Hexabenzocoronene

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Hexabenzocoronene
Hexabenzocoronene.svg
Hexabenzocoronene-3D-balls.png
Hexabenzocoronene AFM.jpg
AFM image of hexabenzocoronene
Names
Preferred IUPAC name
Hexabenzo[bc,ef,hi,kl,no,qr]coronene
Other names
  • Hexa-peri-hexabenzocoronene
  • Hexabenzocoronene
Identifiers
3D model (JSmol)
ChemSpider
PubChem CID
UNII
  • InChI=1S/C42H20/c1-7-19-21-9-2-11-23-25-13-4-15-27-29-17-6-18-30-28-16-5-14-26-24-12-3-10-22-20(8-1)31(19)37-38(32(21)23)40(34(25)27)42(36(29)30)41(35(26)28)39(37)33(22)24/h1-17,35H,18H2
    Key: FYXBXZBCUROVBE-UHFFFAOYSA-N
  • c0cc1c2c3c4c5c1cccc5c6cccc1c6c4c7c8c1cccc8c9cccc1c9c7c3c5c1cccc5c2c0
Properties
C42H18
Molar mass 522.606 g·mol−1
Appearancedark yellow</ref>
Density 1.54 g/cm3 (calc.) [1]
-346.0·10−6 cm3/mol [2]
Structure [1]
monoclinic, P21/a
a = 1.8431(3) nm, b = 0.5119(1) nm, c = 1.2929(2) nm
α = 90°, β = 112.57(1)°, γ = 90°
2
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Hexa-peri-hexabenzocoronene (HBC) is a polycyclic aromatic hydrocarbon with the molecular formula C42H18. It consists of a central coronene molecule, with an additional benzene ring fused between each adjacent pair of rings around the periphery. It is sometimes simply called hexabenzocoronene, however, there are other chemicals that share this less-specific name, such as hexa-cata-hexabenzocoronene.

Contents

Hexa-peri-hexabenzocoronene has been imaged by atomic force microscopy (AFM) providing the first example of a molecule in which differences in bond order and bond lengths of the individual bonds can be distinguished by a measurement in direct space. [3]

Supramolecular structures

Various hexabenzocoronenes have been investigated in supramolecular electronics. They are known to self-assemble into a columnar phase. One derivative in particular forms carbon nanotubes with interesting electrical properties. [4] The columnar phase in this compound further organises itself into sheets, which ultimately roll up like a carpet to form multi-walled nanotubes with an outer diameter of 20 nanometers and a wall thickness of 3 nm. In this geometry, the stacks of coronene disks are aligned with the length of the tube. The nanotubes have sufficient length to fit between two platinum nanogap electrodes produced by scanning probe nanofabrication and are 180 nm apart. The nanotubes as such are insulating, but, after one-electron oxidation with nitrosonium tetrafluoroborate (NOBF
4
), they conduct electricity. [5]

Synthesis

Organic synthesis of a hexabenzocoronene starts with an Aldol condensation reaction of dibenzyl ketone with a benzil derivative to give a substituted cyclopentadienone. A Diels–Alder reaction with alkyne and subsequent expulsion of carbon monoxide gives a hexaphenylbenzene. The adjacent pairs of benzene rings undergo oxidative electrocyclic reactions and aromatization by oxidation by iron(III) chloride in nitromethane.

HexabenzocoroneneRXN.svg

Related Research Articles

<span class="mw-page-title-main">Aromatic compound</span> Compound containing rings with delocalized pi electrons

Aromatic compounds, also known as "mono- and polycyclic aromatic hydrocarbons", or arenes, are organic compounds containing one or more aromatic rings. The word "aromatic" originates from the past grouping of molecules based on odor, before their general chemical properties were understood. The current definition of aromatic compounds does not have any relation to their odor. Aromatic compounds are now defined as cyclic compounds satisfying Hückel's Rule.

<span class="mw-page-title-main">Aromaticity</span> Phenomenon of chemical stability in resonance hybrids of cyclic organic compounds

In chemistry, aromaticity means a molecule has a cyclic (ring-shaped) structure with pi bonds in resonance. Aromatic rings give increased stability compared to saturated compounds having single bonds, and other geometric or connective non-cyclic arrangements with the same set of atoms. Aromatic rings are very stable and do not break apart easily. Organic compounds that are not aromatic are classified as aliphatic compounds—they might be cyclic, but only aromatic rings have enhanced stability. The term aromaticity with this meaning is historically related to the concept of having an aroma, but is a property distinct from that meaning.

Thiophene is a heterocyclic compound with the formula C4H4S. Consisting of a planar five-membered ring, it is aromatic as indicated by its extensive substitution reactions. It is a colorless liquid with a benzene-like odor. In most of its reactions, it resembles benzene. Compounds analogous to thiophene include furan (C4H4O), selenophene (C4H4Se) and pyrrole (C4H4NH), which each vary by the heteroatom in the ring.

<span class="mw-page-title-main">Coronene</span> Chemical compound

Coronene is a polycyclic aromatic hydrocarbon (PAH) comprising seven peri-fused benzene rings. Its chemical formula is C
24
H
12
. It is a yellow material that dissolves in common solvents including benzene, toluene, and dichloromethane. Its solutions emit blue light fluorescence under UV light. It has been used as a solvent probe, similar to pyrene.

