MAS-J-HMQC

Solid-state analogs of the HMQC [103, 104] and HSQC [105] experiment, MAS-J-HMQC and MAS-J-HSQC [106, 107], have been proposed. They rely on the suppression of the large homonuclear dipolar couplings by FSLG irradiation of the protons. In contrast to the liquid-state implementations, both experiments use low-y detection in the solid state. 

Since its introduction, several other coherence transfer pathways have been employed. The described FSLG-HETCOR and recently proposed MAS-J-HMQC pulse sequence uses heteronuclear dipolar couplings, while the REPT-HMQC employs the rotational-echo double resonance (REDOR) recoupling pulse sequence. 

Figure 12. Pulse sequence and coherence transfer pathway diagram for the MAS-J-HMQC experiment, as presented in refs 32 and 124.

H-13C HETCOR spectra obtained for a sample of L-tyrosine-HCl at a H Larmor frequency of 500 MHz using the FSLG-decoupled CP (Figure 11), the MAS-J-HMQC (Figure 12), and the REPT-HSQC (Figure... 

Pharmaceutical Applications. - Through-bond and through-space solid state NMR correlation experiments at natural isotopic abundance (CP INADEQUATE, HETCOR, MAS J-HMQC) have been applied to... 

Figure 4 (A) The standard S l CP/MAS NMR experiment, (B) the multiCP experiment, (C) the MELODI-HETCOR NMR experiment, and (D) the MAS-J-HMQC NMR experiment with 0 denoting the magic angle, ca. 54.7°. In general, different time periods are not drawn to scale. For phase cycling schemes we refer to original articles.

The anhydrous crystalline forms of Naproxen [(S)-(-l-)-2-(6-metho3gr-2-naphthyl)propionic acid], (NAPROA) and its sodium salt (NAPRO-S), widely used anti-inflammatory drugs, have been investigated by means of ID and 2D MAS NMR and DFT based calculations. From calculations, ID CP MAS and CRAMPS and 2D H- c MAS-J-HMQC, refocused INEPT, FSLG-HETCOR, and DQ-CRAMPS solid-state NMR experi-... 

Fig. 28 a /-HMQC pulse sequence and coherence transfer pathways, b Experimental MAS /-HMQC P A1 spectrum, c Simulated MAS /-HMQC P A1 spectrum of microporous aluminophosphateVPl-S.See [70] for details. Reprinted with permission from [72],Massiot D et al. (2003) J Mag Reson 164 160-164. Copyright (2003) Elsevier Science... 

B. Hu, J. Trebosc, J.-P. Amoureux, Comparison of several hetero-nuclear dipolar rec-oupHng NMR methods to be used in MAS HMQC/HSQC, J. Magn. Reson. 192 (2008) 112-122. 

G. Tricot, O. Lafon, J. Trebosc, L. Delevoye, F. Meat, L. Montagne, J.P. Amoureux, Structural characterisation of phosphate materials new insights into the spatial proximities between phosphorus and quadrupolar nuclei using the D-HMQC MAS NMR technique, Phys. Chem. Chem. Phys. 13 (2011) 16786—16794. 

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