rings of five to seven atoms. The molecule may be a hollow sphere, ...
but according to its discoverers, the compound is relatively easy to synthesize starting from
corannulene Corannulene is a polycyclic aromatic hydrocarbon with chemical formula C20 H10. The molecule consists of a cyclopentane ring fused with 5 benzene rings, so another name for it is irculene. It is of scientific interest because it is a geode ...
and a way is opened to produce larger such fragments by stitching. The crystal structure of pentaindenocorannulene has been obtained. An illustration of the crystal packing for pentaindenocorannulene is given below. Another geodesic polyarene that has been synthesized is C50H10. C50H10 can be described as a short, rigid, structurally pure ,5
carbon nanotube A scanning tunneling microscopy image of a single-walled carbon nanotube Rotating single-walled zigzag carbon nanotube A carbon nanotube (CNT) is a tube made of carbon with diameters typically measured in nanometers. ''Single-wall carbon nan ...
. The crystal structure of C50H10 has been obtained. The carbons of the pentagon at the center of C50H10 have a POAV angle of 12.3°, less than that of pentaindenocorannulene. The synthesis is as shown below. FVP stands for flash vacuum pyrolysis. Some bowl-shaped molecules reported in the literature are in fact partially hydrogenated. A C56H40 hydrocarbon has been synthesized containing 54 of the 60 carbon atoms found in fullerene ''Synthesis of a C56H40 Hydrocarbon Bearing a 54-Carbon Framework of C60'' Kung K. Wang, Yu-Hsuan Wang, Hua Yang, Novruz G. Akhmedov, and Jeffrey L. Petersen Org. Lett., 2009


See also

*
Fullerene chemistry Fullerene chemistry is a field of organic chemistry devoted to the chemical properties of fullerenes. Research in this field is driven by the need to functionalize fullerenes and tune their properties. For example, fullerene is notoriously insolub ...
*
Corannulene Corannulene is a polycyclic aromatic hydrocarbon with chemical formula C20 H10. The molecule consists of a cyclopentane ring fused with 5 benzene rings, so another name for it is irculene. It is of scientific interest because it is a geode ...
* Contorted aromatics *
Carbon nanotube A scanning tunneling microscopy image of a single-walled carbon nanotube Rotating single-walled zigzag carbon nanotube A carbon nanotube (CNT) is a tube made of carbon with diameters typically measured in nanometers. ''Single-wall carbon nan ...


References

{{DEFAULTSORT:Geodesic Polyarene