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Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
Drawing 2D, 3D and Resonance Structures from condensed line formulas. 1. Use a condensed line formula to draw a 2D structure (and resonance structures). Smaller structures can use
the mechanical approach suggested below, larger structures will have to use organic intuition and knowledge
of functional groups.
2. Use your 2D structure (and resonance structures) to generate the 3D sigma skeleton. Each sigma bond counts
for 2 electrons.
3. Count all valence electrons (these electrons make up sigma and pi bonds, lone pairs and any radical centers).
4. Subtract sigma electrons from the total valence electrons (these are lone pair, pi and free radical electrons).
5. If there are excess electrons, add them in as lone pairs to fill valencies of most electronegative atoms first
(F > O > N).
6. If there are still excess electrons left add them to carbon atoms with the fewest sigma bonds. If there are still
excess electrons place them at alternate carbon positions to spread out electron density and minimize
electron/electron repulsion, as best you can.
7. 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. Any structures with full octets are usually OK (but, not necessarily the best resonance structure).
8. Evaluate formal charge on all of the atoms.
9. Evaluate resonance structures for relative contributions according to the following rules
a. More bonds and full octets are most important = best.
b. Having charge consistent with relative electronegativities is second best.
10. Write any additional resonance structures using typical resonance patterns of donor and acceptor sites (see
page 7).
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 CC pi bonds from “10a”)
c. good acceptor sites are carbocation positions (empty 2p orbitals on carbon), cationic pi bonds and neutral
polar pi bonds (and CC pi bonds from “10a”)
11. 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 (this shows the 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.
c. subtract any 2p orbitals in pi bonds and cationic carbon from s, p, p, p. Whatever is left over is the
hybridization of the atom (whether C, N, O, S or halogens, in our course). (sp = linear, 180o, sp2 = trigonal
planar, 120o, sp3 = tetrahedral, 109o)
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
2D Structures – Generate 2D structures from condensed line formulas (R = generic organic portion). Very simple examples of the most common functional groups taught in first year organic chemistry are shown below. An example is provided for most of the functional groups on each end of a formula and in the middle of a formula. Simple 2D structures can be generated from condensed line formulas using the mechanical strategy described on page 1. However, more complicated 2D structures will require knowledge of common functional groups and common bonding patterns of the elements of organic chemistry (H, C, N, O, S and halogens).
RCO2H
RCH(CO2H)R'
CR
O
O H
HO2CR
C R
O
OH
CR
H
C
R'
OOH
carboxylic acids in condensed line formulas
on the right end
on the left end
in the middle
CR
O
O C
anhydrides in condensed line formulas RCO2COR'
O
R'
CR
O
O R'
RCO2R'
RCH(CO2CH3)R'
CR
H
C
R'
OO
R'O2CR
C R
O
OR'C
H
H
H
esters in condensed line formulas
RCOCl ClOCR
CR
O
Cl C R
O
Cl
CR
H
C
R'
OCl
acid chlorides in condensed line formulas RCH(COCl)R'
RCONH2
CR
O
N H
H
C R
O
NH
H
H2NOCR
RCH(CONH2)R'
CR
H
C
R'
ONH
H
amides in condensed line formulas
