Disentangling Complex Mixtures of Compounds with Near-Identical1H and13C NMR Spectra using Pure Shift NMR Spectroscopy

Asphaltenes are the most polar oil components with molecular weights between 500 and 1000 Da, which primarily consist of carbons and hydrogens, some heteroatoms, such as nitrogen, sulphur, oxygen and traces of nickel, vanadium and iron. Owing to their extreme complexity, it is almost impossible to completely identify all the compounds present in asphaltene samples. Various analytical techniques and approaches were used to characterize asphaltenes but their structure and composition are still a matter of thorough investigations. NMR spectroscopy can reveal useful information on asphaltene molecular architecture and aggregation process. In that respect, one- and two-dimensional NMR techniques have widely been employed. Although NMR spectra of these complex mixtures are difficult to interpret, they still can provide valuable data, especially in combination with statistical methods. Some distinctive examples of using NMR spectroscopy to study asphaltenes are given in this review.

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Ultrafast double-quantum NMR spectroscopy

Chemical Communications ◽

10.1039/c4cc07232d ◽

2015 ◽

Vol 51 (2) ◽

pp. 354-357 ◽

Cited By ~ 16

Author(s):

Adrien Le Guennec ◽

Patrick Giraudeau ◽

Stefano Caldarelli ◽

Jean-Nicolas Dumez

Keyword(s):

Nmr Spectroscopy ◽

Nmr Spectra ◽

Complex Mixtures ◽

Double Quantum

The acquisition of double-quantum NMR spectra in less than three seconds is demonstrated and the synergies between double-quantum and ultrafast NMR spectroscopy for the analysis of complex mixtures are illustrated.

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NMR spectroscopic investigation of p-substituted 2,4,4,6-tetraphenyl-1,4-dihydropyridines and their oxa and thia analogues

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19891854 ◽

1989 ◽

Vol 54 (7) ◽

pp. 1854-1869 ◽

Cited By ~ 16

Author(s):

Marián Schwarz ◽

Petr Trška ◽

Josef Kuthan

Keyword(s):

Nmr Spectroscopy ◽

Trifluoroacetic Acid ◽

Spectroscopic Investigation ◽

Nmr Spectra ◽

Dynamic Equilibrium

The 1H, 13C and 19F NMR spectra of photochromic p-substituted 2,4,4,6-tetraphenyl-1,4-dihydropyridines IIa-IIg, 1-methyl-2,4,4,6-tetraphenyl-1,4-dihydropyridines IIIa-IIIg, 2,4,4,6-tetraphenyl-4H-pyrans IVa-IVh, and 2,4,4,6-tetraphenyl-4H-thiopyran V were inspected; it was found that compounds IIa-IIg occur in a dynamic equilibrium with their dihydro tautomer VIa-VIg. Also deuteriodeprotonation of IIa and IIIa and their reaction with trifluoroacetic acid were investigated by NMR spectroscopy.

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Unusual Rearrangement of Naphthalene in the Synthesis of a Novel B8-B8-Bridged Derivative in the [(1,2-C2B9H11)2-3-Co]- Series. X-Ray Structure and 11B NMR Spectra of [8,8'-μ-(CH2-C9H6)-(1,2-C2B9H10)2-3-Co]- (CH3)4N+

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19970746 ◽

1997 ◽

Vol 62 (5) ◽

pp. 746-751 ◽

Cited By ~ 7

Author(s):

Andreas Franken ◽

Jaromír Plešek ◽

Christiane Nachtigal

Keyword(s):

Nmr Spectroscopy ◽

Single Crystal ◽

Nucleophilic Substitution ◽

Nmr Spectra ◽

X Ray Diffraction ◽

X Ray ◽

Unusual Rearrangement ◽

Multinuclear Nmr Spectroscopy ◽

11B Nmr ◽

Isolated Compound

On treatment of the [(1,2-C2B9H11)2Co]- ion with naphthalene in presence of AlCl3 a remarkably bridged [8,8'-μ-(CH2-C9H6)-(1,2-C2B9H10)2-3-Co]- ion is obtained as a single isolated compound. The triatomic -CH2-C9H6- bridge is derived from the rearranged naphthalene nucleus. The mechanism of this reaction is obscure but it does resemble the "Electrophile-Induced Nucleophilic Substitution" reported earlier. The structure of the compound was established by multinuclear NMR spectroscopy and by single crystal X-ray diffraction.

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IR and 13C, 17O, and 119Sn NMR spectra of some bis(1-butyl)tin(IV) carboxylates of dicarboxylic acids

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19911908 ◽

1991 ◽

Vol 56 (9) ◽

pp. 1908-1915 ◽

Cited By ~ 18

Author(s):

Jaroslav Holeček ◽

Antonín Lyčka ◽

Milan Nádvorník ◽

Karel Handlíř

Keyword(s):

Infrared Spectroscopy ◽

Nmr Spectroscopy ◽

Dicarboxylic Acid ◽

Nmr Spectra ◽

Dicarboxylic Acids ◽

119Sn Nmr ◽

Carboxylic Groups ◽

Cyclic Oligomers ◽

The Media ◽

Oxygen Atoms

Infrared spectroscopy and multinuclear (13C, 17O, and 119Sn NMR spectroscopy have been used to study the structure of bis(1-butyl)tin(IV) carboxylates of dicarboxylic acids (1-C4H9)2. Sn(X(COO)2), where X = (CH2)n (n = 0-8), CH=CH (cis and trans) and C6H4 (ortho and para).The crystalline compounds are formed by linear or cyclic oligomers or polymers whose basic building units represent a grouping composed of the central tin atom substituted by two 1-butyl groups and coordinated with both oxygen atoms of two anisobidentate carboxylic groups derived from different molecules of a dicarboxylic acid. The environment of the tin atom has a shape of a trapezoidal bipyramid. When dissolvet in non-coordinating solvents, the compounds retain the oligomeric character with unchanged structure of environment of the central tin atom. In the media of coordinating solvents the bis(1-butyl)tin(IV) carboxylates of dicarboxylic acids form complexes whose central hexacoordinated tin atom binds two molecules of the solvent trough their donor atoms. Carboxylic groups form monodenate linkages in these complexes.

