Quadrupolar and Chemical Shift Tensors Characterized by 2D Multiple-Quantum NMR Spectroscopy

Procedures for Labeling the High-Resolution Axis of Two-Dimensional MQ-MAS NMR Spectra of Half-Integer Quadrupole Spins

“…Various radiofrequency (RF) pulse sequences have been suggested [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], including shaped pulses [21,22], optimization of MQ coherence transfers [23][24][25], factors limiting the resolution [26][27][28][29][30], spectral editing [31], correlation between satellite and central transitions [32], suppression of sidebands by variable-speed MAS [33], spectra simulation [34][35][36], quantification of spectra with numerical simulation [37], lineshape analysis [38][39][40], and disorder analysis [41]. This method has been applied to the characterization of: (i) meso-and microporous materials such as alumina [42], aluminophosphate [11,12,[43][44][45]...…”

59Co Chemical Shift Anisotropy and Quadrupole Coupling for K3Co(CN)6 from MQMAS and MAS NMR Spectroscopy

“…Other investigations have focused on inorganic Co 3+ complexes where the 59 Co chemical shift may provide information about crystal-field splittings while the quadrupole coupling parameters reflect the local symmetry at the nuclear 59 Co site [17]. Thus, Medek and Frydman determined the magnitudes and relative orientation of the 59 Co CSA and quadrupole coupling tensor for K 3 Co(CN) 6 from static-powder 3Q, 5Q, and 7Q NMR spectra [9]. Furthermore, they also investigated different spinning variants of these experiments and concluded that only limited correlation between the CSA and quadrupole tensors could be obtained from the sample spinning experiments.…”

“…For powders the techniques generally employed for determination of these two tensorial interactions include lineshape analysis of the central transition in static-powder [1,2] and MAS [3] NMR experiments, observation of the complete manifold of spinning sidebands (ssbs) from the central and satellite transitions in MAS NMR spectra [4,5], and the analysis of the quadrupolar-echo sidebands in quadrupolar Carr-Purcell-Meiboom-Gill (QCPMG) NMR spectra of the central transition [6]. Furthermore, the twodimensional techniques of switched-angle spinning (SAS) [7] and multiple-quantum (MQ) MAS NMR [8][9][10] as well as three-dimensional dynamic-angle correlation spectroscopy (DACSY) [11] have also shown potential for determination of these parameters. The choice of experiment for determination of these parameters depends largely on the magnitudes of the quadrupolar coupling and the chemical shift anisotropy.…”

“…This has been demonstrated by the determination of the 87 Rb CSA for one of the Rb sites in Rb 2 CrO 4 from a 87 Rb 3QMAS NMR spectrum at 11.7 T [8]. Because of the growing interest in employing 59 Co NMR and NQR methods to structural studies involving the Co 3+ ion (e.g., see the recent review on 59 Co NMR spectroscopy [17]), the applicability of MQMAS NMR for determination of the magnitudes and relative orientation of the CSA and quadrupole coupling tensors have been investigated by 59 Co MQ static and MAS experiments [9,10]. In this context it should be mentioned that recent 59 Co NMR studies involve applications to cobalt metal centers in biological materials [18] such as vitamin B 12 [19].…”

“…For these nuclei, the combined effect from the two interactions may conveniently be determined by single-crystal NMR or from MAS NMR spectra recorded at high magnetic field. An improved reflection of the effect from the CSA can alternatively be obtained by the MQMAS NMR experiment [8][9][10], where the CSA is scaled by a factor of 3 in the isotropic dimension of a triple-quantum (3Q) MAS NMR spectrum. This has been demonstrated by the determination of the 87 Rb CSA for one of the Rb sites in Rb 2 CrO 4 from a 87 Rb 3QMAS NMR spectrum at 11.7 T [8].…”