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{{Expand language|langcode=de|topic=chemistry|date=October 2015}}
{{unreferenced|date=October 2015}}
{{notability|date=October 2015}}
{{Chembox
{{Chembox
| verifiedrevid =
| verifiedrevid =
| ImageFile = Spiropentane.svg
| ImageFile = Spiropentane.svg
| ImageSize = 200px
| ImageSize = 200px
| ImageFile2 = Spiropentane-from-xtal-view-4-3D-bs-17.png
| IUPACName = Spiro[2.2]pentane
| PIN = Spiro[2.2]pentane
| OtherNames =
| OtherNames =
|Section1={{Chembox Identifiers
|Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|??}}
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 157-40-74
| CASNo = 157-40-4
| ChemSpiderID = 8734
| ChemSpiderID = 8734
| PubChem = 9088
| PubChem = 9088
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| Appearance =
| Appearance =
| Density =
| Density =
| MeltingPt =
| MeltingPtC = -134.6
| BoilingPt =
| BoilingPtC = 39.0
| Solubility = }}
| Solubility = }}
|Section3={{Chembox Hazards
|Section3={{Chembox Hazards
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}}
}}


'''Spiropentane''' is a [[hydrocarbon]] with formula {{chem2|C5H8}}. It is the simplest [[Spiro compound|spiro]]-connected [[cycloalkane]], a [[triangulane]].<ref name="DonohueHumphrey1945">{{cite journal|last1=Donohue|first1=Jerry|last2=Humphrey|first2=George L.|last3=Schomaker|first3=Verner|title=The Structure of Spiropentane|journal=Journal of the American Chemical Society|volume=67|issue=2|year=1945|pages=332–335|issn=0002-7863|doi=10.1021/ja01218a056}}</ref><ref name="MurrayStevenson1944a">{{cite journal|last1=Murray|first1=M. J.|last2=Stevenson|first2=Eugene H.|title=SPIROPENTANE|journal=Journal of the American Chemical Society|volume=66|issue=2|year=1944|pages=314|issn=0002-7863|doi=10.1021/ja01230a515}}</ref><ref name="MurrayStevenson1944b">{{cite journal|last1=Murray|first1=M. J.|last2=Stevenson|first2=Eugene H.|title=The Debromination of Pentaerythrityl Bromide by Zinc. Isolation of Spiropentane1|journal=Journal of the American Chemical Society|volume=66|issue=5|year=1944|pages=812–816|issn=0002-7863|doi=10.1021/ja01233a047}}</ref><ref name="PriceCoulterpark2011">{{cite journal|last1=Price|first1=J.E.|last2=Coulterpark|first2=K.A.|last3=Masiello|first3=T.|last4=Nibler|first4=J.W.|last5=Weber|first5=A.|last6=Maki|first6=A.|last7=Blake|first7=T.A.|title=High-resolution infrared spectra of spiropentane, C5H8|journal=Journal of Molecular Spectroscopy|volume=269|issue=1|year=2011|pages=129–136|issn=0022-2852|doi=10.1016/j.jms.2011.05.011|bibcode=2011JMoSp.269..129P}}</ref>
'''Spiropentane''' is a [[hydrocarbon]] with formula C<sub>5</sub>H<sub>8</sub>. The simplest [[Spiro compound|spiro]]-connected [[cycloalkane]].
It took several years after the discovery in 1887 until the structure of the molecule was determined.<ref name="Philipow1916">{{cite journal|last1=Philipow|first1=O.|title=Die Konstitution der Kohlenwasserstoffe Gustavsons: Vinyltrimethylen und Äthylidentrimethylen|journal=Journal für Praktische Chemie|volume=93|issue=1|year=1916|pages=162–182|issn=0021-8383|doi=10.1002/prac.19160930112|url=https://zenodo.org/record/1428058}}</ref><ref name="FaworskyBatalin1914">{{cite journal|last1=Faworsky|first1=Al.|last2=Batalin|first2=W.|title=Über das Vinyltrimethylen und Äthyliden-trimethylen von Gustavson|journal=Berichte der Deutschen Chemischen Gesellschaft|volume=47|issue=2|year=1914|pages=1648–1651|issn=0365-9496|doi=10.1002/cber.19140470250|url=https://zenodo.org/record/1426555}}</ref><ref name=burns>{{Cite journal | doi=10.1366/000370272774351778|title = Infrared and Raman Spectra of Spiropentane-H8| journal=Applied Spectroscopy| volume=26| issue=5| pages=540–542|year = 1972|last1 = Burns|first1 = G. R.| last2=McGavin| first2=D. G.|bibcode = 1972ApSpe..26..540B|s2cid = 95384874}}</ref> According to the nomenclature rules for spiro compounds, the systematic name is spiro[2.2]pentane. However, there can be no [[isomer|constitutive isomeric]] spiropentanes, hence the name is unique without brackets and numbers.

