scholarly journals Proton Magnetic Resonance of Metal Ammine Complexes. IV. Paramagnetic Anisotropy of Cobalt(III) Ions as Exemplified in Proton Chemical Shifts

1975 ◽  
Vol 48 (1) ◽  
pp. 209-213 ◽  
Author(s):  
Hayami Yoneda ◽  
Ushio Sakaguchi ◽  
Yoshiaki Nakashima
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Ammine Complexes ◽  
Paramagnetic Anisotropy ◽  
Proton Chemical Shifts

Effect of solvent and anion upon the proton magnetic resonance spectrum of the 1-methylpyridinium ion

1968 ◽  
Vol 46 (17) ◽  
pp. 2787-2791 ◽  
Author(s):  
W. F. Reynolds ◽  
U. R. Priller
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Proton Magnetic Resonance Spectrum ◽  
Concentrated Solutions ◽  
Nonpolar Medium ◽  
Ion Proton ◽  
Acetonitrile Solutions ◽  
Proton Chemical Shifts ◽  
Pyridinium Ion

The proton magnetic resonance spectra of 1-methylpyridinium bromide and iodide have been measured over a range of concentrations in different solvents. It is found that, with the exception of acetonitrile solutions, the infinite dilution chemical shifts are related to solvent dielectric constant. Extrapolated shifts for a nonpolar medium agree with previously calculated chemical shifts for the pyridinium ion. Proton chemical shifts in concentrated solutions are affected by cation–anion interactions. These interactions are interpreted in terms of ion pair formation.

Self Association of Folic Acid in Aqueous Solution by Proton Magnetic Resonance

1972 ◽  
Vol 50 (14) ◽  
pp. 2357-2363 ◽  
Author(s):  
Yui-Fai Lam ◽  
George Kotowycz
Keyword(s):  
Aqueous Solution ◽  
Folic Acid ◽  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Disodium Salt ◽  
Intermolecular Association ◽  
Self Association ◽  
Hydrophobic Portion ◽  
Proton Chemical Shifts

Proton magnetic resonance experiments on the disodium salt of folic acid in aqueous solutions (pD 7.1) indicate that the folate ion exists in an unfolded, extended conformation in solution. However, based on a temperature and concentration dependence of the proton chemical shifts, folate ions are involved in intermolecular association consisting of a vertical stacking interaction. A stacking model is proposed for the association with the hydrophilic ends of the molecule alternating in orientation with respect to the hydrophobic portion of the neighboring molecules.

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