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Mesoscopic simulations of the in situ NMR spectra of porous carbon based supercapacitors: Electronic structure and adsorbent reorganisation effects

Physical Chemistry Chemical Physics ◽

10.1039/d1cp02130c ◽

2021 ◽

Author(s):

Anagha Sasikumar ◽

Anouar Belhboub ◽

Camille Bacon ◽

Alexander C. Forse ◽

John Griffin ◽

...

Keyword(s):

Electronic Structure ◽

Nmr Spectroscopy ◽

Molecular Species ◽

Porous Carbon ◽

Nmr Spectra ◽

Charge Storage ◽

In Situ Nmr Spectroscopy ◽

In Situ Nmr ◽

Carbon Based

In situ NMR spectroscopy is a powerful technique to investigate charge storage mechanisms in carbon-based supercapacitors thanks to its ability to distinguish ionic and molecular species adsorbed in the porous...

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Targeted projection NMR spectroscopy for unambiguous metabolic profiling of complex mixtures

Magnetic Resonance in Chemistry ◽

10.1002/mrc.2661 ◽

2010 ◽

Vol 48 (9) ◽

pp. 727-733 ◽

Cited By ~ 14

Author(s):

Clément Pontoizeau ◽

Torsten Herrmann ◽

Pierre Toulhoat ◽

Bénédicte Elena-Herrmann ◽

Lyndon Emsley

Keyword(s):

Nmr Spectroscopy ◽

Metabolic Profiling ◽

Complex Mixtures

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Magnetic resonance imaging (1H) and spectroscopy (1H, 31P) of growing chicken embryos

Canadian Journal of Animal Science ◽

10.4141/cjas93-096 ◽

1993 ◽

Vol 73 (4) ◽

pp. 953-965 ◽

Cited By ~ 2

Author(s):

A. Lirette ◽

Z. Liu ◽

D. C. Crober ◽

R. A. Towner ◽

U. M. Oehler ◽

...

Keyword(s):

Nmr Spectroscopy ◽

Magnetic Resonance ◽

Nmr Spectra ◽

Surface Coil ◽

Nmr Imaging ◽

Chicken Embryos ◽

H Nmr ◽

Imaging And Spectroscopy ◽

Two Peaks

Nuclear magnetic resonance (NMR) imaging and spectroscopy techniques were used to observe in vivo anatomical and metabolite changes, respectively, in developing chicken embryos. Proton (1H) NMR images of the eggs revealed major changes in yolk shape from day 2 to day 6. Embryos were visible from day 6 to hatching, and good embryonic anatomical images were obtained. Two peaks were observed from 1H-NMR spectroscopy of fertilized eggs: one for lipid methylene protons, and one for water protons. Water peak to lipid peak ratios did not vary significantly (P > 0.05) from day 2 to day 21 of incubation. Localized 31P-NMR spectra of developing embryos were obtained with either a 31P surface coil or a double-tuned 31P/1H volume coil. The surface-coil method gave a greater signal to noise ratio by a factor of four. The 31P-NMR spectra indicated two peaks at day 2; these were attributed to phosphomonoesters and phosphodiesters. The three peaks characteristic of ATP appeared on day 11 and increased in size until hatching. From day 19, phosphocreatine was detectable. There appeared to be a good correlation between 31P-metabolite changes detected by in vivo 31P-NMR spectroscopy and literature values for biochemical analyses of developing chicken embryos. The advantage in using NMR imaging and spectroscopy techniques is that anatomical and metabolic changes can be obtained in vivo, non-invasively and repeatedly as an embryo develops. Key words: NMR, MRI, embryo, poultry

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A Metabolomic Approach to Beer Characterization

Molecules ◽

10.3390/molecules26051472 ◽

2021 ◽

Vol 26 (5) ◽

pp. 1472

Author(s):

Nicola Cavallini ◽

Francesco Savorani ◽

Rasmus Bro ◽

Marina Cocchi

Keyword(s):

Nuclear Magnetic Resonance ◽

Nmr Spectroscopy ◽

Magnetic Resonance ◽

Analytical Methods ◽

Nmr Spectra ◽

Full Spectrum ◽

The Past ◽

Beer Consumption ◽

Metabolomic Approach ◽

Chemometric Tools

The consumers’ interest towards beer consumption has been on the rise during the past decade: new approaches and ingredients get tested, expanding the traditional recipe for brewing beer. As a consequence, the field of “beeromics” has also been constantly growing, as well as the demand for quick and exhaustive analytical methods. In this study, we propose a combination of nuclear magnetic resonance (NMR) spectroscopy and chemometrics to characterize beer. 1H-NMR spectra were collected and then analyzed using chemometric tools. An interval-based approach was applied to extract chemical features from the spectra to build a dataset of resolved relative concentrations. One aim of this work was to compare the results obtained using the full spectrum and the resolved approach: with a reasonable amount of time needed to obtain the resolved dataset, we show that the resolved information is comparable with the full spectrum information, but interpretability is greatly improved.

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