Drawing Organic StructuresFunctional GroupsConstitutional Isomers Dr. Clower CHEM 2411 Spring 2014 McMurry (8th ed.) sections 1.12, 3.1, 3.2
Draw these structures… • C2H6 • CH4O • C3H6(contains C=C) • C4H10(multiple possible answers)
More Lewis structures… • CH5N • CHN • HNO3 • Remember… • Keep in mind total available valence electrons • Try to minimize formal charges • Patterns for formal charge
Drawing Organic Structures • Example: isopropyl alcohol (C3H80) • Lewis structure • Show all bonds, atoms, lone pairs • Condensed structure • Omit some bonds (C─C, C─H, O─H, N─H) • Often omit lone pairs • Skeletal structure/line-angle drawing • Show bond framework as lines • C atoms at intersections of lines (bonds) and end of each line • H atoms bonded to C are not shown • Heteroatoms (atoms other than C and H) are shown
Interpreting line-angle structures • What is the molecular formula for adrenaline? • What is the molecular formula for thalidomide?
Drawing Organic Structures • Draw Lewis and line-angle structures for this condensed structure: (CH3)3CCH2COCHCH2
Functional Groups • Collection of atoms at a site within a molecule with a common bonding pattern • Reacts in a typical way, generally independent of the rest of the molecule • Four broad classes • Hydrocarbons • Compounds containing O • Compounds containing N • Compounds containing S or P
1. Hydrocarbons • Alkane: single bonds, sp3carbons • Cycloalkane: carbons form a ring • Alkene: double bond, sp2 carbons • Cycloalkene: double bond in ring • Alkyne: triple bond, sp carbons • Aromatic (arene): contains a benzene ring • Not a hydrocarbon, but related… • Alkyl halide: R─X • R = any carbon group • X = halogen
2. Compounds containing oxygen • Alcohol: R─OH • Ether: R─O─R' • Carbonyl group: C=O • Aldehyde: RCHO • Ketone: RCOR'
Carboxylic acids and their derivatives • Carboxylic Acid: RCOOH • Acid Chloride: RCOCl • Ester: RCOOR' (RCO2R’) • Amide: RCONH2 • Acid Anhydride: RCO2COR
3. Compounds containing nitrogen • Amines: RNH2, RNHR', or R3N • Amides: RCONH2, RCONHR, RCONR2 • Nitrile: RCN
4. Compounds containing S or P • Phosphates (PO42-) • Thiol(R─SH) • Sulfides (R─S─R) • Sulfoxides (S=O) • Thioester (RCOSR)
Isomers • Isomers have the same molecular formula, but different arrangements of atoms • Constitutional isomers • differ in their connectivity • Stereoisomers • differ in the spatial arrangement/orientation of their atoms
Constitutional Isomers • Molecules with the same molecular formula, but different connectivity • Same number and kinds of atoms • Differ in which atoms are bonded • Example: C4H10 • Straight-chain (“normal”) alkane vs. branched-chain alkane
Constitutional Isomers • Are the following pairs of molecules constitutional isomers, the same molecule, or neither? (a) (b) (c) (d)