Real-time chemical-shift scaling in high-resolution NMR spectroscopy.
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Biomedical subjects
Gareth A Morris
Publications and source records attributed to Gareth A Morris.
Stereodynamics of bond rotation in tertiary aromatic amides.
The degree to which the rotations about the C-N and Ar-CO bonds of aromatic amides occur in a concerted manner was investigated by a variety of NMR and kinetic techniques. Otherwise complex kinetic analyses were simplified by exploiting symmetry and asymmetry in the N-substituents of amides. In 2-unsubstituted 1-naphthamides bearing branched N-substituents, most conformational changes about the amide group were by correlated rotation, though uncorrelated Ar-CO rotation also occurred to some extent. In 2-substituted 1-naphthamides, correlated rotation accounted for all of the Ar-CO rotations, though a significant amount of uncorrelated C-N rotation also occurred. Naphthamides bearing branched N-substituents thus turn out to be efficient molecular gears: Compound 12 showed almost no gear slippage.
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A diffusion-ordered NMR spectroscopy study of the solubilization of artemisinin by octanoyl-6-O-ascorbic acid micelles.
Artemisinin (QHS) is a natural drug with a very low solubility in water. To improve its availability in hydrophilic media, it was solubilized in micellar dispersions of octanoyl-6-O-ascorbic acid (ASC8), a relatively novel surfactant that combines surface activity with powerful performance as radical scavenger. In this article we report a study based on diffusion-ordered NMR spectroscopy (DOSY) measurements carried out on QHS/ASC8 micellar dispersions. QHS is efficiently solubilized by ASC8 micelles, with no significant perturbation of the micellisation.
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A new method for variable temperature gradient shimming.
Sample convection can severely attenuate the signals observed in pulsed field gradient spin--echo experiments such as those used for gradient shimming. A new class of pulse sequences is proposed, in which a double spin--echo refocuses the phase errors caused by sample convection, enabling gradient shimming to be performed reliably over a wide range of temperatures.
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