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Revision as of 04:19, 6 January 2012 editCydebot (talk | contribs)6,812,251 editsm Robot - Speedily moving category Dimers to Category:Dimers (chemistry) per CFDS.← Previous edit Revision as of 08:42, 22 January 2012 edit undo86.1.171.218 (talk) →Organic chemistryNext edit →
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] forms a dimer in the gas phase, the monomer units are held together by ]s. Under special conditions, most OH-containing molecules form dimers, e.g. the ]. ] forms a dimer in the gas phase, the monomer units are held together by ]s. Under special conditions, most OH-containing molecules form dimers, e.g. the ].


] is an unsymmetrical dimer of two ] molecules that have reacted in a ] to give the product. Upon heating, it "cracks" (undergoes a retro-Diels-Alder reaction) to give identical monomers: ] is an asymmetrical dimer of two ] molecules that have reacted in a ] to give the product. Upon heating, it "cracks" (undergoes a retro-Diels-Alder reaction) to give identical monomers:
:C<sub>10</sub>H<sub>12</sub> → 2 C<sub>5</sub>H<sub>6</sub> :C<sub>10</sub>H<sub>12</sub> → 2 C<sub>5</sub>H<sub>6</sub>


Revision as of 08:42, 22 January 2012

For other uses, see Dimer (disambiguation).
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Dimers of carboxylic acids are often found in vapour phase.

A dimer is a chemical entity consisting of two structurally similar monomers joined by bonds that can be either strong or weak.

Organic chemistry

The dimer of cyclopentadiene although this might not be readily apparent on initial inspection

Molecular dimers are often formed by the reaction of two identical compounds e.g.: 2A → A-A. In this example, monomer "A" is said to dimerise to give the dimer "A-A". An example is Diaminocarbenes, which dimerise to give tetraaminoethylenes:

2 C(NR2)2 → (R2N)2C=C(NR2)2

Acetic acid forms a dimer in the gas phase, the monomer units are held together by hydrogen bonds. Under special conditions, most OH-containing molecules form dimers, e.g. the water dimer.

Dicyclopentadiene is an asymmetrical dimer of two cyclopentadiene molecules that have reacted in a Diels-Alder reaction to give the product. Upon heating, it "cracks" (undergoes a retro-Diels-Alder reaction) to give identical monomers:

C10H12 → 2 C5H6

The term homodimer is used when the two molecules are identical (e.g. A-A) and heterodimer when they are not (e.g. A-B). The reverse of dimerisation is often called dissociation.

See also

References

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