SLIDE 1
1
2
From Last Lecture Electronic Sheilding B local B effective = B 0 - B - - PowerPoint PPT Presentation
From Last Lecture Electronic Sheilding B local B effective = B 0 - B - - PowerPoint PPT Presentation
From Last Lecture Electronic Sheilding B local B effective = B 0 - B local Actual magnetic field felt by the nucleus B 0 B effective 1 From Last Lecture = ppm = Chemical Shift from TMS (Hz) Spectrometer Frequency (MHz) 100 Hz = 1.0
SLIDE 2
SLIDE 3
3
From Last Lecture
Difficult - Carbon 13 only 1.1% of all carbon. Number of different carbons Functional Group Regions
200
C C C C O
R R
13C NMR
150 100 50 δ ppm
C O C N C X C O
OR R
C O
NR2 R
SLIDE 4
4
From Last Lecture
Symmetry in molecules can make carbons “Chemically Equivalent”
H3C C CH3 O
same electronic environment
Cl Br
SLIDE 5
5
Substitution of Carbon
The intensity of the peaks roughly correlates with the number of hydrogens on the carbon.
SLIDE 6
6
C13 NMR Regions
200
C C C C O
R R
13C NMR
150 100 50 δ p
C O C N C X C O
OR R
C O
NR2 R
SLIDE 7
7
Bromooctanol
HO Br
SLIDE 8
8
Bromooctanal
O Br H
SLIDE 9
9
Alanine Me-Ester HCl
H3C NH3Cl O OCH3
SLIDE 10
10
Alaninol H3C NH2 OH
SLIDE 11
11
Alaninol - phthalimide
H3C N OH O O
SLIDE 12
12
DEPT
- C13
A - normal C13 B - CH carbons
- nly
C - Odd # up (CH3 and CH) Even # down (CH2)
OH
SLIDE 13
13
Example from 13.7
Cl KOH ethanol
- r
SLIDE 14
14
A Real Example
NH N O O O
NH N O O O NH O N O O OR
H2, Pd/C NH N O O O
H2, Pd/C NH N O O O NH O N O O OR
In the alkane region there would
- nly be 4 peaks
due to symmetry In the alkane region there would be 6 different peaks
SLIDE 15
15
The Answer Is . . .
NH N O O O
NH O N O O
SLIDE 16
16
Proton NMR
Number of chemically different hydrogens Relative Ratios of protons (peak size) How many neighboring hydrogens Chemical shifts and functional groups
SLIDE 17
17
Proton Equivalency
Homotopic Enantiotopic Diastereotopic
H3C C CH3 H H replace H's
- same
H3C C CH3 H X H3C C CH3 X H
H3C C C H2 CH3 H H replace H's - enantiomers H3C C C H2 CH3 X H H3C C C H2 CH3 H X H3C C C CH3 H H replace H's - diastereomers H3C C C CH3 X H H3C C C CH3 H X H Cl Cl Cl H H
SLIDE 18
18
Proton NMR Scale
Range 0-10 ppm
10
C H H H H H
4 1 δ ppm
C X
5 2 3 9 6 7 8
H H H H H H H C C H C O H C O OH 1H NMR
SLIDE 19
19