hept3-example - cosy tocsy1d › ... › Lec › Lec13_hept3--cosy+tocsy1d.p… · 3 O 2.4 2.2 2.0...
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ppm 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 C H 3 CH 2 C CH 2 CH 2 CH 2 CH 3 O 250 MHz 500 MHz 3-heptanone 1H 1d Spectra acquired at 250MHz and 500MHz . plotted in ppm Using a ppm scale, on smaller magnets J-couplings (constant in Hz) appear to be larger. Pg. 1 Copyright @ 2005-2012 CG Fry, All Rights Reserved
Transcript of hept3-example - cosy tocsy1d › ... › Lec › Lec13_hept3--cosy+tocsy1d.p… · 3 O 2.4 2.2 2.0...
ppm0.81.01.21.41.61.82.02.22.4
CH3
CH2
C
CH2
CH2
CH2
CH3
O
250 MHz
500 MHz
3-heptanone 1H 1d Spectraacquired at 250MHz and 500MHz .plotted in ppm
Using a ppm scale, onsmaller magnets
J-couplings (constant in Hz)appear to be larger.
Pg. 1Copyright @ 2005-2012 CG Fry, All Rights Reserved
Hz40060080010001200
CH3
CH2
C
CH2
CH2
CH2
CH3
O
250 MHz
500 MHz
3-heptanone 1H 1d Spectraacquired at 250MHz and 500MHz .plotted in Hz
Note the better resolution apparent in the 250 MHz spectrum; at the same time,reduced 2nd order coupling features displayed at 500 MHz displays the power ofthe higher dispersion provided at this field strnegth..
Pg. 2
CH3
CH2
C
CH2
CH2
CH2
CH3
O
ppm0.81.01.21.41.61.82.02.22.4
4.00 2.09 2.05 2.90 3.34
3-heptanone 1H 1d Spectra: 500MHz
This simple compound can be easily assigned from the 1d spectrum (you shouldbe able to identify the two overlapping multiplets). It is used here to provide an
introduction easy to follow to more sophisticated experiments.� �
Pg. 3
CH3
CH2
C
CH2
CH2
CH2
CH3
O
ppm0.81.01.21.41.61.82.02.22.4
3-heptanone 1H 1d Spectra: 500MHz
Chemical shift easily assigns these four protons to this region. J-coupling patternscan finish this assignment; in a more complex compound, the overlap may preventfinal assignments, so pretend that that is the case here.
Pg. 4
CH3
CH2
C
CH2
CH2
CH2
CH3
O
ppm0.81.01.21.41.61.82.02.22.4
Pg. 5
CH3
CH2
C
CH2
CH2
CH2
CH3
O
ppm0.81.01.21.41.61.82.02.22.4
?
?
3-heptanone 1H 1d Spectra: 500MHz
Again, pretend the compound is sufficiently complex that assignments cannot bemade from the 1H 1d spectrum.
Pg. 6
Modern NMR: Assignment Aids
Two basic classes of experiments:
� correlations via J-couplings
proximity (NOE or ROE)
homonuclear (usually 1H-1H)direct 2 and 3 (sometimes >) bondrelayed (or total)
heteronuclear1-bondn-bond
�
�
�
�
�
�
� [examples next week]
3rd and 4th classes, involving dynamics and diffusion,do not assist with assignments.
F1 (ppm)
0.60.81.01.21.41.61.82.02.22.42.6
F2
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
F1 (ppm)
0.60.81.01.21.41.61.82.02.22.42.6
F2(ppm)
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
CH3
CH2
C
CH2
CH2
CH2
CH3
O
COSY connects
all protons
having >~ 3Hz
J-coupling
expt time:
2.3 min
2.62.8 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8
Pg. 7
F1 (ppm)
0.60.81.01.21.41.61.82.02.22.42.6
F2
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
F1 (ppm)
0.60.81.01.21.41.61.82.02.22.42.6
F2(ppm)
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
CH3
CH2
C
CH2
CH2
CH2
CH3
O
COSY connects
all protons
having >~ 3Hz
J-coupling
diagonal
2.62.8 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8
Pg. 8
F1 (ppm)
0.60.81.01.21.41.61.82.02.22.42.6
F2
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
F1 (ppm)
0.60.81.01.21.41.61.82.02.22.42.6
F2(ppm)
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
CH3
CH2
C
CH2
CH2
CH2
CH3
O
COSY connects
all protons
having >~ 3Hz
J-coupling
center glitchnt=1
2.62.8 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8
Pg. 9
F1 (ppm)
0.60.81.01.21.41.61.82.02.22.42.6
F2
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
F1 (ppm)
0.60.81.01.21.41.61.82.02.22.42.6
F2(ppm)
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
CH3
CH2
C
CH2
CH2
CH2
CH3
O
COSY connects
all protons
having >~ 3Hz
J-coupling
center glitchnt=1
2.62.8 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8
Pg. 9
� Bruker eliminates
via DQD acquisition
F1 (ppm)
0.60.81.01.21.41.61.82.02.22.42.6
F2
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
F1 (ppm)
0.60.81.01.21.41.61.82.02.22.42.6
F2(ppm)
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
CH3
CH2
C
CH2
CH2
CH2
CH3
O
COSY connects
all protons
having >~ 3Hz
J-coupling
3JHH
2.62.8 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8
Pg. 10
F1 (ppm)
0.60.81.01.21.41.61.82.02.22.42.6
F2
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
F1 (ppm)
0.60.81.01.21.41.61.82.02.22.42.6
F2(ppm)
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
CH3
CH2
C
CH2
CH2
CH2
CH3
O
COSY connects
all protons
having >~ 3Hz
J-coupling
3JHH
off-center iscrucial in assignments
2.62.8 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8
Pg. 11
CH3
CH2
C
CH2
CH2
CH2
CH3
O
ppm0.81.01.21.41.61.82.02.22.4
4.00 2.09 2.05 2.90 3.34
3-heptanone 1H 1d Spectra: 500MHz
Here’s sufficient detail such that a complete assignment can be made based offthe 1d spectrum.
