scholarly journals Homonuclear Decoupling in 1 H NMR of Solids by Remote Correlation

2020 ◽  
Vol 59 (15) ◽  
pp. 6235-6238
Author(s):  
Pinelopi Moutzouri ◽  
Federico M. Paruzzo ◽  
Bruno Simões de Almeida ◽  
Gabriele Stevanato ◽  
Lyndon Emsley
Keyword(s):  
Homonuclear Decoupling ◽  
H Nmr

13C and 1H NMR spectra of all methyl O-benzoyl-β-D-xylopyranosides. nonadditivity of acylation effects on 13C chemical shifts in deutoriochloroform solutions

1983 ◽  
Vol 48 (3) ◽  
pp. 877-888 ◽  
Author(s):  
Eva Petráková ◽  
Jan Schraml
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Conformational Heterogeneity ◽  
Additivity Rule ◽  
Homonuclear Decoupling ◽  
First Order ◽  
H Nmr ◽  
C Nmr

All methyl O-benzoyl-β-D-xylopyranosides have been prepared and their 1H and 13C NMR spectra measured in deuteriochloroform solutions. The 1H NMR spectra were analysed to the first order and assigned with the aid of homonuclear decoupling. The 13C chemical shifts were assigned through heteronuclear selective decouling experiments. Some of the 13C chemical shifts observed in di- and tri-O-benzoyl derivatives differ considerably from those calculated according to the direct additivity rule from the shifts in the mono derivatives. It is shown that the nonadditivity is due to a conformational heterogeneity of the series of investigated compounds dissolved in deuteriochloroform. The heterogeneity is evidenced by the vicinal 1H-1H coupling constants and by 13 chemical shifts of C(1) methoxyl carbon atoms.

scholarly journals Homonuclear Decoupling in 1 H NMR of Solids by Remote Correlation

2020 ◽  
Vol 132 (15) ◽  
pp. 6294-6297
Author(s):  
Pinelopi Moutzouri ◽  
Federico M. Paruzzo ◽  
Bruno Simões de Almeida ◽  
Gabriele Stevanato ◽  
Lyndon Emsley
Keyword(s):  
Homonuclear Decoupling ◽  
H Nmr

Das Verhalten der Körpermasse bei einem 81-jährigen Läufer an einem 100-km-Lauf

Praxis ◽  
2009 ◽  
Vol 98 (3) ◽  
pp. 143-149 ◽  
Author(s):  
Knechtle ◽  
Wirth ◽  
Knechtle ◽  
Kohler
Keyword(s):  
H Nmr

Ein 81-jähriger Läufer mit Status nach aortokoronarem Bypass bei bekannter koronarer Herzkrankheit hat einen 100-km-Lauf in 19 h und 45 min erfolgreich beendet. Vor und unmittelbar nach dem Lauf wurden Fett- und Muskelmasse nicht-invasiv sowohl mit der bioelektrischen Impedanzanalyse als auch mit der klassischen Hautfaltenmethode bestimmt. Zusätzlich wurden Blut- und Urinproben zur Beurteilung des Flüssigkeitshaushaltes genommen und eine ¹H-NMR-Spektroskopie des Urins zum Nachweis eines erhöhten Kohlenhydrat-, Fett- oder Eiweissstoffwechsels durchgeführt. Das Körpergewicht nahm um 1.9 kg ab. Während die errechnete Muskelmasse um 0.1 kg zunahm, nahm die errechnete Fettmasse um 0.2 kg (anthropometrische Methode) resp. 3.1 kg (BIA) ab. Das errechnete Körperwasser nahm um 1.2 l zu. Während Hämatokrit, Harnstoff und spezifisches Gewicht des Urins zunahmen, sank das Natrium im Blut ab. Das Plasmavolumen nahm um 19% ab. Die ¹H-NMR-Spektroskopie des Urins zeigte nach der Belastung einen Anstieg der Ketonkörper. Um einen Abbau der Muskelmasse objektivieren zu können, muss der Ausgangswert des Körperwassers abgewartet werden, um keine Fehlinterpretation aufgrund der Methoden zu machen. Unklar bleibt, wieso es zu einer Einlagerung von Wasser kam. In weiteren Untersuchungen könnten zusätzliche Methoden wie DEXA, Muskelbiopsien und Bestimmung von weiteren Blut- und Urinparametern Auskunft geben, ob effektiv und wie viel Muskelmasse abgebaut wird und ob Abbauprodukte der Muskulatur die Nierenfunktion einschränken und somit zu einer Wasserretention führen.

