Question

Indicate whether each structure is aromatic, nonaromatic, or antiaromatic. Assume planarity.

Violation

Answer 1

Concepts and reason

Hückel's Rule is used to classify the behavior of the organic compounds into aromatic, anti-aromatic and non-aromatic.

Fundamentals

Hückel's Rule:

In organic chemistry, aromatic compounds must obey rule and should be planar, cyclic structure and fully conjugated (delocalized) double bonds.

Aromatic compounds must possess the following:

• Cyclic

• Planar

• Conjugated (pi electrons) double bonds

• Obey, where n is whole number.

Anti-aromatic compounds must possess the following:

• Cyclic

• Planar

• Conjugated (pi electrons) double bonds

• Obey, where n is natural number.

Non aromatic compounds: (other than both) It breaks one or more rules.

• acyclic

• non planar

• non conjugated (pi electrons) double bonds

(A)

• Cyclic

• Planar

• Conjugated pi electrons

•

So, the compound is aromatic.

(B)

• Cyclic

• Planar

• Conjugated double bonds

•

So, the compound is aromatic

(C)

• Cyclic

• Planar

• Conjugated (pi electrons) double bonds

•

So, the compound is anti-aromatic.

(D)

• Cyclic

• Planar

• Conjugated (pi electrons) double bonds

•

So, the compound is aromatic.

(E)

• Cyclic

• Planar

• Conjugated (pi electrons) double bonds

•

So, the compound is anti-aromatic.

Ans: Part A