scholarly journals Intermolecular Interactions between Eosin Y and Caffeine Using 1H-NMR Spectroscopy

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Macduff O. Okuom ◽  
Mark V. Wilson ◽  
Abby Jackson ◽  
Andrea E. Holmes
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr Spectroscopy ◽  
Date Rape ◽  
Proton Exchange ◽  
Eosin Y ◽  
Club Drugs ◽  
Hydroxybutyric Acid ◽  
Color Changes ◽  
H Nmr ◽  
Nmr Methods

DETECHIP has been used in testing analytes including caffeine, cocaine, and tetrahydrocannabinol (THC) from marijuana, as well as date rape and club drugs such as flunitrazepam, gamma-hydroxybutyric acid (GHB), and methamphetamine. This study investigates the intermolecular interaction between DETECHIP sensor eosin Y (DC1) and the analyte (caffeine) that is responsible for the fluorescence and color changes observed in the actual array. Using 1H-NMR, 1H-COSY, and 1H-DOSY NMR methods, a proton exchange from C-8 of caffeine to eosin Y is proposed.

Conformational study on ribonucleoside O-phosphonylmethyl derivatives by 1H NMR spectroscopy

1985 ◽  
Vol 50 (8) ◽  
pp. 1899-1905 ◽  
Author(s):  
Milena Masojídková ◽  
Jaroslav Zajíček ◽  
Miloš Buděšínský ◽  
Ivan Rosenberg ◽  
Antonín Holý
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Conformational Study ◽  
H Nmr ◽  
Conformational Properties

Conformational properties of ribonucleoside 5'-O-phosphonylmethyl derivatives have been determined by 1H NMR spectroscopy and compared with those of natural nucleosides and 5'-nucleotides.

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.

Low-field 1H-NMR spectroscopy for compositional analysis of multicomponent polymer systems

The Analyst ◽  
2019 ◽  
Vol 144 (5) ◽  
pp. 1679-1686 ◽  
Author(s):  
Sneha B. Chakrapani ◽  
Michael J. Minkler ◽  
Bryan S. Beckingham
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Compositional Analysis ◽  
Polymer Systems ◽  
H Nmr ◽  
Low Field ◽  
Multicomponent Polymer

A low-field, 60 MHz, 1H NMR spectrometer yields quantitatively comparable results to 400 MHz spectrometers for the compositional analysis of multicomponent polymer systems.

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.

Conformation studies of isomeric 1-acyloxy-2-(4-methoxybenzyl)-cyclohexanes by 1H NMR spectroscopy

1982 ◽  
Vol 47 (10) ◽  
pp. 2763-2767 ◽  
Author(s):  
Miloš Buděšínský ◽  
David Šaman ◽  
Zdeněk Wimmer
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Chair Conformation ◽  
Acetoxy Group ◽  
Cyclohexane Ring ◽  
H Nmr

The conformation of the cyclohexane ring and the p-methoxybenzyl substituent in the series of isomeric 1-acyloxy-2-(4-methoxybenzyl)cyclohexanes was studied by means of 1H NMR spectroscopy. In all the substances investigated the cyclohexane ring assumes chair conformation. trans-Isomers have both substituents in equatorial positions, while in cis-isomers the p-methoxybenzyl group is always equatorial and the hydroxy or acetoxy group axial.

NMR Stratagems for the Study of Multiple Kinetic Hydrogen/Deuterium Isotope Effectsof Proton Exchange. Example: Di-p-fluorophenylformamidine/THF

1989 ◽  
Vol 44 (5) ◽  
pp. 459-472
Author(s):  
Hans-Heinrich Limbach ◽  
Ludger Meschede ◽  
Gerd Scherer
Keyword(s):  
Nmr Spectroscopy ◽  
Magnetization Transfer ◽  
Isotope Effects ◽  
Geometric Mean ◽  
Kinetic Isotope Effects ◽  
Proton Exchange ◽  
Exchange Reactions ◽  
H Nmr ◽  
Kinetic Isotope ◽  
Hydrogen Deuterium

Stratagems are presented for the determination of kinetic isotope effects of proton exchange reactions by dynamic NMR spectroscopy. In such experiments, lineshape analyses and/or polarization transfer experiments are performed on the exchanging protons or deuterons as well as on remote spins, as a function of the deuterium fraction in the mobile proton sites. These methods are NMR analogs of previous proton inventory techniques involving classical kinetic methods. A theory is developed in order to derive the kinetic isotope effects as well as the number of transferred protons from the experimental NMR spectra. The technique is then applied to the problem of proton exchange in the system 15N,15N′-di-p-fluorophenylibrmamidine, a nitrogen analog of formic acid, dissolved in tetrahydrofuran-d8 (THF). DFFA forms two conformers in THF to which s-trans and s-cis structures have been assigned. Only the s-trans conformer is able to dimerize and exchange protons. Lineshape simulations and magnetization transfer experiments were carried out at 189,2 K, at a concentration of 0.02 mol l-1, as a function of the deuterium fraction D in the 1H-15N sites. Using 1H NMR spectroscopy, a linear dependence of the inverse proton lifetimes on D was observed. From this it was concluded that two protons are transported in the rate limiting step of the proton exchange. This result is expected for a double proton transfer in an s-trans dimer with a cyclic structure. The full kinetic HH/HD/DD isotope effects of 233:11:1 at 189 K were determined through 19F NMR experiments on the same samples. The deviation from the rule of geometric mean, although substantial, is much smaller than found in previous studies of intramolecular HH transfer reactions. Possible causes of this effect are discussed.