H NMR Evidence for a Change in The Local Hydrogen Environment of Sites Associated with the Staebler-Wronski Effect in a-Si:H

2002 ◽  
Vol 715 ◽  
Author(s):  
T. Su ◽  
Robin Plachy ◽  
P. C. Taylor ◽  
S. Stone ◽  
G. Ganguly ◽  
...  
Keyword(s):  
Line Shape ◽  
Defect Density ◽  
Hydrogen Atoms ◽  
Hydrogen Environment ◽  
H Nmr ◽  
Line Shapes ◽  
Different Temperatures ◽  
Staebler Wronski Effect

AbstractWe study the H NMR line shapes of a sample of a-Si:H under several conditions: 1) as grown, 2) light-soaked for 600 hours, and 3) light-soaked followed by annealing at different temperatures. At T = 7 K, the NMR line shape of the sample after light soaking exhibits an additional doublet compared to that of the sample as-grown. This doublet is an indication of a closely separated hydrogen pair. The distance between the two hydrogen atoms is estimated to be about (2.3 ± 0.2) Å. The concentration of these hydrogen sites is estimated to be between 1017 and 1018 cm-3 consistent with ESR measurements of the defect density after light soaking. This doublet disappears after the sample is annealed at 200°C for 4 hours.

Solvent-Ligand Interactions in Colloidal Nanocrystals

2018 ◽  
Author(s):  
Jonathan De Roo ◽  
Nuri Yazdani ◽  
Emile Drijvers ◽  
Alessandro Lauria ◽  
Jorick Maes ◽  
...  
Keyword(s):  
Direct Method ◽  
Line Broadening ◽  
H Nmr ◽  
Size Dependent ◽  
Line Shape Analysis ◽  
Wide Range ◽  
Nanocrystal Synthesis ◽  
Ligand Interactions ◽  
Indispensable Tool ◽  
Theoretical Evidence

<p>Although solvent-ligand interactions play a major role in nanocrystal synthesis, dispersion formulation and assembly, there is currently no direct method to study this. Here we examine the broadening of <sup>1</sup>H NMR resonances associated with bound ligands, and turn this poorly understood descriptor into a tool to assess solvent-ligand interactions. We show that the line broadening has both a homogeneous and a heterogeneous component. The former is nanocrystal-size dependent and the latter results from solvent-ligand interactions. Our model is supported by experimental and theoretical evidence that correlates broad NMR lines with poor ligand solvation. This correlation is found across a wide range of solvents, extending from water to hexane, for both hydrophobic and hydrophilic ligand types, and for a multitude of oxide, sulfide and selenide nanocrystals. Our findings thus put forward NMR line shape analysis as an indispensable tool to form, investigate and manipulate nanocolloids.</p>

Enantioselective Recognition of Chiral Guests by the Water-Soluble Chiral Keplerate {Mo132} Spherical Capsule with 30 Inner Lactate Ligands

2019 ◽  
Author(s):  
Nancy Watfa ◽  
Weimin Xuan ◽  
Zoe Sinclair ◽  
Robert Pow ◽  
Yousef Abul-Haija ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Chiral Recognition ◽  
Association Constants ◽  
Water Soluble ◽  
Enantioselective Recognition ◽  
H Nmr ◽  
Dosy Nmr ◽  
Spherical Capsule ◽  
Surface Pores ◽  
Guest Chemistry

Investigations of chiral host guest chemistry are important to explore recognition in confined environments. Here, by synthesizing water-soluble chiral porous nanocapsule based on the inorganic metal-oxo Keplerate-type cluster, {Mo<sub>132</sub>} with chiral lactate ligands with the composition [Mo<sub>132</sub>O<sub>372</sub>(H<sub>2</sub>O)<sub>72</sub>(<i>x-</i>Lactate)<sub>30</sub>]<sup>42-</sup> (<i>x</i> = D or L), it was possible to study the interaction with a chiral guest, L/D-carnitine and (<i>R</i>/<i>S</i>)-2-butanol in aqueous solution. The enantioselective recognition was studied by quantitative <sup>1</sup>H NMR and <sup>1</sup>H DOSY NMR which highlighted that the chiral recognition is regulated by two distinct sites. Differences in the association constants (K) of L- and D-carnitine, which, due to their charge, are generally restricted from entering the interior of the host, are observed, indicating that their recognition predominantly occurs at the surface pores of the structure. Conversely, a larger difference in association constants (K<i><sub>S</sub></i>/K<i><sub>R</sub></i> = 3) is observed for recognition within the capsule interior of (<i>R</i>)- and (<i>S</i>)-2-butanol.

