نتایج جستجو برای: 1h nuclear magnetic resonance
تعداد نتایج: 639091 فیلتر نتایج به سال:
A series of novel substituted benzimidazole (7a - n) derivatives were synthesized and characterized by 1H, 13C Nuclear Magnetic Resonance (NMR) spectra High Resolution Mass Spectrometry (HRMS). The substitution was done in position -1 -2 appropriate groups. These compounds are obtained N-alkylation reaction with thiomethyl-1H-benzimidazole intermediates (5a g). Design g) made condensation betwe...
A recently developed methodology for calculating, analyzing, and visualizing nuclear magnetic shielding densities is used studying spatial contributions including ring-current to 1H resonance (NMR) chemical shifts of aromatic anti-aromatic free-base porphyrinoids. Our approach allows a visual inspection the origin positive (shielding) negative (deshielding) constants. Diatropic paratropic curre...
A tadalafil analogue was detected in a dietary supplement marketed for tonic effect, along with hydroxyhomosildenafil and aminotadalafil. The tadalafil analogue was isolated by preparative thin layer chromatography (TLC) and its structure was elucidated using high-performance liquid chromatography (HPLC), liquid chromatography electrospray ionization-mass spectrometry (LC-ESI-MS), Fourier trans...
Effects of Peach Cultivar on Enzymatic Browning Following Cell Damage from High-Pressure Processing.
Peach cultivars contribute to unique product characteristics and may affect the degree of browning after high-pressure processing (HPP). Nine peach cultivars were subjected to HPP at 0, 100, and 400 MPa for 10 min. Proton nuclear magnetic resonance (1H NMR) relaxometry, light microscopy, color, polyphenol oxidase (PPO) activity, and total phenols were evaluated. The development of enzymatic bro...
In the past fifteen years, interference between molecular dynamics and coherent manipulation of nuclear magnetization in nuclear magnetic resonance (NMR) experiments such as spin decoupling, cross-polarization or magic-angle spinning (MAS) have been identified and studied carefully. Recent experiments performed in our laboratory on model compounds have provided insight into the nature of a pert...
The utility of interleaved odd-number leg birdcage coils is demonstrated for decoupling in double- and triple-tuned multinuclear applications. was designed to geometrically decouple from a planar double-tuned (1H-23Na) array 31P saddle coil insert create configuration. Comparisons between an actively detuned purely decoupled architecture were used demonstrate the capabilities design. In particu...
We report new phenomena in low-field 1H nuclear magnetic resonance (NMR) spectroscopy using parahydrogen induced polarization (PHIP), enabling determination of chemical shift differences, δν, and the scalar coupling constant J. NMR experiments performed with thermal polarization in millitesla magnetic fields do not allow the determination of scalar coupling constants for homonuclear coupled spi...
A number of 2-((4-ethylphenoxy)methyl)-N-(substituted-phenylcarbamothioyl) benzamides (1a-h) were synthesized via reaction of 2-((4-ethylphenoxy)methyl)benzoyl isothiocyanate (2) as a key intermediate with several substituted primary aromatic amines. The new compounds were characterized by proton nuclear magnetic resonance ((1)H-NMR), carbon-13 nuclear magnetic resonance ((13)C-NMR), infrared s...
Photochemically induced dynamic nuclear polarization (photo-CIDNP) is a method to hyperpolarize spins using light. In most cases, CIDNP experiments are performed in high magnetic fields and the sample irradiated by light inside resonance (NMR) spectrometer. Here we demonstrate photo-CIDNP hyperpolarization generated Earth’s field under zero- ultralow-field (ZULF) conditions. Irradiating contain...
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