==Synthesis==

After Gustavson produced [[cyclopropane]] by reacting {{chem name|1,3-dibromopropane}} with ground-up zinc metal, he tried the same reaction with {{chem name|2,2-bis(bromomethyl)-1,3-dibromopropane}} (see formula scheme). The starting material is easily obtained by reacting [[pentaerythritol]] with [[hydrobromic acid]]. A molecule with the formula {{chem2|C5H8}} was obtained. It was called {{chem name|vinyltrimethylene}} in the initial publication.<ref name="Gustavson1896">{{cite journal|last1=Gustavson|first1=G.|title=Ueber Aethylidentrimethylen|journal=Journal für Praktische Chemie|volume=54|issue=1|year=1896|pages=104–107|issn=0021-8383|doi=10.1002/prac.18960540106|url=https://zenodo.org/record/1427990}}</ref> In 1907, Fecht expressed the assumption that it must be spiropentane, a constitutional isomer of vinylcyclopropane.<ref name="Fecht1907">{{cite journal|last1=Fecht|first1=H.|title=Über Spirocyclane|journal=Berichte der Deutschen Chemischen Gesellschaft|volume=40|issue=3|year=1907|pages=3883–3891|issn=0365-9496|doi=10.1002/cber.190704003194|url=https://zenodo.org/record/1426239}}</ref> Further evidence for the structure of the hydrocarbon comes from the fact that it could also be obtained from {{chem name|1,1-bis(bromomethyl)-cyclopropane}} (see formula scheme).<ref name="Zelinsky1913">{{cite journal|last1=Zelinsky|first1=N.|title=Über das Spirocyclan, seine Synthese und sein Verhalten bei der Reduktionskatalyse|journal=Berichte der Deutschen Chemischen Gesellschaft|volume=46|issue=1|year=1913|pages=160–172|issn=0365-9496|doi=10.1002/cber.19130460128|url=https://zenodo.org/record/1426495}}</ref>

:[[File:Spiropentane formation.svg|Spiropentane formation|575x575px]]

Spiropentane is difficult to separate from the other reaction products and the early procedures resulted in impure mixtures. Decades later, the production method was improved. The spiro hydrocarbon can be separated from the byproducts ({{chem name|2-methyl-1-butene, 1,1-dimethylcyclopropane, methylenecyclobutane}}) by [[distillation]].<ref name="ApplequistFanta1958">{{cite journal|last1=Applequist|first1=Douglas E.|last2=Fanta|first2=George F.|last3=Henrikson|first3=Bertel W.|title=Chemistry of Spiropentane. I. An Improved Synthesis of Spiropentane|journal=The Journal of Organic Chemistry|volume=23|issue=11|year=1958|pages=1715–1716|issn=0022-3263|doi=10.1021/jo01105a037}}</ref>
== Properties ==
=== Physical properties ===
Structural determination by electron diffraction showed two different C-C lengths; the bonds to the quaternary ("spiro") carbon atom are shorter (146.9&nbsp;pm) than those between the methylene groups (CH<sub>2</sub>–CH<sub>2</sub>, 151.9&nbsp;pm). The C–C–C angles on the spiro C atom are 62.2°, larger than in [[cyclopropane]].<ref>G. Dallinga, R. K. van der Draai, L. H. Toneman, [[Recueil des Travaux Chimiques des Pays-Bas]] 87, 897 (1968).</ref>

