| 词条 | Cyclotetradecaheptaene |
| 释义 |
| Watchedfields = changed | verifiedrevid = 443551114 | Name = Cyclotetradecaheptaene | ImageFile = (14)Annulene.svg | ImageSize = 110 | IUPACName = (1E,3Z,5E,7Z,9E,11E,13Z)-cyclotetradeca-1,3,5,7,9,11,13-heptaene | OtherNames = [14]Annulene |Section1={{Chembox Identifiers | PubChem = 11988275 | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 10160742 | ChEBI_Ref = {{ebicite|correct|EBI}} | ChEBI = 37523 | SMILES = C1C=CC=CC=CC=CC=CC=CC=1 | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI=1S/C14H14/c1-2-4-6-8-10-12-14-13-11-9-7-5-3-1/h1-14H/b2-1-,3-1-,4-2+,5-3+,6-4+,7-5+,8-6-,9-7-,10-8+,11-9+,12-10+,13-11+,14-12-,14-13- | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = RYQWRHUSMUEYST-ILUIUFOYSA-N | CASNo_Ref = {{cascite|correct|??}} | CASNo = 2873-14-5 | RTECS = |Section2={{Chembox Properties | C=14 | H=14 | Appearance = | Density = | Solubility = Insoluble | SolubleOther = Soluble | Solvent = benzene | MeltingPt = | BoilingPt = | pKa = | pKb = | Viscosity = |Section3={{Chembox Structure | MolShape = | Coordination = | CrystalStruct = | Dipole = |Section7={{Chembox Hazards | ExternalSDS = | MainHazards = Flammable, reactive | FlashPt = | RPhrases = | SPhrases = |Section8={{Chembox Related | OtherAnions = | OtherCations = | OtherCompounds = }}Cyclotetradecaheptaene, often referred to as [14]annulene, is a hydrocarbon with molecular formula C14H14, which played an important role in the development of criteria (Hückel's rule) for the aromaticity, a stabilizing property of central importance in physical organic chemistry. Although the conjugated ring of this annulene contains 4n+2 electrons, it only exhibits limited evidence for being aromatic. It does not fully conform to Hückel's rule because none of its cis/trans isomers can adopt a completely planar conformation due to crowding of the interior hydrogens.[1] There is evidence that it has two isomeric forms of comparable stability (trans, cis, trans, cis, trans, trans, cis- with four interior hydrogens (shown in the infobox) and trans, cis, trans, cis, trans, cis, cis- with three interior hydrogens) which rapidly interconvert at room temperature but can be observed at low temperature by NMR.[2] Its 1H NMR spectrum shows evidence of aromatic ring currents that result in an upfield shift for the interior hydrogens. In contrast, the corresponding [12]- and [16]annulenes, which are weakly antiaromatic or nonaromatic, have downfield shifted interior hydrogens. However, unlike the undoubtedly aromatic [18]annulene, [14]annulene does not bear the hallmark aromatic property of chemical stability, and it quickly decomposes when exposed to light and air.[3] References1. ^{{cite book | title = Aromatic Character and Aromaticity | page = 96 | author = G. M. Badger | publisher = Cambridge University Press}} {{Annulenes}}{{hydrocarbon-stub}}2. ^{{Cite book|url=https://www.worldcat.org/oclc/14214254|title=Mechanism and theory in organic chemistry|last=H.|first=Lowry, Thomas|date=1987|publisher=Harper & Row|others=Richardson, Kathleen Schueller.|isbn=0060440848|edition= 3rd|location=New York|oclc=14214254}} 3. ^{{cite journal | doi = 10.1021/ja01506a061| title = Unsaturated Macrocyclic Compounds. XV. Cyclotetradecaheptaene| journal = Journal of the American Chemical Society| volume = 82| issue = 21| pages = 5765–5766| year = 1960| last1 = Sondheimer| first1 = Franz| last2 = Gaoni| first2 = Yehiel}} 1 : Annulenes |
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