RCONHR'
CR
O
N R'
H
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
nitriles in condensed line formulas
RCN
RCH(CN)R'
NCR
CR N C RN
CR
H
C
R'
N
aldehydes in condensed line formulas
RCHO
RCH(CHO)R'
OHCR
CR
O
H C R
O
H
CR
H
C
R'
OH
ketones in condensed line formulas
RCOR'
RCH(COCH3)R'
ROCR'
CR
O
R' C R'
O
R
CR
H
C
R'
OCH
HH
alcoholes in condensed line formulas
RCH2OHRCHOHR'
CR
H
H
O
CR
H
O
R'H
H
HOCHCH3R
C R
H
C
O
H
H
H
H
thiols in condensed line formulasRCH2SH
RCHSHR'
CR
H
H
S
CR
H
S
R'H
H
HSCHCH3R
C R
H
C
S
H
H
H
H
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
amines in condensed line formulas
RCH2NH2RCHNH2R'
CH3HNCH2R
CR
H
H
N
H
C R
H
H
N
CR
H
N
R'
HH HH
C
H
H
H
ethers in condensed line formulas
RCH2OCH3 RCH(OCH3)R'
CR
H
H
O C
H
H
H
CR
H
O
R'
C
H
HH
RCHCH3SCH3 RCH(SCH3)R'
CR
H
C
S C
H
H
H
CR
H
S
R'
C
H
HH
sulfides in condensed line formulas
H H
H
nitro compounds in condensed line formulas
RCH2NO2
RCH(NO2)R'O2NCH2R
CR
H
H
N
O
O
C R
H
H
N
O
O
CR
H
N
R'
OO
nitroso compounds in condensed line formulas
RCH2NORCH(NO)R'
ONCH2R
CR
H
H
N
O
C R
H
H
N
OCR
H
N
R'
O
azido compounds in condensed line formulas
RCH2NNN
RCH(N3)R'
NNNCH2R
CR
H
H
N
N
C R
H
H
N
NCR
H
N
R'
N
N N
N
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
diazo compounds in condensed line formulas
RCHNNNNCHR
CR
H
N N CR
H
N N C R
H
NN C R
H
NN
alkenes in condensed line formulas (E and Z configurations are possible)
RCHCH2 RCHCHR'
CR C
H
H
H
CR C
H
R'
H
C RC
H
H
H
H2CCHR
RCHCCH3R'
CR C
H
R'
CH
H
H
alkynes in condensed line formulas
RCCH RCCR'
CR C H CR C R'C RCH
HCCR
aromatics in condensed line formulas (different substitution patterns are possibilities)RC6H5 R(C6H4)R'
C C
C
CC
CR
H H
H
HH
CC
C
C C
C R
HH
H
H H
H5C6R
CC
C
C C
C R'
HH
R
H H
orthometapara
halogen compounds in condensed line formulasRBr RCHBrR'
CR
H
H
Br CR
H
Br
R'
RBr
C R
H
H
Br
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
The following are examples of small molecules and ions using 2D and 3D formulas. (2D sketch, just below)
C6H5CH3 C6H5CH2 C6H5CH2
C6H5NH2 C6H5NH3 C6H5NH
C6H5OH C6H5OH2C6H5O
CH3NO2 CH3NO2H CH2NO2
CH3NO CH3NOH CH2NO NNNONOOCO
NO3 NO2HNO3 HNO2
CH2CCH2
CH2CNH CH2CNH2
CH2CO CHCOCH2COH
CH2NN CH3NNN
HH
C6H5F C6H5FH
CH2CN CO CN OO
CH3CO2H CH3CO2H2 CH3CO2
CH3CO2CH3
CH3CHO CH3CHOH CH2CHO
CH3COCH3 CH3COHCH3
CH3CO(OH)CH3 CH2CHO2CH3
CH3COCH2
a
b
c
d
e
f
g
h NN FF
a
C
H
H
C
H
H
C
H
H
HC
H3C
O
OH C
H3C
O
OH C
H3C
O
O
H
b
N
H
H
N
H
H
N
H
HC
H3C
O
OCH3 C
H3C
O
OCH3
H
CH2C
O
OCH3
c
O
H
O
H
H
O CH3C
O
HC
H3C
O
H
H
CH2C
O
H
d
F F
H
CH3C
O
CH3
CH3C
O
CH3
H
CH2C
O
CH3
e
NH3C
O
O
NH3C
O
O
NH2C
O
O
H
CC C
H
H
H
H
NC N
H
H NH3C N
N
f
NH3C
O
NH3C
O
NH2C
OH
NN
NC
O
O
NO
O
g
CH2C O CH2C O CC O
H
H NO
O
O
H
NO
O
ONO
OH
NO
O
hCH2C N CH2C N CC N
H
H
H H
H
H H C O C N OO FFN N
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
Common, Possible Patterns of Resonance Used in Drawing 2D and 3D Organic Structures
There are four common resonance patterns that we encounter, using two donor sites and two acceptor sites. Donor electrons (D) can come from lone pairs and pi bonds. Acceptor sites (A) include an empty 2p orbital (almost always carbon in our course = carbocations) and pi bonds (CC is OK, polar is good, ionic polar is best). Notice that CC pi bonds can donate and accept electrons. In our course resonance systems will always occur through p orbitals. There is another brand of resonance that can use sigma bonds (usually C-H) with p orbitals, called hyperconjugation. We will not emphasize this resonance.
