2D structure drawing
Chem 314
Beauchamp
Mechanical Approach to Drawing 2D, 3D and Resonance Structures from a condensed line formula.
1. Draw a 2D structure based on given arrangement shown in condensed line formula
2. Count all valence electrons (make up bonds, lone pairs and radical centers)
3. Count electron in sigma bonds generated (connections =  skeleton) and compare to total valence electrons
4. If there are excess electrons, add them in as lone pairs to fill valencies of most electronegative atoms first
(F>O>N).
5. If there are still excess electrons place them at alternate carbon positions to spread out electron density and
minimize electron/electron repulsion. If there are still excess electrons left add them to carbon atoms with the
fewest sigma bonds.
6. If any atoms lack a full octet, look for adjacent lone pair electrons that can be shared. These will make pi
bonds. If there is more than one way to do this, there will be resonance structures. Draw as many of these as
are obvious.
7. Evaluate formal charge on all of the atoms.
8. Evaluate resonance structures for relative contributions according to the following rules
a. More bonds and full octets is most important = best.
b. Having charge consistent with relative electronegativities is second best.
9. Write any additional resonance structures using typical resonance patterns of donor and acceptor sites
a. alkene, alkyne and aromatic pi bonds are connector components and can donate or accept electrons
b. donor sites are atoms with lone pairs of electrons (and pi bonds from “a”)
c. acceptor sites are neutral polar pi bonds and cationic pi bonds (and pi bonds from “a”)
10. To decide each atom’s 3D shape, hybridization and bond angles
a. Use a resonance structure where an atom has its maximum number of bonds (shows necessary 2p orbitals
to make any pi bonds (no pi bonds = sp3, one pi bond = sp2, two pi bonds = sp)
b. carbocation carbon atoms use an empty 2p orbital in our course.
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups home.doc
2D structure drawing
Chem 314
Beauchamp
1. Donor = lone pair next to empty 2p orbital acceptors (usually on carbon as a carbocation)
X
X
C
C
X
X
C
sp or sp2
hybridization
is possible on
either X or C
C
H2N
CH2
HN
CH2
O
N
CH2
H2N
C
CH2
HN
C
CH2
HN
C
O
H3C
C
O
HO
CH2
O
CH2
HN
N
CH2
HO
C
CH2
O
C
CH2
O
C
O
H2 N
C
O
F
CH2
H2C
CH2
H2C
F
N
CH2
C
CH2
Many other examples are possible.
H2C
C
CH2
H2 C
C
O
HO
C
O
2. Donor = lone pair next to a pi bond acceptors (polar pi bonds are better acceptors than nonpolar CC pi bonds)
X
X
C
C
R
C
H2N
HO
HN
C
F
O
N
R
HN
NH2
R
O
N
Interesting Variations
C
H
C
H
O
R
HN
N
R
O
C
NH2
R
C
H
C
O
H2C
C
R
O
R
C
O
H2C
C
O
R
R
R
C
O
R
C
O
R
O
H2C
O
R
C
C
R
C
C
C
R
O
R
HN
X
C
C
C
H2C
X
sp or sp2
hybridization
is possible on
either X or C
N3
N
N
N
CO2
O
C
O
NO2
O
N
O
C
NH2
H
3. Donor pi bonds (usually alkene, alkyne or aromatic) next to empty 2p orbital acceptors (usually on carbon as a carbocation)
C
C
C
C
C
C
X
C
C
C
C
C
C
C
C
3. Donor pi bonds (usually alkene, alkyne or aromatic) next to a polar or cationic pi bond acceptors (polar pi bonds are best C=N, C=O, N=N,
N=O, nitrile, but alkene, alkyne and aromatic are possible)
Just a f ew examples.
