PROTON MAGNETIC-RELAXATION DISPERSION IN AQUEOUS GLYCEROL SOLUTIONS OF GD(DTPA)2- AND GD(DOTA)-

Nuclear magnetic relaxation rates are reported as a function of the magnetic field strength over the range of proton Larmor frequencies from 0.01 to 200 MHz for aqueous glycerol solutions of Gd(DTPA)2− and Gd(DOTA)2− ions. The data are qualitatively described by the Solomon-Bloembergen-Morgan equations but are not described in detail by these equations. The effects of viscosity on the water proton relaxation efficiency are studied in particular to gain a better understanding of the dynamical factors controlling relaxation. The response of the nuclear relaxation to changes in the solution viscosity is a function of magnetic field strength because of compensating changes in the contributions of the rotational correlation times of the metal complexes and the electron spin-relaxation times to the effective correlation time for the electron-nuclear interaction. © 1990, American Chemical Society. All rights reserved.