Consider the following compound, which has been

Chapter 10, Problem 44SP

(choose chapter or problem)

Consider the following compound, which has been synthesized and characterized:

(a) Assuming this molecule is entirely conjugated, do you expect it to be aromatic,

antiaromatic, or nonaromatic?

(b) Why was this molecule synthesized with three tert-butyl substituents? Why not

make the unsubstituted compound and study it instead?

(c) Do you expect the nitrogen atom to be basic? Explain. Why doesn’t nitrogen’s lone pair

overlap with the double bonds to give a total of six electrons in the pi system?

(d) At room temperature, the proton NMR spectrum shows only two singlets of ratio 1:2. The smaller signal remains unchanged at all temperatures. As the temperature is lowered to - 100 \({ }^{0} C\), the larger signal broadens and separates into two new singlets, one on either side of the original chemical shift. At  - \(100^{\circ} \mathrm{C}\), the spectrum consists of three separate singlets of areas 1:1:1. Explain what these NMR data indicate about the bonding in this molecule. How does your

conclusion based on the NMR data agree with your prediction in part (a)?

Equation transcription:

Text transcription:

^{0} C

100^{circ}{C}