Chapter 11 : Arenes and Aromaticity |
Larger systems of benzene rings fused together
are also well known. These are the polyaromatic hydrocarbons (sometimes referred
PAHs). A collection of images of some common systems are shown below. The planarity
of these extended π systems can be seen when the JSMOL images are rotated.
Make sure you test out the Huckel rule on each of them and check by holding the mouse over
the line drawing.
The chemistry of these systems is similar to that of the parent benzene, but
they are usually more reactive than benzene. Evidence for this can be seen in
the resonance energy data which shows that their resonance energies are less
than the same number of isolated benzenes.
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36 kcal/mol |
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61 kcal/mol |
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83 kcal/mol |
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91 kcal/mol |
© Dr. Ian Hunt, Department of Chemistry |