1. 14.AROMATIC COMPOUNDS. ( approx. lecture time: 2 lectures) Topics covered: 14.1-14.7A,14.7D,14.8A,14.9. Benzene more than just cyclic conjugation: aromatic stabilization

2. Some Simple Benzene Derivatives

3. The Halifax Explosion of 1917 Halifax Explosion The Halifax Explosion occurred on Thursday, December 6, 1917, when the city was devastated by the huge detonation of the SS Mont-Blanc, a French cargo ship fully loaded with wartime explosives, which accidentally collided with the Norwegian ship the SS Imo in "The Narrows" section of Halifax Harbour. About 2,000 people were killed and over 9,000 people were injured. The Halifax Explosion remains the World’s largest accidental explosion. Picric Acid TNT; 2,4,6-trinitrotoluene If you are from Nova Scotia, you will definitely know about it!

4. The Phenomenon of Aromatic Stabilization

5. Molecular Orbital Picture of the  Bonding in Benzene

6. Mnemonic for Generating Molecular Orbital Energy Levels for Benzene

7. Joining benzene rings to each other will always create an aromatic system ! “mothballs” potent carcinogen

8. Hückel’s 4n + 2 p Electron Rule Hückel’s rule is concerned with compounds containing one planar ring in which each atom has a p z orbital as in benzene. “ Planar monocyclic rings containing 4n + 2  electrons, where n = 0, 1, 2, 3, and so on (i.e., rings containing 2, 6, 10, 14..  electrons) should be aromatic, i.e., show exceptional stability relative to similar systems without this electron count”

9. Examples of Hückel’s 4n + 2  Electron Rule Cyclooctatetraene

11. Imidazole Imidazole is an aromatic compound that is important in biological systems. The two nitrogens are not equivalent! Learn how to tell them apart.

12. The DNA Bases are Aromatic Compounds

13. Sunscreens and Sunblocks Sunscreens and Sunblocks (Organic chemists can become wealthy without making drugs) Sunblocks: just “blocks” the sun’s rays. Use TiO 2 and ZnO 2. But will look geeky. Sunscreens: organic compounds that converts the UV light into thermal energy. These are “designer compounds” so we can charge much more than inorganics. They also have many industrial uses! PABA Oxybenzone Avobenzone 4-MBC Tinosorb M