Chapter 11 ORGANIC CHEMISTRY STUDYOFCARBON -CONTAINING COMPOUNDS.
54
Chapter 1 1 ORGANIC CHEMISTRY STUDY OF CARBON -CONTAINING COMPOUNDS C H H H H Methane HO C om plicated organic m olecule
-
Upload
britton-rodgers -
Category
Documents
-
view
229 -
download
2
Transcript of Chapter 11 ORGANIC CHEMISTRY STUDYOFCARBON -CONTAINING COMPOUNDS.
Chapter 1 1
ORGANIC CHEMISTRYSTUDY OF CARBON-CONTAINING COMPOUNDS
CH
H
H
H
MethaneHO
Complicated organic molecule
Chapter 1 2
SHORT HISTORY OF CHEMISTRY
PRE-1828 ERA
TWO MAJOR DISCIPLINES EMERGING
INORGANIC - MINERAL CHEMISTRY
ORGANIC CHEMISTRY - PLANTS AND ANIMALS
Chapter 1 3
ORGANIC COMPOUNDSCHARACTERISTIC PRODUCTS OF LIVING ORGANISMS
SUBSTANCES LIKE SUGAR AND OLIVE OILINORGANIC COMPOUNDS
PRODUCTS FROM NON-LIVING ENVIRONMENT
SUBSTANCES LIKE WATER AND IRON
BERZELIUS’ DEFINITIONS
Chapter 1 4
Vital Force Theory
INORGANIC MATERIALS COULD BE CONVERTEDTO ORGANIC MATERIALS IN THE PRESENCE OF A VITAL FORCE FOUND ONLY IN LIVING BODIES.
Chapter 1 5
In addition to Vital Force Theory
Organics hard to purify
Appeared to violate the Law of Definite Proportions
Organic Little Studied
Isomerism problem - same molecular formula butDifferent compounds
Consider ethanol and dimethyl ether
Chapter 1 6
Woehler’s urea synthesis
Ammonium isocyanate + heat ------> urea
NH4CNONH2CONH2
“I have been able to make urea without aid of kidneyof man or dog.
1828
1828
Chapter 1 7
Deutsche Museum
Chapter 1 8
STYLES
Chapter 1 9
Schubert
Chapter 1 10
Liszt - Young
Chapter 1 11
BIRTHSJULES VERNE - AROUND THE WORLD IN 80 DAYS
LEO TOLSTOY - ANNA KORNINA
HANS CHRISTIAN ANDERSON
MARRIAGESBARTHOLOMEW HEIFNER AND POLLY GRISHAM.IN SHELBY COUNTY, ENGLAND
Chapter 1 12
IMPORTANT EVENTSANDREW JACKSON ELECTED PRESIDENT OF USA DEFEATED JOHN Q. ADAMS
RUSSO-PERSIAN WAR ENDED
FATH ‘ALI SHAH’ AND RUSSIAN COUNTERPARTSIGNED TURKMANCHAI TREATY
GAVE RUSSIA - GEORGIA, ARMENIA, AND AZERBAIJAN
Chapter 1 13
Post 1828•Over 18,000 million compounds have been synthesized
•Pharmaceuticals
•Biochemicals
•Plastics
•Agrichemicals
•Paints
Chapter 1 14
Why so many organic?
H O N X P S Se
FORMS COVALENT BONDS WITH MANY METALS
Li Mg Al Cd Fe
FORMS COVALENT BONDS WITH NON-METALS
Chapter 1 15
WITH ITSELF
CC
CC
C
CHAINS
CCH
CCH
C
CHAINS WITH BRANCHES
C CC
CC
C
CC
RINGS
No limit
AND
Chapter 1 16
Allotropic Forms of Carbon
Graphite --layers of carbon atoms
Diamond -- 3-D tetrahedral
Buckmeisterfullerene (Bucky Ball) -- Soccer ball
Chapter 1 17
Atomic Structure
• protons, neutrons, and electrons
• isotopes
C12
6 6C14
=>
Chapter 1 18
Atomic Orbitals
2s orbital (spherical)
2p orbital =>
Chapter 1 19
Electronic Configurations
• Aufbau principle: Place electrons in lowest energy orbital first.
• Hund’s rule: Equal energy orbitals are half-filled, then filled.
=>
Chapter 1 20
Table 1-1
=>
Chapter 1 21
Bond Formation
• Ionic bonding: electrons are transferred.
• Covalent bonding: electron pair is shared.
