University of Ottawa NMR Facility Web Site

Please feel free to make suggestions for future posts by emailing Glenn Facey.



Friday, December 5, 2014

1D Selective 1H - 19F HOESY

2D Heteronuclear Overhauser Effect SpectroscopY (HOESY) is an effective way to determine whether or not a pair of heteronuclear spins are close to one another in space.  It is particularly effective for 1H and 19F where both nuclides are 100% naturally abundant.  2D 19F detected 19F - 1H HOESY data are typically obtained which provide all NOE correlations.  2D experiments, however,  can be quite time consuming, especially when only a few NOE correlations are sought after.  In such cases, 1D 1H detected 1H - 19F HOESY experiments1 are very desirable and can save a great deal of time.  When only one 19F resonance is present, they can be obtained by using hard 19F pulses.  This was recently illustrated well by Dr. Michael Lumsden of Dalhousie University.  When more than one 19F resonance is present, one can use a selective 19F pulse and repeat the experiment selecting each type of fluorine.  An example of this is shown in the figure below.  Selective 1D 1H detected 1H - 19F HOESY spectra were collected for 2,3-difluoropyridine using a selective 19F pulse.  The simple 19F spectra are shown on the left with the selected 19F resonance color coded.  The upper two spectra on the right are the HOESY spectra while the spectrum on the bottom right is a simple 1H spectrum.  One can see that when the fluorine in the 3-position is selected, there is a strong NOE to the nearest proton, C.  Alternatively, when the fluorine in the 2-position is selected, there are no strong NOE's as there are no adjacent protons.



1.  L.E. Combettes, P. Clausen-Thue, M.A. King, B. Odell, A.L. Thompson, V. Gouverneur and T.D.W. Claridge. Chem. Eur. J. 18, 13133 (2012).   

11 comments:

Bogdan Marekha said...

What standard Bruker library sequence could be used for such an experiment?

Bogdan Marekha said...

How could one obtain such a pulse sequence for a Bruker Avance II spectrometer?

Glenn Facey said...

Hi Bogdan,

Sorry for the delayed response. As far as as I know there is not a program in the Bruker library for this measurement. I have used the program below.

Glenn

;hoesyfhgp1d
;avance-version (07/04/04)
;1D heteronuclear 19F-1H NOESY
;
;
;L.E. Combettes, P. Clausen-Thue, M.A. King, B.Odell,
;A.L. Thompson, V.Gouverneur, and T.D.W. Claridge
;Chem. Eur. J., 2012, DOI: 10.1002/chem.201201577
;
;$CLASS=HighRes
;$DIM=1D
;$TYPE=
;$SUBTYPE=
;$COMMENT=

;1H observe 19F-1H HOESY
;selective version
;no 19F CPD during 1H observe
;with grad purge and 180 pulse BPP
;with ZQ cancellation after mixing time

;Sequence written for shared 1H/19F transmitter

#include
#include
#include


"p2=p1*2"
"p4=p3*2"
"d11=30m"
"d12=20u"


"TAU1=d8*0.5-p16-d16-53u"
"TAU2=d8*0.5-p16-d16-d12-p3*2-53u"


1 ze
d11 QNP_X
2 30m
d12 SWITO_F
d1 pl2:f2
(p3 ph1):f2
50u UNBLKGRAD
p16:gp1
d16
p11:sp1:f2 ph1:r
p16:gp1
d16
50u BLKGRAD
(p3 ph2):f2
d12 SWITO_H
(p1 ph1):f1
50u UNBLKGRAD
TAU1
p16:gp2
d16
3u
(p2 ph1):f1
d12 SWITO_F
(p4 ph1):f2
3u
p16:gp2*-1
d16
50u BLKGRAD
TAU2
(p3 ph5):f2
(p3 ph6):f2
d12 SWITO_H
(p1 ph4):f1
go=2 ph31
30m mc #0 to 2 F0(zd)
exit


ph1=0
ph2=0 2
ph4=0 0 0 0 1 1 1 1 2 2 2 2 3 3 3 3
;ph4=0 0 0 0
ph5=0 0 0 0
ph6=0 0 2 2
ph31=0 2 0 2 1 3 1 3 2 0 2 0 3 1 3 1
;ph31=0 2 0 2


;pl1 : f1 channel - power level for pulse (default)
;pl2 : f2 channel - power level for pulse (default)
;pl12: f2 channel - power level for CPD/BB decoupling
;p1 : f1 channel - 90 degree high power pulse
;p2 : f1 channel - 180 degree high power pulse
;p3 : f2 channel - 90 degree high power pulse
;p4 : f2 channel - 180 degree high power pulse
;p11: f2 channel - selective 180 degree pulse
;p16: homospoil/gradient pulse
;d1 : relaxation delay; 1-5 * T1
;d8 : mixing time
;d12: delay for power switching [20 usec]
;d16: delay for homospoil/gradient recovery
;NS: 16 * n
;DS: 16



;for z-only gradients:

;gpz1: 40%
;gpz2: 15%

;use gradient files:
;
;gpnam2: SINE.100


;$Id: hoesyph,v 1.6 2007/04/11 13:34:30 ber Exp $

Anonymous said...

