The Chemistry of Life: Organic and Biological Chemistry

1. The Chemistry of Life: Organic and Biological Chemistry BLB 11th Chapter 25

3. 25.1 General Characteristics • Structure • Carbon atoms form 4 bonds. • Backbone consists of –C—C— chains or rings. • C—H bond is nearly nonpolar. • Stabilities • C forms strong bonds with other elements. • Alkanes are stable (unreactive). • Functional groups (sect. 5) change reactivity.

4. General Characteristics • Solubility and acid-base properties • Hydrocarbons: nonpolar, neutral soluble in water? ______ • C—H (hydrocarbons) plus functional groups… • -C—O—H polar, slightly acidic (alcohols) • -C—O—O—H acidic (carboxylic acids) • -C—N—R3 basic (amines) • Surfactants combine both properties

5. 25.2 Hydrocarbons • Compounds containing only C and H • Types: • Alkanes (saturated) – single C–C bonds • Alkenes (unsaturated) – double C=C bonds • Alkynes (unsaturated) – triple C≡C bonds • Aromatic – alternating single and double bonds

7. 25.3 Alkanes (CnH2n+2) • Variations • Unbranched (normal, “straight-chained”) • Branched • Cyclic (CnHn) • Structural isomers – same number and type of atoms but different bonding arrangements

8. 3-D ArrangementTetrahedral geometry

10. Butane Isomers

11. Pentane Isomers

12. Nomenclature • Identify longest C chain → base name • Number C atoms – lowest number nearest substituent (branch) • Give position and name substituents. • More than one substituent? • Alphabetical • Prefixes • Some substituents have common names (Table 25.2, p. 1059)

13. Structure & Nomenclature Examples

14. Structure & Nomenclature Examples

15. Structure & Nomenclature Examples

16. Cycloalkanes (CnH2n) most stable stable strained & unstable structure structure

17. Alkenes & Alkynes • Alkenes: C=C double bonds • Named similarly with an –ene ending and give position of double bond • More reactive than alkanes • Different arrangements of substituents may result in geometric isomers. • Geometric isomers – same atoms, same bonds, but different spatial arrangement of substituent groups. • cis- and trans-

18. Structural isomers Geometric isomers

19. Structure & Nomenclature Examples

20. Structure & Nomenclature Examples

21. Alkenes & Alkynes • Alkynes: C C triple bonds • Named similarly with an –yne ending and give position of triple bond • More reactive than alkenes

22. Aromatic Hydrocarbons • Cyclic unsaturated hydrocarbons with alternating single and double C=C bonds. • Ring system often has common name. • Less reactive than alkenes or alkynes

24. Bonding in Benzene

25. 25.4 Organic Functional Groups • Site of reactivity • R, R', R" represent the alkyl (hydrocarbon) group(s) to which functional group is attached.

28. Functional Group examples Aspartame

29. Functional Group examples

30. 25.5 Chirality • Chiral compounds – compounds containing carbon atoms with four different attached groups • Examples: CHFClBr, CH3—C—CH2CH2CH3 • Enantiomers – nonsuperimposable mirror images Br H

31. Enantiomers

32. Enantiomers

33. Chiral Compounds • D- sugars are preferred • L- amino acids are preferred • Drugs • Ibuprofen: one effective, other inactive • Naproxen: one effective, other toxic