ORGANIC CHEMISTRY
STUDY
OF
CARBON-CONTAINING
COMPOUNDS
H
H
CH
H
HO
Methane
Complicated organic molecule
Chapter 1
1
SHORT HISTORY OF
CHEMISTRY
PRE-1828 ERA
TWO MAJOR DISCIPLINES EMERGING
INORGANIC - MINERAL CHEMISTRY
ORGANIC CHEMISTRY - PLANTS AND ANIMALS
Chapter 1
2
BERZELIUS’
DEFINITIONS
ORGANIC COMPOUNDS
CHARACTERISTIC PRODUCTS OF LIVING ORGANISMS
SUBSTANCES LIKE SUGAR AND OLIVE OIL
INORGANIC COMPOUNDS
PRODUCTS FROM NON-LIVING ENVIRONMENT
SUBSTANCES LIKE WATER AND IRON
Chapter 1
3
Vital Force Theory
INORGANIC MATERIALS COULD BE CONVERTED
TO ORGANIC MATERIALS IN THE PRESENCE OF A
VITAL FORCE FOUND ONLY IN LIVING BODIES.
Chapter 1
4
Organic Little Studied
In addition to Vital Force Theory
Organics hard to purify
Appeared to violate the Law of Definite Proportions
Isomerism problem - same molecular formula but
Different compounds
Consider ethanol and dimethyl ether
Chapter 1
5
1828
Woehler’s urea synthesis
Ammonium isocyanate + heat ------> urea
NH4CNO
NH2CONH2
“I have been able to make urea without aid of kidney
of man or dog.
1828
Chapter 1
6
Deutsche Museum
Chapter 1
7
STYLES
Chapter 1
8
Schubert
Chapter 1
9
Liszt - Young
Chapter 1
10
BIRTHS
JULES VERNE - AROUND THE WORLD IN 80 DAYS
LEO TOLSTOY - ANNA KORNINA
HANS CHRISTIAN ANDERSON
MARRIAGES
BARTHOLOMEW HEIFNER AND POLLY GRISHAM.
IN SHELBY COUNTY, ENGLAND
Chapter 1
11
IMPORTANT EVENTS
ANDREW JACKSON ELECTED PRESIDENT OF USA
DEFEATED JOHN Q. ADAMS
RUSSO-PERSIAN WAR ENDED
FATH ‘ALI SHAH’ AND RUSSIAN COUNTERPART
SIGNED TURKMANCHAI TREATY
GAVE RUSSIA - GEORGIA, ARMENIA, AND AZERBAIJAN
Chapter 1
12
Post 1828
•Over 18,000 million compounds have been synthesized
•Pharmaceuticals
•Biochemicals
•Plastics
•Agrichemicals
•Paints
Chapter 1
13
Why so many organic?
FORMS COVALENT BONDS WITH NON-METALS
H
O
N
X
P
S
Se
FORMS COVALENT BONDS WITH MANY METALS
Li
Mg
Al
Cd
Chapter 1
Fe
14
AND
WITH ITSELF
C
C
C
C
C
C
CH
C
C
C
C
CH
C
C
C
C
C
C
CHAINS
CHAINS WITH BRANCHES
RINGS
No limit
Chapter 1
15
Allotropic Forms of Carbon
Graphite --layers of carbon atoms
Diamond -- 3-D tetrahedral
Buckmeisterfullerene (Bucky Ball) -- Soccer ball
Chapter 1
16
Atomic Structure
• protons, neutrons, and electrons
• isotopes
12
C
6
14
6
C
=>
Chapter 1
17
Atomic Orbitals
2s orbital (spherical)
2p orbital
Chapter 1
=>
18
Electronic Configurations
• Aufbau principle:
Place electrons in
lowest energy
orbital first.
• Hund’s rule:
Equal energy
orbitals are halffilled, then filled.




=>
Chapter 1
19
Table 1-1
Chapter 1
20
=>
Bond Formation
• Ionic bonding: electrons are transferred.
• Covalent bonding: electron pair is shared.
=>
Chapter 1
21
Periodic table
• Here He Beneath Blue Sea ©, Not
• One Frigate Near. Na Might All Sinking
• Poopdecks Shot Cleanly Away,
Potassium,Sodium
• H
He
• Li Be B
C
N
O F
Ne
• Na Mg Al Si
P
S Cl
A
• K Ca
Chapter 1
22
Lewis Structures
• Bonding electrons
• Nonbonding electrons or lone pairs
H
H C O
H
H
Satisfy the octet rule!
Chapter 1
=>
23
TIPS
• Neutral atoms
Carbon 4 bonds (double bonds count as 2
triple bonds count as 3) and NO lone pairs.
