Organic Chemistry Notes

Organic Chemistry

• Chemistry focused on carbon-based molecules (C, N, O, H).
• These are the basic building-block elements for biological systems.

Carbon’s Special Properties

• Four valence electrons enable carbon to form 4 bonds.
• Versatile bonding: single, double, and triple bonds (with C, N, O).
• Non-metal forming covalent bonds with other non-metals (H, O, N, etc.) allows for large, customized molecules.

Hydrocarbons

• Alkanes: Example - Ethane ($CH<em>3CH</em>3$)
• Alkenes: Example - Ethylene ($CH<em>2=CH</em>2$)
• Alkynes: Example - Acetylene ($CH≡CH$)
• Aromatic: Example - Benzene ($C<em>6H</em>6$)

Representations of Organic Molecules

• Condensed Formula: e.g., $CH<em>3CH</em>2CH<em>2CH</em>3$
• Skeletal Representation: A simplified way to draw organic molecules.

Isomers

• Structural Isomers: Same formula, different bond arrangements (connectivity).
• Geometric Isomers: Same formula, same bond arrangements, different spatial orientation (cis/trans).

$\,\,C<em>2H</em>4$ Orbitals

• σ and π bonds are present.
• $sp^2$ hybridization occurs.

Double Bond Rigidity

• Presence of a $\,\,\pi$ bond.
• Restricted rotation around a double bond.

Basic Hydrocarbon Nomenclature (Linear Alkanes)

• Methane ($CH<em>4$) -> Methyl (-$CH</em>3$)
• Ethane ($CH<em>3CH</em>3$) -> Ethyl (-$CH<em>2CH</em>3$)
• Propane ($CH<em>3CH</em>2CH<em>3$) -> Propyl (-$CH</em>2CH<em>2CH</em>3$)
• Butane ($CH<em>3CH</em>2CH<em>2CH</em>3$) -> Butyl (-$CH<em>2CH</em>2CH<em>2CH</em>3$)
• Pentane ($CH<em>3CH</em>2CH<em>2CH</em>2CH<em>3$) -> Pentyl (-$CH</em>2CH<em>2CH</em>2CH<em>2CH</em>3$)
• Hexane ($CH<em>3CH</em>2CH<em>2CH</em>2CH<em>2CH</em>3$) -> Hexyl (-$CH<em>2CH</em>2CH<em>2CH</em>2CH<em>2CH</em>3$)
• Heptane ($CH<em>3(CH</em>2)<em>5CH</em>3$) -> Heptyl (-$CH<em>2(CH</em>2)<em>5CH</em>3$)
• Octane ($CH<em>3(CH</em>2)<em>6CH</em>3$) -> Octyl (-$CH<em>2(CH</em>2)<em>6CH</em>3$)
• Phenyl (-$C<em>6H</em>5$)
• Methylene (-$CH_2$)

Functional Groups

• Hydrocarbon Only: Alkanes, Alkenes, Alkynes, Aromatics
• Oxygen-containing: C-O vs. C=O (Alcohols, Ethers, Ketones, Aldehydes, Carboxylic Acids, Esters)
• Nitrogen-containing: Amines, Amides
• Valence/Bonds: H (1), C (4, no lone pairs), O (2, 2 lone pairs), N (3, 1 lone pair)

Hydrocarbon Functional Groups

• Alkene: C=C
• Alkyne: $\,-C≡C-\,$
• Aromatic: Contains a benzene ring (resonance).

Oxygen-Containing Functional Groups

• Alcohol (Hydroxyl): R-OH
• Ether: R-O-R'
• Ketone: Carbonyl (C=O) bonded to carbon in both R and R'
• Aldehyde: Carbonyl (C=O) bonded to at least one hydrogen
• Carboxylic Acid: R-COOH
• Ester: R-COOR'

Nitrogen-Containing Functional Groups

• Amines: Organic relatives of ammonia ($NH<em>3$); Primary ($NH</em>2R$), Secondary ($NHR<em>2$), Tertiary ($NR</em>3$).
• Amides: $R(C=O)NR_2$