Pentaindenocorannulene JACS 2007 vol129 pp484 commons

A geodesic polyarene in

organic chemistry Organic chemistry is a subdiscipline within chemistry involving the 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.Clayden, J.; ...

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 polytope ...

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 * The concavity In ca ...

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, ...

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 g ...

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 geodesic ...

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 continuing ...

s and

sumanene Sumanene is a polycyclic aromatic hydrocarbon and of scientific interest because the molecule can be considered a fragment of buckminsterfullerene. ''Suman'' means " sunflower" in both Hindi and Sanskrit. The core of the arene is a benzene ring an ...

. 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 orbitals ...

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

but according to its discoverers, the compound is relatively easy to synthesize starting from

and a way is opened to produce larger such fragments by stitching. Synthesis of Pentaindenocorannulene

The crystal structure of pentaindenocorannulene has been obtained. An illustration of the crystal packing for pentaindenocorannulene is given below. Pentaindenocorannulene X-ray crystal structure depiction

Pentaindenocorannulene X-ray crystal structure depiction

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 na ...

. 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 Flash vacuum pyrolysis (FVP) is a technique in organic synthesis. It entails heating a precursor molecule intensely and briefly. Two key parameters are the temperature and duration (or residence time), which are adjusted to optimize yield, convers ...

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

References

{{DEFAULTSORT:Geodesic Polyarene

See also

References