=== Chemical properties ===
When heating molecules of spiropentane labelled with deuterium atoms, a topomerization or "stereomutation" reaction is observed, similar to that of cyclopropane: {{chem name|''cis''-1,2-dideuteriospiropentane}} equilibrates with {{chem name|''trans''-1,2-dideuteriospiropentane}}.<ref name=Gajewski>J. J. Gajewski, L. T. Burka, [[Journal of the American Chemical Society]] 94, Nr. 25, 8857 (1972).</ref>

:[[File:Spiropentane isotopomer.svg|Spiropentane topomerization|434x434px]]

Gustavson (1896) reported that heating spiropentane to 200&nbsp;°C caused it to change into other hydrocarbons. A [[thermolysis]] in the gas phase from 360 to 410&nbsp;°C resulted in ring expansion to the constitutional isomer {{chem name|methylenecyclobutane}}, along with the fragmentation products [[ethene]] and [[propadiene]].<ref>M. C. Flowers, H. M. Frey, [[Journal of the Chemical Society]], 1961, 5550.</ref> Presumably, the longer – and weaker – bond is broken first, forming a diradical intermediate.<ref name=Gajewski />

:[[File:Spiropentane thermo.svg|Spiropentane thermolysis|507x507px]]

==Related compounds==
* [[Spiroheptane]]


==References==
==References==
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{{Hydrocarbons}}
{{Hydrocarbons}}


[[Category:Cycloalkanes]]
[[Category:Cyclopropanes]]
[[Category:Spiro compounds]]
[[Category:Spiro compounds]]
[[Category:Polycyclic nonaromatic hydrocarbons]]

Latest revision as of 14:36, 14 June 2024

Spiropentane
Names
Preferred IUPAC name
Spiro[2.2]pentane
Identifiers
3D model (JSmol)
ChemSpider
  • InChI=1S/C5H8/c1-2-5(1)3-4-5/h1-4H2
    Key: OGNAOIGAPPSUMG-UHFFFAOYSA-N
  • C1CC12CC2
Properties
C5H8
Molar mass 68.119 g·mol−1
Melting point −134.6 °C (−210.3 °F; 138.6 K)
Boiling point 39.0 °C (102.2 °F; 312.1 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Spiropentane is a hydrocarbon with formula C5H8. It is the simplest spiro-connected cycloalkane, a triangulane.[1][2][3][4] It took several years after the discovery in 1887 until the structure of the molecule was determined.[5][6][7] According to the nomenclature rules for spiro compounds, the systematic name is spiro[2.2]pentane. However, there can be no constitutive isomeric spiropentanes, hence the name is unique without brackets and numbers.

Synthesis

[edit]

After Gustavson produced cyclopropane by reacting 1,3-dibromopropane with ground-up zinc metal, he tried the same reaction with 2,2-bis(bromomethyl)-1,3-dibromopropane (see formula scheme). The starting material is easily obtained by reacting pentaerythritol with hydrobromic acid. A molecule with the formula C5H8 was obtained. It was called vinyltrimethylene in the initial publication.[8] In 1907, Fecht expressed the assumption that it must be spiropentane, a constitutional isomer of vinylcyclopropane.[9] Further evidence for the structure of the hydrocarbon comes from the fact that it could also be obtained from 1,1-bis(bromomethyl)-cyclopropane (see formula scheme).[10]

Spiropentane formation

Spiropentane is difficult to separate from the other reaction products and the early procedures resulted in impure mixtures. Decades later, the production method was improved. The spiro hydrocarbon can be separated from the byproducts (2-methyl-1-butene, 1,1-dimethylcyclopropane, methylenecyclobutane) by distillation.[11]

Properties

[edit]

Physical properties

[edit]

Structural determination by electron diffraction showed two different C-C lengths; the bonds to the quaternary ("spiro") carbon atom are shorter (146.9 pm) than those between the methylene groups (CH2–CH2, 151.9 pm). The C–C–C angles on the spiro C atom are 62.2°, larger than in cyclopropane.[12]

Chemical properties

[edit]

When heating molecules of spiropentane labelled with deuterium atoms, a topomerization or "stereomutation" reaction is observed, similar to that of cyclopropane: cis-1,2-dideuteriospiropentane equilibrates with trans-1,2-dideuteriospiropentane.[13]