Is it possible to run this experiment without gradients? Do you have the pulse program?

Glenn Facey said...

Anonymous,

Yes, it should be possible to collect data without the use of gradients. I do not have a pulse program for it.

Glenn

Anonymous said...

Hello, Glenn! It's Andrew from Ukraine!

What shape did you use to excite 19F? Can you give approximate values for p11 and sp1? I have tried to do this experiment with Gauss1.1000, but it was not successful..

Glenn Facey said...

Andrew,
I used the Reburp.1000 shape. Typical values of SP1 and P11 were 22.7 dB and 5000 microseconds, respectively.
Glenn

Anonymous said...

Thank you very much, Glenn!!!

Andrew.

Old NMR guy said...

Hi Glenn. I can't tell you enough how much your blog has meant to me over the years. You've helped me tremendously and you are always a great source for information. I tried the selective HOESY pulse sequence, but it failed no matter what type shape pulse I used, even after a lot of careful calibration of power levels. I asked someone at Bruker and he suggested the change as can be seen in the enclosed sequence. It just involves setting the power level for the 19F channel to 0 (PL0 = 0W)before the selective pulse. It then turns it back up to the normal high power before the next high power 90 deg 19F pulse. This made all the difference in the world and it works beautifully using the Reburp.1000 shape. The pulse sequence is below. Thanks again for everything.

Jim

;A.L. Thompson, V.Gouverneur, and T.D.W. Claridge
;Chem. Eur. J., 2012, DOI: 10.1002/chem.201201577
;
;$CLASS=HighRes
;$DIM=1D
;$TYPE=
;$SUBTYPE=
;$COMMENT=

;1H observe 19F-1H HOESY
;selective version
;no 19F CPD during 1H observe
;with grad purge and 180 pulse BPP
;with ZQ cancellation after mixing time

;Sequence written for shared 1H/19F transmitter

#include
#include
#include

"p2=p1*2"
"p4=p3*2"
"d11=30m"
"d12=20u"


"TAU1=d8*0.5-p16-d16-53u"
"TAU2=d8*0.5-p16-d16-d12-p3*2-53u"


1 ze
d11 QNP_X
2 30m
d12 SWITO_F
d1 pl2:f2
(p3 ph1):f2
50u UNBLKGRAD
p16:gp1
d16 pl0:f2
3u
p11:sp1:f2 ph10:r
3u
p16:gp1
d16 pl2:f2
50u BLKGRAD
(p3 ph2):f2
d12 SWITO_H
(p1 ph1):f1
50u UNBLKGRAD
TAU1
p16:gp2
d16
3u
(p2 ph1):f1
d12 SWITO_F
(p4 ph1):f2
3u
p16:gp2*-1
d16
50u BLKGRAD
TAU2
(p3 ph5):f2
(p3 ph6):f2
d12 SWITO_H
(p1 ph4):f1
go=2 ph31
30m mc #0 to 2 F0(zd)
exit


ph1=0
ph2=0 2
ph4=0 0 0 0 1 1 1 1 2 2 2 2 3 3 3 3
;ph4=0 0 0 0
ph5=0 0 0 0
ph6=0 0 2 2
ph10=0
ph31=0 2 0 2 1 3 1 3 2 0 2 0 3 1 3 1
;ph31=0 2 0 2

;plw0=0 watts
;pl1 : f1 channel - power level for pulse (default)
;pl2 : f2 channel - power level for pulse (default)
;pl12: f2 channel - power level for CPD/BB decoupling
;p1 : f1 channel - 90 degree high power pulse
;p2 : f1 channel - 180 degree high power pulse
;p3 : f2 channel - 90 degree high power pulse
;p4 : f2 channel - 180 degree high power pulse
;p11: f2 channel - selective 180 degree pulse
;p16: homospoil/gradient pulse
;d1 : relaxation delay; 1-5 * T1
;d8 : mixing time
;d12: delay for power switching [20 usec]
;d16: delay for homospoil/gradient recovery
;NS: 16 * n
;DS: 16



;for z-only gradients:

;gpz1: 40%
;gpz2: 15%

;use gradient files:
;
;gpnam2: SINE.100


;$Id: hoesyph,v 1.6 2007/04/11 13:34:30 ber Exp $

Rookie chemist said...

This is a great blog Glen! Thank you very much.

I had a question about the 19F-1H HOESY experiment. How close together should the Hydrogen and fluorine be to show up in spectra?

Glenn Facey said...

Rookie Chemist,
Thank you for your kind words. A precise answer to your question is difficult. The NOE is proportional to the square of the product of the gyromagnetic ratios between the two spins and falls off as the reciprocal 6th power of the distance between spins. For protons, one often hears that there will be an insignificant NOE at a distance greater than 5 Angstroms. This would suggest that 1H-19F NOE's would be insignificant at distances greater than about 4.7 Angstroms.

Glenn