Question

CHEM 224 Organic Chemistry II Name AROMATICITY & NOMENCLATURE OF AROMATICS 1. Rank the following in order of increasing stability: NM NA 2. Determine which compounds are aromatic (A), antiaromatic (AA), or nonaromatic (NA):

Answer 1

| 1. Rank the following in order of increasing stability: 수살 소실

1 is most stable

4 is least stable.

Among 1 and 2, 1 is more stable because trans molecule(1) is more stable than cis molecule. (Steric reason)

3 and 4 dont have conjugation so less stable.

Here in 4 , one carbon have two double bonds. Very unstable.

2. Determine which compounds are aromatic (A), antiaromatic (AA), or nonaromatic (NA):

Aromaticity is tested based on Huckel rules

If there are 4n+2 electrons in a completely cyclic conjugated system, it is aromatic. (Electrons can be from double bond or lone pair). n = any natural number.

If there are 4n electrons in a completely cyclic conjugated system, it is anti arimatic. (From double bond or lone pair)

Molecule is non aromatic if,

1. There is no alternative single bond and double bond.

Or

2. A negative or positive or radical electrons on a carbon which are attached to another two carbon atoms which have double bond.