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ORGANIC CHEMISTRY
1.3 The chemistry of carbon / hydrogen
containing compounds
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HYDROCARBONS
THE SIMPLEST TYPE OF
ORGANIC COMPOUNDS
HYDROCARBONS - CONTAIN ONLY C, H
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HYDROCARBONS
H
H H H H
HH C H H
H
H C C C C
H C
C
C H
H
C
H H H H
HH C H H
H
H
H
H
C H
H
H C C
H
H C
H H
H C C C C H
H H H H
H
H
ALKYNES
H C C C H
H
H
H H
H C C C C C H
H
H H
at least
one
triple
bond
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COMMON HYDROCARBON TYPES
H
Saturated
hydrocarbons
H H H H
HH C H H
H
H C C C C
H C
C
C H
H
C
H H H H
HH C H H
H
H
H
H
Unsaturated
hydrocrabon
C H
H
H C C
H
H C
H C C C C H
H H H H
H
H
ALKYNES
H H
H C C C H
H
H
H H
H C C C C C H
H
H H
only
single
bonds
at least
one
double
bond
at least
one
triple
bond
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HYDROCARBON DERIVATIVES
One or more H’s are replaced
with an atom of O, N, S, F, Cl, Br, I
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HYDROCARBON DERIVATIVES
H H H H
H
H C C C C
C Cl
H H H H
H
H H H H
H
C
H C
C C C OH
H H H H
H
H H H H
H C C C C
C O
H H H H
H
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Saturated Hydrocarbons cont’d
Fig. 1.2 Terms for organic compounds.
3-6)
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1.4 Alkanes
• Acyclic (no rings) = alkane
H
H H H H
HH C H H
H
H C C C C
H C
C
C H
H
C
H H H H
HH C H H
H
H
H
H
C H
H
• Cyclic (contains rings)
Section 1.12
H
H C C
H
H C
H
H C C C H
H
H H
H C C C
C C H
C
HCH H H
H
C
C
H H
C
H C C C C C H
H
H H
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1.4 Alkanes (cont.)
 Are acyclic “saturated” hydrocarbons.
 Contain only single bonds C-C
 Every carbon is sp3 (tetrahedral)
 General formula of alkanes is CnH2n+2
CH4
C2H6
C3H8
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1.4 Alkanes
← Fig. 1.3
Molecular
structures of (a)
methane, (b)
ethane, and (c)
propane, the three
simplest alkanes.
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1.5 Structural formulas
 Expanded (Lewis structure)
H
|
H-C-H
|
H
Methane
H H
| |
H-C-C-H
| |
H H
Ethane
H HH
| | |
H-C-C-C-H
| | |
H HH
Propane
THESE TAKE A LOT OF SPACE TO DRAW
THEY TAKE A LONG TIME TO DRAW
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1.5 Structural formulas
Condensed (easier and faster to draw)
Methane
Ethane
Propane
CH4
CH3-CH3
CH3-CH2-CH3
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1.5 Structural formulas
Condensed
Octane:
CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH3
More condensed
CH3-(CH2)6-CH3
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1.6 Alkane Isomerism
Linear carbon chain
Octane:
CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH3
Branched carbon chain (acyclic)
CH3
|
CH3-CH-CH2-CH2-CH2-CH2-CH3
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CONSTITUTIONAL ISOMERISM
• Same molecular formula, different
connectivity of the atoms
• As the #C increase the #isomers
increases very rapidly (Table 1.1)
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1.7 Conformations of alkanes
H
H
C
H
H
C
H
MOST ATOMS ATTACHED
BY A SINGLE BOND ARE
FREE TO ROTATE AROUND
THE BOND
H
The relative orientation of the atoms is called a CONFORMATION
HOW MANY CONFORMATIONS ARE THERE?
