This document discusses anthracene and phenanthrene, providing their IUPAC and common names, resonance structures showing four structures for anthracene and the structures for phenanthrene. It also describes that both undergo oxidation at the 9 and 10 positions on the central ring, with anthracene sacrificing 12 kcal/mol of energy and phenanthrene sacrificing 20 kcal/mol. Bromination of both occurs at the C9 position, with anthracene more prone to addition forming 9,10-dibromo-9,10-dihydro derivatives.

1. Anthracene and phenanthrene
(i) Systematic or substitutive or IUPAC nomenclature, and
(ii) Common nomenclature
(i) Systematic or substitutive or IUPAC nomenclature
(ii) Common nomenclature

2. Resonance structures of anthracene (Resonance energy = 84 kcal/mol)
There are four resonance structures of anthracene which are shown below:

3. The resonance structures of phenanthrene are shown below (resonance energy
92kcal/mol).

4. Reactions of anthracene and phenanthrene
(a) Oxidation reaction
Both anthracene and phenanthrene are oxidized and reduced in the 9, 10 positions.
Attack at the 9 and 10 positions of the middle ring of anthracene and phenanthrene
leaves two benzene rings intact. Anthracene sacrifice 12 kcal/mol energy (84-2×36
=12; Phenanthrene sacrifice 20 kcal/mol energy (92-2×36=20).

5. Reduction of anthracene and phenanthrene

6. Electrophilic aromatic substitution reaction
Bromination of anthracene and phenanthrene take place at the position-9 (at C9
). In both cases, especially for
anthracene, there is a tendency for addition to take place with the formation of 9,10-dibromo-9,10-dihydro
derivatives.
They also undergo nitration, sulfonation, Friedel-Crafts reactions.

8. Question: How can you chemically distinguish between anthracene and phenanthrene?
Synthesis of anthracene (Haworth Synthesis)

9. Synthesis of phenanthracene (Haworth Synthesis)