NUCLEAR MAGNETIC-RELAXATION AS A SELECTIVE PROBE OF SOLUTE SOLVENT AND SOLUTE SOLUTE INTERACTIONS IN MULTICOMPONENT MIXTURES

Intermolecular nuclear magnetic relaxation may represent a powerful to ol for the detection and study of weak nonspecific molecular interacti ons in liquid solutions. Two intermolecular relaxation mechanisms, the electric quadrupole-field gradient interaction and the magnetic dipol e-dipole relaxation are briefly described and recent applications are presented. The quadrupolar relaxation of Xe-131 in water is shown, whe re the Xe atom can be regarded as an ideal hydrophobic model particle. information about the dynamic behavior of water near the dissolved Xe is derived. Ne-21 and Xe-131 relaxation is used to probe electric fie ld gradients acting in molecular liquids. By Bi-81 and Xe-131 relaxati on an attractive interaction between anions and Xe in aqueous solution is found. Finally, the application of intermolecular dipole-dipole in teraction with respect to self-association of small hydrophobic partic les in aqueous solutions is demonstrated. Salt effects on self-associa tion are detected and their connection to the Hofmeister series is dis cussed.