scholarly journals Gadolinium Complexes as Contrast Agent for Cellular NMR Spectroscopy

2020 ◽  
Vol 21 (11) ◽  
pp. 4042 ◽  
Author(s):  
Nat Sakol ◽  
Ayako Egawa ◽  
Toshimichi Fujiwara
Keyword(s):  
Nmr Spectroscopy ◽  
Contrast Agent ◽  
13C Nmr ◽  
Specific Binding ◽  
Nmr Relaxation ◽  
Cell Membrane Permeability ◽  
Resonance Spectroscopy ◽  
E Coli ◽  
Gadolinium Complexes ◽  
Cellular Components

Aqua Gd3+ and Gd-DOTA (gadolinium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacete) complexes were studied as a contrast agent in cellular NMR (nuclear magnetic resonance) spectroscopy for distinguishing between intracellular and extracellular spaces. The contrast agents for this purpose should provide strong paramagnetic relaxation enhancement and localize in the extracellular space without disturbing biological functions. Cell membrane permeability to Gd complexes was evaluated from the concentrations of gadolinium complexes in the inside and outside of E. coli cells measured by the 1H-NMR relaxation. The site-specific binding of the complexes to E. coli cells was also analyzed by high-resolution solid-state 13C-NMR. The aqua Gd3+ complex did not enhance T1 relaxation in proportion to the amount of added Gd3+. This Gd3+ concentration dependence and the 13C-NMR indicated that its strong cytotoxicity should be due to the binding of the paramagnetic ions to cellular components especially at the lipid membranes. In contrast, Gd-DOTA stayed in the solution states and enhanced relaxation in proportion to the added amount. This agent exhibited strong T1 contrast between the intra- and extracellular spaces by a factor of ten at high concentrations under which the cells were viable over a long experimental time of days. These properties make Gd-DOTA suitable for selectively contrasting the living cellular space in NMR spectroscopy primarily owing to its weak interaction with cellular components.

13C NMR Characterization of Polychloroprene Microstructure I. Spectral Assignments

1977 ◽  
Vol 50 (1) ◽  
pp. 49-62 ◽  
Author(s):  
M. M. Coleman ◽  
D. L. Tabb ◽  
E. G. Brame
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Quantitative Data ◽  
Nmr Relaxation ◽  
13C Nmr Spectroscopy ◽  
Nmr Characterization ◽  
Relaxation Studies ◽  
Structural Irregularities ◽  
Near Future

Abstract 13C NMR spectroscopy has proved to be a very powerful tool for the characterization of polychloroprene microstructure. We have identified and assigned the lines associated with diad and triad sequences involving the predominant trans-1,4 placement, together with other lines associated with cis-1,4, 1,2, isomerized 1,2, and 3,4 structural irregularities. Currently, we are performing 13C NMR, relaxation studies on the chloroprene polymers and will be presenting quantitative data in the near future.

scholarly journals Synthesis and Antibacterial Study of Aspirin-Chalcone Derivatives

1970 ◽  
Vol 3 (1) ◽  
pp. 52-57
Author(s):  
Zainab Ngaini ◽  
Doris Ho Ai Hui ◽  
Hasnain Hussain ◽  
Wan Sharifatun Handayani Wan Zulkiplee ◽  
Meng Guan Tay ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Nmr Spectroscopy ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
Antibacterial Activities ◽  
1H And 13C Nmr ◽  
Antibacterial Study ◽  
E Coli ◽  
Chalcone Derivatives

The chemistry of aspirin and chalcone derivatives has been extensively studied and developed as one of thepharmaceutically important molecules. In this study, new aspirin-chalcone derivatives have been successfullysynthesized and characterized via FTIR, 1H and 13C NMR spectroscopy. The antibacterial activities ofsynthesized compounds were investigated towards Escherichia coli ATCC 8739 via turbidimetric kineticmethod. The newly synthesized aspirin-chalcone derivatives, however showed poor antibacterial activityagainst E. coli ATCC 8739 at the concentration of 50, 80 and 100 ppm. The effect of the molecular structureof the synthesized compounds on the antibacterial activity is discussed.

