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Pyrene

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For other uses, see Pyrene (disambiguation).
Pyrene
Names
IUPAC name
pyrene
Other names
benzo[def]phenanthrene
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.004.481 Edit this at Wikidata
KEGG
RTECS number
  • UR2450000
  • InChI=1S/C16H10/c1-3-11-7-9-13-5-2-6-14-10-8-12(4-1)15(11)16(13)14/h1-10H checkY
    Key: BBEAQIROQSPTKN-UHFFFAOYSA-N checkY
  • InChI=1/C16H10/c1-3-11-7-9-13-5-2-6-14-10-8-12(4-1)15(11)16(13)14/h1-10H
    Key: BBEAQIROQSPTKN-UHFFFAOYAB
  • c1cc2ccc3cccc4c3c2c(c1)cc4
Properties
Template:Carbon16Template:Hydrogen10
Molar mass 202.25 g/mol
Appearance colorless solid

(yellow impurities are often found at trace levels in many samples).

Density 1.271 g/ml
Melting point 145-148 °C (418-421 K)
Boiling point 404 °C (677 K)
0.135 mg/l
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 irritant
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability (yellow): no hazard codeSpecial hazards (white): no code
2
1
Flash point non-flammable
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)
Diagram showing the numbering and ring fusion locations of pyrene according to IUPAC nomenclature of organic chemistry.

Pyrene is a polycyclic aromatic hydrocarbon (PAH) consisting of four fused benzene rings, resulting in a flat aromatic system. The chemical formula is C
16H
10. This colorless solid is the smallest peri-fused PAH (one where the rings are fused through more than one face). Pyrene forms during incomplete combustion of organic compounds.

Occurrence and reactivity

Pyrene was first isolated from coal tar, where it occurs up to 2% by weight. As a peri-fused PAH, pyrene is much more resonance-stabilized than its five-member-ring containing isomer fluoranthene. Therefore, it is produced in a wide range of combustion conditions. For example, automobiles produce about 1 μg/km.[1]

Oxidation with chromate affords perinaphthenone and then naphthalene-1,4,5,8-tetracarboxylic acid. It undergoes a series of hydrogenation reactions, and it is susceptible to halogenation, Diels-Alder additions, and nitration, all with varying degrees of selectivity.[1]

Applications

Pyrene and its derivatives are used commercially to make dyes and dye precursors, for example pyranine and naphthalene-1,4,5,8-tetracarboxylic acid. Its derivatives are also valuable molecular probes via fluorescence spectroscopy, having a high quantum yield and lifetime (0.65 and 410 nanoseconds, respectively, in ethanol at 293 K). Its fluorescence emission spectrum is very sensitive to solvent polarity, so pyrene has been used as a probe to determine solvent environments. This is due to its excited state having a different, non-planar structure than the ground state. Certain emission bands are unaffected, but others vary in intensity due to the strength of interaction with a solvent.

Safety

Although it is not as problematic as benzopyrene, animal studies have shown pyrene is toxic to the kidneys and the liver.

See also

References

  1. ^ a b Selim Senkan and Marco Castaldi "Combustion" in Ullmann's Encyclopedia of Industrial Chemistry, 2003 Wiley-VCH, Weinheim. Article Online Posting Date: March 15, 2003.
  • Birks, J. B. (1969). Photophysics of Aromatic Molecules. London: Wiley.
  • Valeur, B. (2002). Molecular Fluorescence: Principles and Applications. New York: Wiley-VCH.
  • Birks, J.B. (1975). Eximers. london: Reports on Progress in Physics.
  • Fetzer, J. C. (2000). The Chemistry and Analysis of the Large Polycyclic Aromatic Hydrocarbons. New York: Wiley.
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