Some New Allotropes

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Some New Allotropes

• Fullerenes 5- and 6-membered rings arranged to
  form a soccer ball structure.
• Nanotubes half of a C60 sphere fused to a
  cylinder of fused aromatic rings.

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Common Names of Benzene Derivatives
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Disubstituted Benzenes
The prefixes ortho-, meta-, and para-
are commonly used for the 1,2-, 1,3-, and
1,4- positions, respectively.
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3 or More Substituents
Use the smallest possible numbers, but the carbon
with a functional group is 1.
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Common Names forDisubstituted Benzenes
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Phenyl and Benzyl
Phenyl indicates the benzene ring attachment.
The benzyl group has an additional carbon.
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Physical Properties

• Melting points More symmetrical than
  corresponding alkane, pack better into crystals,
  so higher melting points.
• Boiling points Dependent on dipole moment, so
  ortho gt meta gt para, for disubstituted benzenes.
• Density More dense than nonaromatics, less dense
  than water.
• Solubility Generally insoluble in water. gt

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IR and NMR Spectroscopy

• CC stretch absorption at 1600 cm-1.
• sp2 C-H stretch just above 3000 cm-1.
• 1H NMR at ?7-?8 for Hs on aromatic ring.
• 13C NMR at ?120-?150, similar to alkene carbons.
  
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Mass Spectrometry
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UV Spectroscopy
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