scholarly journals Application of 13C Quantitative NMR Spectroscopy to Isotopic Analyses for Vanillin Authentication Source

Foods ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2635
Author(s):  
Concetta Pironti ◽  
Maria Ricciardi ◽  
Oriana Motta ◽  
Federica Camin ◽  
Luana Bontempo ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Stable Isotope ◽  
13C Nmr ◽  
Isotope Ratio ◽  
Stable Isotope Ratio ◽  
Resonance Spectroscopy ◽  
Carbon Stable Isotope ◽  
Quantitative Nmr ◽  
Isotopic Analyses ◽  
Carbon Stable Isotope Ratio

The carbon stable isotope ratio (δ13C) is a valuable chemical parameter in the investigation of the geographic origin, quality, and authenticity of foods. The aim of this study is the evaluation of the feasibility of 13C-NMR (Nuclear Magnetic Resonance) spectroscopy to determine the carbon stable isotope ratio, at natural abundance, of small organic molecules, such as vanillin, without the use of IRMS (Isotope Ratio Mass Spectrometry). The determination of vanillin origin is an active task of research, and differentiating between its natural and artificial forms is important to guarantee the quality of food products. To reach our goal, nine vanillin samples were analyzed using both 13C quantitative NMR spectroscopy (under optimized experimental conditions) and IRMS, and the obtained δ13C values were compared using statistical analysis (linear regression, Bland–Altman plot, and ANOVA (analysis of variance)). The results of our study show that 13C-NMR spectroscopy can be used as a valuable alternative methodology to determine the bulk carbon isotope ratio and to identify the origin of vanillin. This makes it attractive for the analysis in the same experiment of site-specific and total isotope effects for testing authenticity, quality, and typicality of food samples. Moreover, the improvement of NMR spectroscopy makes it possible to avoid the influence of additives on carbon stable isotope ratio analysis and to clearly identify fraud and falsification in commercial samples.

Biological NMR Spectroscopy

1997 ◽  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
State Of The Art ◽  
Critical Assessment ◽  
Resonance Spectroscopy ◽  
History Of ◽  
Structure Of Proteins

This book presents a critical assessment of progress on the use of nuclear magnetic resonance spectroscopy to determine the structure of proteins, including brief reviews of the history of the field along with coverage of current clinical and in vivo applications. The book, in honor of Oleg Jardetsky, one of the pioneers of the field, is edited by two of the most highly respected investigators using NMR, and features contributions by most of the leading workers in the field. It will be valued as a landmark publication that presents the state-of-the-art perspectives regarding one of today's most important technologies.

scholarly journals (2S,3R,6R)-2-[(R)-1-Hydroxyallyl]-4,4-dimethoxy-6-methyltetrahydro-2H-pyran-3-ol

Molbank ◽  
10.3390/m1140 ◽  
2020 ◽  
Vol 2020 (2) ◽  
pp. M1140
Author(s):  
Jack Bennett ◽  
Paul Murphy
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
13C Nmr ◽  
Conjugate Addition ◽  
13C Nmr Spectroscopy ◽  
One Pot ◽  
1H And 13C Nmr ◽  
Esi Mass Spectrometry ◽  
The One

(2S,3R,6R)-2-[(R)-1-Hydroxyallyl]-4,4-dimethoxy-6-methyltetrahydro-2H-pyran-3-ol was isolated in 18% after treating the glucose derived (5R,6S,7R)-5,6,7-tris[(triethylsilyl)oxy]nona-1,8-dien-4-one with (1S)-(+)-10-camphorsulfonic acid (CSA). The one-pot formation of the title compound involved triethylsilyl (TES) removal, alkene isomerization, intramolecular conjugate addition and ketal formation. The compound was characterized by 1H and 13C NMR spectroscopy, ESI mass spectrometry and IR spectroscopy. NMR spectroscopy was used to establish the product structure, including the conformation of its tetrahydropyran ring.

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