Cyclodecapentaene (original) (raw)
环癸五烯全称“1,3,5,7,9-环癸五烯”，是环辛烷的完全不饱和衍生物，化学式C10H10。属于环状，结构与苯相似。 与苯不同的是，环癸五烯虽然与苯一样是一种轮烯，但它不具芳香性，故不是芳香烃。通常状态下为非平面的澡盆型结构；由于不是平面结构，因此环癸五烯既没有芳香性，也没有反芳香性，也不适用于休克尔规则分析。
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| dbo:abstract | Cyclodecapentaene or [10]annulene is an annulene with molecular formula C10H10. This organic compound is a conjugated 10 pi electron cyclic system and according to Huckel's rule it should display aromaticity. It is not aromatic, however, because various types of ring strain destabilize an all-planar geometry. The all-cis isomer (1), a fully convex decagon, would have bond angles of 144°, which creates large amounts of angle strain relative to the ideal 120° for sp2 atomic hybridization. Instead, the all-cis isomer can adopt a planar boat-like conformation (2) to relieve the angle strain. This is still unstable because of the relative higher strain in boat shaped compared to the next planar trans, cis, trans, cis, cis isomer (3). Yet even this isomer is also unstable, suffering from steric repulsion between the two internal hydrogen atoms. The nonplanar trans, cis, cis, cis, cis isomer (4) is the most stable of all the possible isomers. The [10]annulene compound can be obtained by photolysis of cis-9,10-dihydronaphthalene as a mixture of isomers. Because of their lack in stability even at low temperatures the reaction products revert to the original dihydronaphthalene. Aromaticity can be induced in compounds having a [10]annulene-type core by fixation of the planar geometries. There exist two methods to bring it about. One way is to replace two hydrogen atoms by a methylene bridge (-CH2-) gives the planar bicyclic 1,6-methano[10]annulene (5). This compound is aromatic as indicated by from lack in bond length alternation seen in its X-ray structure and evidence of telltale diamagnetic ring current in its NMR spectrum. A classical organic synthesis of this compound starts from a Birch reduction of naphthalene to tetrahydronaphthalene (or isotetralin), is followed by carbene addition of dichlorocarbene (prepared in-situ from chloroform and the potassium salt of tert-butanol) followed by a second organic reduction that removes the chloride substituents and is concluded by the organic oxidation by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). Another way to restore planarity, and therefore aromaticity, in [10]annulene rings is incorporation of a methine bridge to a tricyclic[10]annulene core structure (6). When deprotonated to form the anion this type of compound is even more stabilized. The central carbanion makes the molecule even more planar and the number of resonance structures that can be drawn is extended to 7 included two resonance forms with a complete benzene ring. By computational chemistry it is demonstrated that the tricyclic[10]annulene derivative with an annulated benzene ring and a full set of cyano substituents (7) is one of the most acidic compounds known with a computed pKa in DMSO of −30.4 (compared to for instance −20 for magic acid). Azulene is also a 10 π-electron system in which aromaticity is maintained by direct transannular bonding to form a fused 7–5 bicyclic molecule. (en) 环癸五烯全称“1,3,5,7,9-环癸五烯”，是环辛烷的完全不饱和衍生物，化学式C10H10。属于环状，结构与苯相似。 与苯不同的是，环癸五烯虽然与苯一样是一种轮烯，但它不具芳香性，故不是芳香烃。通常状态下为非平面的澡盆型结构；由于不是平面结构，因此环癸五烯既没有芳香性，也没有反芳香性，也不适用于休克尔规则分析。 (zh) |
| dbo:alternativeName | [10]Annulene (en) |
| dbo:iupacName | Cyclodeca-1,3,5,7,9-pentaene (en) |
| dbo:thumbnail | wiki-commons:Special:FilePath/all-cis-cyclodecapentaene.svg?width=300 |
