TWELVE%20EASY%20PROBLEMS

1
TWELVE EASY PROBLEMS
COMBINED PROBLEMS
FORMULA INFRARED NMR
2
Spectra in these problems were obtained from
SDBSWeb http//www.aist.go.jp/RIODB/SDBS/
(Mar 2002)
NOTE ON INTEGRALS
Integrals (relative number of hydrogens) are
given as 2
The integrals are the simplest ratio.
Expansions are blue and printed above the
baseline.
3
COMBINED PROBLEM 1
4
PROBLEM 1 INFRARED SPECTRUM
C4H10O
5
PROBLEM 1 NMR SPECTRUM
6
C4H10O
2
1
1
doublet
multiplet
doublet
6
Answer to 1

• (CH3)2CHCH2OH

7
COMBINED PROBLEM 2
8
PROBLEM 2 INFRARED SPECTRUM
C9H10O2
1719
9
PROBLEM 2 NMR SPECTRUM
C9H10O2
3
2
5
quartet
triplet
two multiplets
10
Answer to 2
11
COMBINED PROBLEM 3
12
PROBLEM 3 INFRARED SPECTRUM
C10H12O
1688
13
6
PROBLEM 3 NMR SPECTRUM
C10H12O
5
1
doublet
septet
14
Answer 3
15
COMBINED PROBLEM 4
16
PROBLEM 4 INFRARED SPECTRUM
C5H10O2
1712
17
PROBLEM 4 NMR SPECTRUM
3
C5H10O2
1
2
two overlapping multiplets (2 2)
4
triplet
triplet
18
Answer
19
COMBINED PROBLEM 5
20
PROBLEM 5 INFRARED SPECTRUM
C9H12
21
PROBLEM 5 NMR SPECTRUM
C9H12
6
5
1
septet
doublet
22
Answer to 5

• Isopropyl benzene

23
COMBINED PROBLEM 6
24
PROBLEM 6 INFRARED SPECTRUM
C9H12O
25
PROBLEM 6 NMR SPECTRUM
C9H12O
5
3
2
1
1
triplet
quintet
triplet
26
Answer 6
27
CORRELATION CHARTS
28
BASIC INFRARED KNOWLEDGE
EXPANDED CH
3000
BASE VALUES
OH 3600 NH 3400 CH 3000 C N 2250 C
C 2150 CO 1715 CC 1650 C-O 1100
3300 3100 2900 2850
2750
C-H
-C-H
C-H
-CHO
CH2 and CH3 bend 1465 and 1365
1800 1735 1725 1715 1710 1690
acid
aldehyde
ester
acid chloride
amide
ketone
anhydride 1810 and 1760
EXPANDED CO
benzene CC between 1400 and 1600
Also remember the effects of H-bonding,
conjugation and ring size.
29
NMR Correlation Chart
-OH
-NH
DOWNFIELD
UPFIELD
DESHIELDED
SHIELDED
CHCl3 ,
TMS
d (ppm)
12
11
10
9
8
7
6
5
4
3
2
1
0
H
CH2Ar CH2NR2 CH2S C C-H CC-CH2 CH2-C-
CH2F CH2Cl CH2Br CH2I CH2O CH2NO2
C-CH-C
RCOOH
RCHO
CC
C
C-CH2-C C-CH3
O
Ranges can be defined for different general types
of protons. This chart is general, the next slide
is more definite.
30
APPROXIMATE CHEMICAL SHIFT RANGES (ppm) FOR
SELECTED TYPES OF PROTONS
R-CH3 0.7 - 1.3
R-N-C-H 2.2 - 2.9
R-CC-H
R-CH2-R 1.2 - 1.4
4.5 - 6.5
R-S-C-H 2.0 - 3.0
R3CH 1.4 - 1.7
I-C-H 2.0 - 4.0
H
R-CC-C-H 1.6 - 2.6
Br-C-H 2.7 - 4.1
6.5 - 8.0
Cl-C-H 3.1 - 4.1
R-C-C-H 2.1 - 2.4
R-C-N-H
RO-C-H 3.2 - 3.8
5.0 - 9.0
RO-C-C-H 2.1 - 2.5
HO-C-H 3.2 - 3.8
R-C-H
HO-C-C-H 2.1 - 2.5
9.0 - 10.0
R-C-O-C-H 3.5 - 4.8
N C-C-H 2.1 - 3.0
O2N-C-H 4.1 - 4.3
R-C-O-H
R-C C-C-H 2.1 - 3.0
11.0 - 12.0
F-C-H 4.2 - 4.8
C-H 2.3 - 2.7
R-N-H 0.5 - 4.0 Ar-N-H 3.0 - 5.0 R-S-H
R-O-H 0.5 - 5.0 Ar-O-H 4.0 - 7.0
1.0 - 4.0
R-C C-H 1.7 - 2.7
31
m
10 11 12 13 14
15
ALKENES
s
s
Monosubstituted
Disubstituted
cis-1,2-
s
trans-1,2-
s
1,1-
s
Trisubstituted
m
C-H OUT OF PLANE BENDING
Tetrasubstituted
1000
900
800
700
cm-1
32
m
10 11 12 13 14
15
BENZENES
Monosubstituted
s
s
Disubstituted
s
ortho
s
s
m
meta
para
s
RING Hs
Trisubstituted
OOPS
s
m
1,2,4
1,2,3
s
m
1,3,5
s
m
combination bands
1000
900
800
700
cm-1