Effects of Saccharomyces Cerevisiae Strains on Chemical Profiles of Cabernet Sauvignon Wines: Based on the Combined Results of 1H NMR, HS-SPME/GC-MS and HPLC-DAD-ESI-MS/MS

2018 ◽  
Vol 18 (2) ◽  
pp. 115-131
Author(s):  
Liang Heng-Yu ◽  
Su Ning ◽  
Guo Kun ◽  
Wang Yuan ◽  
Yang De-Yu
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Principal Component ◽  
Grape Juice ◽  
Pilot Scale ◽  
Ethyl Esters ◽  
Cabernet Sauvignon ◽  
Esi Ms ◽  
H Nmr ◽  
Chemical Profiles ◽  
Indigenous Yeasts

Five Saccharomyces cerevisiae strains (Chinese indigenous yeasts SC5, WC5, SC8, CC17 and commercial starter F15) were inoculated into Cabernet sauvignon grape must and fermented at pilot scale. For the first time, combination of 1H NMR, HS-SPME/GC-MS and HPLC-DAD-ESI-MS/MS metabonomic profiling techniques was performed to analyze the global chemical fingerprints of sampled wines at the end of alcoholic and malolactic fermentation respectively, then 13 non-volatile flavor compounds, 52 volatile organic aromas and 43 polyphenolic molecules were identified and determined correspondently. All principal component analysis (PCA) of two fermentation stages based on the analytical results of 1H NMR, HS-SPME/GC-MS and HPLC-DAD-ESI-MS/MS divided these strains into three clusters: (1) SC5 and SC8, (2) WC5 and F15 and (3) CC17. The wine fermented by indigenous yeast, CC17, showed a very unique chemical profile, such as low pH and high color intensity, reduced amino acids (including proline) and the lowest total higher alcohols levels, most of the fixed acids, glycerol, ethyl esters and anthocyanins concentrations. The statistical results indicate that CC17 strain possesses very special anabolism and catabolism abilities on such substances in grape juice and has potentiality to produce characteristic wines with high qualities.

Improved drug delivery system for cancer treatment by D-glucose conjugation with eugenol from natural product

2020 ◽  
Vol 17 ◽  
Author(s):  
Mas Amira Idayu Abdul Razak ◽  
Haslinda Abdul Hamid ◽  
Raja Nor Izawati Raja Othman ◽  
Shaik Alaudeen Mohd Moktar ◽  
Azizi Miskon
Keyword(s):  
Drug Delivery ◽  
Water Solubility ◽  
Osteosarcoma Cell ◽  
Drug Effectiveness ◽  
H Nmr ◽  
Proliferative Effect ◽  
Conventional Drug ◽  
Ic50 Value ◽  
Glucose Conjugation ◽  
Diphenyl Tetrazolium Bromide

Introduction: Bioconjugations are swiftly progressing and are being applied to solve several limitations of conventional drug delivery systems (DDS) such as lack of water solubility, non-specific, and poor bioavailability. The main goals of DDS are to achieve greater drug effectiveness and minimize toxicity to the healthy tissues. Objectives: In this study, D-glucose was conjugated with eugenol to target the cancer cells. To identify the implication of the anticancer effect, osteosarcoma (K7M2) cells were cultured and the anti-proliferative effect was performed using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay] test in order to evaluate the viability and toxicity on cells with various concentrations of eugenol and D-glucose-eugenol conjugate in 24-hour incubation. Results: It was found that, the successful confirmation of the conjugation between D-glucose and eugenol was obtained by 1 H NMR spectroscopy. MTT assay showed inhibitory concentration (IC50 value) of D-glucose-eugenol was at 96.2 µg/ml and the decreased of osteosarcoma cell survival was 48%. Conclusion: These findings strongly indicate that K7M2 cells would be affected by toxicity of D-glucose-eugenol. Therefore, the present study suggests that D-glucose-eugenol has high potential to act as an anti-proliferative agent who may promise a new modality or approach as the drug delivery treatment for cancer or chemotherapeutic agent.

Conformational structure of ethylene glycol dibenzoate. Vibrational and NMR spectra

1981 ◽  
Vol 46 (8) ◽  
pp. 1913-1929 ◽  
Author(s):  
Bohdan Schneider ◽  
Pavel Sedláček ◽  
Jan Štokr ◽  
Danica Doskočilová ◽  
Jan Lövy
Keyword(s):  
Ethylene Glycol ◽  
Vibrational Spectra ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Conformational Structure ◽  
Infrared And Raman Spectra ◽  
H Nmr ◽  
Liquid States ◽  
Crystalline Forms ◽  
C Nmr

It was found that three crystalline forms of ethylene glycol dibenzoate can be prepared. Infrared and Raman spectra of these three forms, as well as of the glassy and liquid states, were measured. From 3JHH coupling constants obtained by analysis of the 13C satellite band of the -CH2- group in 1H NMR spectra, and from the 3JCH coupling constants of the -CO.O.CH2- fragment obtained by analysis of the carbonyl band in 13C NMR spectra it was found that in the liquid state the -CH2-CH2- group exists predominantly in the gauche conformational structure, and the bonds C-O-C-C assume predominantly a trans orientation. The results of the analysis of NMR and vibrational spectra were used for the structural interpretation of conformationally sensitive bands in vibrational spectra of ethylene glycol dibenzoate.

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