TY - JOUR
T1 - Double-quantum homonuclear NMR correlation spectroscopy of quadrupolar nuclei subjected to magic-angle spinning and high magnetic field
AU - Wang, Q.
AU - Hu, B.
AU - Lafon, O.
AU - Trébosc, J.
AU - Deng, F.
AU - Amoureux, J. P.
PY - 2009/10
Y1 - 2009/10
N2 - We present a new application of the R 221 symmetry-based dipolar recoupling scheme, for exciting directly double-quantum (2Q) coherences between the central transition of homonuclear half-integer quadrupolar nuclei. With respect to previously published 2Q-recoupling methods (M. Eden, D. Zhou, J. Yu, Chem. Phys. Lett. 431 (2006) 397), the R 221 sequence is used without π/2 bracketing pulses and with an original super-cycling. This leads to an improved efficiency (a factor of two for spin-5/2) and to a much higher robustness to radio-frequency field inhomogeneity and resonance offset. The 2Q-coherence excitation performances are demonstrated experimentally by 27Al NMR experiments on the aluminophosphates berlinite, VPI5, AlPO4-14, and AlPO4-CJ3. The two-dimensional 2Q-1Q correlation experiments incorporating these recoupling sequences allow the observation of 2Q cross-peaks between central transitions, even at high magnetic field where the difference in offset between octahedral and tetrahedral 27Al sites exceeds 10 kHz.
AB - We present a new application of the R 221 symmetry-based dipolar recoupling scheme, for exciting directly double-quantum (2Q) coherences between the central transition of homonuclear half-integer quadrupolar nuclei. With respect to previously published 2Q-recoupling methods (M. Eden, D. Zhou, J. Yu, Chem. Phys. Lett. 431 (2006) 397), the R 221 sequence is used without π/2 bracketing pulses and with an original super-cycling. This leads to an improved efficiency (a factor of two for spin-5/2) and to a much higher robustness to radio-frequency field inhomogeneity and resonance offset. The 2Q-coherence excitation performances are demonstrated experimentally by 27Al NMR experiments on the aluminophosphates berlinite, VPI5, AlPO4-14, and AlPO4-CJ3. The two-dimensional 2Q-1Q correlation experiments incorporating these recoupling sequences allow the observation of 2Q cross-peaks between central transitions, even at high magnetic field where the difference in offset between octahedral and tetrahedral 27Al sites exceeds 10 kHz.
KW - Double-quanta spectroscopy
KW - Fast MAS
KW - Half-integer quadrupolar nuclei
KW - Solid-state NMR
UR - https://www.scopus.com/pages/publications/69949160151
U2 - 10.1016/j.jmr.2009.07.009
DO - 10.1016/j.jmr.2009.07.009
M3 - 文章
C2 - 19646906
AN - SCOPUS:69949160151
SN - 1090-7807
VL - 200
SP - 251
EP - 260
JO - Journal of Magnetic Resonance
JF - Journal of Magnetic Resonance
IS - 2
ER -