=>
Chapter 1 22
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 23
Lewis Structures
• Bonding electrons
• Nonbonding electrons or lone pairs
Satisfy the octet rule! =>
C
H
H
H
OH
Chapter 1 24
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 pairsOne who writes MORE than 3 bonds about a
neutral BORON is a MORON
Chapter 1 25
C H-H+
CH- -
C+
N H-H+
N+ H+
N HH+
O
H-H+
O+H+
O
H+
H
TIPS2
Chapter 1 26
Multiple Bonding
=>
Chapter 1 27
EXAMPLES
CO2SO2 C2H3N
C3H6O isomer problem
Chapter 1 28
Electronegativity and Bond Polarity
Greater EN means greater polarity
=>
Chapter 1 29
C------Br C-------Li
C-------NBr--------Cl
EXAMPLES OF BOND POLARITY
Chapter 1 30
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
C
H
H
H
C
O
O P
O
OO
O
3-
=>
Chapter 1 31
EXAMPLES
C2H3O
HONH3
+
Chapter 1 32
Ionic Structures
C
H
H
H N
H
H
H
+
Cl-
Na O CH3 or O CH3Na+
_
X
=>
Chapter 1 33
Resonance - More than one Lewis Diagram
Example
C
O
C OH
H H
-1
Acetate ion
N
O
O
:
Chapter 1 34
Resonance Example
• 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.
=>
N
O
OO
_ _
N
O
OO
_
N
O
OO
Chapter 1 35
Must be legitimate Lewis structures
N
CH3
H3C
CH3
CH2+
-
N
CH3
H3C
CH3
CH2
NO NO Pentavalent nitrogen atom!!
Resonance Rules
Chapter 1 36
• Only electrons can be moved (usually lone pairs or pi electrons).
Chapter 1 37
Resonance structures?
N
O
O
: N
O
O
:
OK
CH
H
H
O
HCH
HOH
H
NO NO
Chapter 1 38
Nuclei positions and bond angles remain the same.
C=C-C+ +C-C=C
CAN”T SAY “if you turn one around 180o you wouldEnd up with same structure”
Doing so would violate this rule
Chapter 1 39
The number of unpaired electrons remains the same
H3C CH3..
H3C CH3
. .NO NO
Chapter 1 40
DELOCALIZATION OF CHARGE USUALLY IS
STABILIZING
Delocalization of charge results in fractional chargesat alternate atoms
Chapter 1 41
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 42
Major Contributor?
CH
HN
H
H
+C
H
HN
H
H
+
major minor, carbon does
not have octet.
=>
Chapter 1 43
Other Examples
Chapter 1 44
Chemical Formulas
• Full structural formula (no lone pairs shown)
• Line-angle formula
• Condensed structural formula
• Molecular formula• Empirical formula
CH3COOH• C2H4O2
• CH2O =>
C
H
H
H
C
O
O H
OH
O
Chapter 1 45
BrØnsted-Lowry Acids and Bases
• Acids can donate a proton.
• Bases can accept a proton.
• Conjugate acid-base pairs.
CH3 C
O
OH + CH3 NH2 CH3 C
O
O-
+ CH3 NH3+
=>
acid base conjugatebase
conjugateacid
Chapter 1 46
CH3CO2H+ :NH3 CH3CO2
- + NH4+
ACID
BASE
CONJ BASE
CONJ ACID
H3C
O:
OH+ H2SO4
H3C
OH
OH
++ -HSO4
Amphoterism - ability to behave as an acid or base
EXAMPLES
Chapter 1 47
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.
CH3 C
O
OH + CH3 NH2 CH3 C
O
O-
+ CH3 NH3+
pKa 4.74 pKb 3.36 pKb 9.26 pKa 10.64
=>
Chapter 1 48
EXAMPLESWill NaOH neutralize phenol (C6H5OH)?
NaOH +
C6H5OH
HOH + C6H5ONa
pKa = 10 pKa = 15.7
_-OH
C6H5OH
HOH + C6H5O-+
YES!!
Weaker acidStronger acid
Chapter 1 49
Determining Relative Acidity
• Electronegativity
• Size
• Resonance stabilization of conjugate base
=>
Chapter 1 50
ElectronegativityAs the bond to H becomes more
polarized, H becomes more positive and the bond is easier to break.
=>
Chapter 1 51
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 52
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.
CH3CH2OH < CH3C
O
OH < CH3 S
O
O
OH
=>
Chapter 1 53
Lewis Acids and Bases• Acids accept electron pairs = electrophile
• Bases donate electron pairs = nucleophileCH2 CH2 + BF3 BF3 CH2 CH2
+_
nucleophile electrophile
=>
Chapter 1 54
End of Chapter 1
