Polyene

<h2 id="optical-properties">Optical properties</h2>
<p>Some polyenes are brightly colored, an otherwise rare property for a hydrocarbon.  Normally alkenes absorb in the <a href="/facts/Ultraviolet/kncBUqn5">ultraviolet</a> region of a <a href="/facts/Ultraviolet-visible_spectroscopy/MUPLLczo">spectrum</a>, but the absorption energy state of polyenes with numerous conjugated double bonds can be lowered such that they enter the visible region of the spectrum, resulting in compounds which are coloured (because they contain a <a href="/facts/Chromophore/9RykVkek">chromophore</a>).  Thus many natural <a href="/facts/Dye/a1NSlcsG">dyes</a> contain linear polyenes.
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<h2 id="chemical-and-electrical-properties">Chemical and electrical properties</h2>
<p>Polyenes tend to be more reactive than simpler alkenes. For example, polyene-containing <a href="/facts/Triglyceride/BQmjv4A0">triglycerides</a> are reactive towards atmospheric oxygen. <a href="/facts/Polyacetylene/0Adw1YQY">Polyacetylene</a>, which partially oxidized or reduced, exhibits high electrical conductivity. Most <a href="/facts/Conductive_polymer/JbwFx9IL">conductive polymers</a> are polyenes, and many have <a href="/facts/Conjugated_system/Ddx9qzox">conjugated</a> structures. Poly(aza)acetylenes are readily prepared from <a href="/facts/Pyridine/X817hCch">pyridine</a> precursors without the necessity of a controlled atmosphere, simply by <a href="/facts/Ultraviolet/kncBUqn5">ultraviolet</a> irradiation of a mixture of pyridine and poly(4-vinyl) pyridine. Recent research at the <a href="/facts/Weizmann_Institute_of_Science/NXBYn55W">Weizmann Institute</a> and <a href="/facts/Aix-Marseille_University/gNA7xjxn">Aix-Marseille University</a> showed a clear transition between ionic and electronic conductivity with increasing UV dose over 30 hours.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a>
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<h2 id="occurrence">Occurrence</h2>
<p>A few <a href="/facts/Fatty_acid/JGg3erIu">fatty acids</a> are polyenes.  Another class of important polyenes are <a href="/facts/Polyene_antimycotic/3YQ5tTDm">polyene antimycotics</a>,<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a>
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<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Zotchev, Sergey B. (2003). "Polyene macrolide antibiotics and their applications in human therapy". Current Medicinal Chemistry. 10 (3): 211–223. doi:10.2174/0929867033368448. PMID 12570708. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Vaganova, Evgenia; Eliaz, Dror; Shimanovich, Ulyana; Leitus, Gregory; Aqad, Emad; Lokshin, Vladimir; Khodorkovsky, Vladimir (January 2021). "Light-Induced Reactions within Poly(4-vinyl pyridine)/Pyridine Gels: The 1,6-Polyazaacetylene Oligomers Formation". Molecules. 26 (22): 6925. doi:10.3390/molecules26226925. ISSN 1420-3049. PMC 8621047. PMID 34834017. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8621047" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8621047</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>NCBI Bookshelf (1996). "Polyene Antifungal Drugs". The University of Texas Medical Branch at Galveston. Retrieved 29 January 2010. <a href="https://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=mmed&part=A4050" target="_blank">https://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=mmed&part=A4050</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
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Polyene open-in-new

Polyene