Structure and AFM image of a hexadehydrotribenzo[12]annulene
Annulenes are monocyclic hydrocarbons that contain the maximum number of non-cumulated or conjugated double bonds ('mancude'). They have the general formula CnHn (when n is an even number) or CnHn+1 (when n is an odd number). The IUPAC accepts the use of 'annulene nomenclature' in naming carbocyclic ring systems with 7 or more carbon atoms, using the name '[n]annulene' for the mancude hydrocarbon with n carbon atoms in its ring,[1] though in certain contexts (e.g., discussions of aromaticity for different ring sizes), smaller rings (n = 3 to 6) can also be informally referred to as annulenes. Using this form of nomenclature 1,3,5,7-cyclooctatetraene is [8]annulene and benzene is [6]annulene (and occasionally referred to as just 'annulene').[2][3]
The discovery that [18]annulene possesses a number of key properties associated with other aromatic molecules was an important development in the understanding of aromaticity as a chemical concept.
In the related annulynes, one double bond is replaced by a triple bond.
^IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "annulene". doi:10.1351/goldbook.A00368
^Ege, S. (1994) Organic Chemistry:Structure and Reactivity 3rd ed. D.C. Heath and Company
^Dublin City University Annulenes Archived April 7, 2005, at the Wayback Machine
Annulenes may be aromatic (benzene, [6]annulene and [18]annulene), non-aromatic ([8] and [10]annulene), or anti-aromatic (cyclobutadiene, [4]annulene)...
or [18]annulene is an organic compound with chemical formula C 18H 18. It belongs to the class of highly conjugated compounds known as annulenes and is...
the ring and a shielding (upfield shift) of nuclei outside the ring. [12]annulene is an antiaromatic hydrocarbon that is large enough to have protons both...
aromatic compound. Of annulenes larger than benzene, [12]annulene and [14]annulene are weakly aromatic compounds and [18]annulene, Cyclooctadecanonaene...
Cyclodecapentaene or [10]annulene is an annulene with molecular formula C10H10. This organic compound is a conjugated 10 pi electron cyclic system and...
Cyclododecahexaene or [12]annulene (C 12H 12) is a member of the series of annulenes with some interest in organic chemistry with regard to the study of...
hydrocarbon with 4 pi electrons (or π electrons). It is the smallest [n]-annulene ([4]-annulene). Its rectangular structure is the result of a pseudo- (or second...
carbon, but they need not be hydrocarbons. Benzene, as well as most other annulenes (cyclodecapentaene excepted) with the formula CnHn where n ≥ 4 and is...
A cyanostar (pentacyanopentabenzo[25]annulene) is a shape-persistent macrocycle that binds anions. The cyanostar structure is synthesized in a one-pot...
that they had ignored existing literature on Zincke but held on to the annulene structure based on their electrospray ionization (ESI) results which according...
g/mol, exact mass: 234.1409 u) may refer to: Cyclooctadecanonaene, or [18]annulene Retene This set index page lists chemical structure articles associated...
derivative of cyclooctane, with the formula C8H8. It is also known as [8]annulene. This polyunsaturated hydrocarbon is a colorless to light yellow flammable...
molecular formula C11H10 may refer to: Methano[10]annulenes 1,5-Methano[10]annulene 1,6-Methano[10]annulene Methylazulenes 1-Methylazulene 2-Methylazulene...
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