Spiropentane topomerization

Gustavson (1896) reported that heating spiropentane to 200 °C caused it to change into other hydrocarbons. A thermolysis in the gas phase from 360 to 410 °C resulted in ring expansion to the constitutional isomer methylenecyclobutane, along with the fragmentation products ethene and propadiene.[14] Presumably, the longer – and weaker – bond is broken first, forming a diradical intermediate.[13]

Spiropentane thermolysis
[edit]

References

[edit]
  1. ^ Donohue, Jerry; Humphrey, George L.; Schomaker, Verner (1945). "The Structure of Spiropentane". Journal of the American Chemical Society. 67 (2): 332–335. doi:10.1021/ja01218a056. ISSN 0002-7863.
  2. ^ Murray, M. J.; Stevenson, Eugene H. (1944). "SPIROPENTANE". Journal of the American Chemical Society. 66 (2): 314. doi:10.1021/ja01230a515. ISSN 0002-7863.
  3. ^ Murray, M. J.; Stevenson, Eugene H. (1944). "The Debromination of Pentaerythrityl Bromide by Zinc. Isolation of Spiropentane1". Journal of the American Chemical Society. 66 (5): 812–816. doi:10.1021/ja01233a047. ISSN 0002-7863.
  4. ^ Price, J.E.; Coulterpark, K.A.; Masiello, T.; Nibler, J.W.; Weber, A.; Maki, A.; Blake, T.A. (2011). "High-resolution infrared spectra of spiropentane, C5H8". Journal of Molecular Spectroscopy. 269 (1): 129–136. Bibcode:2011JMoSp.269..129P. doi:10.1016/j.jms.2011.05.011. ISSN 0022-2852.
  5. ^ Philipow, O. (1916). "Die Konstitution der Kohlenwasserstoffe Gustavsons: Vinyltrimethylen und Äthylidentrimethylen". Journal für Praktische Chemie. 93 (1): 162–182. doi:10.1002/prac.19160930112. ISSN 0021-8383.
  6. ^ Faworsky, Al.; Batalin, W. (1914). "Über das Vinyltrimethylen und Äthyliden-trimethylen von Gustavson". Berichte der Deutschen Chemischen Gesellschaft. 47 (2): 1648–1651. doi:10.1002/cber.19140470250. ISSN 0365-9496.
  7. ^ Burns, G. R.; McGavin, D. G. (1972). "Infrared and Raman Spectra of Spiropentane-H8". Applied Spectroscopy. 26 (5): 540–542. Bibcode:1972ApSpe..26..540B. doi:10.1366/000370272774351778. S2CID 95384874.
  8. ^ Gustavson, G. (1896). "Ueber Aethylidentrimethylen". Journal für Praktische Chemie. 54 (1): 104–107. doi:10.1002/prac.18960540106. ISSN 0021-8383.
  9. ^ Fecht, H. (1907). "Über Spirocyclane". Berichte der Deutschen Chemischen Gesellschaft. 40 (3): 3883–3891. doi:10.1002/cber.190704003194. ISSN 0365-9496.
  10. ^ Zelinsky, N. (1913). "Über das Spirocyclan, seine Synthese und sein Verhalten bei der Reduktionskatalyse". Berichte der Deutschen Chemischen Gesellschaft. 46 (1): 160–172. doi:10.1002/cber.19130460128. ISSN 0365-9496.
  11. ^ Applequist, Douglas E.; Fanta, George F.; Henrikson, Bertel W. (1958). "Chemistry of Spiropentane. I. An Improved Synthesis of Spiropentane". The Journal of Organic Chemistry. 23 (11): 1715–1716. doi:10.1021/jo01105a037. ISSN 0022-3263.
  12. ^ G. Dallinga, R. K. van der Draai, L. H. Toneman, Recueil des Travaux Chimiques des Pays-Bas 87, 897 (1968).
  13. ^ a b J. J. Gajewski, L. T. Burka, Journal of the American Chemical Society 94, Nr. 25, 8857 (1972).
  14. ^ M. C. Flowers, H. M. Frey, Journal of the Chemical Society, 1961, 5550.
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