scholarly journals Ultrafast 2D 1H-1H NMR spectroscopy of DNP-hyperpolarised substrates for the analysis of mixtures

2021 ◽  
Author(s):  
Kawarpal Singh ◽  
Corentin Jacquemmoz ◽  
Patrick Giraudeau ◽  
Lucio Frydman ◽  
Jean-Nicolas Dumez
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Nmr Spectra ◽  
2D Nmr ◽  
Multiple Quantum ◽  
Dynamic Nuclear Polarisation ◽  
Nuclear Polarisation ◽  
2D Nmr Spectra

We show that TOCSY and multiple-quantum (MQ) 2D NMR spectra can be obtained for mixtures of substrates hyperpolarised by dissolution dynamic nuclear polarisation (D-DNP). This is achieved by combining optimised...

scholarly journals Assessment of 1H NMR Spectroscopy for Specific Metabolite Fingerprinting of Angelica sinensis

2008 ◽  
Vol 3 (5) ◽  
pp. 1934578X0800300
Author(s):  
Dongmin Su ◽  
Jinglan Han ◽  
Shishan Yu ◽  
Hailin Qin
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Authentic Sample ◽  
Angelica Sinensis ◽  
Metabolite Fingerprinting ◽  
H Nmr ◽  
Pure Compounds ◽  
Polar Extracts

The 1H NMR fingerprints of fractionated non-polar extracts (CSPD A) from the roots of Angelica sinensis of six different specimens were assigned by comparison with the 1H NMR spectra of the isolated pure compounds. The 1H NMR fingerprints showed exclusively characteristic resonance signals of the major constituents of the plant. The 1H NMR fingerprint established for an authentic sample of A. sinensis can be used for authenticating A. sinensis species.

NMR study of heterogeneity in pyridine-N-oxide...HCl crystal

Open Physics ◽  
2004 ◽  
Vol 2 (1) ◽  
Author(s):  
Vytautas Balevicius ◽  
Alexandar Gacesa ◽  
Janez Plavec
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Solid Phase ◽  
Mixing Time ◽  
Exchange Process ◽  
2D Nmr ◽  
Spin Coupling ◽  
Nmr Study ◽  
2D Nmr Spectra ◽  
Heterogeneous Phase

AbstractAn origin of narrow 1H NMR signals in pyridine-N-oxide (PyO)...HCl crystal has been investigated by means of MAS, SPEDAS, NOESY and COSY techniques. Spectra of crystalline samples are compared with those of solid phase obtained from liquid PyO...HCl solutions (in acetonitile/H2O) after the heterogeneous phase separation. It has been concluded that partially resolved peaks in 1H NMR spectra of solids are related with heterogeneity of spin system and presence of different H-bond clusters of water molecules. NOESY spectra show no cross-peaks even at very long mixing time (500 ms). This indicates there is no exchange process between spins causing different peaks, and thus the corresponding molecular aggregates are captured in “islands of mobility8 without any channels sufficient for exchange. Appearance of MAS side bands as “pseudo8 cross-peaks in 2D NMR spectra using MAS/COSY technique is reported. In the case of accidental coincidence of spinning frequency (ωMAS) with spectral distances between some diagonal signals, intensive non-diagonal peaks are observed at the corresponding cross-positions. A misleading conclusion concerning spin coupling is easy to avoid using various ωMAS.

Light induced E–Z isomerization in a multi-responsive organogel: elucidation from 1H NMR spectroscopy

2015 ◽  
Vol 51 (53) ◽  
pp. 10680-10683 ◽  
Author(s):  
Sanjoy Mondal ◽  
Priyadarshi Chakraborty ◽  
Partha Bairi ◽  
Dhruba P. Chatterjee ◽  
Arun K. Nandi
Keyword(s):  
Mechanical Properties ◽  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Nmr Spectra ◽  
H Nmr ◽  
Imine Bond

Light induced E–Z isomerization along imine bond in a multiresponsive organogel of anthracene attached 3,4,5-tris(dodecyloxy)benzohydrazide gelator altering morphology, fluorescence and mechanical properties is elucidated from 1H NMR spectra.