Resonance Pattern 1 – Lone pair donation (2p orbital) into an empty 2p orbital (carbocation or pi cation).
Resonance Pattern 2 – Lone pair (2p orbital) donation into pi bonds (many kinds).
Resonance Pattern 3 – Pi bond donation (from alkene, alkyne or aromatic) into an empty 2p orbital (carbocation or pi cation).
Resonance Pattern 4 – Pi bond donation (from alkene, alkyne or aromatic) into a pi bond acceptor (alkene, alkyne, aromatic, carbonyl, imine, nitrile, etc. Polar is better.)
Donorslone pairs
X: = N, O, F; X: = C ,N ,OCC pi bonds
(alkenes, alkynes, aromatics)
empty 2porbitals
(on carbon)
pi bonds(all kinds)
Acceptorspattern 2
pattern 3pattern 1
pattern 4
X C X C
CC
N CC
N
CC
C CC
C
CC
O
CC
C
O
C
X C
O
X C
OH H
ionic pi cation
OC
N OC
N
ionic polar bonds are best
CC
CO
CC
CO
H H
polar is better
CCC
CCC
N N
simple carbocation simple carbocation
CC pi bonds are OK
polar pi bonds are better
OC
N OC
N
H H
CCC
CCC
C C
H H
CC pi bonds are OK
ionic polar bonds are best
H H
ionic pi cation
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
1. Donor = lone pair next to empty 2p orbital acceptors (usually on carbon as a carbocation)
X C
CH2H2N
CH2HO
CH2F
CH2NO
CH2NHN
CH2NH2C
CH2HN
CH2O
CH2H2C
CH2N
CHO
CF
CH2
CH2
CH2
CHN
CO
CH2C
CH2
CH2
CH2
CHN
CO
CH2C
O
O
O
X C X C X C
sp or sp2 hybridization is possible on either X or C, see examples below.
Many other examples are possible.
CH2N O
CHO O
cation neutral
cations neutrals
X = N, O, F
X = C , N , O
CH2N N H
both sides can donateCO O
both sides can donate
H
X = N, O, F
X = C , N , O
2. Donor = lone pair next to pi bond acceptors (CC bonds are OK, polar pi bonds are good and ionic pi bonds are best).
X C
C
X C
C
X C
C
X C
C
CH2C
R
O
CHN
R
O
CO
R
O
CH2N
R
O
CHO
R
O
CF
R
O
CH2C
R
O
CHN
R
O
CO
R
O
R
H
H
CH2C
R
NH2
CHN
R
NH2
CO
R
NH2
CH2C
R
N
CHN
R
N
CO
R
N
R
H
H
sp or sp2 hybridization is possible on either X or C, see examples below.
anions neutrals
Many other examples are possible.
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
3. Donor pi bonds (usually alkene, alkyne or aromatic) next to empty 2p orbital acceptors (usually on carbon as a carbocation)
CC C
R
R
R R
R CC C
R R
RCR C C
R
R
C C
R
R
R
C R
R
C C
R
R
R
C
R
R
resonance, etc. resonance, etc. resonance, etc.
