Electrons incredibly smallsome properties of particlessore properties of waves

For organic chemistry

PropertresotwarestQuantized energies only Guitar

stringharmonics

2 Node no energy at

certain sites

No energy Nodes

3 They can add constructivelyand destructively

aE E hi the tfconstructive yaddition

dE v

hilt 1 1Erodestructive

addition

4 There is just as much energyat the top t amplitudeas at the bottom C J amplitudeof a wave

r

µr

5 If you add X wave equations

together you get A new

wave equations as the

solution

Basis for molecularorbitalthe ry that explainsmolecular structure and bonding

6 Around atoms the location ofelectron density is described

by the Schrodinger equation

describes energyand locationit is therefore

a wave function

Solutions)to)the)Schrodinger)equation)–)atomic)orbitals))

)))))))))))))

))

Ψ1s""""""""""""""""""""Ψ2s""""""""""""""""""""""""""""""""Ψ2px""""""""""""""""Ψ2py"""""""Ψ2pz))

))

)"))

wareeguation3 dimensional waves

Different colors refer to sign of thewave function or Not charge

we plot the 4 2square of ware

function as orbitals

Molecular Orbital TheoryTO quantify bonding in

molecules simply adds all

of the atomic orbital wave functionsassociated with the atoms in the

molecule1 This creates a many

All of new wave functionsthB can molecular orbitals as

explain the number of atonic

Tx bonds orbitals added together

Ettyin

bond 3 Each new molecular

to orbital contains the

humans density of 2 ee

G bonds cylindricalsymmetry

rotate freelyat room temp

H2asidefunctions

in.EE igEnd

di ornu wda

IN bond hot dogbun shape

cannot rotate without

being broken

formed from the overlapof adjacent 2porbitals

addI constructively

IT bondta

image Datomdei

nd

V.at dapproach to

understanding 6 bonds planning

Add the vatenee e

waef.cnon each atomfirst then look for

overlap between atons

Bloody Brilliant

Hybridization)–)Valence)Bond)Approach)to)bonding))

sp3)(Ψ2s))+)Ψ2px))+))Ψ2py)+)Ψ2pz))))))))))))))))

sp2"(Ψ2s))+)Ψ2px))+))Ψ2py))+)Ψ2pz)

)

)

)

)

)

)

sp""(Ψ2s))+)Ψ2px)))+))Ψ2py)+)Ψ2pz)))) )

I

r

)

C

H

H H

HMethane

Valence Bond Theory approach to bonding: Hybridize the atomic orbitals on atoms first, then look for overlap with remaining orbital wave functions:

ΨH1s + ΨH1s + ΨH1s + ΨH1s + ΨC1s + ΨC2s + ΨC2px + ΨC2py + ΨC2pz

Molecular Orbital Theory approach to bonding: Just add the individual orbital wave functions:

ΨH1s + ΨH1s + ΨH1s + ΨH1s + ΨC1s + (ΨC2s + ΨC2px + ΨC2py + ΨC2pz)

C

H

HH

H

O

q

sphybridizer

6 bond

Csps HisThere are four

sp hybrid orbitalson the C atom each H

atom as a Is orbital

C

H

H C

HEthane

Valence Bond Theory approach to bonding: Hybridize the atomic orbitals on atoms first, then look for overlap with remaining orbital wave functions:

ΨH1s + ΨH1s + ΨH1s + ΨH1s + ΨH1s + ΨH1s + ΨC1s + ΨC2s + ΨC2px

Molecular Orbital Theory approach to bonding: Just add the individual orbital wave functions:

H

H

H

+ ΨC2py + ΨC2pz + ΨC1s + ΨC2s + ΨC2px + ΨC2py + ΨC2pz

ΨH1s + ΨH1s + ΨH1s + ΨH1s + ΨH1s + ΨH1s + ΨC1s + (ΨC2s + ΨC2px

+ ΨC2py + ΨC2pz) + ΨC1s + (ΨC2s + ΨC2px + ΨC2py + ΨC2pz)

C C

HH

H H

H H

O Esp3 His

0000Gasp Csp3

Each carbon has 4

sp hybrid orbitals each

H atom has a Is orbital

Ethene(Ethylene)

Valence Bond Theory approach to bonding: Hybridize the atomic orbitals on atoms first, then look for overlap with remaining orbital wave functions:

ΨH1s + ΨH1s + ΨH1s + ΨH1s + ΨC1s + ΨC2s + ΨC2px + ΨC2py + ΨC2pz

Molecular Orbital Theory approach to bonding: Just add the individual orbital wave functions:

+ ΨC1s + ΨC2s + ΨC2px + ΨC2py + ΨC2pz

C CH

H

H

H

C C

H H

H H

ΨH1s + ΨH1s + ΨH1s + ΨH1s + ΨC1s + (ΨC2s + ΨC2px + ΨC2py) + ΨC2pz

+ ΨC1s + (ΨC2s + ΨC2px + ΨC2py) + ΨC2pz 0700 000800 0

NCzpcz.pt

C ChtfGcspa His

Gesps Csp2Each carbon has 3

sp2 hybrid orbitals anda 2 p orbital each H atom as a 1 S orbital

))

Ethyne(Acetylene)

