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Pyrene is a polycyclic aromatic hydrocarbon (PAH) consisting of four fused benzene rings, resulting in a flat aromatic system. The chemical formula is C16H10. This yellow-green 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 properties
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.
= Reactions
=
Oxidation with chromate affords perinaphthenone and then naphthalene-1,4,5,8-tetracarboxylic acid. Pyrene undergoes a series of hydrogenation reactions and is susceptible to halogenation, Diels-Alder additions, and nitration, all with varying degrees of selectivity. Bromination occurs at one of the 3-positions.
Reduction with sodium affords the radical anion. From this anion, a variety of pi-arene complexes can be prepared.
= Photophysics
=
Pyrene and its derivatives are used commercially to make dyes and dye precursors, for example pyranine and naphthalene-1,4,5,8-tetracarboxylic acid. It has strong absorbance in UV-Vis in three sharp bands at 330 nm in DCM. The emission is close to the absorption, but moving at 375 nm. The morphology of the signals change with the solvent. 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). Pyrene was the first molecule for which excimer behavior was discovered. Such excimer appears around 450 nm. Theodor Förster reported this in 1954.
Applications
Pyrene's 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.
Pyrenes are strong electron donor materials and can be combined with several materials in order to make electron donor-acceptor systems which can be used in energy conversion and light harvesting applications.
Safety and environmental factors
Although it is not as problematic as benzopyrene, animal studies have shown pyrene is toxic to the kidneys and liver. It is now known that pyrene affects several living functions in fish and algae.
Its biodegradation has been heavily examined. The process commences with dihydroxylation at each of two kinds of CH=CH linkages. Experiments in pigs show that urinary 1-hydroxypyrene is a metabolite of pyrene, when given orally.
See also
List of interstellar and circumstellar molecules
Perhydropyrene
References
Cited sources
Haynes, William M., ed. (2016). CRC Handbook of Chemistry and Physics (97th ed.). CRC Press. ISBN 9781498754293.
Further reading
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). "Excimers". Reports on Progress in Physics. 38 (8): 903–974. Bibcode:1975RPPh...38..903B. doi:10.1088/0034-4885/38/8/001. ISSN 0034-4885. S2CID 240065177.
Fetzer, J. C. (2000). The Chemistry and Analysis of the Large Polycyclic Aromatic Hydrocarbons. New York: Wiley.
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Pyrene - Wikipedia
Pyrene is a polycyclic aromatic hydrocarbon (PAH) consisting of four fused benzene rings, resulting in a flat aromatic system. The chemical formula is C 16 H 10 . This yellow-green solid is the smallest peri-fused PAH (one where the rings are fused through more than one face).
Pyrene | C16H10 | CID 31423 - PubChem
Jan 22, 2016 · Pyrene is an ortho- and peri-fused polycyclic arene consisting of four fused benzene rings, resulting in a flat aromatic system. It has a role as a fluorescent probe and a persistent organic pollutant. Pyrene is a parent class of polycyclic aromatic hydrocarbons containing four fused rings. (IUPAC 1998) View More... 118728. pyrene.
PYRENE | Occupational Safety and Health Administration
Jan 29, 2021 · Pyrene is a polynuclear aromatic hydrocarbon that OSHA has identified as one of a number of typical components of the benzene-soluble fraction of coal tar pitch volatiles. Other components include anthracene, benzo[a]pyrene, phenanthrene, acridine, and chrysene.
Pyrene Fact Sheet | US EPA ARCHIVE DOCUMENT
pyrene is included in this fact sheet when available. What is pyrene used for? Most of the PAHs are used to conduct research. Like most PAHs, pyrene is used to make dyes, plastics and pesticides. It has also been used to make another PAH called benzo(a)pyrene. How can pyrene enter and leave your body? One of the most common ways pyrene can
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Pyrena - Wikipedia
A pyrena or pyrene (commonly called a "pit" or "stone") is the fruitstone within a drupe or drupelet produced by the ossification of the endocarp or lining of the fruit. [1] It consists of a hard endocarp tissue surrounding one or more seeds (also called the "kernel").
Pyrene (daughter of Bebryx) - Wikipedia
In Greek and Roman mythology, Pyrene (Ancient Greek: Πυρήνη, romanized: Purḗnē) is an Iberian princess whose tragic fate gave the Pyrenees their name. Pyrene was a lover or victim of Heracles, the Tirynthian hero who visited her country during one of his Twelve Labours.
Pyrene 98 129-00-0 - MilliporeSigma
Pyrene is an aromatic discotic crystal which is widely used as a fluorescent dye or as an ambipolar charge carrier in Organic Light Emitting Diodes. [1] Pyrene and its derivatives are electron-donor materials and can be used to prepare electron donor-acceptor systems for energy conversion and light harvesting applications like OLED and solar cells.
Benzo[ a ]pyrene—Environmental Occurrence, Human Exposure, …
Benzo[a]pyrene (B[a]P) is the main representative of polycyclic aromatic hydrocarbons (PAHs), and has been repeatedly found in the air, surface water, soil, and sediments. It is present in cigarette smoke as well as in food products, especially when smoked and grilled.
Pyrene Definition & Meaning - Merriam-Webster
: a pale yellow crystalline hydrocarbon C16H10 that fluoresces blue in solution, that is obtained from coal-tar distillation, from petroleum cracking, and from stupp and is also made …
