organic chemistry the chemistry of carbon and carbon-based compounds

Organic Chemistry

The chemistry of carbon and carbon-based compounds

Carbon is unique amongthe elements because:

it can have up to four bonds per C atom --

single, double, or triple bonds

--

--

it can form REALLY long chains of C atoms

its bonds are strong

–C–C– C=C –C=C–

Why is carbon so special?

Organic ChemistryOrganic Chemistry is everywhere!Smells & tastes fruits, chocolate, fish, mint

Medications Aspirin, Tylenol, Decongestants, Sedatives

Addictive substances Caffeine, Nicotine, Alcohol, Narcotics

Hormones/Neurotransmitters Adrenaline, Epinephrine

Food/Nutrients Carbohydrates, Protein, Fat, Vitamins

Genetics DNA, RNA

Consumer products Plastics, Nylon, Rayon, Polyester

Drawing Organic Structures

Butane: C4H10

C C C C

H

H

H

H

H

H

H

H

H

H

CH3 CH2 CH2 CH3

CH3CH2CH2CH3

CH3(CH2)2CH3

Shortcuts make structures easier & faster to draw

Line Structure• Only shows bonds• C atoms assumed at each end

and intersection of bonds• H atoms not shown• Assume 4 bonds to each C• Fulfill C’s 4 bonds by adding H’s

Lewis Structure

Condensed Structures

Carbon Atoms

Practice Drawing Structures

Formula Lewis Condensed Line

C2H6CH3CH3

C3H8CH3CH2CH3

C5H12CH3CH2CH2CH2CH3

or CH3(CH2)3CH3

C6H14CH3CH2CH2CH2CH2CH3

or CH3(CH2)4CH3

Types of Organic CompoundsClassified according to functional groups

Alkane

Alkene

Alkyne

Haloalkane

Alcohol

Ether

Ketone

Aldehyde

Carboxylic acid

Amine

Amino acid

AmideO

H

O

NH2

O

OH

O

H2NOH

O

OH

Cl

Br

NH2

C C

O

Big Idea in Organic Chemistry

Structure controls Function

Each functional group has predictable reactivity

Naming Alkanes (or Paraffins)• Made only of C and H

• All C atoms are tetrahedral(only C-C single bonds)

• General formula = CnH2n+2

(CH4, C2H6, C3H8, C4H10,

etc.)

• Alkanes are named based on the number of carbons in the longest chain!

Naming Basic Alkanes

Alkane Alkyl substituents# of

C atoms

CH4

CH3CH3

CH3CH2CH3

CH3CH2CH2CH3

-CH3

-CH2CH3

-CH2CH2CH3

Methyl

Ethyl

Propyl

etc.

Methane

Ethane

Propane

Butane

Pentane

Hexane

Heptane

Octane

Nonane

Decane

Root: number of C atomsSuffix: functional group (-ane for alkanes) (-yl for alkyl groups)

1

2

3

4

5

6

7

8

9

10

Linear vs. Branched Alkanes• General formula = CnH2n+2 (CH4, C2H6, C3H8, C4H10)

• Can have linear or branched alkanes

C5H12

• Same molecular formula, different structure: structural isomers

• Branches, including other atoms bonded, are called substituents. Common non-carbon ones are:

C CH2H3C

H

CH3

CH3

–NO2 –NH2 –F –Br –I nitro amino fluoro bromo iodo

Naming Branched Alkanes (IUPAC)

1. Root name: name of longest continuous C chain (parent chain)• Two equally long? Choose the one with more branches

2. Number C atoms in chain, starting at end with first branch

3. Identify substituents, give each a number (C it is connected to)• Two or more identical substituents: use prefixes (di-, tri-, tetra-, etc.)

4. List substituents alphabetically before root name• Do not alphabetize prefixes

5. Punctuation: commas separate numbers from each otherhyphens separate numbers from namesno space between last substituent & root name

4-ethyl-3,5-dimethyloctane1

2

3

65

8

74

4-ethyl

3-methyl and 5-methyl = 3,5-dimethyl

Octane

Provide each counterpart.

4-ethyl-2-methylhexane

octane

1

2

3

4

5

6

7

8

5-ethyl-3-methyl

(C11H24)

(C9H20)

Naming Alkanes Practice

a. 2,4-dimethylpentane

b. 2,4-dimethylhexane

c. 2,4,6-trimethylheptane

d. 3-ethyl-2-methylpentane

e. 2,3-dimethylpentane

f. 2,2-dimethylhexane

g. 2,5-dimethylhexane

h. 4-methylheptane

IsomersThe fat dog shook himself, and then rolled over on the wet rug.

The dog shook the fat rug, then rolled over and wet on himself.

These two statements use the same words...but have very different meanings!

OR

Likewise, isomers may have the same formula, but have very different structures…

Structural Isomer Practice• On piece of your own paper, draw AND name

ALL of the isomers for the following alkanes:

Formulas # isomers

If you complete that, try to draw and name all of the isomers for octane (C8H18) in your HW. There are 18 of them!

Some of your drawings may look different, but they are only different structures (isomers) if they also have different names

C5H12

C6H14

C7H16

359

Structural Isomers: C5H12

pentane

2-methylbutane

2,2-dimethylpropane

Structural Isomers: C6H14

hexane

2-methylpentane

3-methylpentane

2,3-dimethylbutane

2,2-dimethylbutane

Structural Isomers: C7H16

heptane

2-methylhexane

3-methylhexane

2,2-dimethylpentane

2,3-dimethylpentane

Structural Isomers: C7H16

2,4-dimethylpentane

3,3-dimethylpentane

3-ethylpentane

2,2,3-trimethylbutane

1 23

4 56

Naming Practice

F ClF

Cl

IBr

Cl

Br

5-chloro-2-fluorohexane

2-chloro-5-fluorohexane 2-chloro-4-fluoro-2,3-dimethylpentane

2-bromo-3-ethyl-4-iodopentane 2-bromo-4-chloro-3-isopropylpentane

Two equal numbering options? Number based on alpha order

12

34

5

6

Provide each counterpart.

3-bromo-2-chlorohexane

heptane

2-methyl-1-nitrobutane

heptane2-amino-6-nitro-3-propyl

2-ethyl-1,1-diiodo I

I

Cl

Br

NO2

NH2 NO2

Structural Isomers

What are the possible structural isomers of C3H7Br?

BrBr

1-bromopropane 2-bromopropane

What are the possible structural isomers of C4H9Cl?

Cl

Cl

Cl

Cl

1-chlorobutane

2-chlorobutane

2-chloro-2-methylpropane

1-chloro-2-methylpropane

Cycloalkanes• Alkanes with closed ring(s) of C atoms• General formula: CnH2n (C3H6, C4H8, C5H10, etc.)• Naming: use cyclo- prefix before alkane name

cyclopropanen = 3

cyclopentanen = 5

cyclobutanen = 4

cyclohexanen = 6

Naming substituted cycloalkanes:• 1 substituent: no numbering necessary• 2 or more substituents: lowest numbering scheme, then

by alphaCH3

methylcyclopentane

CH3

Cl 1-chloro-3-methylcyclohexane

C3H6 C4H8 C5H10 C6H12

1-chloro-5-methylcyclohexane

Fun Common Names

boxanewindowpane

basketane

brokenwindowpane

Teepane