A cyclooctadiene (often abbreviated COD) is any of several cyclic diene with the formula (CH
2)
4(C
2H
2)
2. Focusing only on cis derivatives, four
isomer
In chemistry, isomers are molecules or polyatomic ions with identical molecular formula – that is, the same number of atoms of each element (chemistry), element – but distinct arrangements of atoms in space. ''Isomerism'' refers to the exi ...
s are possible: 1,2-, which is an
allene
In organic chemistry, allenes are organic compounds in which one carbon atom has double bonds with each of its two adjacent carbon atoms (, where R is hydrogen, H or some organyl group). Allenes are classified as diene#Classes, cumulated dienes ...
, 1,3-, 1,4-, and 1,5-. Commonly encountered isomers are the conjugated isomer 1,3-cyclooctadiene and
1,5-cyclooctadiene, which is used as a
ligand
In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's el ...
for
transition metal
In chemistry, a transition metal (or transition element) is a chemical element in the d-block of the periodic table (groups 3 to 12), though the elements of group 12 (and less often group 3) are sometimes excluded. The lanthanide and actinid ...
s. These dienes are colorless volatile liquids.
[Thomas Schiffer, Georg Oenbrink “Cyclododecatriene, Cyclooctadiene, and 4-Vinylcyclohexene” in Ullmann’s Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim.]
References
External links
1,5-Cyclooctadiene in the NIST Chemistry WebBook
Cycloalkenes
Dienes
Eight-membered rings
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