Triphenylene

Triphenylene
IUPAC name triphenylene
Other names benzo[l]phenanthrene, 9,10-benzophenanthrene, 1,2,3,4-dibenznaphthalene, isochrysene
Identifiers
CAS number	217-59-4 Y
KEGG	C19541 Y
Jmol-3D images	Image 1
SMILES C1(C=CC=C3)=C3C(C=CC=C4)=C4C2=C1C=CC=C2
InChI 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
Properties
Molecular formula	C18H12
Molar mass	228.29 g mol−1
Melting point	198 °C, 471 K, 388 °F
Boiling point	438 °C, 711 K, 820 °F
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

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, but it is also made synthetically using benzyn chemistry. One molecule of triphenylene has delocalized 18-π-electron systems based on a planar structure. It has the molecular formula C₁₈H₁₂.

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 bezenoid 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.^{[citation needed]}

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

• Polycyclic Aromatic Hydrocarbon Structure Index
• Synthesis: Organic Syntheses, Coll. Vol. 5, p.1120 (1973); Vol. 40, p.105 (1960). [1]