H
alkene or
alkene or
alkene or
alkene or
Many more variations.
aromatic
aromatic
aromatic
aromatic
O
C
C
C
C
O
C
C
C
C
C
C
C
C
N
N
R
H
R
H
C
C
C
C
C
C
O
C
C
O
C
C
C
C
N
N
H
R
R
H
C
C
O
C
R
C
C
C
C
C
O
C
N
R
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups home.doc
C
C
C
N
H
2D structure drawing
Chem 314
CH3CH2CH3
H H
C
H
H
C
C
H
CH3CH2CH2
CH3CH2CH2
CH3CH2CH2
H
H
H
H
H
C
C
H
C
H
H
H
1o carbocation
CH3CH2OH
H H
H
O
H
H
H
H
o
O
alkoxide
CH3OCH2
CH3CH2O
H
O
H
H
O
H
C
C
C
C
C
C
H H
H H
H H
H H
H H
H H
use zig-zag drawing
for sp3 chains
H H
2 free radical
H
H
H
C
H
H H
CH3CH2OH2
ether
H
C
H
C
CH3CH2OH
H
H
o
O
protonated alcohol
O
C
H
C
H H
C
H H
H
C
H
CH3CH2O
C
1o free radical
CH3CHCH3
C
CH3CH2OH2
use zig-zag drawing
for sp3 chains
H
C
C
H
H
H
H
2 carbanion
H
H
C
H
H H
H H
H
H
H H
2o carbocation
alcohol
C
C
C
H
C
H
H
H
H
C
CH3CHCH3
H
H
C
1o carbanion
CH3CHCH3
C
H
H
C
H H
use zig-zag drawing
for sp3 chains
H
H
H
C
H H
Beauchamp
protonated ether
carbanion
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups home.doc
H
C
H
O
C
H
free radical
2D structure drawing
Chem 314
CH3NH2CH3
CH3NHCH3
H
H
Beauchamp
H H
2o amine
N
H
H
CH3NCH3
N
H
N
H
H
C
C
C
C
C
C
H H
H H
H H
H H
H H
H H
use zig-zag drawing
for sp3 chains
CH2CHCH3
H
H
C
H
C
H
H
H
C
H
C
H
C
H
monosubstituted alkene
resonance
resonance
H
C
H
C
H
H
H
imine
C
H
C
H
H
C
H
resonance
resonance
H
C
H
1o allylic carbanion
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups home.doc
H
C
C
H
H
H
H
H
C
H
C
H
CH
H
H
H
N
H
H
C
CH
H
resonance
H
C
H
H
C
H
C
H
H
H
1o allylic free radical
H
1 allylic carbanion
C
H
H
o
H
N
C
C
CH2CHNCH3
H
H
H
C
C
H
CH3CHNH2
C
H
H
C
C
H
1 allylic carbocation
N
H
C
resonance
o
H
H
H
H
H
H
H
H
CH3CHNH
C
CH
H
H
C
C
CH
H
H
H
H
C
H
CH2CHCH2
CH2CHCH2
CH2CHCH2
H
C
2o amide anion
dialkylammonium ion
H
H
C
C
H
1o allylic free radical
H
2D structure drawing
Chem 314
CH3CHNH2
CH3CHNH
H
C
C
C
H
N
H
H
H
C
H
H
H
C
H
H
CH2CHO
H
H
O
H
C
C
H
O
C
C
H
C
H
resonance
H
O
C
H
H
O
C
C
H
H
protonated carbonyl
H
H
H
H
resonance
aldehyde
H
H
1o allylic carbanion
H
H
C
C
C
CH3CHOH
H
H
N
C
H
H
resonance
H
N
H
H
H
resonance
CH3CHO
C
C
imine
O
H
H
N
H
H
CH2CHNH
H
H
N
Beauchamp
C
H
enolate anion
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups home.doc
H
2D structure drawing
Chem 314
CH3COCH3
CH3COCH2
CH3COHCH3
C
H
H
H
H
H
C
C
O
O
C
H
C
O
C
H
H
HCCCH3
H
C
H
H
O
H
C
C
H
protonated carbonyl
H
H
resonance
H
H
resonance
H
H
H
C
C
H
H
C
H
H
C
C
ketone
H
H
H
O
Beauchamp
C
H
H
enolate anion
H
HCCCH2
HCCCH2
HCCCH2
H
H
C
C
H
H
C
H
H
C
C
H
C
H
C
C
C
C
C
H
C
C
C
C
resonance
propargyl carbanion
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups home.doc
H
H
H
H
propargyl carbocation
H
H
H
C
C
resonance
