Bruker BioSpin Solid State NMR, User Manual

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HETCOR with DUMBO, PMLG or w-PMLG, Using Shapes
User Manual Version 002 BRUKER BIOSPIN 129 (327)
HETCOR with DUMBO, PMLG or w-PMLG, Using Shapes 9.2
These sequences use phase modulated shapes for homonuclear proton decou-
pling. Apart from some smaller differences, the sequences are in complete analo-
gy to the HETCOR sequence using frequency shifts.
The only differences between these sequences lie in the length and type of shape
used for homonuclear decoupling. DUMBO and e-DUMBO (Emsley et al.) use
principles known from multiple pulse NMR operating on resonance, whereas pmlg
and w-pmlg (Vega et al.) use phase ramps which act like frequency offsets and
are therefore derivatives of FSLG.
References:
1. D. Sakellariou, A. Lesage, P. Hodgkinson and L. Emsley, Homonuclear dipolar decoupling in solid-
state NMR using continuous phase modulation, Chem. Phys. Lett. 319, 253 (2000).
2. Vinogradov, E.; Madhu, P. K.; Vega, S., High-resolution proton solid-state NMR spectroscopy by
phase modulated Lee-Goldburg experiment , Chem. Phys. Lett. (1999), 314(5,6), 443-450.
3. E. Vinogradov, P.K. Madhu and S. Vega, Proton spectroscopy in solid state NMR with windowed
phase modulated Lee-Goldburg decoupling sequences, Chem. Phys. Lett. (2002), 354, 193.
4. Leskes, Michal; Madhu, P. K.; Vega, Shimon, A broad banded z-rotation windowed phase modulated
Lee-Goldburg pulse sequence for 1H spectroscopy in solid state NMR, Chem. Phys. Lett. (2007), 447,
370-374.
5. Leskes, Michal; Madhu, P. K.; Vega, Shimon, Supercycled homonuclear decoupling in solid state
NMR: towards cleaner 1H spectrum and higher spinning rates, J. Chem. Phys. (2007) in press.
The Sequence pmlghet 9.2.1
This sequence uses windowless phase ramped shapes. One can write these
shapes as multiples of FSLG cycles to manipulate the length of the T
1
-increment.
Usually, 2 FSLG cycles make sense. The pulse program calculates the required
shape pulse length from the RF-field during the FSLG-evolution. In pmlghet, a
shape with 2 cycles is assumed in the calculation. The sequence is optimized for
a simple twofold linear phase ramp (supplied as
lgs-2
). The carrier may be placed
in the middle of the proton spectrum during evolution which may allow using fewer
increments and therefore saving time. However, one should be aware of the pres-
ence of proton spinning sidebands along F1 which may inappropriately fold in if
the spectrum window along F1 is chosen too small.
Processing is done in complete analogy to the FSLG-experiment, as for all follow-
ing sequences.