| dbo:wikiPageID | 2423647 (xsd:integer) |
| dbo:wikiPageLength | 5682 (xsd:nonNegativeInteger) |
| dbo:wikiPageRevisionID | 1014182079 (xsd:integer) |
| dbo:wikiPageWikiLink | dbr:Methylene_bridge dbr:Birch_reduction dbr:Annulene dbc:Annulenes dbr:Huckel's_rule dbc:Fully_conjugated_nonaromatic_rings dbr:Cyclic_compound dbr:Decagon dbr:Deprotonation dbr:NMR_spectroscopy dbr:1,6-Methano(10)annulene dbr:Organic_compound dbr:Molecular_formula dbr:Conjugated_system dbr:Angle_strain dbr:Anion dbr:Aromaticity dbr:Magic_acid dbc:Ten-membered_rings dbr:Computational_chemistry dbr:Organic_synthesis dbr:Azulene dbr:2,3-dichloro-5,6-dicyano-1,4-benzoquinone dbr:PKa dbr:Carbanion dbr:Carbene dbr:Chloroform dbr:Bicyclic_molecule dbr:Dichlorocarbene dbr:Dimethyl_sulfoxide dbr:Bond_length dbr:Methine dbr:Tert-Butanol dbr:Naphthalene dbr:X-ray_crystallography dbr:Bridge_(chemical) dbr:Substituent dbr:Annulated dbr:Ring_strain dbr:Organic_oxidation dbr:Bond_angle dbr:Organic_reduction dbr:Photolysis dbr:Cis_isomer dbr:Pi_electron dbr:Resonance_structure dbr:Diamagnetic_ring_current dbr:Cyano dbr:Steric_strain dbr:File:Methanonaphthalene-synthesis.svg dbr:File:10-annulene.svg |
| dbp:imagecaption | all-cis isomer of cyclodecapentaene (en) |
| dbp:imagefile | all-cis-cyclodecapentaene.svg (en) |
| dbp:imagesize | 120 (xsd:integer) |
| dbp:othernames | [10]Annulene (en) |
| dbp:pin | Cyclodeca-1,3,5,7,9-pentaene (en) |
| dbp:wikiPageUsesTemplate | dbt:Chem dbt:Chembox dbt:Chembox_Hazards dbt:Chembox_Identifiers dbt:Chembox_Properties dbt:Cn dbt:Reflist dbt:Why dbt:Annulenes |
| dct:subject | dbc:Annulenes dbc:Fully_conjugated_nonaromatic_rings dbc:Ten-membered_rings |
| gold:hypernym | dbr:Annulene |
| rdf:type | owl:Thing dul:ChemicalObject dbo:ChemicalSubstance wikidata:Q11173 dbo:ChemicalCompound |
| rdfs:comment | 环癸五烯全称“1,3,5,7,9-环癸五烯”，是环辛烷的完全不饱和衍生物，化学式C10H10。属于环状，结构与苯相似。 与苯不同的是，环癸五烯虽然与苯一样是一种轮烯，但它不具芳香性，故不是芳香烃。通常状态下为非平面的澡盆型结构；由于不是平面结构，因此环癸五烯既没有芳香性，也没有反芳香性，也不适用于休克尔规则分析。 (zh) Cyclodecapentaene or [10]annulene is an annulene with molecular formula C10H10. This organic compound is a conjugated 10 pi electron cyclic system and according to Huckel's rule it should display aromaticity. It is not aromatic, however, because various types of ring strain destabilize an all-planar geometry. The all-cis isomer (1), a fully convex decagon, would have bond angles of 144°, which creates large amounts of angle strain relative to the ideal 120° for sp2 atomic hybridization. Instead, the all-cis isomer can adopt a planar boat-like conformation (2) to relieve the angle strain. This is still unstable because of the relative higher strain in boat shaped compared to the next planar trans, cis, trans, cis, cis isomer (3). Yet even this isomer is also unstable, suffering from steric (en) |
| rdfs:label | Cyclodecapentaene (en) 环癸五烯 (zh) |
| owl:sameAs | freebase:Cyclodecapentaene yago-res:Cyclodecapentaene wikidata:Cyclodecapentaene dbpedia-fa:Cyclodecapentaene dbpedia-zh:Cyclodecapentaene https://global.dbpedia.org/id/4ik8W |
| prov:wasDerivedFrom | wikipedia-en:Cyclodecapentaene?oldid=1014182079&ns=0 |
| foaf:depiction | wiki-commons:Special:FilePath/10-annulene.svg wiki-commons:Special:FilePath/Methanonaphthalene-synthesis.svg wiki-commons:Special:FilePath/all-cis-cyclodecapentaene.svg |
| foaf:isPrimaryTopicOf | wikipedia-en:Cyclodecapentaene |
| is dbo:wikiPageWikiLink of | dbr:Annulene dbr:C10H10 dbr:1,5-Methano(10)annulene dbr:1,6-Methano(10)annulene dbr:Aromaticity dbr:Zethrene dbr:Azulene dbr:Cyclooctadecanonaene |
| is foaf:primaryTopic of | wikipedia-en:Cyclodecapentaene |