<span class="mw-page-title-main">Polycyclic aromatic hydrocarbon</span> Hydrocarbon composed of multiple aromatic rings

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. PAHs are uncharged, non-polar and planar. Many are colorless. Many of them are found in coal and in oil deposits, and are also produced by the incomplete combustion of organic matter—for example, in engines and incinerators or when biomass burns in forest fires.

<span class="mw-page-title-main">Sumanene</span> Chemical compound

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 and the periphery consists of alternating benzene rings (3) and cyclopentadiene rings (3). Unlike fullerene, sumanene has benzyl positions which are available for organic reactions.

<span class="mw-page-title-main">Prismane</span> Chemical compound

Prismane or 'Ladenburg benzene' is a polycyclic hydrocarbon with the formula C6H6. It is an isomer of benzene, specifically a valence isomer. Prismane is far less stable than benzene. The carbon (and hydrogen) atoms of the prismane molecule are arranged in the shape of a six-atom triangular prism—this compound is the parent and simplest member of the prismanes class of molecules. Albert Ladenburg proposed this structure for the compound now known as benzene. The compound was not synthesized until 1973.

<span class="mw-page-title-main">Cyclic compound</span> Molecule with a ring of bonded atoms

A cyclic compound is a term for a compound in the field of chemistry in which one or more series of atoms in the compound is connected to form a ring. Rings may vary in size from three to many atoms, and include examples where all the atoms are carbon, none of the atoms are carbon, or where both carbon and non-carbon atoms are present. Depending on the ring size, the bond order of the individual links between ring atoms, and their arrangements within the rings, carbocyclic and heterocyclic compounds may be aromatic or non-aromatic; in the latter case, they may vary from being fully saturated to having varying numbers of multiple bonds between the ring atoms. Because of the tremendous diversity allowed, in combination, by the valences of common atoms and their ability to form rings, the number of possible cyclic structures, even of small size numbers in the many billions.

<span class="mw-page-title-main">Stone–Wales defect</span> Bond transition dependent defect in the structure of molecular materials

A Stone–Wales defect is a crystallographic defect that involves the change of connectivity of two π-bonded carbon atoms, leading to their rotation by 90° with respect to the midpoint of their bond. The reaction commonly involves conversion between a naphthalene-like structure into a fulvalene-like structure, that is, two rings that share an edge vs two separate rings that have vertices bonded to each other.

<span class="mw-page-title-main">Fullerene chemistry</span>

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 insoluble and adding a suitable group can enhance solubility. By adding a polymerizable group, a fullerene polymer can be obtained. Functionalized fullerenes are divided into two classes: exohedral fullerenes with substituents outside the cage and endohedral fullerenes with trapped molecules inside the cage.

In organic and physical organic chemistry, Clar's rule is an empirical rule that relates the chemical stability of a molecule with its aromaticity. It was introduced in 1972 by the Austrian organic chemist Erich Clar in his book The Aromatic Sextet. The rule states that given a polycyclic aromatic hydrocarbon, the resonance structure most important to characterize its properties is that with the largest number of aromatic π-sextets i.e. benzene-like moieties.

<span class="mw-page-title-main">Dicoronylene</span> Chemical compound

Dicoronylene is the trivial name for a very large polycyclic aromatic hydrocarbon. Its formal name is benzo[10,11]phenanthro[2',3',4',5',6':4,5,6,7]chryseno[1,2,3-bc]coronene or benzo[1,2,3-bc:4,5,6-b'c']dicoronene. It has 15 rings and is a brick-red solid. Its formula is C
48
H
20
. Dicoronylene sublimes under high vacuum, 0.001 torr, between 250 °C and 300 °C.

<span class="mw-page-title-main">Kekulene</span> Chemical compound

Kekulene is a polycyclic aromatic hydrocarbon which consists of 12 fused benzene rings arranged in a circle. It is therefore classified as a [12]-circulene with the chemical formula C48H24. It was first synthesized in 1978, and was named in honor of August Kekulé, the discoverer of the structure of the benzene molecule.

<span class="mw-page-title-main">Hexamethylbenzene</span> Chemical compound

Hexamethylbenzene, also known as mellitene, is a hydrocarbon with the molecular formula C12H18 and the condensed structural formula C6(CH3)6. It is an aromatic compound and a derivative of benzene, where benzene's six hydrogen atoms have each been replaced by a methyl group. In 1929, Kathleen Lonsdale reported the crystal structure of hexamethylbenzene, demonstrating that the central ring is hexagonal and flat and thereby ending an ongoing debate about the physical parameters of the benzene system. This was a historically significant result, both for the field of X-ray crystallography and for understanding aromaticity.

