Development of modulated rf sequences for decoupling and recoupling of nuclear-spin interactions in sample-spinning solid-state NMR: Application to chemical-shift anisotropy determination

2006 ◽  
Vol 124 (6) ◽  
pp. 064304 ◽  
Author(s):  
Yusuke Nishiyama ◽  
Toshio Yamazaki ◽  
Takehiko Terao
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Nuclear Spin ◽  
Solid State Nmr ◽  
Chemical Shift Anisotropy ◽  
Spin Interactions

scholarly journals Anisotropic nuclear spin interactions in H 2 O@C 60 determined by solid-state NMR

2013 ◽  
Vol 371 (1998) ◽  
pp. 20120102 ◽  
Author(s):  
M. Concistrè ◽  
S. Mamone ◽  
M. Denning ◽  
G. Pileio ◽  
X. Lei ◽  
...  
Keyword(s):  
Solid State ◽  
Nuclear Spin ◽  
Solid State Nmr ◽  
Room Temperature ◽  
Chemical Shift Anisotropy ◽  
Water Molecules ◽  
Dipole Interactions ◽  
Nmr Study ◽  
Spin Interactions ◽  
Principal Axes

We report a solid-state NMR study of the anisotropic nuclear spin interactions in H 2 O@C 60 at room temperature. We find evidence of significant dipole–dipole interactions between the water protons, and also a proton chemical shift anisotropy (CSA) interaction. The principal axes of these interaction tensors are found to be perpendicular. The magnitude of the CSA is too large to be explained by a model in which the water molecules are partially aligned with respect to an external axis. The evidence indicates that the observed CSA is caused by a distortion of the geometry or electronic structure of the fullerene cages, in response to the presence of the endohedral water.

Determination of the 15 N chemical shift anisotropy in natural abundance samples by proton-detected 3D solid-state NMR under ultrafast MAS of 70 kHz

2019 ◽  
Vol 57 (6) ◽  
pp. 294-303 ◽  
Author(s):  
Federica Rossi ◽  
Nghia Tuan Duong ◽  
Manoj Kumar Pandey ◽  
Michele R. Chierotti ◽  
Roberto Gobetto ◽  
...  
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Solid State Nmr ◽  
Chemical Shift Anisotropy ◽  
Natural Abundance ◽  
3D Solid

scholarly journals Insight into the local environment of magnesium and calcium in low-coordination-number organo-complexes using 25Mg and 43Ca solid-state NMR: a DFT study

2017 ◽  
Vol 73 (3) ◽  
pp. 208-218 ◽  
Author(s):  
Christel Gervais ◽  
Cameron Jones ◽  
Christian Bonhomme ◽  
Danielle Laurencin
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Metal Ions ◽  
Solid State Nmr ◽  
Chemical Shift Anisotropy ◽  
Local Environment ◽  
Coordination Numbers ◽  
Highly Sensitive ◽  
Calcium Complexes ◽  
Insight Into

With the increasing number of organocalcium and organomagnesium complexes under development, there is a real need to be able to characterize in detail their local environment in order to fully rationalize their reactivity. For crystalline structures, in cases when diffraction techniques are insufficient, additional local spectroscopies like 25Mg and 43Ca solid-state NMR may provide valuable information to help fully establish the local environment of the metal ions. In this current work, a prospective DFT investigation on crystalline magnesium and calcium complexes involving low-coordination numbers and N-bearing organic ligands was carried out, in which the 25Mg and 43Ca NMR parameters [isotropic chemical shift, chemical shift anisotropy (CSA) and quadrupolar parameters] were calculated for each structure. The analysis of the calculated parameters in relation to the local environment of the metal ions revealed that they are highly sensitive to very small changes in geometry/distances, and hence that they could be used to assist in the refinement of crystal structures. Moreover, such calculations provide a guideline as to how the NMR measurements will need to be performed, revealing that these will be very challenging.

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