Residual Dipolar Coupling to Quadrupolar Nuclei with Negative Gyromagnetic Ratios in MAS NMR. Implications for (29Si,14N) Effects in29Si Solid-State NMR Spectra

1996 ◽  
Vol 34 (5) ◽  
pp. 365-367 ◽  
Author(s):  
Alejandro C. Olivieri
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
Dipolar Coupling ◽  
Residual Dipolar Coupling ◽  
Mas Nmr ◽  
Quadrupolar Nuclei

scholarly journals Rapid acquisition of wideline MAS solid-state NMR spectra with fast MAS, proton detection, and dipolar HMQC pulse sequences

2016 ◽  
Vol 18 (36) ◽  
pp. 25284-25295 ◽  
Author(s):  
Aaron J. Rossini ◽  
Michael P. Hanrahan ◽  
Martin Thuo
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
Pulse Sequences ◽  
Quadrupolar Nuclei ◽  
Proton Detection ◽  
Rapid Acquisition ◽  
Half Integer ◽  
Fast Mas

Fast MAS and proton detection are applied to rapidly acquire wideline solid-state NMR spectra of spin-1/2 and half-integer quadrupolar nuclei.

scholarly journals Dynamics and interactions of ibuprofen in cyclodextrin nanosponges by solid-state NMR spectroscopy

2017 ◽  
Vol 13 ◽  
pp. 182-194 ◽  
Author(s):  
Monica Ferro ◽  
Franca Castiglione ◽  
Nadia Pastori ◽  
Carlo Punta ◽  
Lucio Melone ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
Ethylenediaminetetraacetic Acid ◽  
Drug Loading ◽  
Structural Features ◽  
Mas Nmr ◽  
Polymeric Scaffold ◽  
Cyclodextrin Nanosponges ◽  
Cp Mas Nmr

Two different formulations of cyclodextrin nanosponges (CDNS), obtained by polycondensation of β-cyclodextrin with ethylenediaminetetraacetic acid dianhydride (EDTAn), were treated with aqueous solutions of ibuprofen sodium salt (IbuNa) affording hydrogels that, after lyophilisation, gave two solid CDNS-drug formulations. 1H fast MAS NMR and 13C CP-MAS NMR spectra showed that IbuNa was converted in situ into its acidic and dimeric form (IbuH) after freeze-drying. 13C CP-MAS NMR spectra also indicated that the structure of the nanosponge did not undergo changes upon drug loading compared to the unloaded system. However, the 13C NMR spectra collected under variable contact time cross-polarization (VCT-CP) conditions showed that the polymeric scaffold CDNS changed significantly its dynamic regime on passing from the empty CDNS to the drug-loaded CDNS, thus showing that the drug encapsulation can be seen as the formation of a real supramolecular aggregate rather than a conglomerate of two solid components. Finally, the structural features obtained from the different solid-state NMR approaches reported matched the information from powder X-ray diffraction profiles.

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