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1 st semester organic chemistry now in lt 1 the time

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1 st semester Organic Chemistry Now in < 1 % the time! Peter Zoogman Jacob Group, Harvard EPS Graduate Student Forum January 12, 2012 What is going on? Will a molecule react? What type of molecule will it react with? What

SLIDE 1

1st semester Organic Chemistry… Now in < 1 % the time!

Peter Zoogman Jacob Group, Harvard EPS Graduate Student Forum January 12, 2012

SLIDE 2

What is going on?

 Will a molecule react?  What type of molecule will it

react with?

 What bonds are likely to be

created/destroyed?

 What will the product look like?

EARTH SURFACE

SLIDE 3

Molecular Orbitals

 2 atomic orbitals combine constructively

and destructively to form 2 molecular

rbitals

Sigma orbital: One region of overlap corresponds to single bond σ∗ antibonding σ bonding σ∗ antibonding σ bonding π∗ antibonding π bonding Pi orbital: Two regions of overlap corresponds to double bond

SLIDE 4

Molecular Orbital Example –H2 vs. He

σ∗ antibonding σ bonding H2 Molecule H Atom H Atom

SLIDE 5

Molecular Orbital Example –H2 vs. He

σ∗ antibonding σ bonding He2 Molecule?? He Atom He Atom

SLIDE 6

Molecular Orbitals – Relative Energy

(lone pairs) σ∗ antibonding σ bonding π∗ antibonding π bonding

SLIDE 7

Molecular Orbital Example -- Ethene

C-H σ bonding C-C π bonding C-C σ bonding C-C π∗ antibonding C-H σ∗ antibonding C-C σ∗ antibonding C H C H H H Ethene: also written as:

SLIDE 8

Frontier Orbitals – HOMOs and LUMOs

 Behaves as electron donor (i.e. Nucleophile, Lewis Base) at Highest Occupied

Molecular Orbital (HOMO)

 Lone pairs (or radicals)  π bonds  Behaves as electron acceptor (Electrophile, Lewis Acid) at Lowest Unoccupied

Molecular Orbital (LUMO)

 Empty atomic orb.  π* antibonding orb.  σ∗ antibonding orb.

SLIDE 9

Molecular Orbital Example -- Ethene

C-H σ bonding C-C π bonding C-C σ bonding C-C π∗ antibonding C-H σ∗ antibonding C-C σ∗ antibonding C H C H H H Ethene: also written as: LUMO HOMO

SLIDE 10

Ethene Hydration

H O H H H H H C C

 What is the HOMO?  What is the LUMO?

SLIDE 11

Ethene Hydration

H O H H H H H C C  What is the HOMO?

 O2 lone pair

 What is the LUMO?

 C-C π* antibonding orbital

SLIDE 12

Ethene Hydration

 What is the HOMO?

 O2 lone pair

 What is the LUMO?

 C-C π* antibonding orbital

H O H H H H H C C

SLIDE 13

Ethene Hydration

H O H H H H H C C

SLIDE 14

Ethene Hydration

H O H H H H H C C

H O H H H H H C C O H H H H H C C H

SLIDE 15

Molecular Orbitals -- Formaldehyde

H H C O

C-H σ bonding C-O π bonding C-O σ bonding C-O π∗ antibonding C-H σ∗ antibonding C-O σ∗ antibonding O Lone Pairs

SLIDE 16

LUMO HOMO

Molecular Orbitals -- Formaldehyde

H H C O

C-H σ bonding C-O π bonding C-O σ bonding C-O π∗ antibonding C-H σ∗ antibonding C-O σ∗ antibonding O Lone Pairs

SLIDE 17

SOA formation by Polymerization

H H C O H H C OH H O H

H+

SLIDE 18

SOA formation by Polymerization

H O H H H C OH H H C OH OH

H H C OH H O H H H C O

SLIDE 19

SOA formation by Polymerization

H O H H H C OH H H C OH OH H H C OH

H H C OH H O H H H C O

SLIDE 20

SOA formation by Polymerization

H H C O

H O H H H C OH

H O H H H C OH H H C OH OH H H C OH H H C OH OH H H C HO O H H C OH H H C OH

SLIDE 21

SOA formation by Polymerization

SLIDE 22

SLIDE 23