4. Donor pi bonds (usually alkene, alkyne or aromatic) next to a polar other pi bond acceptors (CC are OK, polar pi bonds are good (C=N, C=O, N=N, N=O, nitrile), and ionic pi bonds are best.
Just a few examples. Many more variations are possible.
CC
CO
R
R
R
R
CC
C
R
R
RN
CC
CO
R
R
R
R
CC
C
R
R
RN
H
H
alkene or aromatic
CC
CO
R
R
R
R
CC
CO
R
R
R
R
CC
C
R
R
RN
CC
C
R
R
RN
CC
CO
R
R
R
R
CC
CO
R
R
R
R
CC
C
R
R
RN
CC
C
R
R
RN
H
H
H
H
alkene or aromatic alkene or aromatic alkene or aromatic
polar pi bondsionic polar pi bonds
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
antidisestablishmenttarianism = opposition to disestablishment of a church or religious body (how do you say it?)
Break a complicated problem into its
simpler parts
an-ti-dis-es-tab-lish-ment-tar-i-an-ism
OHCCHC(CH3)COC6H4CO2CH(NO)CHOHCH(OCH3)CHCNCONHCH(NO2)CO2H
OHCCHC(CH3)COC6H4CO2CH(NO)CHOHCH(OCH3)CHCNCONHCH(NO2)CO2H
C6 ring has formal charge
C C
O
H
H
C
CH
HH
C
O
C
C C
C
C C
C
HH
HH
O
O C
H
NO
C
O
H
H
C
O
C
H
C
C
N
H
C
O
N
H
C
NOO
H
C
O
O H
Complex condensed line formula (Use your chemical intuition.)
2D structure
Functional group breaks
H H
H
(CH3)3CCCCOCHCNCH(CHO)CH(COCl)CH(CO2CH3)CH(CONH2)NHCH2CONHCH2C6H4CH(COCH3)CH(NO2)-
-CHNH2CO2CHBrCH(NH3)CH(CO2H)CHSHCH(SCH3)CHOHCH2SCH2CHCHCH(CH2OH)CH2OCH2CH(CO2)CHO
has formal chargeC6 ringCondensed line formula with functional group breaks
2D structure
C
CH
HH
C
H
H
H CH
H
H
C C C
O
C
H
C
N
C
H
C
O H
C
C
O
H
C
H
C
O O
CH
H
H
C
H
C
O N
HH
N
H
C C
H
O
N
H
C
H
H
C
C C
C
C C
C
H
CO
HH
H H
C
C
HHH
H
NO O
continue
continue C
H
N
C
H H
O
O C
Br
C
H
H
C
O O
C
H
H
S
H
C
S
C
H H
H
H
C
H
OH
C
H
H
S C
H
H
C
H
C
H
C
H
C
CH H
O
H
H
H
O C
H
H
C
C
H
O H
C
O
O
Cl
C
N
HH
H
H
alkyne
ketone
nitrile
aldehyde ester
acid chloride amide
amide
aromaticketone
nitro
ester
amine
bromo
ammonium ion
carboxylic acid
thiol
sulfide
alcohol
sulfide
alkene
alcohol
ether
aldehyde
carboxylate
amineH
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
3D Problems
Example 1
HNCCHCCH3CCCO2CH(CH3)2
NH C C
H
C
CH
H
H
C C C
O
O C
H
C
C
H
H
HH
HH
NH C C
H
C C
C
C C
O
O CH
HH
H
CC
NH C C
H
C
CH3
C C C
O
O C
H
CH3
CH3
NH C C
H
C
CH3
C C C
O
O C
H
CH3
CH3
NH C C
H
C
CH3
C C C
O
O C
H
CH3
CH3
NH C C
H
C
CH3
C C C
O
O C
H
CH3
CH3
NH C C
H
C C
C
C C
O
OH
HH
Template structure can be used to draw all resonance structures above. On an exam draw out all hydrogens. You should be able to specify the hybridization, shape, bond angles, number of sigma bonds, number of pi bonds and number of lone pairs on every nonhydrogen atoms.