resonance
H
C
H
H
alkyne
H
H
C
C
C
H
propargyl free radical
2D structure drawing
Chem 314
CH3CN
Beauchamp
CH2CN
CH3CNH
H
N
H
H
C
C
H
H
N
N
C
C
H
C
C
H
H
nitrile
resonance
resonance
H
H
H
N
N
C
C
C
C
H
H
nitrile enolate
protonated nitrile
CH3CO2H
CH3C(OH)2
O
O
C
O
H
O
O
C
H
H
C
C
O
C
H
O
C
C
C
H
-2
H
H
O
CH2CO2
CH3CO2
H
H
resonance
H
carboxylic acid
H
H
resonance
H
H
resonance
H
O
O
C
H
O
O
H
O
C
C
H
O
C
C
H
H
resonance
H
C
H
H
resonance
carboxylate anion
H
H
O
O
O
C
H
protonated H
carboxylic acid
H
C
O
C
C
H
carboxylate H
dianion
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups home.doc
H
2D structure drawing
Chem 314
CH3CONH2
CH3CONH
CH3COHNH2
H
H
C
N
H
N
O
Beauchamp
O
H
N
C
H
H
C
H
O
C
C
H
H
C
H
H
H
resonance
H
o
1 amide
H
H
resonance
H
N
O
C
H
N
H
H
O
H
C
H
protonated
amide
H
H
H
CH3CO(OH)CH3
H
O
H
H
C
H
H
H
O
C
H
C
C
H
H
H
resonance
H
ester
resonance
H
O
H
C
H
C
H
H
H
H
ester enolate
C
H
C
H
H
C
H
H
C
C
O
C
H
O
H
H
resonance
H
H
protonated
ester
O
H
C
O
H
H
H
O
C
O
H
C
H
C
H
O
H
H
CH2CO2CH3
H
C
O
C
H
C
CH3CO2CH3
H
H
amide anion
N
O
H
C
H
H
resonance
H
O
C
C
H
H
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups home.doc
H
2D structure drawing
Chem 314
CH3COCl
Beauchamp
CH3COHCl
CH2COCl
H
Cl
Cl
O
C
O
H
C
H
H
C
Cl
O
C
C
C
H
H
H
resonance
H
acid chloride
H
H
resonance
H
Cl
O
Cl
C
H
H
C
O
C
H
H
resonance
H
H
Cl
O
C
C
poor resonance due to inefficient overlap
of 3p chlorine orbital with 2p carbon orbital
C6H5CH3
C
C
H
C
H
H
H
C
C
C
H
C
H
H
H
C
C
C
H
H
resonance
H
C
C
C
C
C
C
H
C
C
C
H
H
resonance
2 more times
(around the ring)
C
H
C
resonance
2 more times
(around the ring)
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups home.doc
H
C
H
C
C
C
H
H
H
H
resonance
C
H
C
C
C
H
H
H
C
C
H
H
C
C
C
C
H
resonance
H
H
H
H
H
H
H
C
C
H
C
C
H
H
C
H
C
C
H
H
C
C6H5CH2
C6H5CH2
H
C
H
C
C
H
H
H
C
H
C6H5CH2
H
H
acid chloride
enolate
(unstable to elimination,
forms ketene)
H
H
H
C
H
C
C
H
H
resonance
2 more times
(around the ring)
2D structure drawing
Chem 314
CH3CH2F
Beauchamp
CH3CHFH
CH3CHF
H H
H
C
H
C
F
C
H
H
CH
C
C
F
H
H H
H
H
F
H H
use zig-zag drawing
for sp3 chains
resonance
fluoroalkane
H
H
C
C
H
F
H
Still to do.
C6H5CH3
C6H5CH2
C6H5CH2
C6H5NH2
C6H5NH3
C6H5NH
C6H5OH
C6H5OH2
C6H5O
CH3CH2F
CH3CHF
CH3CHF
CH3NO2
CH3NO2H
CH2NO2
CH3NO
CH3NOH
CH2NO
ONO
OCO
NO3
NO2
NNN
CH2NN
HNO3
HNO2
CH2CCH2
C6H5CH2
HCCF
NNN
CH2CNH
CH2CNH2
CH3NNN
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups home.doc
CH2CO
CHCO
CH2COH
2D structure drawing
Chem 314
Beauchamp
antidisestablishmenttarianism - opposition to disestablishment of a church or religoius body
an - ti - dis - es - tab - lish - ment - ta - ri - an - ism
Break a complicated problem
down into simpler parts.
