Polyene

Optical properties

Some polyenes are brightly colored, an otherwise rare property for a hydrocarbon. Normally alkenes absorb in the ultraviolet region of a spectrum, 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 chromophore). Thus many natural dyes contain linear polyenes.

Chemical and electrical properties

Polyenes tend to be more reactive than simpler alkenes. For example, polyene-containing triglycerides degrade in atmospheric oxygen via the process of rancidification and drying. Polyacetylene exhibits high electrical conductivity in air.. Most conductive polymers are polyenes, and many have conjugated structures.

Occurrence

A few fatty acids are polyenes. Another class of important polyenes are polyene antimycotics.

File:Amphotericin B new.svg|Amphotericin B is an example of a polyene antifungal (antimycotic) agent. File:Leukotriene A4.svg|Leukotriene A4 is a regulator of the immune response. File:Trans-Polyacetylene.svg|Polyacetylenes are a synthetic polymer of theoretical interest because they exhibit metallic properties upon oxidation.

See also

• Polyyne

References

References

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8. Lam, Jacky W. Y.; Tang, Ben Zhong. "Functional Polyacetylenes", Accounts of Chemical Research, 2005, volume 38, pp. 745–754. {{doi. 10.1021/ar040012f.