Nitrogen 3 bonds and one lone pair
Oxygen 2 bonds and two lone pairs
BORON 3 bonds BUT no lone pairs
One who writes MORE than 3 bonds about a
neutral BORON is a MORON
Chapter 1
24
TIPS2
C
- H
+
+
H N H
H
-
C
+
H
+
N H
H
-H+
-H+
C
N
H
+
O H
+H
+
O
Chapter 1
-H+
O
25
Multiple Bonding
=>
Chapter 1
26
EXAMPLES
CO2
SO2
C2H3N
C3H6O isomer problem
Chapter 1
27
Electronegativity and
Bond Polarity
Greater EN means greater polarity
=>
Chapter 1
28
EXAMPLES OF BOND
POLARITY
C------Br
Br--------Cl
C-------Li
C-------N
Chapter 1
29
Calculating Formal Charge
•
•
•
•
For each atom in a valid Lewis structure:
Count the number of valence electrons
Subtract all its nonbonding electrons
Subtract half of its bonding electrons
3-
H O
O
H C C O
O
P
O
H
Chapter 1
O
=>
30
EXAMPLES
C2H3O
HONH3
+
Chapter 1
31
Ionic Structures
H H
H C N H
H H
X
Na
O CH3
+
-
Cl
+
or Na
_
O CH3
=>
Chapter 1
32
Resonance - More than
one Lewis Diagram
Acetate ion
-1
O
C
H
C
H
O
H
O
:N
O
Chapter 1
Example=>
33
Resonance Example
_
_
O
•
•
•
•
_
O
O
O
N
N
N
O
O
O
O
O
Consider writing Lewis structure for NO3-2
The real structure is a resonance hybrid.
All the bond lengths are the same.
Each oxygen has a -1/3 electrical charge.
=>
Chapter 1
34
Resonance Rules
Must be legitimate Lewis structures
CH3
CH3
-
H3C N CH2
+
CH3
H3C N
CH2
CH3
NO NO
Pentavalent nitrogen atom!!
Chapter 1
35
• Only electrons can be moved (usually lone
pairs or pi electrons).
Chapter 1
36
Resonance structures?
O
O
:N
:N
O
H
H
C
H
O
O
OK
H
C
H
H
NO NO
OH
H
Chapter 1
37
Nuclei positions and bond
angles remain the same.
C=C-C+
+C-C=C
CAN”T SAY “if you turn one around 180o you would
End up with same structure”
Doing so would violate this rule
Chapter 1
38
The number of unpaired
electrons remains the same
..
H C CH
3
.
.
H C CH
3
3
3
NO NO
Chapter 1
39
DELOCALIZATION OF
CHARGE USUALLY IS
STABILIZING
Delocalization of charge results in fractional charges
at alternate atoms
Chapter 1
40
Major Resonance Form
• has as many octets as possible.
• has as many bonds as possible.
• has the negative charge on the most
electronegative atom.
• has as little charge separation as
possible.
Example=>
Chapter 1
41
Major Contributor?
H +
H
C N
H
H
H
+ H
C N
H
H
major
minor,
carbon does
not have octet.
=>
Chapter 1
42
Other Examples
Chapter 1
43
Chemical Formulas
H O
• Full structural formula
(no lone pairs shown)
H C C O H
H
O
• Line-angle formula
OH
• Condensed structural
formula
• Molecular formula
• Empirical formula
Chapter 1
CH3COOH
• C2H4O2
• CH2O
=>
44
BrØnsted-Lowry
Acids and Bases
• Acids can donate a proton.
• Bases can accept a proton.
• Conjugate acid-base pairs.
O
CH3
acid
C OH
O
+ CH3
NH2
CH3
C O
-
conjugate
base
base
+
CH3
+
NH3
conjugate
acid
=>
Chapter 1
45
EXAMPLES
BASE
CH3CO2H
+
CONJ ACID
:NH3
CH3CO2CONJ BASE
ACID
+ OH
O:
+
H3C
OH
+ NH4+
H2SO4
H3C
+ -HSO4
OH
Amphoterism - ability to behave as an acid or base
Chapter 1
46
Acid and Base Strength
•
•
•
•
Acid dissociation constant, Ka
Base dissociation constant, Kb
For conjugate pairs, (Ka)(Kb) = Kw
Spontaneous acid-base reactions
proceed from stronger to weaker.
O
CH3
C OH
pKa 4.74
O
+ CH3
NH2
pKb 3.36
CH3
C O
-
pKb 9.26
+
CH3
+
NH3
pKa 10.64
=>
Chapter 1
47
EXAMPLES
Will NaOH neutralize phenol (C6H5OH)?
NaOH
+
C6H5OH
HOH
+ C6H5ONa
pKa = 10
pKa = 15.7
YES!!
Stronger acid
_
-OH
+
C6H5OH
Weaker acid
+ C6H5OHOH
Chapter 1
48
Determining Relative Acidity
• Electronegativity
• Size
• Resonance stabilization of conjugate
base
=>
Chapter 1
49
Electronegativity
As the bond to H becomes more
polarized, H becomes more positive and
the bond is easier to break.
=>
Chapter 1
50
Size
• As size increases, the H is more loosely
held and the bond is easier to break.
• A larger size also stabilizes the anion.
=>
Chapter 1
51
Resonance
• Delocalization of the negative charge on the
conjugate base will stabilize the anion, so the
substance is a stronger acid.
• More resonance structures usually mean
greater stabilization.
O
CH3CH2OH
<
CH3C OH
O
<
CH3
S
O
Chapter 1
OH
=>
52
Lewis Acids and Bases
• Acids accept electron pairs = electrophile
• Bases donate electron pairs = nucleophile
CH2 CH2
nucleophile
+
BF3
electrophile
_
BF3
CH2
+
CH2
=>
Chapter 1
53
End of Chapter 1
Chapter 1
54