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The rectangular structure is consistent with the existence of two different 1,2-dideutero-1,3-cyclobutadiene valence isomers. This distortion indicates that the pi electrons are localized, in agreement with Hückel's rule which predicts that a π-system of 4 electrons is not aromatic .
Such a resonance structure is called a Clar structure. In other words, a polycyclic aromatic hydrocarbon with a given number of π-sextets is more stable than its isomers with fewer π-sextets. [1] [2] In 1984, Glidewell and Lloyd provided an extension of Clar's rule to polycyclic aromatic hydrocarbons containing rings of any size. [3]
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 ...
Cyclohexa-1,3-diene is an organic compound with the formula (C 2 H 4)(CH) 4. It is a colorless, flammable liquid. It is a colorless, flammable liquid. Its refractive index is 1.475 (20 °C, D).
The reactant passes through a metalated intermediate before forming 1,3-cyclobutadiene, which can then dimerize to form the syn-diene. Hydrogenation of the double bonds will form the saturated syn-[3]-ladderane. To generate the anti product, cis-3,4-dichlorocyclobutene is treated with lithium amalgam. [5]
For example, the aromatic species 1 can be reduced to 2 with a relatively small penalty for forming an antiaromatic system. The antiaromatic 2 does revert to the aromatic species 1 over time by reacting with oxygen in the air because the aromaticity is preferred. [15] The loss of antiaromaticity can sometimes be the driving force of a reaction.
1,3,5,7-Cyclooctatetraene (COT) is an unsaturated derivative of cyclooctane, with the formula C 8 H 8. It is also known as [8] annulene . This polyunsaturated hydrocarbon is a colorless to light yellow flammable liquid at room temperature.
One of its murburn products (CO 2) is a voidable gas and the other product (water, H 2 O) is also the solvent. Owing to colligative effects, the latter is spontaneously mobilized to move out, thereby retaining cellular composition in a dynamic fashion. Physically, these processes also generate heat and turgor.