Organic Chemistry

1. Organic Chemistry

2. At this moment, you are sitting in an “organic” body. Your skin, hair, heart, muscles, and lungs are all made from organic compounds. In fact, the only parts of your body that aren’t mostly organic are your teeth and bones! Medicines, clothing, carpets, and plastic are all made from organic compounds. Outside your window, the grass, trees, squirrels – all organic. What are you having for lunch? Nearly all food is composed of organic compounds – bread, butter, meat, lettuce. For dessert? Sugar, flour, vanilla, and chocolate are all organic. What about a drink? Milk and juice are solutions of organic compounds dissolved in water.

3. “Organic” was defined as coming from living or once-living matter. An organic compound couldn’t be made from inorganic components This was known as “vitalism” – it was a theory that was created from the observation that no one had ever been able to make an organic compound, so they assumed it couldn’t be done Organic compounds had a “vital force” – something you couldn’t cook up in a lab Before 1828…

4. In 1828, a German chemistnamed Friedrich Wohleraccidentally created urea Wohler believed in vitalism,as did most everyone at thattime Wohler’s discovery, accordingto him, was a “great tragedy ofscience… the slaying of abeautiful hypothesis by an ugly fact…” His Petri dish of urea was the ugly fact What Happened?

5. Vitalism wasn’t given upimmediately – Wohler’s ureawas just one experiment However, his experiment gotothers trying – and eventually, other organic molecules were synthesized Vitalism couldn’t stand up to the growing evidence against it It Took time…

6. Even after dozens of organic molecules had been synthesized, there werethose who didn’t want toabandon the vital force theory Louis Pasteur, a very famousscientist, believed that vitalismcould still be used However, other scientistsdeveloped theories to explainorganic chemistry without theuse of vitalism We still use the terms ‘organic’ and ‘inorganic’ from vitalism Some didn’t give up…

7. Modern organic chemistry isthe study of carbon-containingcompounds • Carbon has three majorproperties that make it special • It hybridizes to make sp, sp2, andsp3orbitals (for a total of 4 bonds) • It can form strong single, double, and triple bonds with itself • It can make a variety of structures Why Carbon?

8. Carbon should only form 2 bonds, but it forms 4, as in methane (CH4) When it forms four single bonds, it mixes, or ‘hybridizes’, its 2s orbital and its three 2p orbitals to make four 2sp3orbitals When it forms a double bond, it hybridizes its 2s orbital and two of its 2p orbitalsto make three 2sp2orbitals(and it still has one 2p orbital) When it forms a triple bond or two double bonds, it hybridizes its 2s orbital and one of its 2p orbitals to make two 2sp orbitals (and it still has two 2p orbitals) Hybridization

9. Very few elements can form bonds with themselves – actually, only Carbon and Silicon have any real ability to do this It’s not just single bonds, carbon can bond with itself to make double bonds and triple bonds as well (can it form quadruple bonds?) Being able to bond with itself and a number of other atoms means it can make a nearly endless variety of compounds Carbon-Carbon Bonds

10. Because carbon can bond withitself and other atoms, it canform a variety of structures • Straight chains • Branched chains • Rings • Sheets (like graphite) • Tubes • Spheres • This is unique to carbon Organic structure

11. Carbon can do so much, make so many different molecules Imagine how many different kinds of molecules there are in your body – skin, hair, kidneys, heart, brain, muscles, veins, arteries, genes – all of these are organic, and all of them are different! And that’s just your body – think of all the animals and plants in the world! That’s why life is made of carbon!

12. Most organic compounds weuse come from ‘fossil fuels’,oil and coal we find buriedin the earth or sea Animals and plants that diedlong ago were transformed into fossil fuels by bacteria and extremely high pressure We extract these fuels from the earth and refine them into hundreds of different products – we’ll learn more about this next day Where do they come from?