Valence Bond Theory approach to bonding: Hybridize the atomic orbitals on atoms first, then look for overlap with remaining orbital wave functions:

ΨH1s + ΨH1s + ΨC1s + ΨC2s + ΨC2px + ΨC2py + ΨC2pz + ΨC1s + ΨC2s + ΨC2px + ΨC2py + ΨC2pz

Molecular Orbital Theory approach to bonding: Just add the individual orbital wave functions:

HC CH

ΨH1s + ΨH1s + ΨC1s + (ΨC2s + ΨC2px) + ΨC2py + ΨC2pz + ΨC1s + (ΨC2s + ΨC2px) + ΨC2py + ΨC2pz

C C HH

)A)common)situation,)and)the)one)many)resonance)contributing)structures)describe,)occurs)when)three)2p)orbitals)combine)on)adjacent)atoms.))A)good)example)is)the)carboxylate)anion.))When)three)adjacent)2p)orbitals)interact)(we)add)the)three)2p)orbital)wave)functions)))))))))))))))))))))))))))))))))))))))))),)three)new)molecular)orbitals)are)produced;)a)low)energy)bonding)“piJway”,)a)nonJbonding)orbital)and)an)antibonding)orbital)as)shown)below.))This)pattern)of)three)molecular)orbitals)is)generally)the)same)whenever)three)2p)orbitals)interact)even)if)there)are)different)atoms)involved,)for)example)the)enolate)ion)or)allyl)cation.))There)are)four)electrons)in)the)pi)system)of)the)carboxylate)anion,)(you)

can)see)this)by)looking)at)either)of)the)contributing)structures;)two)electrons)from)the)pi)bond)and)two)from)the)third)lone)pair)on)the)negatively)charge)O)atom).))Note)the)nonJbonding)orbital)contains)the)electron)density)of)two)electrons)that)are)paired,)do)NOT)think)of)it)as)having)one)upaired)electron)on)each)O)atom.)))I)know,)weird,)but)remember)it)is)best)to)think)of)bonding)electrons)as)waves,)not)particles.))Note)the)electron)density)on)only)the)O)atoms)of)the)nonJbonding)orbital)explains)why)the)negative)charge)is)localized)on)the)O)atoms)in)the)carboxylate)anion.))))

))

))))

Antibonding)orbital))))))))))))) NonJbonding))) orbital))))))))))))))))))))))))))))))))))))))))))))) “πJway”)orbital)

Carboxylate anion

H

COO0.50.5

Resonance hybrid

Carboxylate anion

HC

O

O HC

O

O

HC

O

O

0.5

0.5

Resonance hybrid

)

Carboxylate anion

Valence Bond Theory approach to bonding: Hybridize the atomic orbitals on atoms first, then look for overlap with remaining orbital wave functions:

ΨH1s + ΨC1s + ΨC2s + ΨC2px + ΨC2py + ΨC2pz + ΨO1s + ΨO2s + ΨO2px + ΨO2py + ΨO2pz+ ΨO1s + ΨO2s + ΨO2px + ΨO2py + ΨO2pz

Molecular Orbital Theory approach to bonding: Just add the individual orbital wave functions:

HC

O

O HC

O

O

HC

O

O

0.5

0.5

ΨH1s + ΨC1s + (ΨC2s + ΨC2px + ΨC2py) + ΨC2pz + ΨO1s + (ΨO2s + ΨO2px + ΨO2py) + ΨO2pz+ ΨO1s + (ΨO2s + ΨO2px + ΨO2py) + ΨO2pz

Sigma (σ) bonding - overlap of hybridized orbitals

H

C

O

O

π-way bonding - overlap of 3 adjacent unhybridized 2p orbitals

HC

O

O

HC

O

O

HC

O

O

ΨC2pz + ΨO2pz + ΨO2pz

Bonding

Non-bonding

Antibonding

Resonance hybrid

Contributing structures

)

Enolate anion

Valence Bond Theory approach to bonding: Hybridize the atomic orbitals on atoms first, then look for overlap with remaining orbital wave functions:

ΨH1s + ΨH1s + ΨH1s + ΨC1s + ΨC2s + ΨC2px + ΨC2py + ΨC2pz + ΨC1s + ΨC2s + ΨC2px + ΨC2py + ΨC2pz+ ΨO1s + ΨO2s + ΨO2px + ΨO2py + ΨO2pz

Molecular Orbital Theory approach to bonding: Just add the individual orbital wave functions:

HC

O

C HC

O

C

HC

O

C

0.8

0.2

Sigma (σ) bonding - overlap of hybridized orbitals

H

C

O

C

π-way bonding - overlap of 3 adjacent unhybridized 2p orbitals

HC

O

C

HC

O

C

HC

O

C

ΨC2pz + ΨC2pz + ΨO2pz

Bonding

Non-bonding

Antibonding

Resonance hybrid

Contributing structures

H

H

H

H

Minor Major

H

H

ΨH1s + ΨH1s + ΨH1s + ΨC1s + (ΨC2s + ΨC2px + ΨC2py) + ΨC2pz + ΨC1s + (ΨC2s + ΨC2px + ΨC2py) + ΨC2pz+ ΨO1s + (ΨO2s + ΨO2px + ΨO2py) + ΨO2pz

H

H

H

H

H

H

H

H