<span class="mw-page-title-main">Carbon nanothread</span>

A carbon nanothread is a sp3-bonded, one-dimensional carbon crystalline nanomaterial. The tetrahedral sp3-bonding of its carbon is similar to that of diamond. Nanothreads are only a few atoms across, more than 20,000 times thinner than a human hair. They consist of a stiff, strong carbon core surrounded by hydrogen atoms. Carbon nanotubes, although also one-dimensional nanomaterials, in contrast have sp2-carbon bonding as is found in graphite. The smallest carbon nanothread has a diameter of only 0.2 nanometers, much smaller than the diameter of a single-wall carbon nanotube.

<span class="mw-page-title-main">Thermal rearrangement of aromatic hydrocarbons</span>

Thermal rearrangements of aromatic hydrocarbons are considered to be unimolecular reactions that directly involve the atoms of an aromatic ring structure and require no other reagent than heat. These reactions can be categorized in two major types: one that involves a complete and permanent skeletal reorganization (isomerization), and one in which the atoms are scrambled but no net change in the aromatic ring occurs (automerization). The general reaction schemes of the two types are illustrated in Figure 1.

Hexa-<i>cata</i>-hexabenzocoronene Chemical compound

Hexa-cata-hexabenzocoronene (hexabenzo[a,d,g,j,m,p]coronene) is a polycyclic aromatic hydrocarbon with the molecular formula C48H24. It consists of a central coronene molecule, with an additional benzene ring fused onto each ring around the periphery.

<span class="mw-page-title-main">Superphenalene</span> Chemical compound

Superphenalene is a very large polycyclic aromatic hydrocarbon (PAH) with chemical formula C96H30. It can be formally considered to consist of three fused superbenzenes (hexa-peri-hexabenzocoronene).

<i>N</i>-Heterocyclic carbene boryl anion Isoelectronic structure

An N-heterocyclic carbene boryl anion is an isoelectronic structure of an N-heterocyclic carbene (NHC), where the carbene carbon is replaced with a boron atom that has a -1 charge. NHC boryl anions have a planar geometry, and the boron atom is considered to be sp2-hybridized. They serve as extremely strong bases, as they are very nucleophilic. They also have a very strong trans influence, due to the σ-donation coming from the boron atom. NHC boryl anions have stronger electron-releasing character when compared to normal NHCs. These characteristics make NHC boryl anions key ligands in many applications, such as polycyclic aromatic hydrocarbons, and more commonly low oxidation state main group element bonding.

<span class="mw-page-title-main">Boraacenes</span> Boron containing acene compounds

Boraacenes are polycyclic aromatic hydrocarbons containing at least one boron atom. Structurally, they are related to acenes, linearly fused benzene rings. However, the boron atom is electron deficient and may act as a Lewis Acid when compared to carbon. This results in slightly less negative charge within the ring, smaller HOMO-LUMO gaps, as well as differences in redox chemistry when compared to their acene analogues. When incorporated into acenes, Boron maintains the planarity and aromaticity of carbon acenes, while adding an empty p-orbital, which can be utilized for the fine tuning of organic semiconductor band gaps. Due to this empty p orbital, however, it is also highly reactive when exposed to nucleophiles like water or normal atmosphere, as it will readily be attacked by oxygen, which must be addressed to maintain its stability.

References

  1. 1 2 Goddard, Richard; Haenel, Matthias W.; Herndon, William C.; Krueger, Carl; Zander, Maximilian (1995). "Crystallization of Large Planar Polycyclic Aromatic Hydrocarbons: The Molecular and Crystal Structures of Hexabenzo[bc,ef,hi,kl,no,qr]coronene and Benzo[1,2,3-bc:4,5,6-b'c']dicoronene". Journal of the American Chemical Society. 117: 30–41. doi:10.1021/ja00106a004.
  2. Akamatu, Hideo; Kinoshita, Minoru (1959). "On the Magnetic Susceptibility of Hexabenzocoronene and Triphenylene". Bulletin of the Chemical Society of Japan. 32 (7): 773–774. doi: 10.1246/bcsj.32.773 .
  3. Gross, L.; Mohn, F.; Moll, N.; Schuler, B.; Criado, A.; Guitian, E.; Pena, D.; Gourdon, A.; Meyer, G. (2012). "Bond-Order Discrimination by Atomic Force Microscopy". Science. 337 (6100): 1326–9. Bibcode:2012Sci...337.1326G. doi:10.1126/science.1225621. PMID   22984067. S2CID   206542919.
  4. Jonathan P. Hill; Wusong Jin; Atsuko Kosaka; Takanori Fukushima; Hideki Ichihara; Takeshi Shimomura; Kohzo Ito; Tomihiro Hashizume; Noriyuki Ishii; Takuzo Aida (2004). "Self–Assembled Hexa-peri-hexabenzocoronene Graphitic Nanotube". Science . 304 (5676): 1481–1483. Bibcode:2004Sci...304.1481H. doi:10.1126/science.1097789. PMID   15178796. S2CID   39674411.
  5. Sasaki, Tatsuya; Yamada, Yasuhiro; Sato, Satoshi (2018-09-18). "Quantitative Analysis of Zigzag and Armchair Edges on Carbon Materials with and without Pentagons Using Infrared Spectroscopy". Analytical Chemistry. 90 (18): 10724–10731. doi:10.1021/acs.analchem.8b00949. PMID   30079720. S2CID   51920955.

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