View source for Chemistry:(1R,3R)-1,2,3-Trimethylcyclopentane

{{DISPLAYTITLE:(1''R'',3''R'')-1,2,3-Trimethylcyclopentane}}
{{Chembox
| Name           = (1''R'',3''R'')-1,2,3-Trimethylcyclopentane
| ImageFile      = (1R,3R)-1,2,3-trimethylcyclopentane.png
| ImageAlt       = 
| IUPACName      = (1''R'',3''R'')-1,2,3-Trimethylcyclopentane
| OtherNames     = Cyclopentane, 1,2,3-trimethyl-, ''cis''-1,2,''trans''-1,3-<br />''cis''-1,2-''trans''-3-Trimethylcyclopentane<br /><nowiki>Cyclopentane,1,2,3-trimethyl-, (1a,2a,3b)-}}</nowiki>
| Section1       = {{Chembox Identifiers
| CASNo = 15890-40-1
| ChemSpiderID = 25623
| PubChem = 27533
| StdInChI=1S/C8H16/c1-6-4-5-7(2)8(6)3/h6-8H,4-5H2,1-3H3/t6-,7-/m1/s1
| StdInChIKey = VCWNHOPGKQCXIQ-RNFRBKRXSA-N
| SMILES = C[C@@H]1CC[C@H](C1C)C
}}
| Section2       = {{Chembox Properties
|  C = 8 | H = 16
|  Appearance =
|  Density = 
|  MeltingPtC = -113
|  MeltingPt_ref = <ref name=NIST>https://webbook.nist.gov/cgi/cbook.cgi?ID=C15890401&Mask=4#Thermo-Phase</ref>
|  BoilingPtC = 118
|  BoilingPt_ref = <ref name=NIST/>
|  Solubility = }}
| Section3       = {{Chembox Hazards
|  MainHazards = prolonged exposure may result in cancer or health defects 
|  FlashPtC = 9.2
|  AutoignitionPt = }}
}}

'''(1''R'',3''R'')-1,2,3-Trimethylcyclopentane''' is an [[Chemistry:Organic chemistry|organic]] [[Chemistry:Hydrocarbon|hydrocarbon]] [[Chemistry:Alicyclic compound|alicyclic]] [[Chemistry:Cycloalkane|cycloalkane]] compound with the molecular formula C<sub>8</sub>H<sub>16</sub>. It is a saturated cyclopentane with three [[Chemistry:Methyl group|methyl]] substituents branching off carbons 1,2, and 3. The [[Chemistry:Methyl group|methyl group]]s off carbons 1 and 3 are trans with respect to each other, while the methyl group off carbon 2 has undefined stereochemistry, allowing it to be either cis or trans with respect to methyl 1 or 3.<ref>{{cite web|title=(1R,3R)- 1,2,3 -Trimethylcyclopentane|url=http://www.chemspider.com/Chemical-Structure.25623.html|publisher=ChemSpider|accessdate=4 November 2012}}</ref>


Each carbon atom within the cyclopentane ring is [[Physics:Orbital hybridisation|sp<sup>3</sup>]] hybridized with the theoretical C-C-C bond angles near 108 degrees. Therefore [[Chemistry:Ring strain|ring strain]] is less prominent compared to other cycloalkanes as there is minimal deviation from the ideal tetrahedral bond angle, 109.5 degrees. However, in a planar molecule such as (1''R'',3''R'')-1,2,3-trimethylcyclopentane eclipsing interactions of adjacent C-H, adjacent methyl groups, and adjacent methyl groups & C-H bonds can contribute considerable strain. Therefore, the ring distorts slightly to adopt a minimum energy conformation that reduces the unfavorable eclipsing interactions. There are two puckered conformations exist for five-member ring systems. Such conformations include the envelope (IHIPOE, ACUHUB) and the half-chair (LISLOO, ABIKUR); please refer to figure at right. Little energy differences exist between each conformation, and it is not uncommon for five-membered ring systems such as (1''R'',3''R'')-1,2,3-trimethylcyclopentane to adopt a moderate conformation that lies somewhere between the two.<ref>{{cite web|title=Examine the Conformation of Cyclopentane|url=http://www.ccdc.cam.ac.uk/support/documentation/csd/teaching_egs/teaching_examples.3.98.html|publisher=CCDC|accessdate=4 November 2012}}</ref>

==Isomers==
Various stereoisomers exist for (1''R'',3''R'')-1,2,3-trimethylcyclopentane. Because (1''R'',3''R'')-1,2,3-trimethylcyclopentane is a cycloalkane, its three methyl substituents are capable of exhibiting ''cis/trans'' isomerism. This implies that the methyl groups in positions 1,2, and 3 may occupy different spatial arrangements (i.e.they may either lay ''cis'' or ''trans'' with respect to each other). Such stereoisomers include: Cyclopentane, 1,2,3-trimethyl-,(1α,2β,3α)-, Cyclopentane, 1,2,3-trimethyl-,(1α,2α,3β)-, Cyclopentane, 1,2,3-trimethyl-, and 1,2(cis),3(trans)-trimethylcyclopentane.<ref>{{cite web|title=Cyclopentane, 1,2,3-trimethyl-, (1α,2α,3β)-.|url=http://webbook.nist.gov/cgi/cbook.cgi?ID=C15890401|publisher=NIST|accessdate=4 November 2012}}</ref>

==Occurrences==
(1''R'',3''R'')-1,2,3-Trimethylcyclopentane has been identified by the United States Environmental Protection Agency in their Master List of Compounds Emitted by Mobile Sources as a component of mobile source air toxins that can be found in [[Chemistry:Gasoline|gasoline]] exhaust and liquefied petroleum gas (LPG) exhaust.<ref>{{cite web|title=Master List of Compounds Emitted by Mobile Sources|url=http://nepis.epa.gov/Exe/ZyNET.exe/P1004KHZ.txt?ZyActionD=ZyDocument|publisher=EPA|accessdate=4 November 2012}}</ref> Mobile source air toxins are compounds emitted from highway vehicle and non-road equipment via exhaust or evaporative emissions that are known or suspected to cause [[Medicine:Cancer|cancer]] or other serious health or environmental defects. Non-cancer health defects that may result from prolonged exposure to mobile source air toxins include: [[Biology:Neurology|neurological]], [[Biology:Circulatory system|cardiovascular]], [[Biology:Liver|liver]], kidney, and respiratory effects as well as adverse effects on the [[Biology:Immune system|immune]] and [[Biology:Reproductive system|reproductive]] systems. Mobile sources are responsible for direct emissions of air toxins and contribute to precursor emissions which react to form secondary pollutants.<ref>{{cite web|title=Mobile Source Air Toxics|url=http://www.epa.gov/otaq/toxics.htm|publisher=EPA|accessdate=4 November 2012}}</ref>

==References==
{{Reflist}}

{{DEFAULTSORT:Trimethylcyclopentane, (1R,3R)-1,2,3-}}
[[Category:Cyclopentanes]]

{{Sourceattribution|(1R,3R)-1,2,3-Trimethylcyclopentane}}