Enclosed I send you the Avance version for doing tppm
The cpdprogram has to be e.g.
1 p31:0
p31:15
jump to 1
If you have done e.g. the set-up on C-13, then you can use the
same for Si-29, the X nucleus does not matter in this case.
However if you find due to the changed tuning on the X channel that the
proton 90 changes, then you have to change p31 accordingly.
I believe in silicon the set-up is less sensitive than
in carbon, since usually the heteronuclear dipole interaction is
weaker because of the larger distance and the lower gamma. Dependent
on the sample (of course) in many silicon samples the protons are
more dilute than in organic sample, therefore the homonuclear
proton dipole-dipole interactions are also reduced.
Best wishes,
Stefan
--- cut here --------------------------
;cp
;cross polarisatoin pulse program
;uses digital phase shifter
;optional shaped pulse on proton channel during contact
;optional tppm decoupling
;set:
;d1 : recycle delay, at least 1.25 * T1 of protons
;pl1 : power level for X Hartmann-Hahn match
;pl2 : power level for proton 90 degree pulse
;p3 : 90 degree proton pulse at power level pl2
;p15 : contact pulse at power level pl1 and sp0
;sp0 : power level for proton Hartmann-Hahn match (shaped pulse)
; define spnam0 : square, ramp, or other if desired
;pl12 : power level for proton high power decoupling
; define cpdprg2 : cw, tppm, or other if desired
;d3 : pre-acquisition delay
;ns : 2*n
ze
1 d1 do:f2
10u pl1:f1
10u pl2:f2
(p3 ph1):f2
3u
(p15 ph2):f1 (p15:sp0 ph10):f2
1u pl12:f2
3u cpd2:f2
go=1 ph31
wr #0
exit
ph0= 0
ph1= 1 3
ph2= 0 0 2 2 1 1 3 3
ph10= 0
ph31= 0 2 2 0 1 3 3 1
--- cut here --------------------------
=====================================================================
... ... Dr. Stefan Steuernagel
@ . . . Bruker Analytik GmbH
. . . . Silberstreifen
B R U K E R D-76287 Rheinstetten
. . . . Voice: +49-721-5161-146
@ . . . Fax: +49-721-5161-297
... ... EMail: Stefan.Steuernagel@bruker.de
=====================================================================
am not sure of a good sample for setting up decoupling for
29Si. Kaolinite might be a good one; see Rocha and Klinowski,
J. Magn. Reson. 90, 567 (1990). I have seen that it is somewhat
sensitive to decoupling. If you were looking at 13C, I would
suggest the methylene peaks in sucrose.
Usually TPPM works best with a 15 degree phase shift. The mean
(or absolute) phase does not matter, just the difference of 15
degrees. Please check this, because you may have a version of
the TPPM program (once distributed by Bruker) which uses a much
larger phase shift that proved to be far from optimal.
Next, you have to decide on a power level. TPPM works pretty
well at "typical" CPMAS rf levels. If you like, you could
experiment with higher decoupling power, but do this with the
usual caution. Use a power level that is safe for your probe.
After that, the most important parameter is the pulse length.
The optimum pulse flip angle for TPPM is about 160 degrees. You
could run PAROPT on the TPPM pulse length to optimize it. Set
LB=0 when you do this.
For those who are interested: The TPPM pulse program can be
written to allow setting of the phase shift (via PHCOR). Then
you can use PAROPT to explore the dependence on phase shift.
Here is how you do it:
... (ellipsis indicates additional pulse program code)
define loopcounter aqloop
"aqloop=aq/(d2*2)"
...
3 d2:f2 ph10:r
d2:f2 ph11:r
lo to 3 times aqloop
...
ph10 = 0
ph11 = 0
...
Here the two phases are defined by the acquisition parameters
phcor10 and phcor11. If these program segments do not resemble
your pulse program, e-mail me for a complete program.
-- Tony Bielecki Senior Applications Scientist (Solid State NMR) Bruker Instruments, 19 Fortune Drive, Billerica, MA 01821 Telephone: 978-667-9580, ext 145 Facsimile: 978-667-0985 === New e-mail address: tony.bielecki@nmr.bruker.com ===he pulse sequence is called cptppm on your Avance 200. I would set it up on 13C looking at the alpha carbon of glycine. Varying the phase modulation length (p2 in the pulse sequence), I would optimize the decoupling looking at the amplitude (the bigger the signal, the narrower the line) of the alpha carbon line. I would then use the same decoupling power and parameters for the 29Si work, as the 1H shift range is very small.
I hope this helps,
Martine
-- ============================================================================ Martine Ziliox Tel: 978 667 9580 ext 113 Applications Manager Fax: 978 667 2955 Solid State NMR Email: Martine.Ziliox@nmr.bruker.com Bruker Instruments, Inc. 44 Manning Road Billerica MA 01821 ============================================================================ Original Query follows:Dear Bruker Users:
I am working on setting up tppm decoupling for MAS Si-29 solids on an AVANCE DMX system. I do have a pulse program adapted from X32, I think. I seem to be getting results, but I wonder if anyone has a really good test sample to suggest and a quick setup protocol?
Thanks for any suggestions.
Scott