scholarly journals (—)D-und (+)D-4-Methoxyphenylmethyl- thiophosphinsäure, Überprüfung der Racematspaltung mittels 31P{ 1H}-NMR-Spektroskopie/(—)D-and (+ )D-4-Methoxyphenylmethyl- thiophosphinic Acid, Control of the Resolution by 31P{1H} NMR Spectroscopy

1979 ◽  
Vol 34 (9) ◽  
pp. 1332-1333 ◽  
Author(s):  
Wilhelm Kuchen ◽  
Jurgen Kutter
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
Fractional Crystallization ◽  
1H Nmr Spectroscopy ◽  
Optical Purity ◽  
Separation Process ◽  
H Nmr ◽  
Acid Control

Abstract (-)D-and (+)D-4-methoxyphenylmethyl-thiophosphinic acid, quinine salts of (-)D-and (+)D-4-methoxyphenylmethylthiophosphinic acid, checking of resolution by 31P{ 1H} NMR-spectroscopy (-)D-and(+)D-4-CH3OC6H4(CH3)P(S)OH acid were obtained from fractional crystallization of the quinine salt of the racemic acid. 31P{1H} NMR spectroscopy proved to be very useful in checking the separation process as well as the optical purity of the diastereomers and enan­tiomers.

scholarly journals Discrimination of enantiomers of dipeptide derivatives with two chiral centers by tetraaza macrocyclic chiral solvating agents using 1H NMR spectroscopy

2016 ◽  
Vol 3 (12) ◽  
pp. 1716-1724 ◽  
Author(s):  
Lixia Fang ◽  
Caixia Lv ◽  
Guo Wang ◽  
Lei Feng ◽  
Pericles Stavropoulos ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
H Nmr ◽  
New Class ◽  
Chiral Centers

Enantiomers of dipeptide derivatives with two chiral centers were effectively discriminated by a new class of tetraaza macrocyclic chiral solvating agents via1H NMR spectroscopy.

In situ reactions with trichloroacetyl isocyanate and their application to structural assignment of hydroxy compounds by 1H NMR spectroscopy. A general comment

1979 ◽  
Vol 44 (2) ◽  
pp. 558-588 ◽  
Author(s):  
Zdeněk Samek ◽  
Miloš Buděšínský
Keyword(s):  
Nmr Spectroscopy ◽  
Structural Analysis ◽  
Functional Groups ◽  
1H Nmr Spectroscopy ◽  
H Nmr ◽  
Structural Assignment ◽  
Trichloroacetyl Isocyanate ◽  
In Situ Reactions ◽  
Hydroxy Compounds

The application possibilities of the in situ reactions of trichloroacetyl isocyanate (TAI method) to structural assignment of alcohols by means of 1H NMR spectroscopy are critically evaluated. The possibilities of TAI acylations in various solvents are demonstrated and the reactivity of various functional groups, potentially complicating or extending the applications of TAI, is discussed. In addition to their use in structural analysis such reactions also can serve as model experiments for preparative purposes.

In situ reactions of amines and amino alcohols and their application to structural assignment by 1H NMR spectroscopy

1980 ◽  
Vol 45 (10) ◽  
pp. 2784-2803 ◽  
Author(s):  
Miloš Buděšínský ◽  
Zdeněk Samek ◽  
Miloš Tichý
Keyword(s):  
Nmr Spectroscopy ◽  
Structural Analysis ◽  
1H Nmr Spectroscopy ◽  
Amino Alcohols ◽  
Sample Tube ◽  
H Nmr ◽  
Structural Assignment ◽  
Trichloroacetyl Isocyanate ◽  
In Situ Reactions

The in situ reaction of amines with trichloroacetyl isocyanate (TAI) in the NMR sample tube was investigated as a tool in structural analysis by means of 1H NMR spectroscopy. Preferred conformations of the adducts were suggested which explain different behaviour of NH protons and the induced CH protons shifts. On the example of amino alcohols it was shown how to use the TAI method in combination with other in situ reactions (protonation, acetylation, trifluoroacetylation) for simultaneous differentiation between functional groups in polyfunctional molecules.

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