Magnetic relaxation rate protons, water

Richardson, S.J. 1989. Contribution of proton exchange to the oxygen-17 nuclear magnetic resonance transverse relaxation rate in water and starch-water systems. Cereal Chem. 66, 244-246. Richardson, M.J. and Saville, N.G. 1975. Derivation of accurate glass transition temperatures by differential scanning calorimetry. Polymer 16, 753-757. 

Some recent papers permit an exciting outlook on the degree of sophistication of experimental techniques and on the kind of data which may be available soon. In the field of NMR spectroscopy, a publication by Hertz and Raedle 172> deals with the hydration shell of the fluoride ion. From nuclear magnetic relaxation rates of 19F in 1M aqueous solutions of KF at room temperature, the authors were able to show that the orientation of the water molecules in the vicinity of fluoride ions is such that the two protons are non-equivalent. A geometry is proposed for the water coordination in the inner solvent shell of F corresponding to an almost linear H-bond and to an OF distance of approximately 2.76 A, at least under the conditions chosen. 

Fig. 11. The nuclear magnetic spin-lattice relaxation rate for water protons as a function of the magnetic field strength reported as the proton Larmor frequency at 298 K forVolclay ( ), Polargel ( ), and Magnahrite (A) (68).

Fig. 13. The nuclear magnetic spin-lattice relaxation rate for water protons as a function of magnetic field strength reported as the proton Larmor frequency at 298 K for 5% suspensions of the particulate stabilized in a 0.5% agar gel presented as the difference plot (A) Zeolite 3A (B) Zeolite 13X (C) Zeolite NaY (D) kaolin with 7 s added to each point to offset the data presentation (E) Cancrinite with 9 s added to each point to offset the data presentation and (F) 0.5% agar gel profile with 10 s added to each point. The solid lines are fits to a power law (68).

Fig. 19. The magnetic relaxation dispersion for water proton in a Sephadex G-25 sample swollen to equilibrium at different values of pH at 298 K. The open circles are the relaxation rates for the methyl protons of dimethyl sulfoxide. The solid lines were computed from a two-stage exchange model 100).

Figure 1. Dispersion of 7/T/, the magnetic relaxation rate of solvent water protons, for a 65 mg/mL solution of alcohol-dehydrogenase from yeast, 160,000...

The essential property of CAs is their relaxivity , which is defined as the increase in the relaxation rate of water protons achieved by InunolR of magnetic center. These substances act as true catalysts on relaxation they decrease the relaxation times and can reduce therefore the time for... 

Diamagnetic electrolyte solutions Intermolecular nuclear magnetic relaxation rate of proton in water molecules correlation times for molecular rotation in free water and hydrated water self diffusion coefficients of water molecules 84, 85... 

We have seen that copper(II) is a slowly relaxing metal ion. Magnetic coupling of copper to a fast relaxing metal ion increases the electron relaxation rate of copper, as clearly shown by the NMRD profiles of tetragonal copper(II) complexes reacting with ferricyanide (105) (Fig. 38). The electron relaxation time, estimated from the relaxation rate of the water protons coordinated to the copper ion, is 3 x 10 ° s, a factor of 10 shorter than in the absence of ferricyanide. 

NMRD studies (0.01-30 MHz) on bentonite suspensions showed that the water-proton spin-lattice relaxation rates are dominated by magnetic interactions with paramagnetic centers entrapped in the mineral matrix (89). The 1/Ti values were linearly dependent on the concentration of the... 

Fig. 7. H water proton relaxivity i.e., the nuclear spin-lattice relaxation rate per mM of metal, plotted as a function of the magnetic field strength expressed as the proton Larmor frequency for aqueous solutions of manganese(H) and iron(HI) ions at 298 K. (A) 0.10 mM manganese(II) chloride in 2.80 M perchloric acid (B) 0.1 mM aqueous manganese(H) chloride at pH 6.6 (C) 0.5 mM iron(HI) perchlorate in 2.80 M perchloric acid (D) 0.5 mM iron(IH) perchlorate in water at pH 3.1 (F) 2.0 mM Fe(HI) in 2.0 M ammonium fluoride at pH 7, which causes a distribution of species dominated by [FeFe]"-.

Fig. 8. The water-proton spin-lattice relaxation rates vs. magnetic field strength plotted as the Larmor frequency at 282 K for hexacyanochromate(II) ion ( ), trioxalatochromate(III) ion ( ), and trimalonatochromate(III) ion (A). The lines were computed using translational diffusion models developed by Freed with and without the inclusion of electron spin relaxation effects 54,121).

Fig. 17. The water proton spin-lattice relaxation rates as a function of magnetic field strength reported as the proton Larmor frequency in aqueous 1.8 mM samples of bovine serum albumin. The lower data set was taken on the solution, the open circles taken after the sample had been cross-linked with glutaraldehyde to stop rotational motion (89).

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