1H NMR Spectrum: A Team-Based Tabletop Game for Molecular Structure Elucidation

2020 ◽  
Author(s):  
Zachary Thammavongsy ◽  
Michael A. Morris ◽  
Renee Link
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
1H Nmr Spectra ◽  
Molecular Formula ◽  
College Level ◽  
Nmr Spectrum ◽  
Laboratory Course

The 1H NMR Spectrum game, the first example of a team-based tabletop game focused on elucidating the structures of organic small molecules using 1H NMR spectra, was developed and deployed in a college level organic chemistry lecture course and laboratory course. The tabletop game was designed as a collaborative and competitive group activity to encourage multiple rounds of play to help students reinforce their 1H NMR spectra interpretation skills. While playing in either team-based or free-for-all mode, students analyzed the provided chemical shifts, splitting patterns, integrations, and molecular formula within a designated time limit to correctly deduce the structure associated with the 1H NMR spectrum. After playing the game, students in a lecture course and a laboratory course self-reported that they felt more comfortable solving 1H NMR spectroscopy questions, found the game to be an appealing study aid, and were able to complete multiple rounds of play to strengthen their skills in interpreting 1H NMR spectra. The 1H NMR Spectrum tabletop game may serve as an engaging and competitive group learning tool to supplement teaching on 1H NMR spectroscopy.

1H NMR Spectrum: A Team-Based Tabletop Game for Molecular Structure Elucidation

2020 ◽  
Author(s):  
Zachary Thammavongsy ◽  
Michael A. Morris ◽  
Renee Link
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
1H Nmr Spectra ◽  
Molecular Formula ◽  
College Level ◽  
Nmr Spectrum ◽  
Laboratory Course

The 1H NMR Spectrum game, the first example of a team-based tabletop game focused on elucidating the structures of organic small molecules using 1H NMR spectra, was developed and deployed in a college level organic chemistry lecture course and laboratory course. The tabletop game was designed as a collaborative and competitive group activity to encourage multiple rounds of play to help students reinforce their 1H NMR spectra interpretation skills. While playing in either team-based or free-for-all mode, students analyzed the provided chemical shifts, splitting patterns, integrations, and molecular formula within a designated time limit to correctly deduce the structure associated with the 1H NMR spectrum. After playing the game, students in a lecture course and a laboratory course self-reported that they felt more comfortable solving 1H NMR spectroscopy questions, found the game to be an appealing study aid, and were able to complete multiple rounds of play to strengthen their skills in interpreting 1H NMR spectra. The 1H NMR Spectrum tabletop game may serve as an engaging and competitive group learning tool to supplement teaching on 1H NMR spectroscopy.

scholarly journals Assignment of the 1H and 13C spectra of aspidocarpine and assignment of the structure and stereochemistry of the von Braun reaction product of aspidocarpine by 2D nmr spectroscopy

1987 ◽  
Vol 65 (1) ◽  
pp. 200-204 ◽  
Author(s):  
Stewart McLean ◽  
William F. Reynolds ◽  
Xingpei Zhu
Keyword(s):  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Cyanogen Bromide ◽  
2D Nmr ◽  
2D Nmr Spectroscopy ◽  
2D Nmr Spectra

The 13C and 1H spectra of aspidocarpine and the spectra, structure, and stereochemistry of the product of its von Braun reaction with cyanogen bromide have been totally assigned by a combination of homonuclear (COSY-45) and direct and indirect heteronuclear shift-correlated 2D nmr spectra.

