Rapid quantification of starch molecular order through multivariate modelling of13C CP/MAS NMR spectra

2015 ◽  
Vol 51 (80) ◽  
pp. 14856-14858 ◽  
Author(s):  
Bernadine M. Flanagan ◽  
Michael J. Gidley ◽  
Frederick J. Warren
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
Rapid Assessment ◽  
Crystalline Polymer ◽  
Partial Least Squares Model ◽  
Multivariate Modelling ◽  
Cp Mas Nmr ◽  
Rapid Quantification

A partial least squares model has been generated enabling the rapid assessment of ordered molecular structure in a semi-crystalline polymer, starch, directly from solid state NMR spectra.

13C CP/MAS NMR spectra of poly-β-D(1 → 4) mannose: mannan

1990 ◽  
Vol 68 (7) ◽  
pp. 1192-1195 ◽  
Author(s):  
R. H. Marchessault ◽  
M. G. Taylor ◽  
W. T. Winter
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
Repeat Unit ◽  
Intramolecular Hydrogen Bonding ◽  
Lower Mobility ◽  
Intramolecular Hydrogen ◽  
Cp Mas Nmr ◽  
13C Cp Mas Nmr

13C solid-state NMR spectra (CP/MAS) were recorded for mannan polymorphs: mannan I ("ivory nut") and mannan II (Codiumfragile). These pure mannans, poly-β-(1 → 4) mannopyranose, show a single resonance for each carbon of the chemical repeat unit. This is the expected result based on the crystalline P212121 and 1222 symmetries. The T1 values were also recorded and the results are compared to those for cellulose obtained from the literature. The much lower mobility of C-6, even in noncrystalline mannan, compared to native cellulose is attributed to the epimeric difference at C-2 between cellulose and mannan allowing intramolecular hydrogen bonding in the former but not the latter. Keywords: mannan, solid state NMR, T1 relaxation, polysaccharide, ivory nut.

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.

Molecular Structure of Tri(2-thienyl)borane

1996 ◽  
Vol 51 (12) ◽  
pp. 1811-1814 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Wolfgang Milius ◽  
Elias Molla
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
Nmr Spectra ◽  
Structural Parameters ◽  
Mas Nmr ◽  
Monoclinic Space Group ◽  
Nmr Spectrum ◽  
Π Interactions ◽  
Cp Mas Nmr ◽  
C Nmr

The molecular structure of tri(2-thienyl)borane (1) was determined [monoclinic, space group P21/ c; a = 12.216(2), b = 7.765(2), c = 12.605(2) Å, β = 93.13(2)°]; two of the three thienyl groups are disordered, as is also indicated by the solid-state 13C CP/MAS NMR spectrum of 1. The 13C NMR spectra of 1 were measured at variable tem perature in solution and the barrier to rotation about the B-C bonds was found to be <35 kJ/mol. Thus, CB(pp)π interactions must be regarded as rather weak, in spite of suggestive δ11 B. δ13C data and structural parameters.

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.

scholarly journals Chiral Solid Solutions for the NMR Analysis of Enantiomers: A Potential New Approach to Chiral Analysis

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Karel D. Klika
Keyword(s):  
Solid State ◽  
Solid Solutions ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
Weak Interactions ◽  
Chiral Selector ◽  
Mas Nmr ◽  
Nmr Analysis ◽  
New Approach ◽  
Cp Mas Nmr

Differences between the solid-state13C CP-MAS NMR spectra of holemic samples of the two enantiomers of 2,2′-dihydroxy-1,1′-binaphthyl (binol) were not sufficiently emphatic to reliably distinguish them, though they are readily distinguishable from the spectrum of the bimate of the compound crystallized from an equimatic sample. Inducing an additional chiral environment by cocondensation with sucrose as a chiral selector (CS) provided a method to yield differential spectra for the two enantiomers and thus effect enantiodifferentiation by way of solid-state NMR using weak interactions from a CS.

Solid state NMR spectra of rapidly quenched superionic glasses composed of two lithium ortho-oxosalts

1996 ◽  
Vol 86-88 ◽  
pp. 535-538 ◽  
Author(s):  
Masanari Takahashi ◽  
Hiroshi Toyuki ◽  
Masahiro Tatsumisago ◽  
Tsutomu Minami
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Nmr Spectra

Solid-state NMR studies of the molecular structure of Taxol

2006 ◽  
Vol 44 (6) ◽  
pp. 581-585 ◽  
Author(s):  
Yu Ho ◽  
Der-Lii M. Tzou ◽  
Feng-I Chu
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
Solid State Nmr ◽  
Nmr Studies

Solid State NMR Spectra of Tall Fescue Seed

1997 ◽  
pp. 255-256 ◽  
Author(s):  
J. F. Green ◽  
K. D. Gwinn ◽  
G. W. Kabalka ◽  
C. L. Anderson
Keyword(s):  
Solid State ◽  
Tall Fescue ◽  
Solid State Nmr ◽  
Nmr Spectra

Thermosetting Mechanism Study of Organosilicon Polymer Containing Carborane by Solid-State NMR Spectroscopy

1999 ◽  
Vol 576 ◽  
Author(s):  
H. Kimura ◽  
K. Okita ◽  
M. Ichitani ◽  
M. Yonezawa ◽  
T. Sugimoto
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
Main Chain ◽  
Addition Reaction ◽  
Side Chain ◽  
Mechanism Study ◽  
Nmr Method ◽  
Organosilicon Polymer ◽  
Thermal Stable

ABSTRACTThe thermosetting mechanism of an organosilicon polymer containing carborane has been studied utilizing the 13and 29Si solid-state NMR method. The polymer having C≡C bonds in the main chain and CH═CH2, Si-H bonds, and carborane in the bulky side chain, shows a very highly thermal stability in air by curing. From 13C and 29Si NMR spectra of the polymer, it was found that the intermolecular cross-linking reactions of the polymer was due to (1) the diene reaction between Ph-C≡C and C≡C and (2) the addition reaction between side chain terminal and Ph-C≡C and between CH═CH2 and Si–H, and a very highly thermal stable structure is formed.

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