Phenanthrene is a polycyclic aromatic hydrocarbon (PAH) with formula C14H10, consisting of three fused benzene rings. It is a colorless, crystal-like solid, but can also appear yellow. Phenanthrene is used to make dyes, plastics, pesticides, explosives, and drugs. It has also been used to make bile acids, cholesterol and steroids.[3]

Phenanthrene
Ball-and-stick model of the phenanthrene molecule
Phenanthrene
Names
Preferred IUPAC name
Phenanthrene
Identifiers
3D model (JSmol)
1905428
ChEBI
ChemSpider
ECHA InfoCard 100.001.437 Edit this at Wikidata
EC Number
  • 266-028-2
28699
KEGG
MeSH C031181
UNII
  • InChI=1S/C14H10/c1-3-7-13-11(5-1)9-10-12-6-2-4-8-14(12)13/h1-10H ☒N
    Key: YNPNZTXNASCQKK-UHFFFAOYSA-N ☒N
  • InChI=1/C14H10/c1-3-7-13-11(5-1)9-10-12-6-2-4-8-14(12)13/h1-10H
    Key: YNPNZTXNASCQKK-UHFFFAOYAC
  • C1=CC=C2C(=C1)C=CC3=CC=CC=C32
Properties
C14H10
Molar mass 178.234 g·mol−1
Appearance Colorless solid
Density 1.18 g/cm3[1]
Melting point 101 °C (214 °F; 374 K)[1]
Boiling point 332 °C (630 °F; 605 K)[1]
1.6 mg/L[1]
−127.9·10−6 cm3/mol
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
1
0
Flash point 171 °C (340 °F; 444 K)[1]
Structure
C2v[2]
0 D
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Phenanthrene occurs naturally and also is a man-made chemical. Commonly, humans are exposed to phenanthrene through inhalation of cigarette smoke, but there are many routes of exposure. Animal studies have shown that phenanthrene is a potential carcinogen.[3] However, according to IARC, it is not identified as a probable, possible or confirmed human carcinogen.[4]

Phenanthrene's three fused rings are angled as in the phenacenes, rather than straight as in the acenes. The compound with a phenanthrene skeleton and nitrogens at the 4 and 5 positions is known as phenanthroline.

Physical Properties

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Phenanthrene is nearly insoluble in water but is soluble in most low-polarity organic solvents such as toluene, carbon tetrachloride, ether, chloroform, acetic acid and benzene.

Phenanthrene is fluorescent under ultraviolet light, exhibiting a large Stoke shift.[5] It can be used in scintillators.

Chemistry

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Reactions of phenanthrene typically occur at the 9 and 10 positions, including:

Canonical forms

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Phenanthrene is more stable than its linear isomer anthracene. A classic and well established explanation is based on Clar's rule. A novel theory invokes so-called stabilizing hydrogen–hydrogen bonds between the C4 and C5 hydrogen atoms.[citation needed]

Synthesis

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The Bardhan–Sengupta phenanthrene synthesis is a classic way to make phenanthrenes.[11]

 

This process involves electrophilic aromatic substitution using a tethered cyclohexanol group using diphosphorus pentoxide, which closes the central ring onto an existing aromatic ring. Dehydrogenation using selenium converts the other rings into aromatic ones as well. The aromatization of six-membered rings by selenium is not clearly understood, but it does produce H2Se.

Phenanthrene can also be obtained photochemically from certain diarylethenes (Mallory reaction):

 

Other synthesis routes include the Haworth reaction and the Wagner-Meerwein-type ring-expansion, as depicted below:

 

Natural occurrences

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Ravatite is a natural mineral consisting of phenanthrene.[12] It is found in small amounts among a few coal burning sites. Ravatite represents a small group of organic minerals.

In plants

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Phenanthrene derivatives occur in plants as phenanthrenoids. They have been reported from flowering plants, mainly in the family Orchidaceae, and a few in the families Dioscoreaceae, Combretaceae and Betulaceae, as well as in the lower plant class Marchantiophyta (liverworts).[13]

See also

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References

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  1. ^ a b c d e Record of CAS RN 85-01-8 in the GESTIS Substance Database of the Institute for Occupational Safety and Health
  2. ^ Peter Atkins, J. D. P., Atkins' Physical Chemistry. Oxford: 2010. P. 443.
  3. ^ a b "Phenanthrene Fact Sheet" (PDF). archive.epa.gov. U.S. Environmental Protection Agency. Retrieved 19 July 2019.
  4. ^ "Phenanthrene". Sigma-Alrdich.
  5. ^ "Spectrum [Phenanthrene] | AAT Bioquest". www.aatbio.com. Retrieved 2024-07-30.
  6. ^ Organic Syntheses, Coll. Vol. 4, p. 757 (1963); Vol. 34, p. 76 (1954).
  7. ^ Organic Syntheses, Coll. Vol. 4, p. 313 (1963); Vol. 34, p. 31 (1954).
  8. ^ Organic Syntheses, Coll. Vol. 3, p. 134 (1955); Vol. 28, p. 19 (1948).
  9. ^ Organic Syntheses, Coll. Vol. 2, p. 482 (1943); Vol. 16, p. 63 (1936).
  10. ^ Organic Syntheses, Coll. Vol. 5, p. 489 (1973); Vol. 41, p. 41 (1961).
  11. ^ "Bardhan Sengupta Synthesis". Comprehensive Organic Name Reactions and Reagents. Vol. 49. 2010. pp. 215–219. doi:10.1002/9780470638859.conrr049. ISBN 9780470638859.
  12. ^ Ravatite Mineral Data
  13. ^ Kovács, Adriána; Vasas, Andrea; Hohmann, Judit (2008). "Natural phenanthrenes and their biological activity". Phytochemistry. 69 (5): 1084–1110. Bibcode:2008PChem..69.1084K. doi:10.1016/j.phytochem.2007.12.005. PMID 18243254.
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