CH3OCH2COC(CH 3)2CO2CH2CHNH2CH2CONHCH2CH(NO2)CH2CH(CN)CH2CH(CHO)CHNH2CHOHCH2CCCHCHC6H4CO 2H
RCH 2OH
RCH(OH)R'
RCO2H
RSO3H
RCH2SH
RCH(SH)R'
RCOCl
RSO2Cl
RCO2C(CH3)3
RSO3CH3
RNH2
RCH(NH 2)R'
ROCH(CH3)2
RCH(OCH2CH3)R'
RSCH3
RCH(SCH2CH3)R'
RCHCH2
RCHCHCH2CH3
RCONH2
RSO2NH2
RCONHCH3
RSO2N(CH3) 2
RCN
RCCCN
RCCH
RCCC(CH3) 3
RCH(CN)CO2CH 3
RCHO
OHCCCC(CH3)3
RNO2
RC6H5
RC6H4CHOHCHO
RN3
R2CN2
RCOCHCHCH 3
RNO
RONO
RCOCH3
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups home.doc
CH3COC6H4CHCHCH(OH)CHO
RCH(NO2)R'
2D structure drawing
Chem 314
H
H
H
H O C O
H
H C O C
H
C
H
H
C C
C
H N H
H
H
H
H
C
C N C
C C
C
H H N H C
O
O N
H
R'
R C
H
S
thiol
R
R C N
R C
H
H
H H
C HH
C O C C H
H
R
H C H
H
t-butyl ester
amine
H
H
H H
C H
R O C
R'
H
R'
H
C
H
H
H
R C R'
R C S
thio ether
H
S
sulfide
CH3
H
C C H
H
thio ether / sulfide
H H
H
R C
C C
alkyne
R C
H
aldehyde
H
C
R
C
C
C
H
C
C
ketone
C
H
O
nitrile
C
N
O
H
H
R C
C
ketone
H
C
ketone
ester
H
O
H
C H
C
C
H H
H
R
C
C
H alcohol H
H
O
C
C
C C
O
C
H
R
O
O
nitro
C
N
R'
O
nitro
R
R
C N N
N N N
O
azide
C
H
aldehyde
C
C C
O H
H H
carboxylic
H
H alkene
acid
aromatic
N
R
N N N
R
R
diazonium
R
C N N
R
R O
N
alkene
C H
H H
C N
O
H alcohol
H
C C
O
H
CH3
alkyne nitrile
H
R C C
H
R
nitrile
H
C
C
H
O
R C
CH3
N
sulfonamide
R C N
O
C
C
aromatic
H
S
O
H
amide
H
C H
H H
H
C
R
H
O
R
N CH3
C
H
C
H
H
aromatic
C
H
N
sulfonamide
H H
O alkyne C H H
C C C C C H
H
H
H C H
aldehyde
H
O
S
O
R C
H H
C HH
R C C C C H
H
alkyne
H C H
H
H
H
C
alkene
H
R
H
R C
C
alkene
R
H
H
O
O
H
CH3
S O
methyl sulfonate
H
amide
H
H
Cl
O
N H
C
H
H
H
O
O
R
R C
O
ether
ether H C H
H
S
O
R C
O
C
O
sulfonyl chloride
O
N
H
amine
S
R
R C
acid chloride
Cl
H
H
C
C
O
H
H
C
O
sulfonic acid
O
R'
C
O
O
C
H
carboxylic acid
S
C
H
O H
H
R C
thiol
H
C C
R C
H
H
C
H
C
H C H O H
H
O
H
O
alcohol
C C
H
O
R C
H
alcohol
C
C C
H
H
R C O
H
H
H
H H H H H H N H H
H H H O
C C O
Beauchamp
O
nitroso
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups home.doc
N
O
nitrite