Conformational study of blocked pentofuranoses and their 1,5-anhydro derivatives by 1H NMR spectroscopy

1984 ◽  
Vol 49 (1) ◽  
pp. 235-243
Author(s):  
Jaroslav Zajíček ◽  
Miloš Buděšínský ◽  
Jiří Farkaš
Keyword(s):  
Spectral Analysis ◽  
Nmr Spectroscopy ◽  
Quantum Chemical Calculations ◽  
1H Nmr ◽  
Quantum Chemical ◽  
1H Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Conformational Study ◽  
H Nmr

Preferred conformations of the furanose ring and conformer population about the C(5)-C(4) bond in a series of benzoylated pentofuranosyl cyanides have been determined from their 1H NMR spectra. For the 1,5-anhydropentofuranose derivatives the results of the 1H NMR spectral analysis have been compared with the quantum chemical calculations.

1H—NMR-spektroskopische Bestimmung der diastereomeren Reinheit und der absoluten Konfiguration am Phosphoratom von tButyl-phenyl-phosphinsäure-(—)-menthylester / Determination of the Diastereomeric Purity and the Absolute Configuration at Phosphorus of tButyl-phenyl-phosphinic Acid (—)-Menthyl Ester by Means of 1H NMR Spectroscopy

1977 ◽  
Vol 32 (5) ◽  
pp. 589-593 ◽  
Author(s):  
Reiner Luckenbach ◽  
Hans-H. Bechtolsheimer
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
Absolute Configuration ◽  
1H Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Phosphinic Acid ◽  
H Nmr ◽  
The Absolute ◽  
Diastereomeric Purity

The preparation and separation into diastereomers of tbutyl-phenyl-phosphinic acid (—)-menthyl ester (1a) is reported. The diastereomeric purity as well as the absolute configuration at phosphorus of 1 a can be deduced from the detailed analysis of the 1H NMR spectra of samples of 1a differing in their diastereomer ratios.

scholarly journals APPLICATION OF 1H-NMR SPECTA AND MULTIVARIATE ANALYSIS FOR THE AUTHENTICATION OF CURCUMA XANTHORRHIZA FROM ZINGIBER CASSUMUNAR

2019 ◽  
pp. 258-263
Author(s):  
THERESIA WIJAYANTI ◽  
SUGENG RIYANTO ◽  
ENDANG LUKITANINGSIH ◽  
ABDUL ROHMAN
Keyword(s):  
Multivariate Analysis ◽  
Nmr Spectroscopy ◽  
Binary Mixtures ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Partial Least Square ◽  
1H Nmr Spectra ◽  
Curcuma Xanthorrhiza ◽  
Zingiber Cassumunar

Objective: This study was aimed to apply metabolite fingerprinting for the authentication of Curcuma xanthorrhiza adulterated with Zingiber cassumunar using 1H-NMR spectroscopy and multivariate analysis (chemometrics) methods, namely principal component analysis (PCA) and partial least square–discriminant analysis (PLS-DA). Methods: The pure dried powder samples of C. xanthorrhiza from different regions, Z. cassumunar, and its binary mixtures of C. xanthorrhiza with various concentrations of Z. cassumunar as adulterants were prepared for 1H-NMR measurements. The binary mixtures were prepared by mixing C. xanthorrhiza with various concentrations (10%, 25%, 40%, 50%, and 75%) of Z. cassumunar. 1H-NMR spectra were subjected to multivariate analysis for classification using PCA and PLS-DA. Results: A diverse group of metabolites could be detected by 1H-NMR spectroscopy. PCA using the chemical shift in 1H-NMR spectra of the plant extracts as variables clearly discriminated pure C. xanthorrhiza extracts from different origins and C. xanthorrhiza extract adulterated with Z. cassumunar. PLS-DA employed to enhance the separation obtained from the PCA model resulted in well separation and good classification of pure C. xanthorrhiza from the adulterated ones. Conclusion: The developed method could be a useful and powerfull tools to assess adulteration practice and to evaluate the authentication of C. xanthorrhiza extracts.

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