In
organic chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, ...
, pentadienyl refers to the organic
radical, anion, or cation with the formula , where ''z'' = 0, −1, +1, respectively.
Organometallic chemistry
In
organometallic chemistry, the pentadienyl anion is a ligand, the acyclic analogue of the more-common
cyclopentadienyl anion
In chemistry, the cyclopentadienyl anion or cyclopentadienide is an aromatic species with a formula of and abbreviated as Cp−. It is formed from the deprotonation of the molecule cyclopentadiene.
Properties
The cyclopentadienyl anion i ...
. The pentadienyl anion is generated by
deprotonation
Deprotonation (or dehydronation) is the removal (transfer) of a proton (or hydron, or hydrogen cation), (H+) from a Brønsted–Lowry acid in an acid–base reaction.Henry Jakubowski, Biochemistry Online Chapter 2A3, https://employees.csbsju. ...
of
pentadiene In chemistry, pentadiene is any hydrocarbon with an open chain of five carbons, connected by two single bonds and two double bonds. All those compounds have the same molecular formula . Specifically, it may be
* 1,2-pentadiene, or ethyl allene, =C ...
. A number of complexes are known, including bis(pentadienyl) iron, , the "open" analog of
ferrocene. Only few pentadienyl complexes feature simple ligands. More common is the dimethyl derivative 2,4-. Additionally, many pentadienyl ligands are cyclic, being derived from the addition of hydride to ''η''
6-arene complexes or hydride abstraction from
cyclohexadiene Cyclohexadiene may refer to:
* 1,3-Cyclohexadiene,
* 1,4-Cyclohexadiene,
See also
* Benzene or its theoretical isomer ''1,3,5-Cyclohexatriene''
* Cyclohexene
Cyclohexene is a hydrocarbon with the formula C6H10. This cycloalkene is a colorle ...
complexes.
The first pentadienyl complex to be reported was derived from protonolysis of a complex of pentadienol:
:
Fe(C5H7OH)(CO)3 + H+ -> e(C5H7)(CO)3 + H2O
Treatment of this cation with
sodium borohydride
Sodium borohydride, also known as sodium tetrahydridoborate and sodium tetrahydroborate, is an inorganic compound with the formula Na BH4. This white solid, usually encountered as an aqueous basic solution, is a reducing agent that finds applica ...
gives the pentadiene complex:
:
e(C5H7)(CO)3 + H- -> Fe(C5H8)(CO)3
Organic chemistry
In organic chemistry, the pentadienyl radical, , is of some significance as an especially stabilized radical. The radical is delocalized over five carbon centers. Consequently the C−H bond in the diene (C''H''
2(CH=CH
2)) is especially weak. Fats derivatives containing this "doubly
allylic" group are collectively called
drying oil
A drying oil is an oil that hardens to a tough, solid film after a period of exposure to air, at room temperature. The oil hardens through a chemical reaction in which the components crosslink (and hence, polymerize) by the action of oxygen (no ...
s. They tend to polymerize in a useful way upon exposure to air.
:
Biochemistry
Cyclooxygenase
Cyclooxygenase (COX), officially known as prostaglandin-endoperoxide synthase (PTGS), is an enzyme (specifically, a family of isozymes, ) that is responsible for formation of prostanoids, including thromboxane and prostaglandins such as pr ...
s ("COX") are
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...
s that generate
prostanoid
Prostanoids are active lipid mediators that regulate inflammatory response. Prostanoids are a subclass of eicosanoids consisting of the prostaglandins (mediators of inflammatory and anaphylactic reactions), the thromboxanes (mediators of vasocons ...
s, including
thromboxane
Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2. The distinguishing feature of thromboxanes is a 6-membered ether-containing ring.
Thromboxane is named for i ...
and
prostaglandins such as
prostacyclin
Prostacyclin (also called prostaglandin I2 or PGI2) is a prostaglandin member of the eicosanoid family of lipid molecules. It inhibits platelet activation and is also an effective vasodilator.
When used as a drug, it is also known as epoprosten ...
.
Aspirin
Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat inc ...
and
ibuprofen exert their effects through inhibition of COX.
References
{{Reflist
Anions
Free radicals