BackBiphenyl has the following structure.
c. The heat of hydrogenation for biphenyl is about 418 kJ/mol (100 kcal/mol). Calculate the resonance energy of biphenyl.
d. Compare the resonance energy of biphenyl with that of naphthalene and with that of two benzene rings. Explain the difference in the resonance energies of naphthalene and biphenyl.
Which of the following are aromatic?
d.
e.
f.
Which of the following are aromatic?
a.
b.
c.
Which ion in each of the following pairs is more stable?
a.
Classify the following compounds as aromatic, antiaromatic, or nonaromatic.
(c)
(d)
The following molecules and ions are grouped by similar structures. Classify each as aromatic, antiaromatic, or nonaromatic. For the aromatic and antiaromatic species, give the number of pi electrons in the ring.
(a)
The following molecules and ions are grouped by similar structures. Classify each as aromatic, antiaromatic, or nonaromatic. For the aromatic and antiaromatic species, give the number of pi electrons in the ring.
(c)
One of the following compounds is much more stable than the other two. Classify each as aromatic, antiaromatic, or nonaromatic.
Which ion in each of the following pairs is more stable?
b.
Which ion in each of the following pairs is more stable?
c.
Which ion in each of the following pairs is more stable?
d.
Biphenyl has the following structure.
a. Is biphenyl a (fused) polynuclear aromatic hydrocarbon?
b. How many pi electrons are there in the two aromatic rings of biphenyl? How does this number compare with that for naphthalene?
How would you convert the following compounds to aromatic compounds?
(a)
(b)
(c)
Some of the following compounds show aromatic properties, and others do not.
1. Predict which ones are likely to be aromatic, and explain why they are aromatic.
(n)
(o)
(i) Classify the following molecules as aromatic, nonaromatic, or antiaromatic.
(ii) For the aromatic and antiaromatic molecules, solve for n in Hückel’s/Breslow’s rule. For the other molecules, explain which of the rules of aromaticity is being broken.
(b)