Dipolar and Scalar Coupling in Magic-Angle-Spinning Solid-State NMR Spectra of Spin- Nuclei Affected by Quadrupolar Nuclei with Large Quadrupole Coupling Constants

1993 ◽  
Vol 101 (3) ◽  
pp. 313-316 ◽  
Author(s):  
A.C. Olivieri
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
Magic Angle Spinning ◽  
Coupling Constants ◽  
Scalar Coupling ◽  
Magic Angle ◽  
Quadrupolar Nuclei ◽  
Quadrupole Coupling ◽  
Angle Spinning

High sensitivity and resolution in 43Ca solid-state NMR experiments

2015 ◽  
Vol 93 (8) ◽  
pp. 799-807 ◽  
Author(s):  
Kevin M.N. Burgess ◽  
Frédéric A. Perras ◽  
Igor L. Moudrakovski ◽  
Yijue Xu ◽  
David L. Bryce
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
High Sensitivity ◽  
Magic Angle Spinning ◽  
Signal Enhancement ◽  
Magic Angle ◽  
Multiple Quantum ◽  
Central Transition ◽  
Angle Spinning

A thorough investigation of solid-state NMR signal enhancement schemes and high-resolution techniques for application to the spin-7/2 43Ca nuclide are presented. Signal enhancement experiments employing double frequency sweeps, hyperbolic secant pulses, and rotor-assisted population transfer, which manipulate the satellite transitions of half-integer quadrupolar nuclei to polarize the central transition (m = + 1/2 ↔ –1/2), are carried out on four well-characterized 43Ca isotopically enriched calcium salts: Ca(NO3)2, Ca(OD)2, CaSO4·2H2O, and Ca(OAc)2·H2O. These results, in conjunction with numerical simulations of 43Ca NMR spectra under magic-angle spinning conditions, are used to identify the technique that provides the most uniform (or quantitative) polarization enhancement as well as the largest signal enhancement factors independent of size of the 43Ca quadrupolar coupling constant, which is the most significant source of resonance broadening in 43Ca NMR spectra. These samples are further investigated using 43Ca double-rotation NMR spectroscopy to yield isotropic, or solution-like, NMR spectra with exquisite resolution. In addition, three unique calcium sites are resolved for the hemihydrated form of calcium acetate (unknown structure), Ca(OAc)2·0.5H2O, with double-rotation NMR, whereas the more common, but more time-consuming, multiple quantum magic-angle spinning technique only clearly resolves two calcium sites. The results shown herein will be useful for other NMR spectroscopists attempting to acquire 43Ca solid-state NMR data for unknown and more complex materials with a higher degree of both sensitivity and resolution.

Solid-State NMR Spectra of Lipid-Anchored Proteins under Magic Angle Spinning

2014 ◽  
Vol 118 (9) ◽  
pp. 2405-2413 ◽  
Author(s):  
Kaoru Nomura ◽  
Erisa Harada ◽  
Kenji Sugase ◽  
Keiko Shimamoto
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Angle Spinning
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