Azulene is antiaromatic.
Answer
654.3k+ views
Hint: There are some necessary conditions for the compounds to be aromatic. The compound should have a single cyclic cloud of delocalized $\pi -electrons$, the compound must be planar, and it should contain ($4n+2$)$\pi -electrons$ where n = 1, 2, 3…....etc.
Complete step by step answer:
Based on the molecular orbital theory, Hukel has predicted that electrons in cyclic conjugated polyenes (cyclic polyenes having alternate single and double bonds) containing ($4n+2$)$\pi -electrons$ where n = 1, 2, 3, 4, ….etc are completely delocalized. This makes the compound stable and such compounds are called aromatic compounds.
So the necessary and sufficient conditions for the compound to aromatic are that it should have a single cyclic cloud of delocalized $\pi -electrons$ above and below the plane of the molecule, the compound must be planar, and the compound must contain ($4n+2$)$\pi -electrons$ where n = 1, 2, 3, …….etc.
The molecule that doesn't satisfy any one or more of the above conditions then is non-aromatic.
And if the compound is having ($4n$)$\pi -electrons$then the compound is antiaromatic.
So, in Azulene there are 5 double bonds which means that it has 10 $\pi -electrons$ as shown below:
So, when we put n as 2 in the equation of aromatic compound, we get:
\[(4n+2)\text{ }\pi -electrons\]
\[(4(2)+2)\text{ }\pi -electrons\]
$10\,\pi -electrons$
So, the Azulene compound is aromatic, not antiaromatic and it will give all the reactions of an aromatic compound. Thus the statement is false.
Note: The $10\,\pi -electrons$ in Azulene is contributed by two aromatic ions, by tropylium cation and the cyclopentadienyl anion. Azulene gives Friedel-Crafts-like reactions and both its peripheral bonds have the same length.
Complete step by step answer:
Based on the molecular orbital theory, Hukel has predicted that electrons in cyclic conjugated polyenes (cyclic polyenes having alternate single and double bonds) containing ($4n+2$)$\pi -electrons$ where n = 1, 2, 3, 4, ….etc are completely delocalized. This makes the compound stable and such compounds are called aromatic compounds.
So the necessary and sufficient conditions for the compound to aromatic are that it should have a single cyclic cloud of delocalized $\pi -electrons$ above and below the plane of the molecule, the compound must be planar, and the compound must contain ($4n+2$)$\pi -electrons$ where n = 1, 2, 3, …….etc.
The molecule that doesn't satisfy any one or more of the above conditions then is non-aromatic.
And if the compound is having ($4n$)$\pi -electrons$then the compound is antiaromatic.
So, in Azulene there are 5 double bonds which means that it has 10 $\pi -electrons$ as shown below:
So, when we put n as 2 in the equation of aromatic compound, we get:
\[(4n+2)\text{ }\pi -electrons\]
\[(4(2)+2)\text{ }\pi -electrons\]
$10\,\pi -electrons$
So, the Azulene compound is aromatic, not antiaromatic and it will give all the reactions of an aromatic compound. Thus the statement is false.
Note: The $10\,\pi -electrons$ in Azulene is contributed by two aromatic ions, by tropylium cation and the cyclopentadienyl anion. Azulene gives Friedel-Crafts-like reactions and both its peripheral bonds have the same length.
Recently Updated Pages
Write structures of the following compounds i 2 Chloro3methylpentane class 11 chemistry CBSE

What is BLO What is the full form of BLO class 8 social science CBSE

Explain the Treaty of Vienna of 1815 class 10 social science CBSE

A Paragraph on Pollution in about 100-150 Words

XIX+XXX A 49 B 51 C 55 D 44 class 5 maths CBSE

If x a + bt + ct2 where x is in meters and t is in class 11 physics CBSE

Trending doubts
One Metric ton is equal to kg A 10000 B 1000 C 100 class 11 physics CBSE

Find the value of the expression given below sin 30circ class 11 maths CBSE

What do you mean by retardation What is its SI uni class 11 physics CBSE

Draw a diagram of nephron and explain its structur class 11 biology CBSE

10 examples of friction in our daily life

Difference between physical and chemical change class 11 chemistry CBSE