resonance
resonance
resonanceseparate
resonanceusing ester
alkoxy oxygen
H
HH
HH
H
C
H
CC
H
HH
HH
H
3D representation of A
A
B C
DE
Template
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
Example 2
HOHCCCC(CHO)C(OCH3)NH2
C
O
H
C
H
C C
C
C
N
O
O H
C
H
H
HH H
C C C
C
C O
N
O
H
H
H
CH
HH
=
3D of first structure
O
H
C C
H
C C
C H
C
O
N
O
H
H
C
H
H H
C
O
H
C
H
C C
C
C
N
O
O H
C
H
H
HH H
resonance
resonance C
O
H
C
H
C C
C
C
N
O
O H
C
H
H
HH H
resonance
C
O
H
C
H
C C
C
C
N
O
O H
C
H
H
HH H
resonanceC
O
H
C
H
C C
C
C
N
O
O H
C
H
H
HH H
resonance
C
O
H
C
H
C C
C
C
N
O
O H
C
H
H
HH H
Template structure can be used to draw all resonance structures above. On an exam draw out all hydrogens. You should be able to specify the hybridization, shape, bond angles, number of sigma bonds, number of pi bonds and number of lone pairs on every nonhydrogen atoms.
A
B C
DE
F
Template
at various locations
O
H
C
H
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
2D / 3D resonance structures with formal charge
N
H
H C
H
H
C
H
H
O C
H
H
C
H
H
C
O
C
H
C C C
C
C C
C
C
C N H
HH
HH
NH2CH2CH2OCH2CH2C(O)CHCCC6H4CNH
N
H
H C
H
H
C
H
H
O C
H
H
C
H
H
C
O
C
H
C C C
C
C C
C
CH
C N H
HH
HH
N
H
H C
H
H
C
H
H
O C
H
H
C
H
H
C
O
C
H
C C C
C
C C
C
C
C N H
HH
HH
N
H
H C
H
H
C
H
H
O C
H
H
C
H
H
C
O
C
H
C C C
C
C C
C
C
C N H
HH
HH
N
H
H C
H
H
C
H
H
O C
H
H
C
H
H
C
O
C
H
C C C
C
C C
C
C
C N H
HH
HH
sigma skeleton
Example 3
next page
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
Template structure can be used to draw all resonance structures above. On an exam draw out all hydrogens. You should be able to specify the hybridization, shape, bond angles, number of sigma bonds, number of pi bonds and number of lone pairs on every nonhydrogen atoms.
N
H
H C
H
H
C
H
H
O C
H
H
C
H
H
C
O
C
H
C C C
C
C C
C
C
C N H
HH
HH
N
H
H C
H
H
C
H
H
O C
H
H
C
H
H
C
O
C
H
C C C
C
C C
C
C
C N H
HH
HH
previous page
C
C
C C
C C
C
C C
C
HH
H H
Example 3 (3D)
N HC
H
O
CC
OC
CN
HH
H H H
H
HHH
H
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
HOCH2CH2NHCHCHCCC6H4COHNH2
OH C
H
H
C
H
H
N C
H
C
H
C C
C
C C
C
C
C N H
HH
HH
C
O
H
HH
OH C
H
H
C
H
H
N C
H
C
H
C C
C
C C
C
C
C N H
HH
HH
C
O
H
HH
sigma skeleton
OH C
H
H
C
H
H
N C
H
C
H
C C
C
C C
C
C
C N H
HH
HH
C
O
H
HH
OH C
H
H
C
H
H
N C
H
C
H
C C
C
C C
C
C
C N H
HH
HH
C
O
H
HH
Example 4
OH C
H
H
C
H
H
N C
H
C
H
C C
C
C C
C
C
C N H
HH
HH
C
HO
H
HH
next page
at various locations
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
OH C
H
H
C
H
H
N C
H
C
H
C C
C
C C
C
C
C N H
HH
HH
C
O
H
HH
previous page
OH C
H
H
C
H
H
N C
H
C
H
C C
C
C C
C
C
C N H
HH
HH
C
O
H
HH
OH C
H
H
C
H
H
N C
H
C
H
C C
C
C C
C
C
C N H
HH
HH
C
O
H
HH
OH C
H
H
C
H
H
N C
H
C
H
C C
C
C C
C
C
C N H
HH
HH
C
O
H
HH
Example 4 (3D)
CC C C
C C
C
C C
C
O
N
H
H
HHH
H H
H
C
H
Example 4 template, can be used for all resonance structures.
