TY - JOUR

T1 - Determination of NMR interaction parameters from double rotation NMR

AU - Hung, I.

AU - Wong, A.

AU - Howes, A. P.

AU - Anupõld, Tiit

AU - Past, J.

AU - Samoson, A.

AU - Mo, X.

AU - Wu, G.

AU - Smith, Mark E.

AU - Brown, S. P.

AU - Dupree, Ray

PY - 2007/10/1

Y1 - 2007/10/1

N2 - It is shown that the anisotropic NMR parameters for half-integer quadrupolar nuclei can be determined using double rotation (DOR) NMR at a single magnetic field with comparable accuracy to multi-field static and MAS experiments. The O-17 nuclei in isotopically enriched L-alanine and OPPh3 are used as illustrations. The anisotropic NMR parameters are obtained from spectral simulation of the DOR spinning sideband intensities using a computer program written with the GAMMA spin-simulation libraries. Contributions due to the quadrupolar interaction, chemical shift anisotropy, dipolar coupling and J coupling are included in the simulations. In L-alanine the oxygen chemical shift span is 455 ??- 20 ppm and 350 ??- 20 ppm for the O1 and O2 sites, respectively, and the Euler angles are determined to an accuracy of ??- 5-10 degrees. For cases where effects due to heteronuclear J and dipolar coupling are observed, it is possible to determine the angle between the internuclear vector and the principal axis of the electric field gradient (EFG). Thus, the orientation of the major components of both the EFG and chemical shift tensors (i.e., V-33 and delta(33)) in the molecular frame may be obtained from the relative intensity of the split DOR peaks. For OPPh3 the principal axis of the O-17 EFG is found to be close to the O-P bond, and the O-17-P-31 one-bond J coupling ((1)J(OP) = 161 ??- 2 Hz) is determined to a much higher accuracy than previously. (C) 2007 Elsevier Inc. All rights reserved.

AB - It is shown that the anisotropic NMR parameters for half-integer quadrupolar nuclei can be determined using double rotation (DOR) NMR at a single magnetic field with comparable accuracy to multi-field static and MAS experiments. The O-17 nuclei in isotopically enriched L-alanine and OPPh3 are used as illustrations. The anisotropic NMR parameters are obtained from spectral simulation of the DOR spinning sideband intensities using a computer program written with the GAMMA spin-simulation libraries. Contributions due to the quadrupolar interaction, chemical shift anisotropy, dipolar coupling and J coupling are included in the simulations. In L-alanine the oxygen chemical shift span is 455 ??- 20 ppm and 350 ??- 20 ppm for the O1 and O2 sites, respectively, and the Euler angles are determined to an accuracy of ??- 5-10 degrees. For cases where effects due to heteronuclear J and dipolar coupling are observed, it is possible to determine the angle between the internuclear vector and the principal axis of the electric field gradient (EFG). Thus, the orientation of the major components of both the EFG and chemical shift tensors (i.e., V-33 and delta(33)) in the molecular frame may be obtained from the relative intensity of the split DOR peaks. For OPPh3 the principal axis of the O-17 EFG is found to be close to the O-P bond, and the O-17-P-31 one-bond J coupling ((1)J(OP) = 161 ??- 2 Hz) is determined to a much higher accuracy than previously. (C) 2007 Elsevier Inc. All rights reserved.

KW - solid-state NMR

KW - double rotation

KW - quadrupolar interaction

KW - chemical shift anisotropy

KW - J-coupling

KW - dipolar coupling

KW - oxygen-17

U2 - 10.1016/j.jmr.2007.07.009

DO - 10.1016/j.jmr.2007.07.009

M3 - Journal article

VL - 188

SP - 246

EP - 259

JO - Journal of Magnetic Resonance

JF - Journal of Magnetic Resonance

SN - 1096-0856

IS - 2

ER -