Hexaphenylbenzene

Hexaphenylbenzene is an aromatic compound composed of a benzene ring substituted with six phenyl rings. It is a colorless solid. The compound is the parent member of a wider class of hexaarylbenzenes, which are mainly of theoretical interest.^[2]

Hexaphenylbenzene

Names
Preferred IUPAC name 23,24,25,26-Tetraphenyl-11,21:22,31-terphenyl
Other names Hexaphenylbenzene
Identifiers
CAS Number	992-04-1 Y
3D model (JSmol)	Interactive image
ChemSpider	63611 Y
ECHA InfoCard	100.012.356
PubChem CID	70432
UNII	35L5JAJ94N Y
CompTox Dashboard (EPA)	DTXSID30243983
InChI InChI=1S/C42H30/c1-7-19-31(20-8-1)37-38(32-21-9-2-10-22-32)40(34-25-13-4-14-26-34)42(36-29-17-6-18-30-36)41(35-27-15-5-16-28-35)39(37)33-23-11-3-12-24-33/h1-30H Y Key: QBHWPVJPWQGYDS-UHFFFAOYSA-N Y InChI=1/C42H30/c1-7-19-31(20-8-1)37-38(32-21-9-2-10-22-32)40(34-25-13-4-14-26-34)42(36-29-17-6-18-30-36)41(35-27-15-5-16-28-35)39(37)33-23-11-3-12-24-33/h1-30H Key: QBHWPVJPWQGYDS-UHFFFAOYAG
SMILES c1cc(ccc1)c3c(c(c(c(c3c2ccccc2)c4ccccc4)c5ccccc5)c6ccccc6)c7ccccc7
Properties
Chemical formula	C42H30
Molar mass	534.702 g·mol−1
Appearance	white solid
Melting point	454 to 456 °C (849 to 853 °F; 727 to 729 K)[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Preparation

It is prepared by heating tetraphenylcyclopentadienone and diphenylacetylene in benzophenone or other high-temperature solvent. The reaction proceeds via a Diels-Alder reaction to give the hexaphenyldienone, which then eliminates carbon monoxide.^[1]

Together with 1,2,3,4-tetraphenylnaphthalene, hexaphenylbenzene forms by the chromium-catalyzed oligomerization of diphenylacetylene.^[3] It may also be prepared by the dicobalt octacarbonyl-catalyzed alkyne trimerisation of diphenylacetylene.^[2]

Structure

Perspective view of the crystal structure of hexaphenylbenzene, showing the rotation of the phenyl rings. Hydrogen atoms have been omitted for clarity.^[4]

The stable conformation of this molecule has the phenyl rings rotated out of the plane of the central benzene ring. The molecule adopts a propeller-like conformation in which the phenyl rings are rotated about 65°,^[4] while in the gas phase, they are perpendicular with some slight oscillations.^[5]

References

1. Louis Fieser (1966). "Hexaphenylbenzene". Organic Syntheses. 46: 44. doi:10.15227/orgsyn.046.0044.
2. Varun Vij, Vandana Bhalla, and Manoj Kumar (2016). "Hexaarylbenzene: Evolution of Properties and Applications of Multitalented Scaffold". Chemical Reviews. 116 (16): 9565–9627. doi:10.1021/acs.chemrev.6b00144. PMID 27498592.{{cite journal}}: CS1 maint: multiple names: authors list (link)
3. W. Herwig, W. Metlesics, H. Zeiss (1959). "π-Complexes of the Transition Metals. X. Acetylenic π-Complexes of Chromium in Organic Synthesis". J. Am. Chem. Soc. 81 (23): 6203–6207. doi:10.1021/ja01532a024.{{cite journal}}: CS1 maint: multiple names: authors list (link)
4. Bart, J. C. J. (1968). "The crystal structure of a modification of hexaphenylbenzene" (PDF). Acta Crystallographica Section B. 24 (10): 1277–1287. Bibcode:1968AcCrB..24.1277B. doi:10.1107/S0567740868004176.^{[permanent dead link‍]}
5. Gust, D. (1977). "Restricted Rotation in Hexaarylbenzenes". J. Am. Chem. Soc. 99 (21): 6980–6982. doi:10.1021/ja00463a034.