Cyclooctyne is the

cycloalkyne In organic chemistry, a cycloalkyne is the cyclic analog of an alkyne (). A cycloalkyne consists of a closed ring of carbon atoms containing one or more triple bonds. Cycloalkynes have a general formula Because of the linear nature of the alkyn ...

with a formula . Its molecule has a ring of 8

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with o ...

atoms, connected by seven

single bond In chemistry, a single bond is a chemical bond between two atoms involving two valence electrons. That is, the atoms share one pair of electrons where the bond forms. Therefore, a single bond is a type of covalent bond. When shared, each of th ...

s and one

triple bond A triple bond in chemistry is a chemical bond between two atoms involving six bonding electrons instead of the usual two in a covalent single bond. Triple bonds are stronger than the equivalent single bonds or double bonds, with a bond order o ...

. Cyclooctene is the smallest cycloalkyne that is stable enough to be isolated, although the chemical is still highly reactive. The alkyne region of the structure attempts to adopt a

linear molecular geometry In chemistry, the linear molecular geometry describes the geometry around a central atom bonded to two other atoms (or ''ligands'') placed at a bond angle of 180°. Linear organic molecules, such as acetylene (), are often described by invoking ...

, but the nature of the ring creates substantial

ring strain In organic chemistry, ring strain is a type of instability that exists when bonds in a molecule form angles that are abnormal. Strain is most commonly discussed for small rings such as cyclopropanes and cyclobutanes, whose internal angles are su ...

. As a result, cyclooctyne and other compounds containing this ring structure readily react in ways that reduce the

by converting the alkyne to a functional group that does not require linear geometry. An important application of this reactivity is in

click chemistry In chemical synthesis, click chemistry is a class of biocompatible small molecule reactions commonly used in bioconjugation, allowing the joining of substrates of choice with specific biomolecules. Click chemistry is not a single specific reaction ...

, where cyclooctynes undergo

cycloaddition In organic chemistry, a cycloaddition is a chemical reaction in which "two or more Unsaturated hydrocarbon, unsaturated molecules (or parts of the same molecule) combine with the formation of a cyclic adduct in which there is a net reduction of th ...

reactions with

azide In chemistry, azide is a linear, polyatomic anion with the formula and structure . It is the conjugate base of hydrazoic acid . Organic azides are organic compounds with the formula , containing the azide functional group. The dominant applic ...

s or

nitrone In organic chemistry, a nitrone is a functional group consisting of an ''N''-oxide of an imine. The general structure is , where R’ is not a hydrogen. A nitrone is a 1,3-dipole, and is used in 1,3-dipolar cycloadditions. Other reactions of ...

s, forming

triazole A triazole is a heterocyclic compound featuring a five-membered ring of two carbon atoms and three nitrogen atoms with molecular formula C2H3N3. Triazoles exhibit substantial isomerism, depending on the positioning of the nitrogen atoms within t ...

s or

isoxazoline Isoxazolines are a class of five-membered heterocyclic chemical compounds, containing one atom each of oxygen and nitrogen which are located adjacent to one another. The ring was named in-line with the Hantzsch–Widman nomenclature. They are stru ...

s, respectively.

References

External links

*{{Commons category-inline Alkynes Eight-membered rings