16. Conjugated Systems

Answer the following questions for the molecular orbitals (MOs) of 1,3,5,7-octatetraene:

f. What is the relationship between HOMO and LUMO and symmetric and antisymmetric orbitals?

Identify the isoprene units in the terpenes shown. In cross-linked or ring-containing terpenes, linkages can be formed between more than just C₁ and C₄ of isoprene.

(e)

For the following terpenes, identify the isoprene units. In cross-linked or ring-containing terpenes, linkages can be formed between more than just C₁ and C₄ of isoprene

(b)

For the following terpenes, identify the isoprene units. In cross-linked or ring-containing terpenes, linkages can be formed between more than just C₁ and C₄ of isoprene.

(d)

Identify the isoprene units in the terpenes shown. In cross-linked or ring-containing terpenes, linkages can be formed between more than just C₁ and C₄ of isoprene.

(c)

a. How many MOs does 1,3,5,7-octatetraene have?

b. What is the designation of its HOMO (c1, c2, etc.)?

c. How many nodes does its highest energy MO have between the nuclei?

Why is this not a viable representation of the ψ₂, molecular orbital of buta-1,3-diene?

How can you use UV spectroscopy to distinguish between the compounds in each of the following pairs?

c.