Cavitands as superior sorbents for benzene detection at trace levelElectronic supplementary information (ESI) available: synthetic procedures for the preparation of cavitands 2, 3; 29Si and 13C CP/MAS NMR spectra of MeCav and QxCav coated silica; desorption pattern of BTX observed for Tenax TA® at 50 °C; GC traces obtained from the desorption at 75 °C of the BTX mixture trapped on AXCav trap and Carbotrap 100®. See http://www.rsc.org/suppdata/nj/b2/b210942e/

2003 ◽  
Vol 27 (3) ◽  
pp. 502-509 ◽  
Author(s):  
Federica Bianchi ◽  
Roberta Pinalli ◽  
Franco Ugozzoli ◽  
Silvia Spera ◽  
Maria Careri ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Mas Nmr ◽  
Supplementary Information ◽  
Cp Mas Nmr ◽  
13C Cp Mas Nmr

scholarly journals 13C CPMAS NMR as a Tool for Full Structural Description of 2-Phenyl Substituted Imidazoles That Overcomes the Effects of Fast Tautomerization

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3770
Author(s):  
Nikola Burdzhiev ◽  
Anife Ahmedova ◽  
Boris Borrisov ◽  
Robert Graf
Keyword(s):  
Solid State ◽  
Gas Phase ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Spectroscopic Method ◽  
Mas Nmr ◽  
Structural Description ◽  
Tautomeric Forms ◽  
Cp Mas Nmr ◽  
13C Cp Mas Nmr

Tautomerization of 2-phenylimidazolecarbaldehydes has not been studied in detail so far, although this process is a well-known phenomenon for imidazole derivatives. That is why we focus our study on a series of 2-phenylimidazolecarbaldehydes and their parent alcohols that were synthesized and studied by detailed 1H and 13C NMR in solution and in the solid state. The apparent problem is that the fast tautomerization impedes the full structural description of the compounds by conventional 13C NMR measurements. Indeed, the 13C NMR spectra in solution exhibit poor resolution, and in most cases, signals from the imidazole ring are not detectable. To avoid this problem, we used 13C CP-MAS NMR as an alternative spectroscopic method for unambiguous spectroscopic characterization of the studied series of 2-phenylimidazoles. The data were analyzed in combination with quantum chemical DFT-GIAO methods by considering the tautomerization process and the intermolecular interactions. The DFT (B3LYP/6-31G(d,p)) calculations allowed to identify and suggest the preferred tautomer in the gas phase and in DMSO solvent, which for alcohols are (2-phenyl-1H-imidazol-4-yl)methanol and its analogs, and for the aldehydes are the 2-phenyl-1H-imidazole-5-carbaldehydes. The gas-phase calculated energy differences between the two possible tautomeric forms are in the range 0.645–1.415 kcal/mol for the alcohols and 2.510–3.059 kcal/mol for the aldehydes. In the DMSO solvent, however, for all compounds, the calculated energy differences go below 1.20 kcal/mol. These data suggest that both tautomeric forms of the studied 2-phenylimidazoles can be present in solution at room temperature. Our data from detailed 2D NMR measurements in the solid state (1H-13C HETCOR and 1H-1H double-quantum coherence MAS NMR) suggested that also in the solid state both tautomers coexist in different crystalline domains. This fact does not obscure the 13C CP-MAS NMR spectra of the studied 2-phenyl substituted imidazoles and suggests this spectroscopic method as a powerful tool for a complete structural description of tautomeric systems with aromatic conjugation.

Residual dipolar splittings in 13C CP/MAS NMR spectra due to quadrupolar halogen nuclei in uracil halides

1994 ◽  
Vol 222 (5) ◽  
pp. 486-492 ◽  
Author(s):  
Bunsow Nagasaka ◽  
Sadamu Takeda ◽  
Nobuo Nakamura
Keyword(s):  
Nmr Spectra ◽  
Mas Nmr ◽  
Cp Mas Nmr ◽  
13C Cp Mas Nmr

i.r. and 13C-CP-MAS-NMR spectra of pyromellitide and of its precursor based on 4,4′-diaminodiphenylmethane

1990 ◽  
Vol 26 (9) ◽  
pp. 941-945 ◽  
Author(s):  
B Schneider ◽  
P Schmidt ◽  
M Marek ◽  
J Straka ◽  
B Bednář ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Mas Nmr ◽  
Cp Mas Nmr ◽  
13C Cp Mas Nmr

13C CP–MAS NMR spectra of tropical hardwoods

1995 ◽  
Vol 36 (3) ◽  
pp. 247-259 ◽  
Author(s):  
Olumide A. Sosanwo ◽  
Allan H. Fawcett ◽  
David Apperley
Keyword(s):  
Nmr Spectra ◽  
Mas Nmr ◽  
Cp Mas Nmr ◽  
13C Cp Mas Nmr

Direct quantification of M/G ratio from 13C CP-MAS NMR spectra of alginate powders by multivariate curve resolution

2009 ◽  
Vol 344 (15) ◽  
pp. 2014-2022 ◽  
Author(s):  
Tina Salomonsen ◽  
Henrik Max Jensen ◽  
Flemming Hofmann Larsen ◽  
Stefan Steuernagel ◽  
Søren Balling Engelsen
Keyword(s):  
Nmr Spectra ◽  
Mas Nmr ◽  
Multivariate Curve Resolution ◽  
Curve Resolution ◽  
G Ratio ◽  
Cp Mas Nmr ◽  
13C Cp Mas Nmr ◽  
Direct Quantification

scholarly journals Solid-State 13C CP MAS NMR Spectroscopy as a Tool for Detection of (1→3, 1→6)-β-D-Glucan in Products Prepared from Pleurotus ostreatus

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
O. Fričová ◽  
M. Koval'aková
Keyword(s):  
Solid State ◽  
Pleurotus Ostreatus ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
Mas Nmr ◽  
Oyster Mushroom ◽  
Trace Compounds ◽  
Cp Mas Nmr ◽  
Nmr Solid ◽  
13C Cp Mas Nmr

The 13C CP/MAS NMR solid-state NMR technique was used to detect the presence of β-D-glucan and trace compounds in samples prepared from dried, naturally grown oyster mushroom (Pleurotus ostreatus) and commercially available products of dried, specially cultivated oyster mushroom and β-D-glucan isolated from this mushroom. The NMR spectra of all samples displayed signals typical for (1→3, 1→6)-β-D-glucan; however, signals which could be assigned to other trace compounds—(1→3)-α-glucan, chitin, and proteins—were also observed in the spectra. The amount of trace compounds was negligible in the commercially available products.

Solid state 13C CP-MAS NMR spectra of iron (alkyne) carbonyl compounds

1989 ◽  
Vol 368 (3) ◽  
pp. 331-338 ◽  
Author(s):  
Silvio Aime ◽  
Mauro Botta ◽  
Geoffrey E. Hawkes ◽  
Keith D. Sales ◽  
Lu-Yun Lian
Keyword(s):  
Solid State ◽  
Carbonyl Compounds ◽  
Nmr Spectra ◽  
Mas Nmr ◽  
Cp Mas Nmr ◽  
13C Cp Mas Nmr
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