N
H
CC
OH
H H
H H
The first and last resonance structures are best according to our rules.
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
Additional structure Example 5 (2D and 3D)
(CH3)2NCCC(OCH3)CHCOHCH3
H C N C C C C
O
C H
H
H
C
C
sigma skeleton
HH
H
H
H
O
C
HH
H
H
H
N
C
C
C C C
C
O
H
C
C
O
C
H
H
H
H
H
HH
H
H
H
H
H
H
3D template
H C N C C C C
O
C H
H
H
C
CH
HH
H
H
O
C
HH
H
H
H
add in pi bonds and lone pairs
H C N C C C C
O
C H
H
H
C
CH
HH
H
H
O
C
HH
H
H
H
H C N C C C C
O
C H
H
H
C
CH
HH
H
H
O
C
HH
H
H
H
H C N C C C C
O
C H
H
H
C
CH
HH
H
H
O
C
HH
H
H
H
H C N C C C C
O
C H
H
H
C
CH
HH
H
H
O
C
HH
H
H
H
H C N C C C C
O
C H
H
H
C
CH
HH
H
H
O
C
HH
H
H
H
at various locations A
BC
D E
F
F > A = D > B = C = E
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
CH3CH2CH3 CH3CH2CH2 CH3CH2CH2 CH3CH2CH2
CH3CHCH3 CH3CHCH3CH3CHCH3
CH C
CH
H H H H
H H
use zig-zag drawingfor sp3 chains
CC
H
HCH
H H
H H
CC
H
HCH
H H
H H
CC
H
HCH
H H
H H
1o carbocation 1o carbanion 1o free radical
CC
C
HH
H H
2o carbocation
H
H H
2o carbanion 2o free radical
CC
C
HH
H H
H
H H
CC
C
HH
H H
H
H H
alkane
H3C
H2C
CH3
alkane
CH3CH2OH CH3CH2OH2CH3CH2O
CH C
OH
H H
H H
use zig-zag drawing
for sp3 chains
CH C
OH
H H H
H Halcohol
CH C
O
H H
H H
alkoxideprotonated alcohol
CH3OCH3 CH3OHCH3
CH O
CH
H H
use zig-zag drawingfor sp3 chains
CH O
CH
H H H H
Hether
protonated ether
H H
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
CH3NHCH3CH3NH2CH3 CH3NCH3
CH N
CH
H H
H
use zig-zag drawingfor sp3 chains
CH N
CH
H H H H
H H2o amine
CH N
C
H H H H
2o amide aniondialkylammonium ion
H H
H
CH2CHCH3 CH2CHCH2 CH2CHCH2 CH2CHCH2
C
H
C
C
HH
H
H H
monosubstituted alkene
C
H
C
C
HH
H
H
C
H
C
C
HH
H
H
resonance
1o allylic carbocation
C
H
C
C
HH
H
H
C
H
C
C
H
H
H
resonance
1o allylic carbanion
C
H
C
C
HH
H
H
C
H
C
C
H
H
H
resonance
1o allylic free radical
H H
H2C
HC
CH3
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
CH3CHO CH3CHOH CH2CHO
O C
C
H
H
H H
aldehyde resonance
O C
C
H
H
H
O C
C H
H
resonance
enolate anion
H
O C
C
HH
H
H H
O C
C
HH
H
H Hprotonated carbonyl
CH3COCH3 CH3COHCH3 CH3COCH2
O C
C
C
H
H Hketone resonance
O C
C H
H
O C
C H
H
resonance
enolate anion
O C
C
