hexaphenylbenzene
{{chembox
|Watchedfields = changed
|verifiedrevid = 400368712
|ImageFile = Structural formula of hexaphenylbenzene.svg
|ImageFile2 =Hexaphenylbenzene_xtal.png
|PIN = 23,24,25,26-Tetraphenyl-11,21:22,31-terphenyl
|OtherNames = Hexaphenylbenzene
|Section1={{Chembox Identifiers
|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
|InChIKey = QBHWPVJPWQGYDS-UHFFFAOYAG
|StdInChI_Ref = {{stdinchicite|correct|chemspider}}
|StdInChI = 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
|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
|StdInChIKey = QBHWPVJPWQGYDS-UHFFFAOYSA-N
|CASNo_Ref = {{cascite|correct|??}}
|CASNo =992-04-1
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 35L5JAJ94N
|PubChem =70432
|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
|ChemSpiderID = 63611
|SMILES = c1cc(ccc1)c3c(c(c(c(c3c2ccccc2)c4ccccc4)c5ccccc5)c6ccccc6)c7ccccc7
}}
|Section2={{Chembox Properties
|C=42|H=30
|Appearance = white solid
|MeltingPtC = 454 to 456
}}
}}
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.{{cite journal|title=Hexaarylbenzene: Evolution of Properties and Applications of Multitalented Scaffold|author=Varun Vij, Vandana Bhalla, and Manoj Kumar|journal=Chemical Reviews|year=2016|volume=116|issue=16|pages=9565–9627|doi=10.1021/acs.chemrev.6b00144|pmid=27498592}}
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.{{cite journal| title = Hexaphenylbenzene | journal = Organic Syntheses | author = Louis Fieser | volume= 46 | pages = 44| year = 1966|doi=10.15227/orgsyn.046.0044}}
:Image:HexaphenylbenzeneCheletropic.png
Together with 1,2,3,4-tetraphenylnaphthalene, hexaphenylbenzene forms by the chromium-catalyzed oligomerization of diphenylacetylene.{{cite journal|title=π-Complexes of the Transition Metals. X. Acetylenic π-Complexes of Chromium in Organic Synthesis|author=W. Herwig, W. Metlesics, H. Zeiss|journal=J. Am. Chem. Soc.|year=1959|volume=81|issue=23|pages=6203–6207|doi=10.1021/ja01532a024}} It may also be prepared by the dicobalt octacarbonyl-catalyzed alkyne trimerisation of diphenylacetylene.
Structure
File:Hexaphenylbenzene xtal perspective.png
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°,{{cite journal | doi = 10.1107/S0567740868004176 | title = The crystal structure of a modification of hexaphenylbenzene | year = 1968 | last1 = Bart | first1 = J. C. J. | journal = Acta Crystallographica Section B | volume = 24 | issue = 10 | pages = 1277–1287 | bibcode = 1968AcCrB..24.1277B | url = http://journals.iucr.org/b/issues/1968/10/00/a06258/a06258.pdf }}{{Dead link|date=February 2022 |bot=InternetArchiveBot |fix-attempted=yes }} while in the gas phase, they are perpendicular with some slight oscillations.{{cite journal |title= Restricted Rotation in Hexaarylbenzenes |author= Gust, D. |journal= J. Am. Chem. Soc. |year= 1977 |volume= 99 |issue= 21 |pages= 6980–6982 |doi= 10.1021/ja00463a034}}
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