Phenanthrene

Phenanthrene
Ball-and-stick model of the phenanthrene molecule
Names
Preferred IUPAC name
Phenanthrene
Other names
Tricyclo[8.4.0.02,7]tetradeca-1,3,5,7,9,11,13-heptaene
Identifiers
3D model (JSmol)
1905428
ChEBI
ChemSpider
ECHA InfoCard 100.001.437
EC Number 266-028-2
28699
KEGG
MeSH C031181
UNII
Properties
C14H10
Molar mass 178.23 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
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
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).
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Infobox references

Phenanthrene is a polycyclic aromatic hydrocarbon composed of three fused benzene rings. The name 'phenanthrene' is a composite of phenyl and anthracene. In its pure form, it is found in cigarette smoke and is a known irritant, photosensitizing skin to light. Phenanthrene appears as a white powder having blue fluorescence.

The compound with a phenanthrene skeleton and nitrogens at the 4 and 5 positions is known as phenanthroline.

Chemistry

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.

The Bardhan–Sengupta phenanthrene synthesis is a classic way to make phenanthrenes.[3]

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.

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

Canonical forms

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.

Natural occurrences

Ravatite is a natural mineral consisting of phenanthrene.[9] It is found in small amounts among a few coal burning sites. Ravatite represents a small group of organic minerals.

In February 2014, NASA announced a greatly upgraded database for tracking polycyclic aromatic hydrocarbons (PAHs), including phenanthrene, in the universe. According to scientists, more than 20% of the carbon in the universe may be associated with PAHs, possible starting materials for the formation of life. PAHs seem to have begun forming a couple of billion years after the Big Bang, are widespread throughout the universe, and are associated with new stars and exoplanets.[10]

In plants

See also

References

  1. 1 2 3 4 5 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. Pg.443
  3. ↑ "Bardhan Sengupta Synthesis". Comprehensive Organic Name Reactions and Reagents. 49. 2010. pp. 215–219. doi:10.1002/9780470638859.conrr049.
  4. ↑ Organic Syntheses, Coll. Vol. 4, p.757 (1963); Vol. 34, p.76 (1954) Link
  5. ↑ Organic Syntheses, Coll. Vol. 4, p.313 (1963); Vol. 34, p.31 (1954) Link.
  6. ↑ Organic Syntheses, Coll. Vol. 3, p.134 (1955); Vol. 28, p.19 (1948) Link.
  7. ↑ Organic Syntheses, Coll. Vol. 2, p.482 (1943); Vol. 16, p.63 (1936) Link.
  8. ↑ Organic Syntheses, Coll. Vol. 5, p.489 (1973); Vol. 41, p.41 (1961) Link.
  9. ↑ Ravatite Mineral Data
  10. ↑ Hoover, Rachel (February 21, 2014). "Need to Track Organic Nano-Particles Across the Universe? NASA's Got an App for That". NASA. Retrieved February 22, 2014.
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