Oligomer

Source: Wikipedia, the free encyclopedia.
(Redirected from
Hetero-oligomer
)
"Hexamer" redirects here. For other uses, see Hexamer (disambiguation).
15-crown-5 crown ether, a cyclic oligomer, and its monomer, ethylene oxide
.

In

repeating units which could be derived, actually or conceptually, from smaller molecules, monomers.[1][2][3] The name is composed of Greek elements oligo-, "a few" and -mer, "parts". An adjective form is oligomeric.[3]

The oligomer concept is contrasted to that of a polymer, which is usually understood to have a large number of units, possibly thousands or millions. However, there is no sharp distinction between these two concepts. One proposed criterion is whether the molecule's properties vary significantly with the removal of one or a few of the units.[3]

An oligomer with a specific number of units is referred to by the Greek prefix denoting that number, with the ending -mer: thus

1,3,5-trioxane, a cyclic trimer of formaldehyde); or a more complex structure (as in tellurium tetrabromide, a tetramer of TeBr4 with a cube-like core). If the units are identical, one has a homo-oligomer; otherwise one may use hetero-oligomer. An example of a homo-oligomeric protein is collagen
, which is composed of three identical protein chains.

amine group
H2N− of the next one.

Some biologically important oligomers are macromolecules like

RNA, or similar fragments of analogs of nucleic acids such as peptide nucleic acid or Morpholinos
.

A pentamer unit of the major capsid protein VP1. Each monomer is in a different color.

The units of an oligomer may be connected by covalent bonds, which may result from bond rearrangement or condensation reactions, or by weaker forces such as hydrogen bonds. The term multimer (

polio virus
is a self-assembling multimer of 72 pentamers held together by local electric charges.

Many

crude oil. Polybutene is an oligomeric oil used to make putty
.

Oligomerization is a chemical process that converts monomers to macromolecular complexes through a finite degree of polymerization.[3] Telomerization is an oligomerization carried out under conditions that result in chain transfer, limiting the size of the oligomers.[4][3] (This concept is not to be confused with the formation of a telomere, a region of highly repetitive DNA at the end of a chromosome.)

Green oil

In the oil and gas industry, green oil refers to oligomers formed in all C2, C3, and C4 hydrogenation reactors of ethylene plants and other petrochemical production facilities; it is a mixture of C4 to C20 unsaturated and reactive components with about 90%

alkenes.[5] Different heterogeneous and homogeneous catalysts are operative in producing green oils via the oligomerization of alkenes.[6]

See also

References

  1. ^ "Oligomer". Merriam-Webster. Retrieved 25 October 2014.
  2. doi:10.1351/goldbook.O04286
  3. ^
    doi:10.1351/pac199668122287
    .Quote: Oligomer molecule: A molecule of intermediate relative molecular mass, the structure of which essentially comprises a small plurality of units derived, actually or conceptually, from molecules of lower relative molecular mass.
  4. doi:10.1351/goldbook.T06260
  5. ^ "Chemicals & Polymers". www.pall.com.
  6. S2CID 103664623
    .

External links

  • Media related to Oligomers at Wikimedia Commons
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