Nuclear magnetic relaxation dispersion studies

Geraldes, C.F. et al. (1995) Nuclear magnetic relaxation dispersion studies of water-soluble gadolinium(III)-texaphyrin complexes, J. Magn. Reson. Imag. 5, 725-729. 

Bertini I, Briganti F, Xia ZC, Luchinat C (1993) Nuclear magnetic relaxation dispersion studies of hexaaquo Mn(II) ions in water-glycerol mixtures. J Magn Reson A 101 198-201... 

In this connection, attention should be paid to an unusual NMR technique called nuclear magnetic relaxation dispersion (NMRD). In contrast with NMR spectroscopy, the NMRD signal arises from the nuclei of the abundant solvent molecules and not from the dissolved substances. The relaxation properties of the solvent molecules are profoundly modified if the solvent contains paramagnetic particles (see a review by Desreux 2005). A solvent molecule sails in the vicinity of an ion-radical and finds itself in the local magnetic field of this paramagnetic particle. Then, induced magnetism of the solvent molecule dissipates in the solvent bulk. This kind of relaxation seems to be registered by NMR. NMRD is applicable to studies on ion-radical solvation/desolvation, ion-pair dynamics, kinetics of ion-radical accumulation/consumption, and so on. 

A methodology for structural studies of the first and second coordination shells in [Cr(OH2)6]3+ and related complexes in aqueous solutions, based on multiple-scattering modeling of XAFS spectra, has been developed by Munoz-Paez and co-workers.523-525 Another technique, recently applied to studying of inner- and outer-sphere H20 coordination in [Cr(OH2)6]3+, is H nuclear magnetic relaxation dispersion (NMRD).526 Applications of different instrumental methods led to consistent results, indicating the presence of 13 1 H20 molecules with an average Cr "0 distance of 4.02 A in the second coordination shell of [Cr(OH2)6]3+ in aqueous solutions.9... 

In addition, these anion-binding studies have been supported by optical titrations and by nuclear magnetic relaxation dispersion (NMRD) measurements. An example is presented of cyanide-treated erythrocuprein (Fig. 16). 

More recent nuclear magnetic relaxation dispersion (NMRD) studies involving water oxygen-17 find a much shorter residence time, in the range 10-50 ps [7]. These results are in better agreement with recent studies that seemed to rule out the existence of slower dynamics. 

Roose et al. (1996) studied the magnetic-field dependence of the proton spin-lattice relaxation time Tj (referred to as nuclear-magnetic-relaxation dispersion) in aqueous colloidal silica containing paramagnetic Mn + ions (Figure 1.112). The experimental relaxation rate of solvent protons in aqueous colloidal silica suspensions containing Mn + ions can be expressed as a weighted mean of several contributions ... 

Biomembranes are complex structures composed of various lipids and proteins. Different membrane compositions affect viscoelastic and hydrodynamic properties of membranes, which are critical to their functions. Cholesterol-rich vesicles are similar to cell membranes in structure and component. Therefore, cholesterol-rich vesicles can represent a typical model for studying membrane dynamics and functions. Nuclear magnetic relaxation dispersion was used to investigate the detailed molecular dynamics of membrane differences between vesicles and cholesterol vesicles in the temperature range of 278-298 K. Vesicles of two different sizes were prepared. The effect of cholesterol mainly affected the order fluctuation of membranes and the diffusional motion of lipid molecules. ... 

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