Pg. 12
F1 (ppm)
0.60.81.01.21.41.61.82.02.22.42.6
F2
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
F1 (ppm)
0.60.81.01.21.41.61.82.02.22.42.6
F2(ppm)
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
CH3
CH2
C
CH2
CH2
CH2
CH3
O
COSY connects
all protons
having >~ 3Hz
J-coupling
3JHH
2.62.8 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8
Pg. 13
ppm0.81.01.21.41.61.82.02.22.4
CH3
CH2
C
CH2
CH2
CH2
CH3
OTOCSY-1D is similar to COSY:
J-coupling larger than ~3 Hz “mix”
coupled protons. [Note: COSY can
observe smaller J; TOCSY cannot.]
One multiplet is selected in the 1d
vesion of the TOCSY experiment.
mix=0
Without COSY or chemical shiftarguments, all e know is that oneof the methyls has been cleanlyselected.
w
Pg. 14
ppm0.81.01.21.41.61.82.02.22.4
TOCSY-1D: short mix times show
primarily 2- and 3-bond coupling,
similar to COSY spectra.
mix=0
mix=30ms
Pg. 15
CH3
CH2
C
CH2
CH2
CH2
CH3
O
ppm0.81.01.21.41.61.82.02.22.4
TOCSY-1D: with longer mix times,
the coupling transfers magnetization
to more distant protons, as long as
J-couplings remain large.
mix=0
mix=30ms
mix=55ms
Pg. 16
CH3
CH2
C
CH2
CH2
CH2
CH3
O
ppm0.81.01.21.41.61.82.02.22.4
TOCSY-1D: with longer mix, the
coupling transfers magnetization
through the proton spin network, as
long as J-couplings remain large.
1D provides high-resolution.
mix=0
mix=30ms
mix=55ms
mix=80ms
Pg. 17
CH3
CH2
C
CH2
CH2
CH2
CH3
O
CH3
CH2
C
CH2
CH2
CH2
CH3
O
ppm0.81.01.21.41.61.82.02.22.4Pg. 18
TOCSY-1D: we will see better
examples later in the course, but
note that the multiplet structure can
be discerned, and compared properly
to the 1d spectrum.
CH3
CH2
C
CH2
CH2
CH2
CH3
O
ppm0.81.01.21.41.61.82.02.22.4
TOCSY-1D: this experiment
separates protons into spin-coupling
networks, very useful for mixture
analysis and spin subsystems (e.g.,
peptides/proteins/oligosaccharides).
mix=0
mix=30ms
mix=55ms
mix=80ms
X
Pg. 18
CH3
CH2
C
CH2
CH2
CH2
CH3
O
CH3
CH2
C
CH2
CH2
CH2
CH3
O
ppm020406080100120140160180200
3-heptanone 13C 1d Spectra: 500MHz
Proton NMR does not always provide sufficientinformation, even with more complex experiments.Let’s look at the 13C NMR.
Pg. 19
ppm020406080100120140160180200
CH3
CH2
C
CH2
CH2
CH2
CH3
O
?
?
3-heptanone 13C 1d Spectra: 500MHz
Again, let’s pretend that we could not make theseassignments.
Pg. 22
F1 (ppm)
0510152025303540455055
F2
0.5
1.0
1.5
2.0
2.5
3.0
3.5
F1 (ppm)
0510152025303540455055
F2(ppm)
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Indirectly detected 13C axis
Dir
ectl
y d
ete
cte
d 1
H a
xis
CH3
CH2
C
CH2
CH2
CH2
CH3
O
1JCH
HSQC: this experiment can
provide 13C chemical shifts
than normal 13C 1d.> 100 faster�
Pg. 24
F1 (ppm)
0510152025303540455055
F2
0.5
1.0
1.5
2.0
2.5
3.0
3.5
F1 (ppm)
0510152025303540455055
F2(ppm)
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Indirectly detected 13C axis
Dir
ectl
y d
ete
cte
d 1
H a
xis
CH3
CH2
C
CH2
CH2
CH2
CH3
O
1JCH
HSQC: a major utility of hetero-
correlation is the dispersion
provided by the X nucleus
Pg. 24
