Triphenylene

In chemistry, the organic compound triphenylene is a flat polycyclic aromatic hydrocarbon (PAH) consisting of four fused benzene rings. Triphenylene can be isolated from coal tar. It is also made synthetically by synthesis and trimerization of benzyne.[1] One molecule of triphenylene has delocalized 18-π-electron systems based on a planar structure. It has the molecular formula C
₁₈H
₁₂.

Triphenylene

Names
Preferred IUPAC name Triphenylene
Other names Benzo[l]phenanthrene 9,10-Benzophenanthrene 1,2,3,4-Dibenzonaphthalene Isochrysene
Identifiers
CAS Number	217-59-4^Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:33080^N
ChEMBL	ChEMBL1797416^N
ChemSpider	8816^N
ECHA InfoCard	100.005.385
EC Number	205-922-9
KEGG	C19541^Y
MeSH	C009590
PubChem CID	9170
UNII	18WX3373I0^Y
CompTox Dashboard (EPA)	DTXSID9059757
InChI InChI=1S/C18H12/c1-2-8-14-13(7-1)15-9-3-4-11-17(15)18-12-6-5-10-16(14)18/h1-12H^N Key: SLGBZMMZGDRARJ-UHFFFAOYSA-N^N InChI=1/C18H12/c1-2-8-14-13(7-1)15-9-3-4-11-17(15)18-12-6-5-10-16(14)18/h1-12H
SMILES c1(cccc3)c3c(cccc4)c4c2c1cccc2
Properties
Chemical formula	C18H12
Molar mass	228.294 g·mol^−1
Melting point	198 °C; 388 °F; 471 K
Boiling point	438 °C; 820 °F; 711 K
Magnetic susceptibility (χ)	-156.6·10^−6 cm^3/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is ^YN ?)
Infobox references

Triphenylene is a fully benzenoid PAH, meaning its structure is composed only of full benzene rings interconnected by carbon–carbon single bonds. The three benzene rings can be drawn as the three outer rings, with the central ring formed by one face of each and the three carbon–carbon single bonds.

Being a fully benzenoid PAH means that triphenylene is much more resonance stable than its isomers chrysene, benz[a]anthracene, benzo[c]phenanthrene, and tetracene. This makes it much more difficult to hydrogenate to the saturated hydrocarbon.

In light of these characteristics, triphenylene may have uses in optics and electronics. Triphenylene is a disc-shaped molecule with a planar structure and three-fold rotation axes. Consisting of colorless needle-like crystals, it emits bluish purple fluorescence by UV irradiation.

In terms of its crystallographic point group, the symmetry of triphenylene is classified as D_3h in Schoenflies notation. Because of these characteristics, six-fold (in the 2, 3, 6, 7, 10, and 11 positions) alkyloxy- or alkylthiol-substituted triphenylenes can be used as a discotic mesogen in liquid crystalline materials.

References

1. Heaney, H.; Millar, I. T. (1960). "Triphenylene". Organic Syntheses. 40: 105.; Collective Volume, 5, 1973, p. 1120

External links

• Polycyclic Aromatic Hydrocarbon Structure Index