Methylenecyclopropene: Difference between revisions

| Verifiedfields = changed

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| verifiedrevid = 441173223

| ImageFile=Methylenecyclopropene.svg

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| PIN = 3-Methylidenecycloprop-1-ene

| OtherNames= 3-Methylenecyclopropene<br />Triafulvene

| CASNo_Ref = {{cascite|correct|??}}

| CASNo=4095-06-1

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = CA6K4MSR8T

| PubChem=138112

| SMILES=C=C1C=C1

| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}

| ChemSpiderID = 121753

| InChI = 1/C4H4/c1-4-2-3-4/h2-3H,1H2

| InChIKey = GOSMMPKSWSOPRZ-UHFFFAOYAD

| StdInChI_Ref = {{stdinchicite|changed|chemspider}}

| StdInChI = 1S/C4H4/c1-4-2-3-4/h2-3H,1H2

| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}

| StdInChIKey = GOSMMPKSWSOPRZ-UHFFFAOYSA-N

| C=4 | H=4

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'''3-Methylenecyclopropene''', also called '''methylenecyclopropene''' or '''triafulvene''', is a [[hydrocarbon]] with [[chemical formula]] {{chem2|auto=1|C4H4}}. It is a colourless gas that [[polymer]]izes readily as a liquid or in solution but is stable as a gas.<ref>W. E. Billups , Long Jin Lin , Edward W. Casserly "Synthesis of Methylenecyclopropene" J. Am. Chem. Soc., 1984, volume 106, pp 3698–3699. {{doi|10.1021/ja00324a064}}</ref> This highly strained and reactive molecule was synthesized and characterized for the first time in 1984, and has been the subject of considerable experimental and theoretical interest. It is an example of a [[Cross-conjugation|cross-conjugated]] alkene, being composed of cyclopropene with an exocyclic double bond attached.

==Description==

Methylenecyclopropene is the smallest of the [[fulvenes]] (a family of unstable, cyclic molecules, conjugated transversally with an odd number of carbon atoms in the ring).

The structure of methylenecyclopropene has two interacting double bonds, which represents the simplest transversally conjugated π-bonding system. It is fundamentally not an [[alternant hydrocarbon]]. The value of its dipole moment (which is around four times that of pentafulvene) can be calculated by the [[Hückel method]] (HMO).

Its study has involved the use of isotopic isomers.

==Reactivity==

Most fulvenes are typically non-aromatic in nature (based on spectroscopic data), having properties closer to [[alkene]]s. In the case of tria- and pentafulvene, the possibility of [[Electric dipole moment|dipole]] forms of resonance suggests an aromatic character to the cyclic structure; furthermore, as opposed to pentafulvene, one of the triafulvene resonance structures has a negative charge on the methylidene carbon.

Similarly to [[heptafulvene]] (fulvene containing a 7-atom cyclic ring), triafulvene [[Polymerization|polymerizes]] easily at −20&nbsp;°C and is stabilized by [[Electron affinity|electron-accepting groups]] bonded to the methylidene carbon atom.

*[[Methylenecyclopropane]]

*[[Fulvene]]

*[[Cyclopropenone]]

*[[Methylene group]]

==References==

<references />

==External links==

*{{Commonscatinline}}

[[Category:Hydrocarbons]]

[[Category:Cyclopropenes]]

[[Category:Vinylidene compounds]]