H
H
H H
O C
C
H
H
H Hprotonated carbonyl
H
H
HC
H
H
H
C
H
H
H
C
H
H
H
C
H
H
H
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
HCCCH3 HCCCH2 HCCCH2 HCCCH2
C C CHC C CH
H
HH
alkyne
H
H
C C CHH
H
propargyl carbocation
resonance
C C CHH
H
C C CHH
H
propargyl carbanion
resonance
C C CHH
H
C C CHH
H
propargyl free radical
resonance
CH C CH3
CH3CN CH3CNH CH2CN
N C C N C CH
H
HH
nitrile
N C CH
protonated nitrile
resonance
N C CH
H
N C CH
H
nitrile enolate
resonance
CN CH3
H
H
H
H
HH
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
CH3CO2H CH3C(OH)2 CH3CO2 CH2CO2
-2
O C
CH
H H
carboxylic acid
O C
C H
H
O C
C H
Hresonance
carboxylate anion
O
H
O
H
C
CH
H H
protonated carboxylic acid
O
H
resonance
O
H
C
CH
H H
O
H
O
H
C
CH
H H
O
H
resonance
O C
CH
H H
O
O C
CH
H H
O
resonance
O
O
O C
C H
H
O
carboxylate dianion
resonanceH3C
C
O
OH
CH3CONH2 CH3COHNH2 CH3CONH
O C
CH
H H
1o amide
amide anion
N H
H
O
H
C
CH
H H
protonated amide
N H
H
resonance
O
H
C
CH
H H
N H
H
O
H
C
CH
H H
N
Hresonance
O C
CH
H H
N H
O C
CH
H H
N
resonance
H
H
H3CC
O
NH2
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
CH3COCl CH3COHCl CH2COCl
O C
CH
H H
acid chloride
acid chlorideenolate
(unstable to elimination,forms ketene)
Cl
O
H
C
CH
H H
Poor resonance due to inefficient overlap of 3p chlorine orbital with 2p carbon orbital. Even worse for Br and I.
Cl
H
resonance
O
H
C
CH
H H
Cl
H
O
H
C
CH
H H
Cl
Hresonance
O C
C H
H
O C
C H
H
resonance
Cl
Cl
H3CC
O
Cl
Beauchamp 2D / 3D structure drawing & Resonance
y:\files\classes\314\314 Special Handouts\drawing 2D functional groups school 2.doc
C6H5CH3 C6H5CH2 C6H5CH2 C6H5CH2
C
C
C
C
C
C
H H
HH
CH
H
H
H
C
C
C
C
C
C
H H
HH
CH
H
H
resonance
C
C
C
C
C
C
H H
HH
CH
H
H
resonance
C
C
C
C
C
C
H H
HH
CH
H
H
resonance
C
C
C
C
C
C
H H
HH
CH
H
HC
C
C
C
C
C
H H
HH
CH
H
HC
C
C
C
C
C
H H
HH
CH
H
H
resonance2 more times
(around the ring)
resonance2 more times
(around the ring)
resonance2 more times
(around the ring)
C C
C
CC
C CH3
HH
H
H H
aromatic
CH3CH2F
CH C
F
H H
H H
use zig-zag drawingfor sp3 chains
fluoroalkane
C
F
H
C C
F
resonance
H
CH3CH2FH
H
H
H
C
H
H
HH3C
H2C
F
CH3CO2COH3
O C
C
anhydride
O C
H
H3CC
O
OC
O
CH3
O
CH
HHH
HH