Using three fluorinated steroids as examples, it is demonstrated that for simple multi-fluorinated organic molecules single-pulse and cross-polarization magic-angle spinning experiments with proton decoupling are both feasible and informative. Spinning sideband manifolds are used to obtain shielding
19F SPEDA NMR spectra in rotating solids
β Scribed by Shangwu Ding; Charles A. McDowell
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 495 KB
- Volume
- 259
- Category
- Article
- ISSN
- 0009-2614
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β¦ Synopsis
High resolution ~9F NMR spectra of rotating polycrystalline solids can be obtained by single pulse excitation with a long delay before acquisition (SPEDA). However, the overall spectral range is influenced by the chemical shift anisotropy which, unlike the situation for protons, might be large for 19F nuclei. Three typical cases can be distinguished according to the relative magnitudes of the chemical shift anisotropies and homonuclear dipolar interactions. The second-order effect arising from the non-commutability of the chemical shift and homonuclear dipolar interactions is discussed. The linewidths of the central bands and the characteristics of the sidebands are analyzed. It is found that Anderson-Weiss approximation of the memory equation must be modified to explain the sideband phenomena observed.
π SIMILAR VOLUMES
Protoninhanced deutenum NhlR spectra hare been obtamed III rotatmg sohds wth substantnlgaln III scnsrtwrty. Cross polarlzatlon from proton to deutermm systems occurs VEI effective field mutual smglequantum fhp-flops. ## Sample rotation modulates the deutenum quadrupole couplmng which leads to com
CHEbllCAL PHYSICS LETTERS 12 hlarch 1982 RESOLUTION LIMITS IN MAGIC-ANGLE ROTATION NMR SPECTRA OF POLYCRYSTALLINE SOLIDS hl ALLA and E. LIPPMAA Dcpcndcnce of IIIW ldth III portondccoupkd r3C h'blR spcctrl oi dnmagneuc polycrystallme samples on ewrnal mag-nct~s Geld suength IS studled Spectral rrsolu