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CONFORMATIONS OF BUTANE
SAWHORSE PROJECTIONS OF PREVIOUS SLIDE
SYN
CH3CH3
C H
C
H
H
H
GAUCHE
H
CH3H CH
3
C
C
H H
CH3H
C C H
H
CH3
H
ECLIPSED
ANTI
H
GAUCHE
CH3H H
C C
H CH3
CH3H
C C CH3
H
H
H
ECLIPSED
CH3
CH3
C
H
C
H H
H
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1. 8 IUPAC RULES
systematic nomenclature
I nternational
U nion of
P ure and
A pplied
C hemistry
colloquially:
“eye-you-pac”
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FEATURES OF THE IUPAC SYSTEM
It is a system where every compound (even isomers)
has a unique name.
If the rules are followed, everyone gets the same name
for a given compound.
Once given the name, anyone can draw the structure
of the compound.
STRUCTURE
IUPAC
NAME
WORKS
BOTH
DIRECTIONS
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1.2
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IUPAC METHOD
1. Find the longest continuous chain of
carbon atoms and name it using the linear
alkane names.
2. Number the chain starting from the end
nearest a branch.
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IUPAC METHOD
3. Give each substituent a name based on the
number of carbon atoms it has.
4. Give each substituent a locant number
determined by its location on the chain.
5. Assemble the name.
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RULE 1. FIND THE LONGEST CONTINUOUS
CHAIN OF CARBON ATOMS AND NAME IT
C-C
C-C-C-C-C-C-C-C-C
C
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it won’t always be
the horizontal one
as shown here
NONANE
all possibilites must be examined
C-C
C-C
C- C-C-C-C-C-C-C-C
C
try these also ……..
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C-C-C- C-C-C-C-C-C
C
8
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RULE 2. Number the chain starting from
the end nearest a branch
1 2
C-C
nonane
3 4 5 6 7 8 9
C-C-C-C-C-C-C-C-C
C
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RULE 3. Give each substituent a name based on
the number of carbon atoms it has.
substituent
C-C
1 2
nonane
3 4 5 6 7 8 9
C-C-C-C-C-C-C-C-C
C
substituent
Groups attached to the main chain are called
substituents.
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(substituents)
methyl
ethyl
propyl
butyl
pentyl
hexyl
heptyl
octyl
nonyl
decyl
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RULE 3. Give each substituent a name based on
the number of carbon atoms it has.
ethyl
C-C
1 2
nonane
3 4 5 6 7 8 9
C-C-C-C-C-C-C-C-C
C
methyl
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Rule 4. Give each substituent a locant number
determined by its location on the chain.
4-ethyl
C-C
1 2
nonane
3 4 5 6 7 8 9
C-C-C-C-C-C-C-C-C
C
2-methyl
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RULE 5. Assemble the name.
LOCANT
number
SUBSTITUENT
word
MAIN CHAIN
STEM
word
name of the
substituent
indicates
position of the
substituent
on the chain
indicates the
number of
carbon atoms
in the chain
ENDING
“ane”
suffix
indicates
the type
of compound
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PUNCTUATION RULES
1. Numbers are separated from words
by hyphens
2-methyl…….
2. Numbers are separated from numbers
by commas. 2,3- ……..example coming shortly
3.Substituents are named in alphabetical
……4-ethyl-2-methyl….
order
4. All words are joined - no breaks
……methylnonane
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ASSEMBLING A NAME
4-ethyl
C-C
1 2
nonane
3 4 5 6 7 8 9
C-C-C-C-C-C-C-C-C
C
2-methyl
4-ethyl-2-methylnonane
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ORGANIC NOMENCLATURE
4
3
2
1
butane
CH3 CH2 CH CH3
1. find longest chain
and name
CH3
2- methyl
2. number from end
nearest a branch
3. name substituents
4. locant number
5. assemble name
2-methylbutane
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Name this compound
1
2
3
CH3 CH2 CH CH3
CH2 CH3
4
5
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Name this compound
4
3
2
1
CH3 CH2 CH CH2 CH2 CH3
CH2 CH2 CH3
5
6
7
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Use multipliers if there are MORE THAN
ONE of the same substituent
2
3
4
5
6
7
8
9
10
DITRITETRAPENTAHEXAHEPTAOCTANONADECA-
These are ignored
when alphabetizing
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How would you name this one?
Every substituent
must get a number
CH3
CH3 CH2 C
CH2 CH2 CH3
1
4
2
3
5
6
CH3
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